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Lessons from a Post-Eruption Landscape

Fri, 04/24/2020 - 14:00

From March to May 1980, magma rose high into Mount St. Helens (MSH), swelling and—as it turned out—destabilizing its north flank. Scientists knew the volcano had been highly active at times over the past 40,000 years, but the mountain, located amid the Cascade Range in southwestern Washington, had been mostly quiet since the mid-19th century. The collapse of the north flank on 18 May shattered that quiet, triggering a cascade of events that left resounding impressions not only on those who witnessed and studied them but also on the surrounding landscape [Lipman and Mullineaux, 1981; Waitt, 2015].

40 Years of Science at Mount St. Helens

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The eruption of MSH also provided unparalleled opportunities for advancing several disciplines [e.g., Shore et al., 1986; Newhall, 2000; Franklin and MacMahon, 2000]. Among these was an intensification of research investigating biophysical impacts of eruptions and subsequent responses [e.g., Dale et al., 2005; Pierson and Major, 2014; Crisafulli and Dale, 2018]. Long-term research on the biophysical responses at MSH has provided important new insights, challenged long-standing ideas, and provided many societal benefits.

The fortieth anniversary of the eruption this year offers a timely opportunity to reflect on these insights and influences. This long-term vantage is important because sustained, place-based studies following landscape disturbances are rare; because the MSH eruption spurred the greatest depth and breadth of multidisciplinary studies of biophysical responses to landscape disturbance; and because these responses created some of the most significant societal challenges to emerge after the eruption. We summarize key biophysical disturbances and responses, highlight salient insights, and suggest actions that can extend the usefulness of these insights to volcanically vulnerable communities worldwide.

Smothered, Battered, and Singed

The flank collapse at MSH on the morning of 18 May initiated several catastrophic events over the next several minutes (Figure 1). The resulting colossal landslide smothered 60 square kilometers of river valley to a mean depth of 45 meters, obstructed tributaries to the North Fork Toutle River, or NFTR (consequently impounding two permanent and several ephemeral lakes), and blocked the outlet of Spirit Lake at the foot of the volcano. An associated energy blast from the eruption unleashed a scorching cloud of rocky debris known as a pyroclastic density current (hereinafter called the blast PDC) that swept over 600 square kilometers of rugged mountain terrain, removing, toppling, and singeing tracts of forest. Parts of that cloud also sped down the volcano’s snowclad east and west flanks, triggering meltwater flash floods that swept up sediment to become large, swift volcanic mudflows (lahars) that traveled many tens of kilometers downstream.

Fig. 1. Map showing the distribution of different deposits following the 1980 Mount St. Helens eruption. (The distribution of tephra fall is not shown). Locations of U.S. Geological Survey (USGS) stream and sediment gauges (e.g., TOW; see Figure 2 for other names and abbreviations) are also shown. Abbreviations are SRS, sediment-retention structure; PDC, pyroclastic density current.

A vigorous vertical eruption plume soon followed these events, raining shards of volcanic debris (tephra fall) downwind and producing pumice-rich pyroclastic flows that settled atop the landslide deposit. Hours after the landslide emplacement, parts of the newly deposited material liquefied, forming muddy slurries that coalesced into the massive NFTR lahar that reached distant communities and choked navigation on the Columbia River more than 100 kilometers downstream from the volcano.

Erosion, burial, heat, blunt force, and abrasion produced a mosaic of landscape disturbances that extended tens of kilometers from the volcano.These eruption processes battered forest, meadow, riparian, riverine, lake, and lakeshore environments. Erosion, burial, heat, blunt force, and abrasion produced a mosaic of landscape disturbances that extended tens of kilometers from the volcano. The magnitude of disturbances ranged widely, from the near-total removal of all vestiges of plants and animals in areas nearest the volcano to terrain dusted with only a thin layer of tephra. This patchwork of disturbances created an exceptional natural experiment for assessing physical and biological responses to spatially variable impacts.

The Backdrop for Biophysical Research

Biophysical research at MSH following the eruption was influenced by prevailing ideas in 1980 of how landscapes and ecosystems change in response to large disturbances, by the state of the new landscape, and by management of public lands at the volcano. In 1980, U.S. scientists had little direct experience with explosive volcanism or biophysical responses to eruptions. Lahars were a known volcanic process, but scientists poorly understood how they evolved downstream and how landscapes responded to other hydrogeomorphic impacts, such as riverine responses to vast injections of sediment or modifications to basin hydrology caused by expansive changes in forest cover, tephra deposition, and channel disruption. Meanwhile, conventional ecological wisdom held that most organisms would likely perish where intense volcanic forces affected the landscape. It was also thought that recovery of decimated areas would be regulated by their distance from neighboring, unaffected areas, from which hardy pioneering species could migrate and reestablish conditions favorable for later successional species [Franklin and MacMahon, 2000].

The 1980 eruption upended the normal hydrogeomorphic functioning of much of the landscape. Loss of hillside vegetation and deposition of impermeable silty tephra promoted rapid surface water and sediment runoff; immense amounts of material introduced to stream channels disrupted major river corridors; landslide debris tenuously dammed existing and developing lakes; and lahar deposits compromised navigation and flood protection capacity in distant communities by raising channel beds. These conditions created intense concerns over public safety related to flood and sediment hazards and afforded needs and opportunities for subsequent studies.

Prior to the Mount St. Helens eruption, ecologists had commonly studied organism responses years to centuries after an eruption.Prior to the MSH eruption, ecologists had commonly studied organism responses years to centuries after an eruption and typically had studied single groups of organisms affected by single volcanic processes or deposits. After the eruption, the mosaic of different volcanic deposits and widely varying impacts to numerous organisms across multiple environments afforded ecologists opportunities to make significant strides in understanding linkages among disturbance, survival, and succession.

Research efforts at MSH have influenced, and have been affected by, political and institutional processes that determined human engagement with this new landscape. In 1982, Congress created the 445-square-kilometer Mount St. Helens National Volcanic Monument (NVM), identifying science, education, and recreation as the primary objectives of land management. The U.S. Forest Service was charged with “allowing geologic forces and ecological succession to continue substantially unimpeded,” except as necessary to ensure public safety. Meeting this charge has entailed striking a delicate balance among competing interests, including public desire for full access, minimization of access to certain areas to protect ecological research values, and the NVM’s responsibility to manage geologic hazards to ensure protection of public safety and the environment. It’s a challenge complicated by changing landscape conditions, evolving social values, and emerging scientific knowledge.

A Landscape Reshaped

Geomorphic responses to the landscape disturbances far outweighed hydrological responses. The nature, magnitude, and duration of geomorphic responses around MSH varied substantially and reflect the types and severities of different eruption processes. Stormflows from basins that were heavily affected by the eruption, however, increased by a few percent to a few tens of percent compared with pre-eruption flows for roughly 5–10 years [Major and Mark, 2006].

The most substantial geomorphic response occurred in the NFTR basin, which was affected by all the eruption processes; this response continues today because the basin’s upper valley was smothered in thick deposits. In the NFTR basin, water runoff, small lake breakouts, and water pumped from Spirit Lake (to lower the lake level from 1982 to 1985 until an outlet was constructed) efficiently carved the landslide and pyroclastic flow deposits, leading to exceptional erosion of new channels (tens of meters of incision and hundreds of meters of widening) and driving extreme levels of sediment delivery (Figure 2). Although that extraordinary sediment yield declined rapidly as channels widened and beds coarsened, it remains elevated decades later because of ongoing, low-magnitude lateral erosion of the deep channels [Major et al., 2018].

In comparison, in basins affected solely by the blast PDC and tephra fall, stream channel responses were minor and hillside erosion decreased swiftly owing to mechanically driven (versus vegetation-driven) increases in infiltration and the complex topography created by downed trees [Collins and Dunne, 2019]. In those basins, such as the Green River and Clearwater Creek basins, elevated sediment delivery was brief and returned to background levels within about 5 years (Figure 2). After 40 years, more than 80% of all MSH eruption-deposited sediment remains in place—and much of that might remain permanently—but problematic sediment delivery from the NFTR basin will likely persist for decades to come.

Fig. 2. Suspended sediment yields (in kilotons per square kilometer) as measured by USGS sediment gauging stations (see Figure 1 for station locations) along various waterways near Mount St. Helens. The horizontal dashed line depicts the median value of suspended sediment yields measured at several western Cascade Range rivers (exclusive of rivers near Mount St. Helens), which is used as a proxy for typical pre-1980 sediment yield at Mount St. Helens. The gray his-togram represents annual mean streamflow (in cubic meters per second) along the Toutle River measured at stream gauge TOW, highlighting the broadly similar trends between sediment and water runoff, especially after 1990. SRS indicates the onset of sediment trapping by the U.S. Army Corps of Engineers’ sediment-retention structure; “spillway bypass” indicates when sediment began passing over the SRS spillway and its trapping efficiency declined substantially.

Hydrogeomorphic responses to volcanic disturbances can result in socioeconomic consequences more damaging than the direct impacts of eruptions themselves [Pierson and Major, 2014]. The great flush of sediment into waterways around MSH, to date more than 400 million tons, has compounded eruption impacts, greatly prolonging navigation problems and flood hazards to vulnerable communities, for example. This forced the U.S. Army Corps of Engineers (ACOE) to conduct extensive, but unsustainable, channel dredging [Willingham, 2005]. In 1989, ACOE completed a 56-meter-tall, 800-meter-long sediment-retention dam to minimize sediment reaching the Cowlitz and Columbia Rivers (Figure 1). But persistent erosion and sediment delivery have proved to be a formidable foe; by 1998, sediment behind the dam reached the spillway level, prompting further efforts to curtail sediment delivery downstream [Sclafani et al., 2018]. To date, ACOE has spent more than $435 million mitigating eruption and post-eruption impacts on the Cowlitz and elsewhere, and no immediate end is in sight.

In 1989, the U.S. Army Corps of Engineers completed construction of a sediment-retention dam on the North Fork Toutle River to minimize the amount of sediment reaching the Cowlitz and Columbia Rivers. Less than a decade later, sediment delivered by the North Fork Toutle River began passing over the dam’s spillway (left side of image). This photograph was taken circa 1990. Credit: U.S. Army Corps of Engineers.

Insights from hydrogeomorphic studies at MSH have had wide influence. They have sharpened global understanding of post-eruption landscape functioning by elucidating the nature and pace of landscape responses, and they have informed flood management planning and policies locally by quantifying magnitudes and durations of sediment delivery and by identifying sources of sediment erosion and sinks of deposition. These studies have also helped hone interpretations of hydrogeomorphic responses to other types of disturbances, such as wildfires (which in some ways mimic those following tephra falls) and abrupt injections of channel sediment following large-dam removals and mining.

Legacies Live On

After the eruption, ecologists quickly discovered that biological legacies (surviving plants and animals) from pre-eruption ecosystems persisted and were widely distributed; even some of the most heavily affected landscapes were not as sterile as initially assumed. The seasonal timing of the eruption and its time of day played important roles in determining which plants and animals lived or died; many organisms in subalpine lakes and on hillsides, protected beneath snow or ice, were spared the brunt of eruptive forces, for example, and nocturnal animals were in their dens. Those protections resulted in numerous patches of surviving organisms embedded within a vast expanse of disturbed land (Figure 3).

Fig. 3. Two views showing the development of plant communities between 1983 and 2014 at a site along upper Smith Creek (see Figure 1), an area affected by the blast pyroclastic density current and tephra fall. The site was snow-free at the time of the eruption. The ecological response reflects the influences of individual survivors as well as of colonizing plants arriving from distant source populations. Credit: C. M. Crisafulli, U.S. Forest Service

Researchers found that the types, amounts, and distributions of biological legacies were the most important factors affecting rates of ecological recovery [Dale et al., 2005; Crisafulli and Dale, 2018]. But ecological recovery also involved colonizing organisms. Forests and aquatic systems surrounding the disturbed landscape were largely intact and supported plants and animals that served as source populations for post-eruption recovery [Crisafulli and Dale, 2018]. These populations were particularly important for the recovery of species that experienced complete mortality in the blast PDC zone, such as many large mammals and birds.

Certain species, called keystone species, were exceptionally important in the recovery process. For example, lupines and alders flourished in the nutrient-impoverished volcanic substrates because of their ability to partner with root-borne, nitrogen-fixing bacteria. These pioneer species facilitated colonization of many other plants and animals by ameliorating inhospitable nutrient conditions and initiating soil development. Other species, such as the northern pocket gopher, facilitated recovery by mixing inert tephra with buried nutrient-rich soil, thus improving conditions for plant growth. American beavers modified streamflow and plant communities through herbivory and dam building, which created habitats with high biodiversity.

Abiotic factors were also important to ecological recovery. The unconsolidated texture of eruption deposits allowed animals to excavate burrows. Surviving plants penetrated thin (50 centimeters or less) deposits by sprouting new shoots upward, and roots of seedlings penetrated downward into nutrient-rich pre-eruption soils. The mild, wet maritime climate at MSH further facilitated ecological response.

The importance of biological legacies in promoting recovery emerged as an epiphany from long-term ecological research at Mount St. Helens.Lessons from long-term ecological research at MSH have advanced fundamental understanding of how individual species and biological communities respond to large, intense disturbances. Locally, this work has assisted management of NVM lands. More broadly, it has allowed ecologists to address a fundamental question in ecology: How do biological communities arise from a seemingly barren slate? The importance of biological legacies in promoting recovery emerged as an epiphany, one that has informed research at other volcanoes [Crisafulli et al., 2015] and at sites experiencing intense wildfires and windstorms. The work has also prompted fresh perspectives on management of forest landscapes in the United States and abroad, such as using variable-retention harvesting, rather than clear-cutting, to preserve forest structures and processes [Franklin and Donato, 2020].

Feedbacks Between Life and Land

Geomorphic and ecologic responses at MSH have evolved jointly and interacted in important ways. For example, on hillsides affected by the blast PDC, concentrated surface runoff eroded tephra, which exposed surviving seeds and rootstocks in pre-eruption soil and allowed them to flourish (Figure 4). Trees and shrubs are now widespread in some basins and have established enough cover, root mass, and strength to help anchor hillside tephra deposits, which minimizes additional erosion by runoff and landslides.

A similar example is seen along river corridors, where a certain degree of geomorphic stability has been needed before riparian vegetation could effectively be established. As that riparian vegetation has matured and gained stronger footholds, it has increased geomorphic stability. Furthermore, the combination of increased geomorphic stability and expanding riparian vegetation has helped establish animal communities. Areas where channel banks and floodplains remain unstable support little vegetation and few animals.

Fig. 4. Sequence of images showing geomorphic and vegetation change at a site in upper Smith Creek valley that received 50 centimeters of blast PDC and tephra fall deposits. Vegetation initially sprouted from surviving rootstocks in pre-eruption soils that, after the eruption, were re-exposed in the floors of gullies eroded through the new deposits. By 1994, trees were established on the hillside between the gullies and both surviving and colonizing species anchor the sediments. Helicopter circled for scale in the top two images. Credit: F. J. Swanson, U.S. Forest Service A Call to Action

Results from 4 decades of hydrogeomorphic and ecological research at MSH affirm the value of long-term monitoring and research at disturbed landscapes, as well as of the establishment of collaborative research communities. This multidisciplinary research continues to inform not only basic science but also societally important endeavors to understand and manage disturbed landscapes. These endeavors include efforts to manage flooding and sediment delivery in waterways affected by the eruption—especially as mitigation measures have failed or become less effective with age—and to manage native and invasive species on NVM lands. The research has also provided important, factual information about the eruption that is shared with the public at local visitor centers and through global media.

As populations living near volcanoes increase, more can be done to impart lessons learned from biophysical research at Mount St. Helens.As populations living near volcanoes increase, more can be done to impart lessons learned from biophysical research at MSH. We propose five steps for the volcano science community to take that would extend the reach of these lessons:

Improve public awareness in communities vulnerable to volcanic hazards of the biophysical responses to eruptions. Scientists can fold discussions of these responses into other volcano hazard awareness efforts, such as workshops and public presentations. Include instruction about biophysical impacts and responses to eruptions in academic courses focused on natural hazards to pass on the knowledge gained to future generations of students and scientists. Include post-eruption sedimentation hazards in volcano hazards assessments to more accurately portray the full range and duration of hazards associated with volcanism. Develop an international volcano ecology and hydrology network—either informally or formally through scientific societies—to connect ecologists, hydrologists, and geomorphologists; facilitate information sharing; and identify key issues that arise in post-eruption landscapes. Foster collaborations among hydrologists, geomorphologists, and ecologists who can consult with local volcano observatories and provide training for local science agencies, civil authorities, and emergency managers. Training could address what to anticipate in the immediate and long-term aftermath of future eruptions, appropriate hazard assessment methods, possible options and approaches to mitigating posteruptive hydrogeomorphic hazards, and advice for restoring ecosystems to desired states. The U.S. Geological Survey’s Volcano Disaster Assistance Program [Lowenstern and Ramsey, 2017], which is funded by the U.S. Agency for International Development, is one example of such a team; international scientific societies could facilitate others.

Following these steps can further advance the rich scientific understanding of the myriad and dynamic processes that occur in post-eruption landscapes, which studies at Mount St. Helens since 1980 have sharpened, and could help reveal how this understanding can best be applied for the benefit of public safety and the environment.

Eight Lessons from COVID-19 to Guide Our Climate Response

Fri, 04/24/2020 - 13:41

Just a few months ago, travel and trade crisscrossed the world, scientific research proceeded uninterrupted, farmers accessed global markets, and, to many, the climate crisis seemed far away and insurmountable. In the time since, millions of people have been infected with the novel coronavirus, and more than 100,000 people have died from coronavirus disease 2019 (COVID-19). The climate crisis remains far from people’s minds in the face of the present disaster, yet its progress has not stopped.

“With climate change, it’s as if we are where we were at with the pandemic 4 [or more] weeks ago.”“So many people might be wondering, ‘Why are we having a conversation about climate change when all we can think about is our current pandemic?’” said Katharine Hayhoe, an atmospheric scientist at Texas Tech University in Lubbock. “With climate change, it’s as if we are where we were at with the pandemic 4 [or more] weeks ago.”

Countries’ responses to COVID-19 outbreaks have ranged from swift, decisive, and forward-thinking to delayed, contradictory, and reactionary. In a webinar hosted by Trinity College Dublin (TCD) in Ireland on 7 April, climate experts discussed what the global responses to the ongoing pandemic can teach us about what’s needed to act on climate change in an effective and equitable way. Here are eight takeaways from the discussion.

1. We Need Transformative Change

A 2019 United Nations report called for transformative change to address plummeting biodiversity across the world. Such change would include responsible corporate practices, disincentivizing unsustainable practices like deforestation and fossil fuel production, and strengthening green policy initiatives, said ecologist Jane Stout of TCD.

“And you could say that this pandemic has created transformative change. Unplanned, but transformative all the same,” Stout said. “It’s shown us that society can change. The way that we live and work can change. People don’t have to be traveling all the time. There’s more remote working. There’s more connection with nature in our free time.”

Nitrogen dioxide concentrations were reduced dramatically over Europe as the continent shut down during the coronavirus pandemic. Most of the change was due to lower industrial output. Credit: Contains modified Copernicus Sentinel data (2019–2020), processed by KNMI/ESA

But, Hayhoe added, the pandemic has demonstrated that “it is industry, it’s not personal choices” that have the largest impact on the climate crisis. “Even if we as individuals did everything we could to cut our carbon footprint, to live within our personal boundaries, that in and of itself as individuals would not be sufficient to fix either the ecological crises or the climate crisis. And that’s why we need system-wide change.”

2. We Need Biodiversity to Remain Healthy

“Research has shown that high biodiversity reduces the risk of animal vector diseases in human populations,” Stout said. Many species have been rapidly losing habitat because of deforestation and continued warmer-than-average temperatures, Hayhoe added. Those animals have been pushed toward human-populated areas, which increases the risk of transmission of zoonotic diseases.

“For example,” Stout said, “in mosquito- and tick-borne diseases, where there’s a high diversity of wild vertebrates in a particular area, the mosquitoes and the ticks feed on them instead of on us. They feed on this diversity of hosts, most of which are actually poor reservoirs for the pathogens. This results in lower infection rates in humans.”

3. We Need to Invest in Nature

Preserving coastal habitats would save communities money from property damage related to sea level rise and tropical storms. Farms would lose fewer crops from increasing floods. Green energy technologies could boost economies through job production and market investments.

“Lots of people don’t like the idea of monetizing nature,” Stout said. “But it’s not all about monetizing. It’s about shining a light and showing the value of nature so that we have got those voices, so that we have got that power, to rebuild an economy in a different way.”

4. We Need to Close the Psychological Distance

The biggest climate change myth is that the problem won’t affect us as individuals.The biggest climate change myth, Hayhoe said, is that the problem won’t affect us as individuals. This same type of psychological distance was seen in many countries that had not yet seen cases of the novel coronavirus. “The health and the safety of our family, our loved ones, our friends, our community, the people and places we care about,” Hayhoe said, “that’s what the pandemic puts at risk, and that is exactly what climate change puts at risk as well.”

5. We Need to Make It Personal

Climate scientists and communicators can help the general population close psychological distance through effective stories and counterarguments about the consequences of climate change, said TCD humanities professor Michael Cronin.

This image from NASA’s Aqua 5 satellite in January 2020 shows locations of active burning in Australia (red) and wildfire smoke drifting over the Pacific Ocean. Credit: NASA

“It struck me about the bushfires in Australia, where terrible things were happening, hundreds of thousands of hectares of bush were being destroyed. But it’s when the koala bears came center stage that all of a sudden you got this kind of global resonance.”

“The people who are hell-bent on destroying the planet are supremely good at using particular forms of rhetoric…. So it seems to me that [climate activists must] go back and school ourselves in rhetorical arts of the ancients as one way of dealing with the current crisis.”

6. Small Businesses Need Help to Make Big Changes Quickly

Widespread shutdowns of schools and businesses have been necessary to slow the spread of COVID-19, yet those actions have also put millions of people out of work and threatened the survival of small businesses.

“This is a whole community, a whole swath of our population, who feel like they’re facing annihilation in climate change.”“This is a whole community, a whole swath of our population, who feel like they’re facing annihilation in climate change,” said Darragh McCullough, a journalist and farmer in eastern Ireland. In the past weeks, McCullough’s farm and many others have had to adapt as world markets, trade, and travel policies changed without notice. Many fear similar economic annihilation from climate solutions that threaten their livelihoods.

“Farmers are more than willing to put their arms around alternatives,” McCullough said, but they need support during the transition. “We’re getting there,” he added, “but it brought home to me that a lot of people talk about, ‘Well, farmers, why don’t they try this or why don’t they change what they’ve always been doing and try a new way [to mitigate climate change]?’ It’s not very easy.”

7. We Need a Just Transition

As we outline the needed transformative change for the climate, we must ensure that the transition is just and fair for workers, said McCullough. In Europe, the United Kingdom, and the United States, Black people and Native and Indigenous peoples are dying of COVID-19-related causes at much higher rates than white people. Also, economically vulnerable people are forced to work in ever more dangerous conditions or lose the paycheck they need to feed their families. The changing climate puts these same groups at risk.

“The poorest in society will suffer most.”Both in the current pandemic and under climate change, “migrant workers are some of the most vulnerable workers in any economy,” McCullough said. They have been deemed essential to the agriculture sector yet are offered little to no protection. “Whether it’s Ireland, or America, or anywhere else, they tend to be at the bottom of the economic heap on minimum wages with minimal supports.”

“The poorest in society will suffer most,” McCullough added, so drastic, transformative change will need a support system in place ahead of time for the most vulnerable members of society.Society now needs to respond to the climate crisis with the same urgency and at the same comprehensive scale.

8. We Can Fix This

The coronavirus pandemic has “shown us that governments can implement socially unpopular policies in the interest of public good and to the detriment of the economy,” Stout said. “It’s shown that we can respond to a crisis when we need to. And climate change and biodiversity loss are global crises that are also threatening human health.” Society now needs to respond to the climate crisis with the same urgency and at the same comprehensive scale.

“What this pandemic has brought home,” Hayhoe said, “is that we are all part of this interconnected system. To care about biodiversity, to care about the integrity of our ecosystems, to care about our planetary boundaries and the limits on the resources we can use, and, last but not least, to care about climate change, the great threat multiplier, we only have to be one thing. And that one thing is a human living on planet Earth.”

—Kimberly M. S. Cartier (@AstroKimCartier), Staff Writer

This story is a part of Covering Climate Now’s week of coverage focused on Climate Solutions, to mark the 50th anniversary of Earth Day. Covering Climate Now is a global journalism collaboration committed to strengthening coverage of the climate story.

Getting to the Bottom of Slow-Motion Earthquakes

Fri, 04/24/2020 - 13:38

Earthquakes can be devastating bursts of destruction, lasting for a few seconds or minutes at most. But not all release of pent-up seismic energy is quick or violent. Slow-motion quakes—also called slow-slip events—can last for days or even months, releasing small amounts of energy over time. Slow-slip events are so gentle they are usually detectable only by GPS networks. Though slow-slip events were first recognized about 2 decades ago, researchers are still learning about the mechanisms that cause them.

The relatively shallow depth of the Hikurangi subduction zone allowed researchers to drill and collect samples from locations in the Pacific plate shortly (in geological terms) before it moves under the Australian plate.A new study published in Science Advances indicates that geological heterogeneity may be at the bottom of at least some slow-slip events. This study focused on the Hikurangi subduction zone off of the coast of New Zealand’s North Island, where the Pacific tectonic plate slides under the Australian plate. The Hikurangi subduction zone is one of the shallowest sites where researchers have observed slow-slip events—at depths of less than 15 kilometers—which opens up some unique research opportunities.

“Previously, many of the areas where we detected slow-slip events were completely inaccessible to direct geological observation,” said Philip Barnes, lead author of the study and a geologist at New Zealand’s National Institute of Water and Atmospheric Research. For example, slow-slip events at the Cascadia subduction zone in North America occur at depths of around 40 kilometers.

The relatively shallow depth of the Hikurangi subduction zone allowed researchers—on two International Ocean Discovery Program (IODP) expeditions—to drill and collect samples from locations in the Pacific plate shortly (in geological terms) before it moves under the Australian plate. By analyzing these core samples, the researchers determined the composition and physical properties of the plate before it moves into areas where slow-slip events have been observed. Then they combined these analyses with previously acquired seismic reflection data—measurements of how sound waves reflect off of different kinds of rocks.

Sections of volcaniclastic rock core collected on the JOIDES Resolution on IODP Expedition 375 from the top of a seamount at the Hikurangi subduction margin. Such rocks are thought to form part of the slow-slipping subduction fault zone. Credit: Philip Barnes (NIWA) The Heterogeneous Hikurangi

These experiments showed that the area of the Pacific plate located before the Hikurangi subduction zone is extremely heterogeneous. The core samples contained several different kinds of rocks, which had highly variable properties, such as strength, porosity, and texture. “Some rocks were mushy and weak, whilst others were hard, cemented and strong,” Barnes said in a press release.

In some areas, properties such as porosity—a measure of empty spaces within a rock type—varied almost twofold within tens of centimeters. Not only was the Pacific plate made up of heterogeneous rock types, its geology was variable as well, including seamounts rising more than a kilometer above the seafloor.

This geological and physical heterogeneity could explain the slow-slip events observed in the area, according to Barnes. “Many people think faults with slow-slip events are in a transitional frictional state,” he said. “They are very close to failing (which would cause a typical earthquake), but something is holding back that failure.”

The patchwork of rock types and geological features entering the Hikurangi subduction zone could mean that some parts of the fault get periodically stuck and unstuck (what’s called stick slip), whereas other parts are sliding along without much ado (aseismic or fault creep), ultimately yielding an overall area with slow-slip events.

Direct Observations

The direct observations from the study will help improve numerical and computer models attempting to solve the enigma of slow-slip events. “Studies of slow-slip environments have either been from various geophysical observations, which tend to be fuzzy, or from ancient geological exposures, which can be difficult to relate to active systems,” said Roland Bürgmann, a geologist at the University of California, Berkley, who was not connected with the study. “This study provides new, directly sampled, and beautifully imaged information about the stuff that is being subducted into a slow-slip zone.”

But of course, this study provides only a couple of data points. “More comprehensive work on multiple subduction zone segments with and without slow-slip zones would need to happen to confirm the association of slow slip with subducted heterogenous rocks and structures,” Bürgmann said.

Other factors, such as fluid pressure changes, probably influence slow-slip events, both at Hikurangi and at other locations. Also, the degree of heterogeneity that the authors found may make interpretations more challenging. “The very heterogeneity and randomness of the Pacific plate means it’s difficult to simply extrapolate that what the researchers see on the incoming plate will be the same when it enters the subduction zone,” said Jean-Philippe Avouac, a geologist at the California Institute of Technology not connected with the study. “While this study is an impressive effort to characterize the incoming seafloor [at the Hikurangi subduction zone], how it plays out in explaining slow-slip events is yet to be fully determined.”

Barnes agrees that more work needs to be done. “This paper is one of the first outputs of a very large research project,” he said. “We are at the beginning stages of what I hope will be a much fuller exploration of slow-slip events.”

—Adityarup Chakravorty (chakravo@gmail.com), Science Writer

This Week: Green Reads for Earth Week

Fri, 04/24/2020 - 13:28

Solar Power Has a Diversity Problem. People of color face the highest risk of pollution from fossil fuel production, and yet an industry set to lower pollution is overwhelmingly white. The solar power industry workforce was 73% white in 2019, despite a skyrocketing job growth rate in the past few years. Julia Pyper highlights recent efforts by solar companies to turn the tide, including new hire incentives, diversifying boards and leadership, hiring subcontractors with diverse backgrounds or minority-owned firms, and other solutions. —Jenessa Duncombe, Staff Writer


A Virtual Ice Sheet Expedition.

Instead of disappearing from Twitter for fieldwork for the next 35 days, I'll guide a virtual expedition, with an ice-sheet post every day for the next 35 days.

Day 1/35 – Stepping off the C-130 at Camp Raven skiway. Ah, the feeling of walking on squeaky snow! pic.twitter.com/fROhHZn1lP

— William Colgan, Ph.D. (@GlacierBytes) April 21, 2020

The pandemic may have shut down most research trips, but that doesn’t mean we can’t explore Earth from the safety of our homes. Glaciologist William Colgan is taking people on a monthlong virtual expedition to explore the world’s (shrinking) ice sheets. Bundle up! —Kimberly Cartier, Staff Writer


Scholastic’s Celebrate Earth Day. This compilation of resources collected over the past 10 or so years is aimed mostly at K–8 students and includes activities for kids to do in their classrooms and communities, as well as ideas for relevant reading and for learning about ecosystems, pollution, and the three R’s (reducing, reusing, recycling). —Timothy Oleson, Science Editor


It’s Not Easy Being (Consistently) Green. Good, short read from a fresh perspective (behavioral science and marketing). How do we encourage “positive spillovers” among environmentalists? We make green behaviors observable, set a high bar for having a “green reputation,” and (I love this) prime the threat of reputation loss. —Caryl-Sue, Managing Editor

Planetary Lightning: Same Physics, Distant Worlds

Fri, 04/24/2020 - 12:11

Lightning Science Strikes Lightning Research Flashes Forward   Planetary Lightning: Same Physics, Distant Worlds   Returning Lightning Data to the Cloud   Understanding High-Energy Physics in Earth’s Atmosphere   Mapping Lightning Strikes from Space   New Study Hints at Bespoke Future of Lightning Forecasting   Students Launch Balloon-Borne Payloads into Thunderstorms   Investigating the Spark

What do you think of when you imagine lightning?

If you pictured a zigzagging bolt of electricity striking the ground from a rolling thundercloud, you’re right. If you pictured elves, sprites, spiders, jets, or volcanoes, you’re also correct.

You’re also right if you pictured any of those phenomena on another planet.

In 1979, NASA’s Voyager 1 spacecraft flew past Jupiter and saw flashes of light illuminating areas of the planet’s nighttime sky larger than the United States. Accompanying those flashes were extremely low frequency radio signals, called whistlers. On Jupiter, as on Earth, those two signs taken together unequivocally point to lightning.

Since that first Voyager 1 detection of planetary lightning, scientists have found proof of lightning and other lightning-related transient luminous events elsewhere in the solar system. In our solar system and beyond, planetary lightning goes beyond the simple scheme of the “haves” and the “have-nots.” There are plenty of “maybes” and “why nots,” too.

A Recipe for Lightning

Generating lighting requires a few key ingredients, explained Karen Aplin, an associate professor of space science and technology at the University of Bristol in the United Kingdom. “Because it’s like a spark, you need to have the charges separated. You need to have the positive and negatives far enough apart so that the voltage between them is big enough” to cause an electrical breakdown of the air. Lightning is the manifestation of that electrical breakdown.

Earth’s thunderstorms have those key ingredients, and above thunderstorm clouds different methods of discharging electricity can create sprites, elves, and blue jets.

Volcanic lightning is quite common anytime there’s volcanic ash, like during this eruption of Sakurajima in Japan. Credit: Mike Lyvers/Moment/Getty Images

But thunderstorms aren’t the only environment that creates the conditions needed for lightning. “Volcanic lightning is really common in explosive eruptions. It’s not a rare, unusual phenomenon,” explained Alexa Van Eaton, a volcanologist at the U.S. Geological Survey’s Cascades Volcano Observatory in Vancouver, Wash. “It happens during most intermediate or larger explosions, and it gets started in a simple way.”

“As the magma rises to the surface,” she said, “it can become really frothy and bubbly and break itself apart. The water bubbles expand and blow themselves up. That breakage process is highly electrifying. Once those tiny rock particles—volcanic ash—are shooting up into the atmosphere at high speed, they’re colliding, exchanging electrons, and creating a charge right at the base of the volcanic plume. Then once the plume rises high enough to freeze, the ice particles help to generate even more lightning” by separating more charge.

“You can expect that if it’s an ash-producing eruption, it is capable of making lightning.”“You can expect that if it’s an ash-producing eruption, it is capable of making lightning,” said Sonja Behnke, a scientist who researches volcanic lightning at Los Alamos National Laboratory in New Mexico. “It’s very common, and even if it doesn’t produce lightning, the ash plume might still have charge to it.”

The ingredients for lightning—polarized gas molecules, atmospheric movement, and the possibility of electrical breakdown—exist to some degree on any world in the solar system with an atmosphere. Scientists have found that this so-called planetary lightning creates signals similar to those Earth lightning makes.

Lightning superheats the surrounding atmosphere into a plasma and creates a visible flash of light. It emits electromagnetic pulses at high, low, and broadband radio frequencies. Lightning can also create audible pressure pulses—thunder—and magnetic pulses, but these two signals are more difficult to detect even when in a close orbit around a planet.

Volcanic lightning, which might also exist on other worlds, puts out a unique signal: thousands of tiny sparks. “Unfortunately, you have to be pretty near to the volcano to detect them,” Behnke said. “But they are a signature that could be exploited…because thunderstorms don’t make a whole swarm of these itty bitty discharges. It’s a very distinct signature.”

Blue hour and night timelapse of Taal Volcano eruption. pic.twitter.com/DSJqHOaAS5

— shuajo (@joshibob_) January 12, 2020

The Haves: Jupiter, Saturn, and Uranus

On Jupiter scientists observed lightning storms almost anywhere and anytime they looked, said Yoav Yair, dean of the School of Sustainability at the Interdisciplinary Center Herzliya in Israel and a scientist whose research focuses on atmospheric electricity.

Jovian lightning has been observed for 4 decades in visible, low-frequency radio, and high-frequency radio wavelengths by visiting spacecraft and atmospheric probes. After studying thousands of lightning events, scientists now know that most of Jupiter’s lightning occurs above midlatitudes and near its poles (where there are large convective storms) and can occur at a rate similar to Earth lightning. Data also reveal that a flash of Jovian lightning has 10 times the total electromagnetic energy of a terrestrial lightning flash.



Saturn, too, has lightning. During its Saturn flyby in 1980, Voyager 1 detected lightning-generated radio pulses, initially suspected to come from the rings but later found to be from the atmosphere. But it wasn’t until the a few years into the Cassini mission that optical flashes of lightning became visible. The lightning storms, or Saturn electrostatic discharges, are intermittent but can last for months at a time.

Most of the lightning observed by Cassini occurred right before or after Saturn’s equinox in 2009, suggesting that it’s triggered by a seasonal change in the weather. Saturn has also produced some of the most spectacular planetary lightning seen to date, including the “Dragon Storm” of 2005 and, in 2013, the largest and most energetic storm ever recorded in the solar system.

Is there lightning on Uranus? “The answer is quite certainly yes.”Is there lightning on Uranus? “The answer is quite certainly yes,” affirmed Philippe Zarka. Zarka is an astrophysicist and a senior scientist at Observatoire de Paris, Centre National de la Recherche Scientifique, Université Paris Sciences et Lettres.

Lightning-related signals “were detected with Voyager 2 during the Uranus flyby,” he said. “We found radio spikes very, very similar to the ones at Saturn. Also we observed a different setup on the dayside and nightside of the planet. So it’s quite clear that it’s lightning.”

Voyager 2, the only mission to visit Uranus, didn’t see visible flashes of lightning, and Aplin said that it’s not likely we ever will. “People think that the lightning was quite deep in the atmosphere,” she said. “If there were flashes, we wouldn’t have seen them anyway because they’re too deep be detected. There are many layers of cloud above the layers of cloud that would have had lightning in them.”

Planetary scientists have used radio telescopes on Earth to study lightning on Jupiter and Saturn. Observations of Uranus, too, might be possible. “If you do some back of the envelope calculations,” Aplin said, “it looks like the signal might just about be detectable from Uranus lightning, based on the sort of strength that we estimate it is.”

The Have-Nots: Mercury, Moon, Titan, and Pluto

Any place in the solar system that does not have a convective atmosphere or similar process cannot have atmospheric lightning. That rules out Mercury, the Moon, and other airless bodies like asteroids for atmospheric or volcanic lightning. Despite this, solar wind can impart charge onto a dusty surface, including the Moon’s, which can present an electric discharge hazard to equipment and astronauts alike.

Unlike the Moon, Saturn’s moon Titan does have a thick atmosphere. “Methane clouds on Titan are not that good for producing electricity,” Yair said. The clouds are made of an organic substance (methane), he explained, which is poorly electrified. As a result, the clouds tend to be less capable of building up a charge strong enough to produce lightning.

In 2011, the Cassini spacecraft imaged this blue flash of lightning (left) in a storm cloud on Saturn. Thirty minutes later (right) no lightning was flashing in the cloud. Cassini saw no similar evidence of lightning on Titan. Credit: NASA/JPL-Caltech/SSI

No lightning was observed on Titan before the Huygens Probe landed in 2005, and the team had calculated a less than 1% chance that the moon’s hydrocarbon-rich atmosphere and surface could generate or discharge enough electricity to create lightning.

However, organic molecules, like those that make up wildfire ash on Earth, can still create lightning when lofted to high altitudes because of ice formation in upper levels of the clouds, Van Eaton explained. And Titan’s atmosphere does have trace amounts of water.

Huygens was equipped with lightning safety measures but didn’t experience any lightning. Furthermore, Cassini saw no evidence of lightning on Titan during its 10-year mission. “If lightning occurs at all, and it may not, then it likely occurs in rainstorms,” said Ralph Lorenz, a planetary scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md.

Lorenz and the rest of the team behind NASA’s upcoming Dragonfly mission to Titan are, nonetheless, exercising caution. “Rainstorms do not occur at the latitude and season of Dragonfly’s nominal mission. We are, however, taking, like aircraft on Earth, precautions against electrostatic discharge, just in case that occurs when sand blows around.”

Last on the list of worlds that likely doesn’t have lightning is Pluto. Although Pluto has layers of atmospheric haze, Yair explained, that haze is composed of nonconductive hydrocarbons like those surrounding Titan and much too thin to produce or conduct electricity.

The Maybes: Venus and Neptune

Although Neptune is similar to Uranus in many ways, lightning might not be one of them. “In 1989 during the [Voyager 2] flyby of Neptune,” Zarka said, “we recorded data similar to the data recorded at Saturn and Uranus. We analyzed the data in a similar way.…The analysis just showed 5 events similar to lightning. To give a comparison, at Saturn we saw something like 10,000 or so. At Uranus, it was 140.”

“We cannot seriously claim that we detected lightning on Neptune.”“With five [events], we cannot say it was detected because it may be spurious,” he said. “It may be some electrostatic discharge on the spacecraft. So we cannot seriously claim that we detected lightning on Neptune.” There’s no reason to suspect that Neptune wouldn’t have lightning, Zarka said. It simply might be more sporadic than on Uranus because of a slightly different atmospheric composition and vertical convection.

Neptune, like Uranus, likely makes lightning below thick upper clouds that would block any visible flashes, Aplin said. Radio measurements from Earth are out, too. “The energy we estimate for the lightning is lower for Neptune, and because it’s further away that means the signal would be so weak, you couldn’t detect it,” she said. Resolving this puzzle, however, will likely require an orbital mission to the ice giant.

If Venus has lightning, “it’s a bit weird, and we don’t quite understand it. It’s not behaving in ways that we expect.”On Venus, there has been some evidence of lightning, but the matter is still very much up for debate. “Venus is quite controversial,” Aplin said. “I think probably the best evidence at the moment [suggests] there’s probably not lightning at Venus. But if there is, it’s a bit weird, and we don’t quite understand it. It’s not behaving in ways that we expect.”

In the 1970s, the Soviet Venera 11–14 missions detected whistlers and other radio emissions, as did the Pioneer Venus Orbiter in 1980, the Galileo spacecraft in 1991, and the Venus Express mission in 2007. On the other hand, NASA’s Cassini mission flew by Venus in 1998 and 1999, and Japan’s Venus Climate Orbiter “Akatsuki” has been orbiting Venus since 2015. Both were equipped with an instrument designed for detecting lightning, and neither craft found any.

Maybe Venusian lightning is rare and localized, Zarka said, or maybe Venus’s atmosphere just can’t create lightning at all. “At Venus, there is a very, very strong horizontal superrotation of the atmosphere,” he said. “That could prevent vertical convection.”

Too, Venus’s clouds aren’t rolling thunderstorms like on Earth, Jupiter, and Saturn, Aplin said. “On Venus, it’s not like that at all. There’s no known mechanism by which the lightning could be generated. That’s not saying it’s not there, but just saying it’s different to the simplest interpretation.”

What data would resolve this debate? “Ideally, you’d like a radio detection and an optical detection at the same time,” Aplin said, “because people can argue about one or the other, but if you have them both at the same time, then it’s not really controversial.”

Lorenz agreed and added that “if radio emissions characteristic of lightning could be repeatedly associated with [a] specific formation mechanism—e.g., the geographical location of a known volcano—or with specific atmospheric conditions identified by other means like cloud updrafts or fronts, then that would be a compelling indication of a lightning-like phenomenon.”

The Why Nots: Mars, Io, and Exoplanets In 2007, the New Horizons spacecraft took this sequence of images of Io’s Tvashtar volcano erupting. The plume of volcanic debris extends 330 kilometers above the moon’s surface. This sequence also captured two smaller volcanic plumes: from Masubi at the lower left and from Zal just to the left of the main plume. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

And then there are the worlds where we have not detected convincing evidence of lightning but have no reason to think lighting couldn’t exist there.

Mars’s atmosphere is generally considered too thin and dry to create lightning storms. But more frequent phenomena like dust devils and dust storms might create something like large-scale static electricity. Just like volcanic lightning, dust particles colliding with one another will build up some charge and then the storm or vortex could separate the charge like a convective cell, Zarka explained. This type of static charging could also create lightning at Jupiter’s moon Io, which regularly spews volcanic debris into space, according to Yair.

What it come down to is that if there’s a way to create lightning, there’s probably somewhere in the solar system that does it. And that holds true for worlds beyond the solar system, too.

“It’s just standard atmospheric physics,” Zarka said. “Lightning is quite common. There’s really no reason not to have lightning at exoplanets.”

It’s not likely that astronomers will be able to detect exolightning any time soon, Zarka said. “The answer is no, absolutely no,” he said. Typical radio signals from lightning are much weaker than background noise from a planetary magnetosphere. To be seen from so far away, the lightning would have to be billions or trillions of times stronger than terrestrial lightning. That’s just not realistic, Zarka explained.

What Use Is Lightning?

Lightning—whether atmospheric, volcanic, or otherwise—can be a powerful tool for understanding the complexities of distant worlds, especially on planets where we have not explored in situ or cannot do so.

The rate, duration, and frequencies of radio pulses as well as the optical flash duration can distinguish between lightning sources. The spatial distribution can tell scientists whether lightning is associated with thunderclouds, hurricanes, or a specific geographic feature like a volcano. How lightning strikes vary over time can also reveal daily or seasonal weather patterns.

“Lightning is not just beautiful, but it’s also really valuable.”Moreover, “people are so sure that lightning’s about convection that if they see lightning, they just know it’s convection,” Aplin said. And lightning can spark unique chemical reactions that might not otherwise happen, some of which might be important for developing life.

But back home on Earth, lightning has been gaining ground as a way to detect eruptions of remote volcanoes and assess their hazards to aviation, shipping, agriculture, and people.

“Lightning is becoming very useful for scientists to track volcanic ash clouds,” Van Eaton said. “And we want to make better and better instruments and improve our scientific understanding so that lightning is not just beautiful, but it’s also really valuable for keeping people out of harm’s way.”

Author Information

Kimberly M. S. Cartier (@AstroKimCartier), Staff Writer

Lightning Research Flashes Forward

Fri, 04/24/2020 - 12:08

Lightning Science Strikes Lightning Research Flashes Forward   Planetary Lightning: Same Physics, Distant Worlds   Returning Lightning Data to the Cloud   Understanding High-Energy Physics in Earth’s Atmosphere   Mapping Lightning Strikes from Space   New Study Hints at Bespoke Future of Lightning Forecasting   Students Launch Balloon-Borne Payloads into Thunderstorms   Investigating the Spark

Ashley Ravenscraft had a decision to make. Over the past several hours as a storm rolled through northern Alabama on 11 January, her team at the National Weather Service (NWS) office in Huntsville had already issued two tornado warnings.

Ravenscraft, a meteorologist, had issued the warnings using the Three Ingredients Method, which uses radar inputs to estimate the likelihood a linear storm will shift into a vortex. Then the azimuth motor went down on the closest radar to the storm—a technician had been sent to repair it, but it would be a least an hour before he arrived and would be able to get it back online. The remaining radar stations were far enough from the storm that they were capturing only data above several thousand meters in altitude—too high to make accurate judgments on storm rotation close to the ground.

But Ravenscraft was getting consistent data about one piece of the storm that would become key: lightning.

The NWS had brought a new application online in 2018—Ravenscraft was using it for only the second time. Her color-coded screen was showing 1-minute flash extent density data, or the rate at which lightning was flashing in the area. It was pulling in real-time data from the Geostationary Lightning Mapper (GLM), a near-infrared instrument aboard the GOES-R satellite. As the frequency of flashes increases, the colors on the map move from cool to warm.

“If we start to see these lightning jumps, and we see these updrafts grow, especially combined with the surge in the line we can see on radar, then there’s a good chance we’re going to end up with a tornado.”A month earlier, on 16 December 2019, Ravenscraft had been on radar for her first big storm and had GLM data up on her screen. As the storm line approached the Huntsville region through northern Mississippi, “I was watching the nature of the lightning jumps [the flash extent density data]—how high it got, how quick it got,” she said. “I knew that they were putting out tornado warnings, and I knew how the radar looked, so I thought, ‘If we start to see these lightning jumps, and we see these updrafts grow, especially combined with the surge in the line we can see on radar, then there’s a good chance we’re going to end up with a tornado.’”

When the storm reached her coverage area, eight reported tornados touched down. Ravenscraft had successfully predicted and sent out a warning for each one.

But there was one additional warning she issued that night, for residents in Lincoln County, Tenn. The lightning jump had been lower than the others she had seen, but combined with what she saw on radar, she made the call. That night, no tornado was reported in that location. A few weeks later, however, her team was looking over the data and became so convinced that something had to have happened there that a colleague drove out to inspect the scene for himself. Ravenscraft had been right: A line of uprooted trees and an eyewitness account from a neighbor confirmed a small twister had touched down. “From that event, we realized how significant the GLM data was.”

A screen capture of data viewed by the National Weather Service office at Huntsville on 11 January 2020 as a severe storm rolled through northern Alabama. With the radar closest to the storm down, the meteorologist on call that night used lightning rate information from the Geostationary Lightning Mapper (GLM; lower left) to issue tornado warnings. The screens, clockwise from upper left, show bulk shear vectors and reflectivity; storm relative velocity; warnings issued for severe storms (yellow) and tornadoes (red); and GLM flash extent density data. Click image for larger version. Credit: NASA SPoRT

Now Ravenscraft was studying the January storm on her monitors, with very limited radar data, and the current tornado warning was just about to expire, which meant residents would believe it was safe to leave shelter. “I started to notice that every minute, the [lightning flash] rate was going up.…I said, this is not good, obviously the updraft was strengthening.” Then the GLM data spiked.

Ravenscraft issued the alert. The action began a cascade of notifications in the area: Weather radios blared the alarm, local media was instantly notified, automated scripts went out on all the regional NWS social media pages, and within about 10 seconds, anyone with a mobile app that pulled NWS data and was within cell range was alerted to take—or, in this case, stay in—shelter.

Almost immediately, an EF2 tornado touched down and slammed into an elementary school, causing significant damage—thankfully, it was a Saturday. “GLM was the decision maker,” Ravenscraft said. “If we had only had radar, we may not have decided to issue that warning.”

Reaching the Perfect Storm of Lightning Detection

GLM is the most recent lightning detection instrument to go online in what is still a relatively young field. In the early 1980s, detection sensors were popping up in regions around the United States. In 1989, they were consolidated into the National Lightning Detection Network (NLDN). Today, a little more than 100 low-frequency sensors are distributed across the continental United States under the operation of Vaisala, a company that performs industrial and environmental observations and makes them available to clients like the NWS.

About 15 years ago, Ryan Said was in the electrical engineering doctoral program at Stanford University. His research group was taking very powerful sensors that had been used for studying the ionosphere and repurposing them into exceptionally sensitive lightning detectors. Where the NLDN sensors can detect lightning around 800 kilometers away, these sensors can pick up lightning emissions up to 10,000 kilometers away. About halfway through development, Vaisala got wind of the project and invested in it—one of the head engineers at the company became Said’s dissertation adviser. That network, called the Global Lightning Dataset 360, or GLD360, launched in 2009. Said wrote the sensor software and location algorithms for it and has been at Vaisala as a senior scientist and systems engineer since 2012.

Between NLDN and GLD360, explained Said, “we can detect these radio signatures from lightning happening anywhere on Earth.” (And he really does mean anywhere. Last June, GLD360 detected the closest flashes to the North Pole ever observed.) When a sensor detects a radio impulse from a flash, the GPS-synchronized data are sent to a central hub and processed into lightning location data. Clients who subscribe to the data get a near-real-time feed that includes the time of each detected stroke within a flash to within a microsecond, the location to within 200 meters in the United States (2 to 3 kilometers for the GLD360), the peak current, and the polarity of a lightning flash.

NLDN tells you, among other things, precisely where powerful strokes may be causing damage, and GLM tells you how far away that storm is still churning.Many of the people who use this information, like Ravenscraft and her colleagues at NWS Huntsville, use streams from several environmental monitoring networks simultaneously. “They take that real-time feed and then overlay it on their AWIPS [Advanced Weather Interactive Processing System] software,” explained Said, “which is sort of a Swiss Army knife tool that can overlay satellite and radar and lightning data for meteorological information on the same display.”

The major benefit of the NLDN—which detects radio emissions in the very low frequency and low-frequency ranges—is in its precise location pinpointing. GLM observations, meanwhile, capture the flashes from above, making one of its major benefits the ability to see the horizontal extent of a storm and to detect the majority intracloud flashes—flashes that don’t make ground contact but tend to indicate stronger updrafts as they occur in greater numbers (NLDN sensors can detect only about half of all intracloud flashes). In other words, NLDN tells you, among other things, precisely where powerful strokes may be causing damage, and GLM tells you how far away that storm is still churning.

One of the experiments Said and his team are pursuing is using these complementary data  sets to study lightning-triggered wildfires. The numbers here themselves are wild: Lightning causes around 16% of wildfires, but those fires cause 56% of the acreage burned, making it a priority for many in the forest services to track these triggering events [Balch et al., 2017].

It’s not as simple as monitoring lightning data during storms. Wildfires are often caused by continuing currents—that’s when a lightning flash establishes a conductive channel to the ground, but instead of concluding in a fast-return stroke, a weaker sustained electrical current continues on the ground for 10 to 100 times longer than the stroke. “An analogy I often give is a hot poker: If you just touch something quickly it might not do much damage, but if you hold it for awhile it can heat up.” If you heat up a patch of underbrush long enough, it catches fire.

The GLM can see this type of sustained flash—from 10 to several hundred milliseconds long—but can resolve its location only to around 64 square kilometers. Vaisala is testing software that takes these broad GLM data points and combines them with NLDN data to narrow down the location to 200 meters. That’s information that emergency management personnel could use to go investigate potentially smoldering locations before they catch.

What Lightning Tells You at a Glance

Going one step further, one group is trying to take these data and create automated wildfire detection algorithms. Chris Schultz is a research meteorologist at NASA’s Short-term Prediction Research and Transition Center, or SPoRT, in Huntsville. He recently led a team that looked at how long an area might smolder before catching fire after it has been struck by lightning. In a paper published last year, they found that half of causal flashes occurred the same day as the fire, but the rest were tracked largely between 2 and 5 days before the fire was spotted—one fire in New Mexico didn’t catch until 12 days after the causal lightning strike [Schultz et al., 2019].

A new lightning detection application could be used by public safety leaders such as football game managers and lifeguards to easily and accurately know when people can safely come back outside.“The end goal is to develop an algorithm where you have all the inputs of precipitation, storm type, and land surface and soil moisture that forecasters look for as assessment of the fire danger,” said Schultz, “and then as thunderstorms roll through you can evaluate the likelihood of a fire” from a lightning strike, even if it doesn’t ignite for a week.

SPoRT is tasked with developing all sorts of tools that can help forecasters and anyone charged with public safety to handle the ever-changing weather. Later this year, the National Oceanic and Atmospheric Administration will be rolling out the Time Since Last Flash tool, an operational version of a concept that SPoRT created that uses GLM data. The tool automatically changes colors on a digital map from red to yellow to, finally, green, when lightning was last detected 30 minutes ago. It’s a simple application that could be used by football game managers or lifeguards to easily and accurately know when people can safely come back outside.

Other applications are those that meteorologists like Ravenscraft use, such as the colors that indicate a spike in lightning rates. “The hardest thing to measure in atmospheric sciences is vertical motion,” said Schultz, so forecasters use lightning as a proxy for that motion.

“We’ve got to this point where forecasters are comfortable taking their radar data, taking their lightning data, taking their satellite data and understanding the formation of that storm and its impact for the next 30 to 40 minutes,” said Schultz. And applications like the ones SPoRT provides to meteorologists allow them to make faster and more confident predictions and get people to safety. “That’s what gives me that warm, fuzzy feeling, when forecasters are able to utilize the things we’ve been working on.”

Modern Lightning Safety in the United States

Last year, the NLDN recorded 20 million lightning flashes that hit the ground in the United States. But as modern, grounded buildings were erected, metal-topped cars proliferated, and the percentage of people working outside went down, fatalities from lightning have gone from around 400 annually in the early 20th century to 27 for the past decade.

Maybe you’ve called your kids in from the yard because you know “When thunder roars, go indoors.” Or perhaps you know the 30-30 rule: When the time between lightning and thunder is less than 30 seconds, it’s not safe to be outside; when 30 minutes have passed since the last strike, it’s safe to go back outside (the rule behind Schultz’s Time Since Last Flash concept).

If so, you can thank Ron Holle, Mary Ann Cooper, and a group of colleagues determined to educate the public on lightning safety. The group met to discuss these ideas in 1998 at the American Meteorological Society conference. The timing (30 seconds, 30 minutes) was based on data they were collecting from the NLDN. Then Holle and Cooper, today known as the preeminent lightning safety experts in the world, went on a media blitz, giving thousands of interviews to local and national reporters to spread these simple messages [Cooper and Holle, 2012].

Even with this progress, Holle, who is now a consultant for Vaisala, argues there’s a long way to go—in developed countries like the United States, that means vulnerability regarding our infrastructure.

“A lot of the power companies are not using lightning data,” Holle said, noting that 50 years ago it may not have been a huge issue if a transformer blew and power went out for an evening, but today, even a few seconds of outage can cause major problems. Nevertheless, Holle said, the list of companies—utilities, airports, major sports facilities—that could still benefit is significant. “It’s a bit frustrating to know that we’re sitting on the data that really could help people.”

The Current That Kills Can Come from Below

Lightning safety is an entirely different issue in developing countries. When thunder roars, go indoors? “Not if you have a thatched roof.”Lightning safety is an entirely different issue in developing countries. When thunder roars, go indoors? “Not if you have a thatched roof,” said Cooper.

In June 2011, 18 children were killed, and 38 were injured when lightning struck Runyanya Primary School in Uganda. The tragedy moved Richard Tushemereirwe, an adviser on science and technology to the president of Uganda, to found the African Centres for Lightning and Electromagnetics Network, or ACLENet. The organization collects injury data, educates communities on lightning dangers, and raises funds to protect schools and other buildings with lightning safety devices.

The first thing Tushemereirwe did was recruit Cooper to run the organization. (She brought on Holle, who serves on the board.) Cooper is a medical doctor and one of the first experts in modern emergency medicine. She quite literally wrote the book on it—helping to design the first protocols and accreditation standards for the doctors who treat you in the emergency room today. While Cooper was in school, a family friend suffered a high-voltage industrial accident; several years later, it inspired her to give a lecture on electrical injuries at which an attendee asked about lightning injuries. She discovered there was almost nothing published on the topic. She decided to do it herself, searching back through a century of literature for the few documented cases and eventually developing a handful of correlations on location and type of burns and their impact on mortality.

There are five electrical mechanisms through which lightning can kill or injure a person. Only a small percentage of victims are killed or injured by a direct lightning strike. An equally small number are hit through conduction, or contact injury, such as touching a faucet when lightning strikes it. Fifteen to 20% are killed or injured through what’s called a sideflash, the electrical current that strikes outward once lightning has hit something nearby, like a tree.

Another 15% to 20% of victims suffer through a terrifying mechanism called an upward streamer. “As a thunderstorm is coming through the area—it doesn’t even need to be over top of you—this intense, huge electrical field starts, inducing opposite charges in whatever’s underneath it, whether it’s a TV tower or a tree or a person or a cow,” said Cooper. “It turns out that sometimes that opposite charge can be strong enough that an upward streamer will actually start up from the skull of that person or tower.” Sometimes a lightning flash will attach to that upward streaming charge, but it doesn’t have to—the charge itself can be strong enough to kill you. Cooper herself wrote the first medical report on the mechanism after studying the case of a man who was killed during a lightning storm but presented none of the usual high-voltage burns and neither his nearby crew members nor the electrical equipment he was working on suffered any damage. [Cooper, 2002]

Lightning protection equipment, provided by the African Centres for Lightning and Electromagnetics Network, is installed at the Shone School in Uganda. The school now serves as a model where students, teachers, and par-ents from other school districts learn about lightning safety. Bottom: A community member digs a trench around the Palabak school in Uganda. The trench will hold a cable attached to conductors running up the building to a lightning rod on the roof. When lightning hits the school, the electricity will be channeled down into the trench to dissipate. Credit: ACLENet

But it’s the final mechanism that’s responsible for half of all people killed or injured through lightning: ground current. That is largely the challenge in Africa, where many buildings still have dirt floors, and schools are collections of unsafe buildings in close proximity. In the United States, it’s extremely rare for more than one person to be killed by a single strike; in Africa, it’s not uncommon for groups of 10 or more people to be killed while sitting together in a room—often children attending class.

Cooper and her team presented their data on the high incidents of lightning deaths of African schoolchildren at an international conference in 2014, urging the attendees to focus on safety in schools. The presentation fostered a partnership with German lightning protection company DEHN, and together, they developed a system that was first installed at Runyanya in 2016.

The system starts with a simple lightning rod. “There’s nothing that’s superior to the old-fashioned Ben Franklin lightning rod,” said Cooper. The building is then retrofitted with wires or metal fittings, and the system ends in a ground ring.

In Runyanya, community members were greatly involved with the project, using their farming tools to dig a trench about a half a meter deep around each building to bury cables, said Holle. “When the lightning hits the building, it comes down the conductors and goes directly into the ground, into this long loop around the building, and dissipates.” It took about 3 days to retrofit all six Runyanya buildings plus a local church.

ACLENet has now protected six schools around Uganda and is currently negotiating some plans with the government to increase and better fund these efforts, including developing workshops in lightning safety building codes for engineers in Africa.

Big Questions Remain on the Big Spark

A better understanding of the mechanisms of lightning itself can better support prediction and mitigation efforts on the ground, researchers say.

This figure shows the time development of a lightning flash as observed by the Lightning Mapping Array (left) compared to an image from a high-speed camera. The arrows show the direction of propagation of the observed lightning channels, with blue indicating earliest in time and red, the latest. The gray shaded area shows the field of view of the camera. Credit:Kotovosky et al., 2018

“Lightning is just a big spark,” said Bill Rison, a research professor at Langmuir Laboratory for Atmospheric Research at the New Mexico Institute of Mining and Technology in Socorro. “You can measure sparks quite well in the laboratory.” But when researchers compared lab conditions to measurements taken by balloons or aircraft inside storms, he said, “you find that the electric field in the thunderstorm is about an order of magnitude smaller than it would take to generate a spark in the laboratory.”

In 1996, Rison was flying back with his colleagues from AGU’s Fall Meeting in San Francisco when they had a bit of an epiphany. They had been working with NASA on a novel very high frequency (VHF) detection system at Kennedy Space Center in Florida that could map lightning flashes in 3-D. But the cost was exorbitant—about $1 million for each of 10 stations. The key to this kind of instrument is highly accurate timing, and highly accurate GPS technology was just becoming available.

These new GPS-based 3-D instruments that make up the Lightning Mapping Array (LMA) cost about 5% of the original NASA stations, which meant Rison’s New Mexico Tech team could deploy them all over. [Rison et al., 1999] Today, there are about 15 of these arrays around the world, and the data they produce are “supercool,” said Vaisala’s Ryan Said. “There are some things we can’t measure,” referring to the NLDN. Unlike radio detectors, VHF instruments can measure all the very small electric discharges that a flash produces to create that detailed 3-D structure. “It’s remarkable,” said Said. “The amount of intuition we have from this research into lightning flashes is ridiculous.”

Vaisala engineers install a precision lightning sensor using a solar panel for power in Australia. The sensitive antennas under the white dome detect powerful radio bursts from lightning. The electronics in the enclosure dig-itize, process, and transmit these signals to a central server in real-time. Credit: Vaisala

Lately, Rison’s team has been working in collaboration with the University of Utah, which runs a cosmic ray observatory. Thunderstorms can produce gamma rays, as NASA discovered in the early 1990s, and the Utah team was seeing these terrestrial gamma rays in their data. The New Mexico team already had an LMA in the area, “so now we could actually see characteristics of lightning that were producing the terrestrial gamma ray flashes,” said Rison [e.g., Abbasi et al., 2018]. In 2017, researchers in Japan used instruments outside a nuclear power plant to detect what’s called the relativistic runaway electron avalanches produced by the strong electrical fields in a storm. [Enoto et al., 2017] “Lightning is actually a slow nuclear reactor,” said Rison; his team is working on a new paper from the Utah observations that will offer “more details with exactly what processes of lightning are to generate the terrestrial gamma ray flashes.”

A Second Golden Age

When Chris Schultz looks around at the field of lightning study today, he sees immense progress. “We have a lot of new instrumentation that’s come online in the last 2 years, so we’re trying to integrate all that new information and build a better picture of how that lightning is forming and how it begins in the cloud,” he said.

When Ashley Ravenscraft looked back at the stats for the eight tornados that touched down in northern Alabama in December 2019, she found “we were giving 30 to 45 minutes of lead time” through tornado warnings that told local residents to get to safety. “It tears me up that we had two fatalities, but to not have more is a step in the right direction.”

As researchers build that better picture—through the NLDN and GLD360, through optical images obtained by the GLM in low-Earth orbit, through 3-D lightning mappers—the practical applications for how we protect our communities from dangers of lightning proliferate. Schultz concludes, “We’re in the second golden age of lightning measurement.”

Returning Lightning Data to the Cloud

Fri, 04/24/2020 - 11:59

Lightning Science Strikes Lightning Research Flashes Forward   Planetary Lightning: Same Physics, Distant Worlds   Returning Lightning Data to the Cloud   Understanding High-Energy Physics in Earth’s Atmosphere   Mapping Lightning Strikes from Space   New Study Hints at Bespoke Future of Lightning Forecasting   Students Launch Balloon-Borne Payloads into Thunderstorms   Investigating the Spark

This past December at AGU’s Fall Meeting in San Francisco, I presented a poster with not a shred of new science on it. Yet it might turn out to be the highest-impact presentation I’ve made.

With the poster, several colleagues and I introduced WALDO to the world. WALDO, or the Worldwide Archive of Low-frequency Data and Observations, is a large—and growing—trove of low-frequency (0.5 to 50 kilohertz) radio data collected over decades at sites around the world. Mark Golkowski of the University of Colorado Denver (CU Denver) and I jointly manage the database.

Such data have all kinds of uses in geophysics, including in lightning detection and characterization, remote sensing of ionospheric and magnetospheric phenomena, and detection of solar flares, gamma ray flashes, and gravity waves. Until recently, however, the data on WALDO have been amassed and stored mainly on tens of thousands of DVDs—and thus have been largely inaccessible to anyone interested in using them.

Our goal with WALDO is to transfer and organize these historical data, augmented with ongoing data collection, into a single, standardized cloud-based repository so that scientists today and in the future can access them and put them to use in studies of lightning, the ionosphere, the magnetosphere, space weather, and more.

The Science of ELF/VLF

Each of the millions of lightning strokes per day on Earth releases an intense, roughly 1-millisecond-long pulse of extremely low frequency to very low frequency (ELF/VLF) radio energy known as a sferic. These sferics reflect from the lower ionosphere (60–90 kilometers altitude) and off the ground, allowing them to travel—and be detected—globally. A handful of VLF receivers scattered around the globe can geolocate most lightning flashes with incredible kilometer-level accuracy [Said et al., 2010]. Sferic detection can also be used to characterize the electrical properties of the lower ionosphere between the source and a distant receiver.

A VLF/LF antenna stands mounted on the National Oceanic and Atmospheric Administration’s R/V Ronald H. Brown, while the ship was docked in Puerto Rico. Credit: Morris Cohen

Narrowband beacons used by the U.S. Navy, nominally for submarine communications, also transmit in the ELF/VLF frequency band, providing another means of ionospheric remote sensing. Although these messages are encrypted for security, the radio signals themselves are a useful ionospheric diagnostic that can be picked up anywhere on Earth. Changes in ionospheric conditions, namely, the electron density, manifest as changes to either the amplitude or the phase of received signals. In turn, the ionosphere can be used as a sensor to monitor all kinds of geophysical phenomena, including solar flares, electron precipitation from the magnetosphere, solar eclipses, lightning-related heating, cosmic gamma rays, gravity waves, and much more. Each of these phenomena disturbs VLF signals propagating under the ionosphere in different ways—affecting how quickly a disturbance begins and ends, for example—and these signatures allow them to be distinguished from one other. Some ionospheric disturbances are very reliable and repeatable, like the effect of the Sun rising and setting.

Studying ELF/VLF radio waves allows us to piece together mysteries of what happens during space weather events and geomagnetic storms.Some ELF/VLF energy also escapes into the magnetosphere (as lightning-generated plasma waves called whistlers), where it can interact with trapped energetic electrons in Earth’s radiation belt and trigger precipitation of electrons into the atmosphere. ELF/VLF waves are also generated and accelerated in the magnetosphere (as waves called chorus and hiss) as a result of wave-particle interactions and thus play a role in the dynamics of space weather at Earth. Studying ELF/VLF radio waves allows us both to study and better understand these processes and to piece together mysteries of what happens during space weather events and geomagnetic storms.

These uses of ELF/VLF data, reviewed by, for example, Barr et al. [2000], Inan et al. [2010], and Silber and Price [2017], have been developed since the late 1800s, when natural ELF/VLF signals could be heard coupling into long telegraph lines. But a number of other applications outside the traditional uses of ELF/VLF data have also popped up recently. For example, detection of objects inside metal boxes using ELF/VLF waves [Harid et al., 2019] could be used to discover a cache of guns hidden inside a shipping container.

In partnership with a cybersecurity research group at the Georgia Institute of Technology (Georgia Tech), colleagues and I are also using ELF/VLF data to boost the security of the power grid against cyberattacks, such as the major attack in Ukraine in December 2015 in which hackers disabled multiple electrical substations. ELF/VLF data detected by radio receivers can be used to monitor power grid signals for irregularities. These data are also littered with sferics from lightning flashes around the world, which arrive at receivers at quasi-random times as lightning occurs. Nature thus provides an effective and detectable random number generator that because lightning flashes cannot be predicted in advance, allows us to validate the integrity of other data detected by the receivers [Shekari et al., 2019].

Developing WALDO

The WALDO database—currently about 200 terabytes and growing daily—already contains or will soon contain data that could enrich studies of all of the above phenomena and applications. Much of the data were collected by Stanford University ELF/VLF receivers and, more recently, by new sites deployed by Georgia Tech and CU Denver. .

This map shows a selection of VLF antenna sites that have, or still are, collecting data included in the WALDO database. Credit: Morris Cohen

. WALDO also includes ELF/VLF recordings from experiments carried out as part of the High-frequency Active Auroral Research Program (HAARP) in Alaska [Cohen and Golkowski, 2013], which has been running experiments to study the high-latitude ionosphere since the mid-1990s. It includes many years of data from Palmer Station on the Antarctic Peninsula. And it will eventually include a lot of data from the famous Siple Station ELF experiment, which ran from 1973 to 1988 to study the amplification and triggering of ELF signals in the magnetosphere using a 42-kilometer antenna in Antarctica. By the end of the year, we anticipate having 500–1,000 terabytes of data available.

We have developed an online interface that allows easy access to the data. Through the website, users can view automatically generated quick-look plots to make it easy to find out what’s available.The effort to compile these disparate data sets into a single database began in fall 2018, when the space at Stanford University where these data were physically stored—on roughly 80,000 DVDs and CDs and on one badly corrupted server—had to be cleared. The disks, some of which were damaged after decades of storage, were packed and shipped to either Georgia Tech or CU Denver, where DVD-reading robots that can rip a stack of 300 disks at a time are used to move the data onto hard drives. Meanwhile, John DeSilva at Stanford has slowly extracted the contents of the old server and placed those data into temporary cloud storage for us to retrieve.

After retrieval, the data are passed through a digital sorting scheme that updates the formatting so it is all consistent and then places the data into sorted folders. We have developed an online interface that allows easy access to the data, which can also be shared with anyone with a Google account upon request. Through the website, users can view automatically generated quick-look plots to make it easy to find out what’s available, for example, maps of receiver sites from which data from a given day are available, annual calendars showing data availability, and summary charts of the data on a day-by-day basis.

The Value of Dusty Data

The work of preserving data is hard and time-consuming but also rewarding. We have seen evidence of this in many fields. Historical and long-term data sets have been critical in studies of climate and ecosystems, for example, shedding light not only on past conditions but also on the present and future. And thanks to preservation efforts, we are fortunate to have sunspot data extending back more than 400 years—data that underlie critical early discoveries of space weather dynamics.

As a junior at Stanford in January 2002, I approached one of my professors, Umran Inan, and asked whether I could get involved in research. I suspect he wasn’t anticipating much from a student who had just gotten a C in his class. Days later I found myself in a dusty, nearly abandoned warehouse near the Stanford Dish, rummaging through 15-year-old Betamax and Ampex magnetic tapes filled with ELF/VLF radio data. The tapes were still stuffed in their original cardboard boxes and were lined up on shelves stacked 5 meters high in several rows, each probably 30 meters long. Why was I there?

A very low frequency radio antenna sits atop a glacier in 2006 (top) near Palmer Station on the Antarctic Peninsula (bottom). Credit: Morris Cohen (top); Christopher Michel (bottom), CC BY 2.0

In 1994, bursts of high-energy gamma rays called terrestrial gamma ray flashes (TGFs) were discovered serendipitously from space [Fishman et al., 1994]. It appeared that TGFs originated with lightning, but that was pretty much all we knew about them. ELF/VLF data can be used to characterize the lightning that caused the phenomenon, but scientists had only two examples in hand of TGFs that could be directly linked with lightning via ELF/VLF data. My job was to find more examples hidden in the data on all those tapes.

As I coughed away the cobwebs, I thought about all the trouble people had gone through to keep these Betamax tapes (long an obsolete format even by then) flowing. The data I was looking through were recorded at Palmer Station, Antarctica, by a receiver mounted on a shifting glacier that was carefully watched by a full-time science technician and serviced every year by a student in the group. With each boat trip from the station, the tapes were shipped out in large boxes, then stacked and stored in this rodent-infested space—all funded by American taxpayer dollars via the National Science Foundation. And this sort of data collection had been going on for decades at sites all over the world maintained by this research group.

Living Data Sets

I learned that geophysical data sets are living and that their intellectual value shifts as our scientific priorities do.“Was it worth it?” I thought while slogging away in that warehouse. The answer, as I came to find out, is an unequivocal yes (and not just because these data led to my first peer-reviewed research papers and helped me get my foot in the door of research). I learned that geophysical data sets are living and that their intellectual value shifts as our scientific priorities do.

When the measurements recorded on those Betamax tapes were obtained, no one envisioned eventually needing them to study TGFs; the measurements were originally collected for other reasons. It would have been easy to throw the data away before they proved useful for studying TGFs—or even after that too. Following the use of Betamax tapes, we shifted to recording digital data on CDs, then on DVDs, then on external hard drives, then onto a large data server—and now we’re moving them into the cloud. At every step, we had to drag all the accumulated data from old media into the present day. But because these data haven’t been discarded, they are still available today for studying numerous natural phenomena and processes.

It’s fair to ask whether it’s worth it given the expense and effort. I think it is. You never know how these data might be used. I would have never expected geophysical lightning data to make an impact in the cybersecurity world, for example. Today we are seeing high-performance computing and machine learning reveal new insights from old data, and interdisciplinary projects often find surprising uses for historical data sets. In the not-too-distant future, I suspect someone will think of a new way to look at ELF/VLF data collected a decade ago. But will the data still be available?

We owe it to future scientists—and to U.S. taxpayers, who have funded much of this work—to ensure that they are available. Since announcing WALDO in December, we’ve gotten several inquiries and notifications from people using the database. Our hope is that by preserving these data in WALDO, we will open doors for surprising and unexpected discoveries.

Investigating the Spark

Fri, 04/24/2020 - 11:55

Lightning Science Strikes Lightning Research Flashes Forward   Planetary Lightning: Same Physics, Distant Worlds   Returning Lightning Data to the Cloud   Understanding High-Energy Physics in Earth’s Atmosphere   Mapping Lightning Strikes from Space   New Study Hints at Bespoke Future of Lightning Forecasting   Students Launch Balloon-Borne Payloads into Thunderstorms   Investigating the Spark

“There’s a term in French that describes falling in love at first sight: coup de foudre,” said Yoav Yair. “Literally translated, it means ‘bolt of lightning.’” Yair is the dean of the School of Sustainability at the Interdisciplinary Center Herzliya in Israel and Eos’s Science Adviser for AGU’s Atmospheric and Space Electricity section. “This is how I felt about atmospheric electricity when I started my master’s degree at Tel Aviv University back in the 1980s: instant fascination, deep curiosity, and a desire to know more.”

I was excited when Yair suggested that we cover lightning in our May issue of Eos. As a magazine editor, I certainly think you can’t beat the photography, but more than that, I was intrigued by the number of questions that remain about this phenomenon nearly all of us have grown up experiencing, watching from our windows as storms roll in. “Lightning is indeed beautiful, dangerous, and multifaceted, and it hides a lot and reveals a lot. And although it has been known to humanity for millennia—feared and worshiped—we still don’t fully understand it,” explained Yair.

Chris Schultz of NASA’s Short-term Prediction Research and Transition Center assures me we are living in a “second golden age” of lightning observations. In “Lightning Research Flashes Forward,” meteorologist Ashley Ravenscraft explains how she uses data recently made available to the National Weather Service from the Geostationary Lightning Mapper on board the GOES-R satellite that show the rate of lightning strikes in an area. She uses these data—sometimes these data alone, when necessary—as a proxy to predict tornadoes and issue warnings to the nearby Huntsville, Ala., community. Like so many meteorologists, she got into the field to save lives, and with this new information, she’s giving her neighbors sometimes as long as 45 minutes to get to safety.

“In recent decades, we have made tremendous progress and devised sophisticated ways to decipher lightning and its associated impacts on the atmosphere,” said Yair, “here on Earth and also on other planets.” In “Planetary Lightning: Same Physics, Distant Worlds,” we take a trip through the solar system to investigate why lightning is pervasive on Jupiter, how Neptune and Uranus are similar in so many ways except in generating lightning, and, in this case and so many others, why Venus is just so weird.

Finally, where are all these lightning data when you need them? Morris Cohen, professor of electrical engineering at Georgia Institute of Technology (and president-elect of AGU’s Atmospheric and Space Electricity section) tells us about WALDO—the Worldwide Archive of Low-frequency Data and Observations—in “Returning Lightning Data to the Cloud.” He and a colleague manage this database of radio measurements meant to facilitate research not only in lightning but also in space weather, terrestrial gamma rays, and gravity waves, among other phenomena.

“As our society becomes more technological, urban, [and] densely populated, and as our climate is changing, we need to know what lightning will be like in the future,” said Yair. We hope our coverage this month gives you some idea of how lightning affects us, as well as of the interdisciplinary nature of the exciting science questions it presents.

—Heather Goss (@heathermg), Editor in Chief

How to Turn Our Cities Into Treetopias

Thu, 04/23/2020 - 15:34

The 21st century is the urban century. It has been forecast that urban areas across the world will have expanded by more than 2.5 billion people by 2050.

The scale and speed of urbanization has created significant environmental and health problems for urban dwellers. These problems are often made worse by a lack of contact with the natural world.

With research group the Tree Urbanistas, I have been considering and debating how to solve these problems. By 2119, it is only through re-establishing contact with the natural world, particularly trees, that cities will be able to function, be viable and able to support their populations.

Future Cities

The creation of urban forests will make cities worth living in, able to function and support their populations: Treetopias.

This re-design will include the planting of many more urban trees and other vegetation—and making use of new, more creative methods. Although we didn’t fully realize it at the time, the 1986 Hundertwasserhaus in Vienna, a building that incorporated 200 trees in its design, was the start of more creative urban forestry thinking.

The urban forest needs to be designed as a first principle, part of the critical infrastructure of the whole city, not just as a cosmetic afterthought.This has been carried on in Stefano Boeri’s Bosco Verticale apartments in downtown Milan, which incorporates over 800 trees as part of the building. Similar structures are being developed around the world, such as in Nanjing in China and Utrecht in The Netherlands.

The urban forest needs to be designed as a first principle, part of the critical infrastructure of the whole city, not just as a cosmetic afterthought. We know for example that in 2015, urban forest in the United Kingdom saved the National Health Service over £1 billion by helping to reduce the impact of air pollutants. In 2119, we may well look back on this present time as the equivalent of the Victorian slum.

Trees can create places which can greatly improve our health and well-being. Our urban forest can give us the spaces and places to help manage our mental health and improve our physical health. Research has indicated for example that increasing the canopy cover of a neighborhood by 10% and creating safe, walkable places can reduce obesity by as much as 18%.

Cities Built on Trees

As rural areas become less productive as a result of climate change, cities—which previously consumed goods and services from a large hinterland—will have to become internally productive. Trees will be at the center of that, contributing to the city energy balance through cooling, regulating and cleaning our air and water flows, and ensuring that our previously neglected urban soils function healthily.

Urban forests could also provide timber for building. We have a history of productive woodlands in the United Kingdom, yet alternative construction materials and a growth in an urban population with less knowledge of forest management means that the urban forest is rarely viewed as productive. We are now recognizing the potential productivity of the urban forest, as campaigns to stimulate homegrown timber markets and achieve more efficient management efficiencies are proving to be successful.

Furthermore, economic growth is still deemed to be the prime symbol of the effectiveness of a city, but we need to be equally aware of other invisible values. This will open up new approaches to governance. Governance needs to embrace all forms of value in a balanced way and facilitate a new vision, considering how trees can help create liveable cities.

New Opportunities

As the urban population rises, we need to get better at understanding the breadth and diversity of the values held about our urban forest. Individual people can hold several distinct values at once, as urban forests may contribute to their wellbeing in different ways.

We need to develop viable partnerships between tree managers, community members and businesses to support trees in our cities.The current guardians of our urban forest, mainly local authority tree officers, spend much of their time managing risks rather than maximizing the opportunities of trees. They often receive complaints about trees and tree management, and it can sometimes be difficult to remember that people do care about trees. We need to develop viable partnerships between tree managers, community members and businesses to support trees in our cities.

Although the canopy cover of cities worldwide is currently falling, this is not the case in Europe, where it is increasing. Many European countries are acknowledging the fact that we have over-designed our towns and cities to accommodate the car, and now it is time to reclaim the public realm for our people—either pedestrians on foot or on bicycles.

Creative developments like the Hundertwasserhaus are not the only answer to creating Treetopia. We are and will continue to plant more street trees, urban groves and informal clusters of trees in our parks and green spaces. Treetopia has begun.

—Alan Simson, The Conversation (UK)

This story originally appeared in The Conversation (UK). It is republished here as part of Eos’s partnership with Covering Climate Now, a global journalism collaboration committed to strengthening coverage of the climate story.

How Fast Did an Ancient Martian Delta Form?

Thu, 04/23/2020 - 13:45

An ancient river delta is the target of the next Mars rover, chosen because it will provide insight into early Martian climate and, perhaps, yield organic material. Lapôtre & Ielpi [2020] have adapted a model calibrated from meandering rivers on Earth to determine how long it took this Martian delta to form. They conclude that, at minimum, only a few decades were required. This timescale is consistent with the idea that ancient Mars was mostly cold and dry, with brief intervals of more clement conditions and surface water flow arising from meteorite impacts or volcanic emissions. They also argue that the relatively rapid sediment emplacement makes burial and preservation of organic materials quite likely. With luck, the rover — Perseverance — will test these predictions in the near future.

Citation: Lapôtre, M. & Ielpi, A. [2020]. The pace of fluvial meanders on Mars and implications for the western delta deposits of Jezero crater. AGU Advances, 1, e2019AV000141. https://doi.org/10.1029/2019AV000141 

—Francis Nimmo, Editor, AGU Advances

Predicting the Future of Greenland’s Melting Ice Sheet

Thu, 04/23/2020 - 12:11

Climate change drives increased melting of glaciers around the world, including about 280 glaciers that drain ice from Greenland’s massive ice sheet through deep fjords into the ocean. Greenland’s ice has the potential to increase global sea level by more than 7 meters, but the exact effects and their timing are difficult to predict.

In a new review, Catania et al. synthesize recent progress and highlight ongoing challenges in understanding and forecasting the future of Greenland’s ice sheet–draining glaciers. They emphasize that a deeper understanding is needed to predict not just the resulting sea level rise but impacts on ocean circulation and other ocean properties, nutrient cycling, and ecosystem functioning—from local to global scales.

Advances in computational modeling and observational capabilities, especially via aircraft and satellites, have greatly improved knowledge of the interconnected processes that underlie depletion of the Greenland ice sheet. For example, scientists now know that meltwater from the surface of a glacier flows under the ice and promotes submarine melting where the glacier meets the sea.

Much of the uncertainty in predicting the future of Greenland’s ice arises from the difficulty of observing and modeling complex links between processes that occur where ice meets atmosphere, ice meets ocean, or ice meets land. Models must account for numerous factors at varying spatial and temporal scales, including ocean temperature, the shape and depth of fjords, iceberg calving, shifts in global climate, local weather patterns, and many more.

The researchers recommend several courses of action to address these uncertainties. They stress the need for improved technology to conduct long-term observations at the boundaries between ice and ocean and between ice and land. They also call for stronger links to be made between models of glaciers and models of the atmosphere and ocean.

To accomplish these goals, the authors say, glacier researchers should strive to make their data and visualizations easily accessible for colleagues and stakeholders. They also recommend efforts be made to increase diversity within the community of researchers studying Greenland’s ice and to expand collaborations with researchers from other fields as well as with representatives from Greenlandic communities. (Journal of Geophysical Research: Earth Surface, https://doi.org/10.1029/2018JF004873, 2020)

—Sarah Stanley, Science Writer

Oktoberfest’s Methane Rise Is the Wurst

Thu, 04/23/2020 - 12:10

Millions of people convene at large festivals like Carnival in Rio de Janeiro and Dia de los Muertos in Mexico City. These gatherings are more than just wild parties or cultural heritage, however—they’re a rich trove of scientific data. Researchers now have calculated the methane emissions associated with Oktoberfest, a harvest celebration held in the fall in Munich, Germany. The scientists found that Oktoberfest’s area-normalized methane flux was about half that of an average dairy farm. Festivals—often unaccounted for in emissions inventories—can be significant, albeit temporary, sources of greenhouse gases, the team concluded.

Beer, Sausage, and Methane

“Festivals could be a notable methane source even though they have not yet been included in the existing emission inventories.”At Munich’s Oktoberfest, typically held over 16 days, revelers consume more than 8,000,000 liters of beer and copious amounts of grilled sausages, fish, and oxen. But the natural gas used to heat Oktoberfest’s massive tents and power its grills consists primarily of methane, which is a potent greenhouse gas: Kilogram for kilogram, methane traps roughly 30 times as much energy as carbon dioxide.

Jia Chen, an electrical engineer focused on environmental science at the Technical University of Munich, and her colleagues set out to quantify Oktoberfest’s methane emissions. “Festivals could be a notable methane source even though they have not yet been included in the existing emission inventories,” said Chen. “Oktoberfest is the largest folk festival worldwide.”

Many Rounds for Science

In 2018, Chen and her collaborators walked and biked around the 2.5-kilometer perimeter of the Oktoberfest site carrying portable methane sensors. The team made 94 rounds with the instruments, which were about the size of a backpack and weighed roughly 11 kilograms. “It’s good exercise,” said Chen.

The sensors determined gas concentrations by pumping air into a cavity and then measuring the attenuation of different wavelengths of laser light. The team combined these data with wind information to accurately estimate methane fluxes. “The higher the wind speed, the lower concentration we will measure because the methane is more diluted,” said Chen.

The researchers found that on average, about 7 micrograms of methane per second were being emitted from each square meter of the Oktoberfest premises. That’s significant and only about a factor of 2 smaller than the flux escaping from a dairy farm, the team noted. (Cows are notorious methane emitters, mostly because of their belches.)

Roughly 20% of these emissions can be ascribed to biogenic methane produced by attendees’ exhalations and flatulence, Chen and her colleagues calculated on the basis of published estimates. The remainder, the researchers suggest, likely derived from incomplete combustion in gas-powered heaters or cooking appliances. Chen and her collaborators also found that methane fluxes were higher on weekends when more visitors were in attendance. That’s not surprising, because these emissions are all anthropogenic in nature, the team concluded.

These results were published last month in Atmospheric Chemistry and Physics.

Allowed in the Next Time

In 2019, the researchers returned to Oktoberfest, this time on the actual premises. “We were allowed to go inside,” said Florian Dietrich, an engineer at the Technical University of Munich and a member of the team. “We went closer to the sources.”

“Studies like this help individuals understand their greenhouse gas footprint a little bit better.”This time, they made measurements with portable methane sensors and also collected air samples. Back in the laboratory, they determined the ratio of ethane to methane in the samples to shed light on the origin of the emissions—biogenic sources produce very little ethane, whereas fossil fuels (e.g., natural gas) typically contain ethane. The results are being prepared for publication.

“There are so many different sources of methane,” said Ben Poulter, a carbon cycle scientist at the NASA Goddard Space Flight Center in Greenbelt, Md., not involved in the research. “Studies like this help individuals understand their greenhouse gas footprint a little bit better.”

—Katherine Kornei (@KatherineKornei), Science Writer

Looking Back at Our Pale Blue Dot

Thu, 04/23/2020 - 12:08

The hunt for exoplanets has been remarkably successful. Over 4,000 have been teased out of the vastness of space, a feat that wows even the experts who know how to pull it off.

However, as of 13 April, roughly 4% of exoplanets found are likely terrestrial, meaning only a small fraction of them are similar in size to the rocky inner planets of our solar system, including Earth. Future tools like the James Webb Space Telescope (JWST) and the Extremely Large Telescope (ELT) should allow researchers to resolve these smaller celestial bodies with higher precision. In the meantime, researchers are working to match this future experimental power with similarly strong theoretical tools.

Recently, a team of planetary scientists from the Carl Sagan Institute at Cornell University in Ithaca, N.Y., led by Lisa Kaltenegger, published models of how Earth would have looked to distant observers over its geologic history. The researchers outlined their results in a paper published in the Astrophysical Journal Letters. The data, available online, will allow future telescopes to zero in on signals from Earth-like planets and bring an entire network of as-yet-unknown exoplanets to life.

Spectroscopic Fossils

Ever since Carl Sagan peered back at Earth in the early 1990s through the eyes of Voyager 1, exoplanet researchers have used our home as the ideal reference point for what to look for outside the solar system. Years of scrutiny have yielded detailed atmospheric models and spectra of our modern Earth. But would an exoplanet researcher on another planet in a galaxy far, far away see the same data?

“Even though extrapolations from our findings suggest that one out of five stars hosts a planet which could be like Earth, it would be extremely surprising if all of them were at our Earth’s evolutionary stage.”“Even though extrapolations from our findings suggest that one out of five stars hosts a planet which could be like Earth, it would be extremely surprising if all of them were at our Earth’s evolutionary stage,” said Kaltenegger. “So taking Earth’s history into account to me is critical to characterize other Earth-like planets.”

Drawing on previous studies of her own and by other researchers, Kaltenegger and her team produced transmission spectra, records of the chemical signatures of a planet’s atmosphere as it passes in front of its star, for five epochs throughout Earth’s geologic history. These epochs represent Earth’s evolution from a prebiotic, low-oxygen, Archean world to an oxygen-rich planet teeming with life.

Earth’s chemical signatures have been in constant flux as land cover, vegetation, temperature, and many more variables have changed over geologic time. Some of these chemicals, most notably oxygen (O2) and methane (CH4), can be used as signs of life, or biosignatures. “This combination of gases is currently our most robust sign of life in a planet’s atmosphere,” Kaltenegger said.

Broadening Other Horizons

Measuring biosignatures like O2 and CH4 in the atmosphere of a rocky exoplanet would be a significant achievement in astronomy. Timothy Lyons, a professor at the University of California, Riverside and a member of the NASA Astrobiology Institute not involved in the new study, leads a research group that studies how detectable certain compounds would have been in the early history of life on Earth. “In many cases, the concentrations may have been too low in the atmosphere—giving rise to the concept of the false negative,” he noted. The opposite concept, in which detected concentrations of O2 and CH4 result from abiotic processes instead of life, is known as false positives.

Another uncertainty, found within the modeled spectra themselves, lies in the relationship between the spectral signatures for CH4 and water (H2O). Zifan Lin, an undergraduate research assistant associated with the study, found significant overlap between these two molecules in the spectra, suggesting that researchers should “beware” that water features they see could partially stem from CH4.

Nevertheless, these difficulties benefit the research community by forcing a certain degree of creativity and flexibility. Jack Madden, a graduate student associated with the study, works on expanding our theoretical models to explore what makes a planet habitable. In addition, Earth-like planets found using these new spectra will broaden our understanding of planetary evolution in new ways.

“I think that finding other planets like ours will give us fascinating insights into how Earth-like planets evolve,” said Kaltenegger.

—Christian Fogerty (@ChristianFoger1), Science Writer

How Earth Day Lost Its Way

Wed, 04/22/2020 - 16:00

If you ask Adam Rome, Earth Day isn’t as punk as it used to be.

“Earth Day is so tame nowadays,” says Rome, the author of The Genius of Earth Day: How a 1970 Teach-In Unexpectedly Made the First Green Generation. “For adults, it’s often a trade show where you can see the latest green stuff, and for kids it’s often a day with some corporate-sponsored lesson about what you can do individually to save the planet.”

But the first Earth Day in 1970, Rome says, was an “intense” day of protest and activism for the 20 million people who participated. “It was a day to ask soul-searching questions about why we had environmental problems,” Rome says.

It’s not just Rome who sees a short-sightedness in the way we mark Earth Day today. For Elizabeth Yeampierre, a Puerto Rican attorney and the executive director of Brooklyn-based community organization UPROSE, Earth Day is merely one marker in a long global history of environmental injustice.

“When you talk about Earth Day, for us, it’s not 50 years, it’s 500 years of extraction, it’s 500 years since slavery, since colonialism,” she says. “And in those 500 years, our communities have managed to survive all of it. Now we are faced with the consequences of those 500 years.”

For better or worse, Earth Day is the closest that the modern environmental movement has to a birthday: a time to celebrate milestones, to look back and plot a way forward. And as Earth Day has morphed since its inception, this year promises to be radically different. The surge of energy from youth activism over the past few years has been impeded by the coronavirus and bans on in-person gatherings. Organizers are hoping that the energy of the original Earth Day can take hold with a new generation grappling with a rapidly changing world.

A Green Revolution

Environmental protections in the United States essentially did not exist 50 years ago. Before the 1970s, industries of all types were allowed to pollute with little to no oversight, and Americans were largely in the dark about the impact air and water pollution could have on their health.

Prior to the first Earth Day, people across the country were disturbed by a 1969 oil spill in California, and their environmental consciousness was beginning to be raised, thanks in part to Rachel Carson’s seminal 1962 book Silent Spring. Then, in 1970, Senator Gaylord Nelson, a Democrat from Wisconsin, recruited grassroots organizers across the country to coordinate events on a single day—April 22—to educate the public on environmental issues.

“The original founders of Earth Day literally borrowed pages from the then-happening civil rights movement to engage in righteous civil disobedience, righteous group mass action, to have humanity look at environmental degradation and the degradation of lives of individuals.”The scale of the organizing effort involved in the first Earth Day was massive, but Earth Day didn’t happen in a vacuum. The year 1970 came after a tumultuous decade of social upheaval and change, with the Vietnam War mobilizing thousands of young people to speak out; second-wave feminism bringing women out of the home and into the workforce; and the civil rights movement providing a model for what a nationwide environmental organizing effort could look like.

“The original founders of Earth Day literally borrowed pages from the then-happening civil rights movement to engage in righteous civil disobedience, righteous group mass action, to have humanity look at environmental degradation and the degradation of lives of individuals,” Aaron Mair, the Sierra Club’s first black president, told The New Republic in 2017.

The result was a resounding success. Environmental safeguards that we consider basic today—the Environmental Protection Agency, the Clean Air and Water Acts, the Endangered Species Act—came about following the massive impact of the early-1970s movements.

According to Rome, Earth Day also gave rise to the formation of robust “eco infrastructure” around protecting the environment. Activists involved in the early movement went on to create new careers to protect the changes they’d made and continue pushing for more—as environmental lawyers, lobbyists, nonprofit leaders, professors. Newspapers hired reporters to write about environmental issues. Green groups like the Sierra Club, now a household name, beefed up membership and bulked up their activism, while many others were born in the day’s aftermath.

For a moment in the 1970s, the future looked bright, inclusive—and green.

Going Mainstream

When Yeampierre joined UPROSE in 1996, she says she considered herself a social justice activist, and she had no history of working on environmental issues. But as young people in the community began telling her their concerns, she recognized common fights.

“They started talking to me about asthma, about truck traffic, about paint,” she remembers. “It became clear that if we couldn’t breathe, we couldn’t fight against bad policing.”

“We think that the environmental movement is sort of lefty, but a lot of environmental organizations are not self-identified as part of a broader progressive movement.”It may seem now as though community-based organizations like UPROSE, which started organizing around climate justice in the early 2000s, would be the natural heirs to the grassroots organizers behind the early Earth Day movement. But throughout the ’90s and the 2000s, many small organizations felt that the mainstream green conversation—which focused on sustainability, enacting bipartisan climate policy, and promoting climate science—left out the needs of justice activists.

Rome attributes much of this disconnect to the original Earth Day movement’s success. After agreeing to make changes to their business models to preserve the environment, companies began to recognize the financial cost of environmental regulations and push to have them relaxed. Ronald Reagan unleashed a wave of pro-business activity in the Republican Party, and the GOP took up the mantle of deregulation.

The “eco infrastructure” set up in the wake of Earth Day mobilized to save what their movement had created. With partisan divisiveness escalating, grassroots movements—including movements helmed by people of color—were left by the wayside as a more nationally oriented white, middle-class environmental movement took hold.

“The big green groups are always happy to have the help of somebody who’s not an environmentalist,” Rome explains. “A labor union wants to help them, great, but they’re not on the street picketing when labor goes on strike. We think that the environmental movement is sort of lefty, but a lot of environmental organizations are not self-identified as part of a broader progressive movement.”

Yeampierre says that big green groups—which have carried the national conversation, run the policy agenda, and received much of the green funding since Earth Day—have not only ignored activists of color but exploited them.

“The big greens always knew who we were because we got into fights about the distribution of resources, the distribution of power, how the big greens would sort of heavy-foot into our communities and undermine the work that we were doing, how they would supplant not only our leadership, but make it impossible for us to move the dial,” she says. “The culture of these institutions has been an extractive culture.”

What’s Next for Earth Day?

In late March, representatives from a coalition of grassroots green organizations held a press call to explain how the coronavirus crisis was changing their original plans for massive Earth Day demonstrations. Naina Agrawal-Hardin, a 17-year-old activist with the Sunrise Movement, sounded upbeat even as she acknowledged the huge changes taking hold.

The rapid global response to this health crisis shows that a similar mobilization is possible to address the climate emergency.The pandemic is a disaster, Agrawal-Hardin, says, but “is also a moment of opportunity and of hope of rebuilding our society into one that works for all people.” She emphasized the movement’s demands for a “short-term COVID response which will prioritize people over profits,” part of a longer-term plan to “deliver a just and livable future for my generation.”

Other youth climate activists, like Zero Hour’s Jamie Margolin, have pointed out that the rapid global response to this health crisis shows that a similar mobilization is possible to address the climate emergency. And they’re trying to lead the way.

In 2019, 4 million people around the world took to the streets during one week in September as part of the largest-ever climate mobilization. A generation increasingly anxious and outraged about climate change helped persuade Americans that preserving the environment was inextricably linked to social, political, and environmental justice—and that we don’t have a lot of time to figure out what to do about it.

Rome sees this kind of movement as returning to the spirit of the original Earth Day. “Now it’s often the local community groups that have the overwhelming focus on health” and justice, he says. “They live with the burden directly—they’re the ones getting asthma; they’re the ones getting cancer. In 1970, that was a major focus of a lot of Earth Day organizing, period.”

The coronavirus has cut millions of Americans off from health care, sources of income, community connection—all key elements that have traditionally enabled organizing to thrive.

Want to make Earth Day and other events more representative? We have some resources to support you:

Scientific Meetings for All Laying Proper Foundations for Diversity in the Geosciences What’s in a Seminar? Promoting Racial Diversity in Geoscience Through Transparency Building a Culture of Safety and Trust in Team Science

It’s a daunting moment for climate activists to overcome. But the pandemic, Yeampierre says, is a harbinger of a future marked by disastrous extreme-weather events, and it’s proof that we need to work toward environmental justice and preparedness right now.

“What do we do if a climate disrupts governance?” Yeampierre asks. “If climate disrupts all of our systems, how do we survive? How do we reclaim the traditions that were taught to us, so that we can create local livable economies, so that we can survive the impacts of what’s coming?”

—Molly Taft (@mollytaft), Teen Vogue

This story originally appeared in Teen Vogue. It is republished here as part of Eos’s partnership with Covering Climate Now, a global journalism collaboration committed to strengthening coverage of the climate story.

GeoGirls: Confidence Erupts from a Camp at a Volcano

Wed, 04/22/2020 - 12:08

At the culmination of an empowering weeklong experience, Elizabeth Urban was coconspirator of a quirky celebration—a geology dance party. “Instead of a disco ball, we had a petrographic microscope,” she said. Dancing to ABBA while admiring the projected cross-polarized light on the wall was just one of the memorable moments that Urban, now a University of Washington undergraduate student in Earth and space sciences, recalls from her time as a high school mentor at GeoGirls.

The camp, now in its sixth year, is staffed by working scientists, science teachers, and high school student mentors.Run by the Mount St. Helens Institute, the 5-day, 4-night volcanology and technology summer camp for middle school cis and transgender girls has 25 coveted spots for participants, allocated in a competitive application process each year.

GeoGirls is a collaboration between the Mount St. Helens Institute and the U.S. Geological Survey (USGS) Cascades Volcano Observatory, with support from universities, schools, agencies, and private companies. The camp experience, held each summer in the area affected by the 1980 eruption, is fully funded, allowing participation by girls who might never have been to camp before. GeoGirls cofounder Kate Allstadt said, “I really love that we are able to take anyone who seems like they might really benefit from it.”

Allstadt, a geophysicist at the USGS Geologic Hazards Science Center in Golden, Colo., cofounded the camp during her National Science Foundation postdoctoral fellowship. The camp, now in its sixth year, is staffed by working scientists, science teachers, and high school student mentors. The idea is to engage girls in understanding that female scientists are normal people with interesting lives, “not just nerds in white lab coats,” Allstadt said.

GeoGirls’ coveted 25 spots are open to all interested middle school cis and transgender girls. Credit: Sophia Grechishkin “Big Volcano Nerd” and Other Mentors

In her career with the USGS, Allstadt uses geophysics to model where landslides and liquefaction might happen after earthquakes. She traces her own start in science to two inspiring teachers, science and math camps, and visits to national parks. “I’ve visited a lot of amazing landscapes across our country,” she said. GeoGirls grew out of her vision to merge science mentorship with the beautiful landscape of Mount St. Helens.

Another of the scientists involved in GeoGirls is Angie Diefenbach, a geologist with the U.S. Agency for International Development (USAID)–USGS Volcano Disaster Assistance Program at Cascades Volcano Observatory in Vancouver, Wash. Diefenbach’s expertise is photogrammetry—creating 3-D models of terrain. During the 2019 GeoGirls camp, she led a challenge in which student participants worked in teams to design a device that could fly over and photograph the volcanic landscape.

The camp overlooks Mount St. Helens. Credit: Sophia Grechishkin

“They gave us a camera that could survey the pumice plains, and we had to come up with a way to suspend it from an air balloon, trialing different designs,” said Sophia Grechishkin, 13, who attended in summer 2019.

Upon arrival at camp, “I was really nervous,” said Grechishkin. She soon found the reception welcoming. “Right off the bat I made a lot of friends,” she said. Indeed, some of the girls become close friends, and networking between year cohorts created a hub of “strong women that help each other out,” Diefenbach says.

A transformation from nervous and uncertain to poised and confident is something GeoGirls science education manager Sonja Melander sees as a hallmark of the program. Melander, a self-identifying “big volcano nerd,” made a career shift from research to education after earning a master’s degree studying Italian caldera volcanism.

When talking about challenges and how to deal with them, “gender always comes up in a big way, whether it’s about being a woman in general or if it’s about nonbinary gender identity.”GeoGirls, explained Melander, creates a space where it’s okay to talk about challenges and how to deal with them. “Gender always comes up in a big way,” said Melander, “whether it’s about being a woman in general or if it’s about nonbinary gender identity.”

The program is valuable, she explained, because many participants feel overlooked in their regular settings. “There’s a big confidence gap,” said Melander. Geoscientists are often portrayed as “the stereotypical image of someone with a beard and a hammer—someone who [most girls] can’t quite relate to,” she said.

During their multiday experience with scientists, participants “see how awesome [the scientists] are in their careers and come to know them as a humans,” perhaps discovering a shared admiration for Harry Potter, for example.

Importance of Mentorship

Diefenbach wishes she’d had an opportunity like GeoGirls as a middle schooler. She credits her own interest in geology to a female mentor—her older sister, now a practicing geologist. “I didn’t really want to do the same thing as my older sister,” she said, but caved after exploratory university courses, realizing geology combined her love of the outdoors with science.

Among high-tech and low-tech activities, participants may get the opportunity to crawl through lava tubes. Credit: Sophia Grechishkin

At GeoGirls, working in small groups, the mentorship benefits are multifaceted. Middle schoolers benefit from high school mentors, who in turn benefit from mentorship by scientists and teachers. Urban is one of several former GeoGirls high school mentors now pursuing studies in geology.

Paralleling the program itself, during the impromptu dance party, where costumes ranged from dinosaurs to cavemen and knights, “the middle schoolers were a little more hesitant,” said Urban, “but they gradually broke out of their shells.”

Grechishkin, who described herself as “not really a nature girl,” summoned the courage to crawl through a lava tube and wade into ponds and rivers to sample volcanic sediments.

“Even if geology doesn’t end up being your career path…it will open you up to lots of different opportunities,” said Urban. So as advice for other girls considering the program, Urban said, “Absolutely do it! It’s kind of a once in a lifetime experience.”

—Lesley Evans Ogden (@ljevanso), Science Writer

How Financial Markets Can Grow More Climate Savvy

Wed, 04/22/2020 - 12:06

Energy investors looking to steel themselves against topsy-turvy market transitions could try something new: factoring extreme weather risks into their investments.

At present, financial markets may be failing to account for the physical risks of extreme weather from climate change. That’s a problem, according to Paul Griffin, an accounting professor at the University of California, Davis, because overpricing could lead to an extreme correction to the market down the road.

“If the market doesn’t do a better job of accounting for climate, we could have a recession—the likes of which we’ve never seen before,” Griffin said in a press release.

A market adjustment and reducing emissions are things “that will benefit generations beyond ourselves.”On the other hand, if markets do adjust and societies reduce emissions, “a couple of generations from now, we might have a more stable planet,” Griffin told Eos. “This is something that will benefit generations beyond ourselves.”

Although researchers are just starting to understand possible links between market pressures of the coronavirus crisis and the climate crisis, Griffin said that lessons learned may help with climate-related transitions. Crude oil prices plunged below zero this week, and the pandemic has revealed weaknesses in global supply chains.

But unlike the market’s “forward-looking” response to the pandemic, the costs associated with climate change “are far more distant,” and the markets have a “tough time” grappling with them, Griffin said. In the long-term, addressing climate risks “is much more important than what we’re going through now,” Griffin added.

Invisible Risks

Energy firms are at particular physical risk due to climate change, yet they’ve been slow to price these risks.

Many energy firms have infrastructure in vulnerable areas. The Gulf Coast, where numerous oil refineries are located, is facing rising seas and more extreme storms. Southern states are also seeing skyrocketing temperatures, which threatens worker safety. California and other western states are exposed to arid air and wildfires, causing power disruptions.

Investors and asset managers have been “conspicuously slow to connect physical climate risk to company market valuations.”Despite these vulnerabilities, investors and asset managers have been “conspicuously slow to connect physical climate risk to company market valuations,” Griffin wrote. Company stock prices do not reflect these risks, and it’s unclear whether insurance will provide cover. Future litigation could also prove costly.

“This is an issue that needs to be addressed, so the markets correct themselves in a reasonable or orderly basis,” Griffin said. If they don’t, a correction all at once “can be very horrific for markets.”

The Great Recession is the “best analogy” of the present situation, according to Griffin. A sudden correction to the market from unpriced risk in the subprime mortgages kicked off the financial crisis in 2007, which in turn triggered the Great Recession that rippled around the world.

Making a Shift

To avoid a large market correction from extreme weather impacts, investors need to pin down the exact risk from future events. Extreme weather risks pose a unique challenge for climate risk modelers because some investors normalize extreme weather impacts over time. Some emerging companies, like Jupiter Intelligence and Four Twenty Seven, could work to fill this gap, and others could work to make data digestible for investors and asset managers.

Recently, Norway’s Government Pension Fund Global divested part of their fossil fuel holdings, and the Saudi Aramco corporation began offering some public shares. “For investors and asset managers, the Norwegian and Saudi actions are a further sign of climate risk underpricing,” Griffin wrote in his comment in the journal Nature Energy earlier this year.

Jesse Keenan, an associate professor of real estate at Tulane University, said that the shift could help markets bear the risks of future transitions as well. “Advancing more disclosure on the physical risks (e.g., generation facilities, transmission equipment, etc.) could be catalytic for forcing greater analysis of the transition risks, which are closely interconnected,” noted Keenan.

Factoring climate change into market decisions is difficult, said Griffin, because “you’ve got these massive costs that are far more distant that the markets have a really hard time grappling with.” Moving forward will take both political will and a responsive judicial system to tackle the task, said Griffin.

—Jenessa Duncombe (@jrdscience), Staff Writer

This story is a part of Covering Climate Now’s week of coverage focused on Climate Solutions, to mark the 50th anniversary of Earth Day. Covering Climate Now is a global journalism collaboration committed to strengthening coverage of the climate story.

Building a Culture of Safety and Trust in Team Science

Tue, 04/21/2020 - 12:40

As scientists become part of larger teams and join broader and more diverse scientific endeavors, they must all become leaders in creating cultures of safety, inclusion, and trust.Some of the most scientifically exciting places are also some of the most difficult to study. The Arctic, for example, is rapidly changing, as evidenced by melting sea ice, thawing permafrost, disappearing glaciers, and greening hillslopes. Increasingly, scientists from around the world and across a wide spectrum of disciplines are working together to advance our understanding of this vulnerable and globally important biome.

As scientists become part of larger teams and join broader and more diverse scientific endeavors, they must all become leaders in creating cultures of safety, inclusion, and trust. Ideally, all participants on such teams, as well as local communities and other stakeholders, feel that their views, concerns, and efforts are acknowledged and respected. Such a culture facilitates the physical and emotional well-being of individuals in scientific teams and in the local communities where scientists work.

Here we share lessons learned from an “experiment within an experiment” begun as part of a large-scale, decade-long research project in Alaska. The experiment was focused on answering the question, How can we intentionally create a project-wide culture of safety, inclusion, and trust that facilitates strong cross-disciplinary collaboration and exciting scientific discoveries?

Who We Are and What We Do

Our team of more than 150 people includes empiricists, modelers, and data scientists from four U.S. Department of Energy National Laboratories as well as from the University of Alaska Fairbanks (UAF), all working together on the Next-Generation Ecosystem Experiments–Arctic (NGEE Arctic) project. Our overarching goal with the project, which began in 2012 and is now in its third phase, is to improve physical representations of the tundra in the virtual space of Earth system models that predict the future of the Arctic and the world.

During their first trip to Nome, Alaska, NGEE Arctic team members look at an areal map of the road system and surrounding vegetation and land features and discuss where they might focus their scientific endeavors. Credit: Roy Kaltschmidt, Lawrence Berkeley National Laboratory

NGEE Arctic team members make observations at field sites ranging from the wet, cold North Slope of Alaska to the warmer hillslopes that span the accessible road systems of the Alaskan Seward Peninsula. We work separately in smaller teams, fanning out across the tundra (or in the case of the modelers on the team, across the rugged terrain of computer clusters). We also come together for annual “all-hands” meetings to share our work and tend to our long-distance collaborations.

Since the project began, team members have published more than 200 papers and have released nearly 150 data sets. Equally as important, we have grieved together for lost loved ones and have joyfully celebrated the birth of 18 babies—these shared personal experiences have strengthened the professional relationships among our team members.

A Culture of Safety and Security

Many scientists work in remote places. These endeavors often require working for long hours in environments that include unique physical hazards.Many scientists work in remote places. They say goodbye to families; get on a plane, bus, or boat; and travel to patches of earth or water to collect data and make discoveries that advance our understanding of the natural world.

These endeavors often require working for long hours in environments that include unique physical hazards—as well as living for weeks or months in crowded spaces that often lack basic amenities. The NGEE Arctic team, underpinned by a strong safety culture at our national laboratories and our partner institutions, has made the safety of individuals and of the team its number one concern before, during, and after field and laboratory campaigns.

We do this by encouraging rigorous planning and continuous dialogue and by questioning our assumptions regarding team safety and security. Early in the project, we spent many hours discussing and developing a culture of safety, and we prioritized listening sessions with local Alaskan institutions (e.g., our partners at the University of Alaska Fairbanks) and scientific support groups (e.g., UIC Science in Utqiaġvik, Alaska), as well as Native corporations and the Indigenous community, to determine best practices and to learn more about the place they call home. We encoded these discussions into documents—short field and laboratory manuals, safety plans and checklists, and codes of conduct—that are required annual reading for our scientists and that established shared expectations across the team (and in some cases, these provided the foundation for improved culture at individual institutions). Our field manual covers topics ranging from using a buddy system and emergency communication devices to negotiating rough terrain, getting necessary permits, conducting daily safety and planning meetings, and the need for respectful interactions with the surrounding communities. Our laboratory safety manual covers the planning, preparation, and training needed prior to working in on-site laboratories, as well as chemical disposal and how to appropriately store and ship samples home. Safety checklists and codes of conduct are unique to each institution but set expectations for safe, secure, and successful science. Accompanying videos emphasize how to dress for the harsh environmental conditions of the Arctic and what to do if you encounter a bear (hint: it depends on the bear!). .

The scientific interests of the NGEE Arctic team range from geomorphology to greenhouse gas fluxes, from permafrost thaw to photosynthesis, from snow cover to shrubification, and from remote sensing to root-soil interactions. Credit: left: Roy Kaltschmidt, Lawrence Berkeley National Laboratory; middle and right: Stan D. Wullschleger, Oak Ridge National Laboratory

. In turn, each team member is empowered to freely voice his or her opinion, up to and including an emphatic “stop” if something doesn’t seem right. For instance, if a team member voices a safety concern, field work is immediately suspended until a solution is found. “Stop” can also mean discontinuing an escalating discussion or even canceling a series of sampling campaigns. For example, the leadership team recently made the difficult decision to suspend travel to Alaska given uncertainties surrounding the spread of COVID-19; we placed the safety of our team members and the surrounding communities where we live or work (especially those that may be particularly vulnerable) ahead of scientific observations.

Although the documents we created were an important part of the process, the enduring legacies are the adoption of a safety mindset that underlies all our work, a heightened understanding of the need for respect and common purpose, and a broad set of values endorsed by everyone.

Summarized, our values promote safe and harassment-free work environments, respect for local culture and knowledge of the environment in areas and communities where we are guests, and collaboration and open science.

A Safe and Harassment-Free Work Environment

Scientific discovery is increasingly facilitated by cross-disciplinary collaboration and the inclusion of scientists from diverse backgrounds, but fostering these positive attributes in teams requires a culture in which all voices are welcomed and respected. To achieve this goal, the leadership team, along with the team members within each of the major project tasks, frequently talks about how to achieve a safe, secure, diverse, and inclusive science environment.

We realized that we needed to be more transparent in our decision-making, more explicit in valuing and empowering each team member, and more inclusive in the voices chosen to guide the scientific conversation.The leadership team has learned to listen when team members suggest improvements in culture and attitude. For example, we realized that we needed to be more transparent in our decision-making, more explicit in valuing and empowering each team member, and more inclusive in the voices chosen to guide the scientific conversation at our annual meetings. We grew to realize that uncomfortable conversations are an opportunity to grow as a team rather than something to be avoided.

Even so, there have been rare instances of inappropriate behavior in our remote field settings. Some examples include inappropriate conversations or crude humor during field work, actual or perceived bullying among team members, and unwanted sexual advances or innuendos from local residents or scientists involved with other projects. These instances are recognized, acknowledged, and handled immediately.

Issues are resolved over the phone, through in-person discussions upon return from the field, or, in extreme cases, through removal from the field. Leadership has also recognized the importance of including the injured party in decisions made to resolve a bad situation. And when appropriate and safe, we have found that the team leader or another member of the leadership team can facilitate group discussions while scientists are still in the field to help to resolve potential interpersonal conflicts and restore and strengthen trust.

We further recommend that project safety protocols explicitly address workplace harassment and bullying. Protocols that clearly address these issues were highlighted by a National Academies of Sciences, Engineering, and Medicine report about combating sexual harassment and have been developed for other situations where scientists are working in close proximity at remote locations.

We Are Guests in the Arctic

It is important that we tread lightly in these communities where we are privileged to be guests and that we conduct ourselves and our science in ways that are both ethical and inclusive.As the Arctic thaws at a worrying rate, Indigenous and other local communities are visited by increasing numbers of scientists, entrepreneurs, and businesses from warmer climates. It is important that we tread lightly in these communities where we are privileged to be guests and that we conduct ourselves and our science in ways that are both ethical and inclusive.

Prior to the development of scientific research plans for the NGEE Arctic project, team members spent time with the local and Indigenous communities and Native corporation land holders to better understand their intimate knowledge of the natural processes in their world, the areas of land available for scientific endeavor and the permits needed to work in those areas, and how we could communicate our findings to the local community. In the years since, we have participated in community outreach by giving talks and teaching workshops or classes, participating in local science fairs, and providing annual reports to the Native corporations who provide us land use permits. .

The first annual “BARC-becue”—a combined barbeque and science fair—was hosted by UIC Science at the Barrow Arctic Research Center (BARC) building to facilitate interactions among scientists and local and Indigenous communities in Utqiaġvik, Alaska, in 2018. Credit: Ravenna Koenig/KTOO

. Recently, we invited an Indigenous Knowledge holder, Kaare Erickson of UIC Science, to speak at our annual all-hands meeting. He gave us a history of Indigenous communities in Alaska from “time immemorial” and suggested ways to improve our interactions with local and Indigenous communities. An overarching message was that Indigenous Knowledges and Western science are complementary and not competing and that Western scientists should engage Indigenous Knowledge holders before, during, and after each scientific endeavor. Echoing these conclusions, we recommend early and frequent engagement with local communities.

Prioritizing Collaboration and Open Science

The increasingly cross-disciplinary and global nature of scientific collaborations requires new ways of communicating. At the outset of our project, our sponsor in the U.S. Department of Energy’s Office of Science set an expectation for ongoing and iterative cross-disciplinary collaboration between empiricists making observations in the field and in the laboratory and the modelers encoding those hard-won observations into mathematical algorithms that improve physical representations of the tundra in Earth system models.

Over time, this model-experiment interaction philosophy has become central to the way we think, plan experiments, and communicate findings. Modelers are embedded within teams addressing overarching science questions, and they often travel to the field, where they learn firsthand the complexity of natural ecosystems and the importance of good boots and duct tape. In turn, empiricists have learned to speak the mathematical language of models and are helping to guide the development of next-generation models that more faithfully simulate the processes they study.

The NGEE Arctic team is a cross-disciplinary team of empiricists, modelers, and data scientists. Each of these circles represents one member of the NGEE Arctic team; the size of the circle indicates the number of publications associated with an individual team member, and the lines between circles show the connections through coauthorship. Team members coalesce into disciplinary clusters (different colors) but integrate with others across the project. Credit: Stan D. Wullschleger, Oak Ridge National Laboratory

Furthermore, across the project, we respect and value intellectual input, whether it comes from summer students or senior scientists, and we facilitate cross-project interactions in monthly conference calls. Our annual all-hands meetings feature a variety of brief “lightning” talks in which students and scientists speak about their individual research projects in formats ranging from 2-minute sales pitches, to 5-minute “Ignite” presentations featuring quick-hitting slides, to “Up-Goer Five” descriptions in which speakers only use the most common words in the English language to describe their work. We also hand out awards for safety and data contributions, and host “Arctic cafe” roundtables, small group discussions where team members shuffle among tables to encourage all voices to be heard and new ideas to be considered. These activities both communicate our science and celebrate our scientists.

We underpin these new and nurtured collaborations with a philosophy of open science. Data are immediately available to other scientists within the project. Then, when the data are published, they become freely available to scientists and citizens around the world.We underpin these new and nurtured collaborations with a philosophy of open science. Data, once collected, are immediately uploaded to a data portal where they are available to other scientists within the project. Then, when the data are published, they become freely available to be used by scientists and citizens around the world.

We implemented a required project-wide data sharing policy very early in the project, but we were slow to recognize the way in which it could facilitate trust and collaboration among team members. For example, our data portal, which was built by our project data scientists but can be accessed by anyone, is a living record of the teams that have shared their observations, simulations, or synthesized data. But it is also a feedback system that notifies data owners when data are downloaded for use by other team members or the broader community, helping to jumpstart conversations about collaboration and coauthorship. We recommend both formalizing a data management plan at the onset of a project and allocating enough resources necessary to ensure its success; our success has been underpinned by a system that tracks both data sharing and data use.

Lessons Learned Maintaining a culture of mutual respect and safety helps to remove obstacles that impede understanding within scientific teams and between these teams and their host communities. Credit: Shawn Serbin, Brookhaven National Laboratory

Over a decade of working at remote field sites in the Alaskan Arctic, NGEE Arctic team members have learned a lot about project and safety planning, inclusive and collaborative team building, and open and immediate data sharing that we believe can be extrapolated to other scientific endeavors. Our success in these efforts emerged not only because of expectations set at the start from our sponsor and our project leadership but also because of the work of our team across many years to create systemic changes in our science culture and the way our scientists work. This success is quantified through continuous feedback—from students to mentors, from team members to the leadership team, and between the leadership team and our sponsor.

Central to our culture is the trust that all staff have in our leadership and in each other: trust to question the status quo, trust that alternative views and approaches will be heard and validated, and trust to share ideas and data. Our experiment within an experiment continues.


We thank the Biological and Environmental Research (BER) program with the U.S. Department of Energy’s Office of Science for funding the NGEE Arctic project. We thank the participating institutions, Brookhaven National Laboratory (contract DE-SC0012704), Lawrence Berkeley National Laboratory, Los Alamos National Laboratory, Oak Ridge National Laboratory, and the University of Alaska Fairbanks, as well as the NGEE Arctic team for their leadership, collaboration, and friendship across the years. We also thank UIC Science and the Council Native Corporation, Mary’s Igloo Native Corporation, and Sitnasuak Native Corporation for allowing us to conduct our research on their land. Special thanks go to Lily Cohen and Kaare Erickson for helping us appreciate each other and the native communities that so cherish the Arctic.

Author Information

Colleen M. Iversen (iversencm@ornl.gov), Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Tenn.; W. Robert Bolton, International Arctic Research Center, University of Alaska Fairbanks; Alistair Rogers, Environmental and Climate Sciences Department, Brookhaven National Laboratory, Upton, N.Y.; Cathy J. Wilson, Earth and Environmental Sciences Division, Los Alamos National Laboratory, N.M.; and Stan D. Wullschleger, Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Tenn.

Two Moons and a Magnetosphere

Tue, 04/21/2020 - 12:36

Jupiter’s two innermost moons, Io and Europa, play a central role in sculpting and interacting with the planet’s magnetosphere—the vast region where Jupiter’s magnetic field influences a swirling mass of charged particles surrounding the planet and its many moons.

In a new review, Bagenal and Dols pull together decades of research on this intricate system. While prior reviews have focused on either Io’s or Europa’s space environment alone, this paper addresses both in harmony. It draws on data from the early Voyager missions, later flybys by other spacecraft, the latest Earth-based observations, innovative computational modeling efforts, and more.

The researchers paint a detailed picture of what is known about the two moons’ individual atmospheres. While Io’s is thought to consist mostly of sulfur dioxide, Europa’s is mostly oxygen. Each moon’s atmosphere interacts with the magnetosphere’s charged particles, known as plasma, causing clouds of neutral atoms to escape from the atmospheres.

In turn, these neutral clouds serve as the primary source of new plasma in Jupiter’s magnetosphere: Existing plasma electrons ionize neutral atoms, transforming them into charged plasma particles.

Io plays a particularly intriguing role in this system. At any given moment, 50–100 of its many volcanoes are actively erupting, emitting sulfur dioxide into the moon’s atmosphere. Every second, roughly a ton of this gas becomes plasma that feeds an ever present doughnut-shaped belt, or torus, of dense plasma that encircles Jupiter.

While many details of these physical processes have become clear in recent years, questions remain. For instance, what are the precise compositions of the moons’ atmospheres? How do plasma–atmosphere interactions vary at different locations around each moon? And what impact do changes in Io’s volcanic activity have on the system?

The ongoing Juno mission, Earth-based observations, and computational modeling should continue to provide new insights into the Io–Europa–magnetosphere system. In the future, NASA’s Europa Clipper and the European Space Agency’s Jupiter Icy Moons Explorer (JUICE) missions promise to illuminate more about Europa, which is thought to harbor an intriguing liquid ocean under its icy crust. The authors note that a flyby mission to Io is needed to answer many questions about its unique role. (Journal of Geophysical Research: Space Physics, https://doi.org/10.1029/2019JA027485, 2020)

—Sarah Stanley, Science Writer

Are Cosmic Rays a Key to Forecasting Volcanic Eruptions?

Tue, 04/21/2020 - 12:33

Forecasting volcanic eruptions is notoriously challenging, but a team of Japanese scientists may have found a new method using relativistic particles from space.

A new pilot study, conducted on a highly active Japanese volcano, used a type of high-energy particle called a muon to map the interior structure of the volcano. When analyzed with machine learning algorithms, these maps could help diagnose when a volcano is about to blow. Thus far, the feasibility of the method has been examined on only one volcano, but it could eventually be more widely applied as the technique is further refined.

By placing specialized detectors that record muons passing through a volcano, scientists can use the particles to create more finely defined maps of the interior of a volcano than possible with previous techniques.Eruption forecasting typically relies on volcanic gas emissions, surface changes, or seismography—which measures trembles in the ground that are often a precursor to eruptions. The new method instead took a visual approach and built on the imaging technique known as muography. First developed in the 1970s to map secret chambers in Egyptian pyramids, muography uses cosmic rays—high-energy particles originating on the Sun and across the galaxy—to map giant objects, similar to an oversized X-ray machine.

Cosmic rays continually rain down into Earth’s atmosphere from outer space. When they run into atmospheric particles, they decay into smaller components, including an elementary particle called a muon. Muons’ relatively high mass allows them to penetrate deeply into materials, even solid rock. By placing specialized detectors that record muons passing through a volcano, scientists can use the particles to create more finely defined maps of the interior of the volcano than possible with previous techniques.

For over a decade, scientists have been using muography to peer inside volcanoes around the world. The new work by the Japanese team, recently published in Scientific Reports, was the first effort to use muographic images to forecast eruptions.

Deep Learning

In medical imaging, scientists have applied a type of artificial intelligence called deep learning to X-ray images. Deep learning has been highly successful in identifying changes between images, tracking features such as cancer tumor growth. Since X-ray radiography and muography are conceptually similar, the scientists adapted a deep learning algorithm to analyze the volcano images. Although the specific type of deep learning they used—convolutional neural networks—has been previously used in the geosciences, it hadn’t been applied to muographic images.

The scientists applied the technique to the Sakurajima volcano, one of the most active in the world. (It has erupted 7,000 times in the past decade.) This stratovolcano, located in southern Kyushu, Japan, has been monitored by the Sakurajima Muography Observatory for 6 years, providing a wealth of historical data. Deep learning suffers from the need of an extensive library of images in which to train the algorithm, but the long timeline of data collection provided a sufficient set of images for calibration.

One of the instruments—a muographic observation system—measures muons traveling through Sakurajima. Credit: University of Tokyo

“For around 500 eruption events, daily muographic images were learned and interpreted by a machine for the 7 days [leading up to the eruption] to judge whether the eruption would occur or not on the following day,” said Hiroyuki Tanaka, a coauthor on the new study and a researcher at the Earthquake Research Institute and the International Muography Research Organization (MUOGRAPHIX) at the University of Tokyo.

The researchers’ results showed a correlation between the images and eruptions, which suggests that this technique could be used to forecast future eruptions. The method might also allow predictions more than a few days out, but that will require additional refinement of the technique.

Although this pilot study was conducted on only one volcano (Sakurajima), it has the potential to be extended to other volcanoes in the future.Although this pilot study was conducted on only one volcano, it has the potential to be extended to other volcanoes in the future, though there are potential roadblocks. Deep learning works only for large data sets, which don’t yet exist for many volcanoes. And acquiring sufficient data requires a large number of eruptions, a limiting factor for volcanoes that aren’t as active as Sakurajima. But some scientists are hopeful that key features that can signal imminent eruptions can be identified from Sakurajima and applied to other, less active volcanoes. Procedures used in the new research could also be combined with existing methods to more fully study volcanic activity.

“Forecasting of a volcanic eruption rarely relies upon a single parameter, and therefore, the combined use of monitoring tools and forecasting methods is likely to give the ‘best’ outcome,” said Rebecca O. Salvage, a geophysicist and volcanologist at the University of Calgary. “Since Sakurajima has been well monitored for a long time, it would be interesting to see how muography compares to other, more traditional, monitoring techniques, such as seismicity, deformation, and gas emission, in terms of its ability to successfully forecast an eruption.”

—Mara Johnson-Groh ( marakjg@gmail.com), Science Writer

Photography Focuses on Sea Level Rise and Eroding Communities

Tue, 04/21/2020 - 12:33

The winning photographers, Aji Styawan and Greg Kahn, on opposite sides of the world, captured the stories of the impact of rising sea levels in Indonesia and the United States and the resilience with which communities have responded.

Their local knowledge, individual photographic style and cultural sensitivity shone through to the grant judges. Both reveal restrained emotion and a surreal sense of place.

The landscape, communities, political structures, religions and people these photographers work with are diverse. Their proposals and photography work impressed the jury and embraced the Climate Visuals seven principles for impactful photography.

Drowning Land by Aji Styawan

Indonesia is one of the largest archipelago nations in the world, with more than 17,000 islands. The majority of the small islands are only a meter above sea level. Deforestation, land reclamation and groundwater extraction make these areas even more vulnerable to rising sea levels.

A resident of the Sayung subdistrict in Demak, Central Java, slowly makes his way through the inundated streets of the village. Credit: Aji Styawan / Getty Images Climate Visuals Grant Recipient

Experts predict that before 2050, thousands of small islands and millions of houses in coastal areas across Indonesia will disappear due to rising sea levels.

Demak is on the northern coast of Central Java, about 300 miles east of Jakarta. More than 500 households have been displaced in the past 20 years.

A raft takes Javan students across a flooded area to a road from where they can go to school. Their usual road to school collapsed due to abrasion caused by rising sea levels. Credit: Aji Styawan / Getty Images Climate Visuals Grant Recipient

As the sea levels rose, farmland became fish ponds and mangrove forests, which are now also submerged. Today it’s all sea.

At a public cemetery in Demak, a tomb is protected from coastal erosion by rock filled bags. Credit: Aji Styawan / Getty Images Climate Visuals Grant Recipient  

3 Millimeters by Greg Kahn

Three extra millimeters of water every year will make land vanish. It will swallow communities. It will change environmental habitats forever. It will cause record pollution. For townspeople along the inner coastal region of the Chesapeake Bay in Maryland, the impact of sea level rise is no longer an abstract worry debated by politicians. They see the land becoming more saturated beneath their feet. Thirteen of the bay’s southern islands, many of them once inhabited, are gone.

Water spills onto Hoopers Island Road in Hoopersville, Md., during high tide. The Eastern Shore of Maryland has a rate of sea level rise that is twice the global average. The results are high tides that wash out roads connecting communities, and land that is slowly disappearing into the Chesapeake Bay. Credit: Greg Kahn / Getty Images Climate Visuals Grant Recipient

3 Millimeters explores the waterways of Maryland, where, due to the region’s makeup and Atlantic Ocean flow, sea levels are rising twice as fast as the global average and will leap by as much as 5ft by 2100. This will submerge more than 250,000 acres of land, displacing more than half a million people. Farms once fertile and productive now wilt as mounting salinity levels force families to abandon their way of life.

A glove from an oyster shucker is covered in so much sand and mud that it retains its shape even when the shucker goes on a break. Credit: Greg Kahn / Getty Images Climate Visuals Grant Recipient

There is nothing to stop Hoopers Island from slowly drowning. Locals point 100 yards into the bay, telling stories of a baseball field where they used to play. Graves containing the island founders, once buffered by a forest, now jut out from an eroding shoreline patched with makeshift rock walls. “I doubt there’ll be any human life here in 100 years,” said Donald Webster, who works for the Maryland Department of Natural Resources.

While nothing can reverse rising seas in places like Smith Island, there is hope for others. Gradient sea walls, vegetation renourishment and public education are all trying to preserve natural habitat and homes along the coast. The hope is that it will stop erosion as well as maintain habitat for sealife such as horseshoe crabs and terrapins.

Water from the Chesapeake Bay intrudes on the marsh of Blackwater National Wildlife Refuge on the Eastern Shore of Maryland, killing trees and drowning the land in its path. Credit: Greg Kahn / Getty Images Climate Visuals Grant Recipient

—The Guardian     This story originally appeared in The Guardian. It is republished here as part of Eos’s partnership with Covering Climate Now, a global journalism collaboration committed to strengthening coverage of the climate story.

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