EOS

Syndicate content
Earth & Space Science News
Updated: 1 day 15 hours ago

NASA Wants to Get Back to the Moon, and Fast

Fri, 02/15/2019 - 20:16

NASA administrator Jim Bridenstine wants to get U.S. spacecraft and astronauts back to the Moon soon.

“What we are trying to accomplish is really a balance between getting to the Moon as fast as possible and also making sure that when we get to the Moon it’s sustainable.”“Right now, what we are trying to accomplish is really a balance between getting to the Moon as fast as possible and also making sure that when we get to the Moon it’s sustainable,” Bridenstine said at a media roundtable Thursday at NASA headquarters in Washington, D.C., to discuss the design and development of reusable and open architecture to return to the Moon.

The next chapter in U.S. lunar exploration will be different, he said. “This time when we go to the Moon, we’re actually going to stay,” he said at the roundtable that preceded an industry forum on the topic. “We’re not going to leave flags and footprints and then come home to not go back for another 50 years.” The Apollo 17 mission, which took place close to 50 years ago in December 1972, was NASA’s last crewed mission to the Moon.

The architecture to return to the Moon should allow NASA to “go back and forth over and over again and not just to one or two parts of the Moon but to all parts of the Moon with landers and rovers, robots, and even humans,” he said.

Developing the Architecture

The agency published a solicitation on 7 February inviting U.S. companies to submit proposals to partner with NASA on designing and developing reusable lunar human landing systems (HLSs). Those proposals are due by 25 March, and NASA currently plans to make initial partnership selections in May. NASA is planning for the launch of the first HLS element demonstration mission in 2024 and for having astronauts land on the Moon in 2028.

The system for sending astronauts will require “three separate elements that will provide transfer, landing, and safe return,” according to a 7 February NASA press release related to the solicitation. “A key aspect of this proposed approach is to use the Gateway”—a planned lunar-orbiting spacecraft—“for roundtrip journeys to and from the surface of the Moon.”

Why So Fast?

Space Policy Directive 1, which President Donald Trump issued on 11 December 2017, calls for the United States to “lead the return of humans to the Moon for long-term exploration and utilization, followed by human missions to Mars and other destinations.”“We have already seen the immense amount of international interest there is in the Moon,” Bridenstine said. “Of course, it’s in our interest to make sure that we are represented there as well, as soon as possible.”

The push to get back to the Moon fast also comes from his own background, Bridenstine said. “It’s in response to me [formerly] being a member of Congress, and wanting to see more speed out of NASA long before I came to the agency,” he quipped. “But you know what’s happened here? We have a new direction and that new direction is to get to the Moon. That’s part of the president’s Space Policy Directive 1, and we’re trying to make that happen as soon as possible.”

It’s in the nation’s interest to return to the Moon, Bridenstine added. “We have already seen the immense amount of international interest there is in the Moon. And we have seen an immense amount of international interest in specific parts of the Moon, because it could be advantageous from a geostrategic perspective,” he said. “Of course, it’s in our interest to make sure that we are represented there as well, as soon as possible.”

International Partnerships

Bridenstine added that not only does NASA intend to go to the Moon “back and forth regularly with humans” but that “we want to take all of our international partners and have them be part of this effort to get to the Moon.”

However, Bridenstine drew the line at China being a partner in the effort. “As far as partnering with China, of course, we are prohibited from doing bilateral cooperation by law,” he said, referring to legislation known as the Wolf Amendment after former Rep. Frank Wolf, which bans almost all bilateral U.S.-China space cooperation.

“Certainly, I’m not going to do anything that would violate the law. To the extent that we had multilateral cooperation, of course, it would be done through the interagency process, and it would be done in consultation with Congress as well,” he said. “So, I’m not going to close that door, but certainly, it’s not a door that I’m opening wide up.”“We are doing very, very well. You know, somebody lands on the far side of the Moon and NASA lands on the far side of Mars.”

Is the U.S. Falling Behind?

Bridenstine added that the United States is doing great in space exploration.

“I’ve seen media reports saying that the United States of America is falling behind. That is not the case when it comes to exploration,” he said. “We are doing very, very well. You know, somebody lands on the far side of the Moon and NASA lands on the far side of Mars.”

—Randy Showstack (@RandyShowstack), Staff Writer

The post NASA Wants to Get Back to the Moon, and Fast appeared first on Eos.

Brief, Repetitive Floods in Coastal Cities Cause Economic Losses

Fri, 02/15/2019 - 19:01

Scientists have put a price tag on the cost of high-tide floods on the coastal community of Annapolis, Md. High-tide floods, also called nuisance or sunny day floods, are small-scale inundations that last a few hours and flood areas with tens of centimeters of water during high tides. Rising sea levels are making high-tide floods more common: the Annapolis district of City Dock had 44 high-tide floods in 2017 alone.

“High-tide flooding is already measurably disrupting the economic activity in this location.”A study published today in Science Advances quantified the decrease in visits and the loss of revenue to downtown businesses due to 1 year of high-tide floods. The total parking lot visits to the downtown Annapolis district of City Dock decreased by about 3,000 in 2017 because of the floods. Miyuki Hino, the lead author and a doctoral student at Stanford University, said in a media briefing Thursday that “high-tide flooding is already measurably disrupting the economic activity in this location.”

The researchers also projected losses that rising seas could bring to the community. “With just three more inches [7.6 centimeters] of additional sea level rise,” Hino noted, “loss of visits would double.” The authors predict this will happen in the next 2 decades at the present rate of sea level rise.

Floods Scare Away Shoppers

Many towns around the United States may face challenges similar to Annapolis. A recent report found that more than 170 coastal communities will face flooding as frequently as 26 times per year by 2035. Small floods disrupt daily life by blocking streets, closing schools, and damaging vehicles.

The latest study calculated the impact of high-tide floods by tracking the dip in parking ticket sales in the downtown district of City Dock. The researchers created their own tally of high-tide floods using social media posts, police footage, and tidal gauges. The floods are often so ephemeral that no record was previously available.

The lack of customers translated to “about a hundred thousand dollars in lost revenue.”“We found that high-tide flooding reduced visits to City Dock by about 2%,” Hino explained. The depression in visits lasted after the flood subsided, even up to 5 hours after the flood occurred. The lack of customers translated to “about a hundred thousand dollars in lost revenue across about 16 businesses” in 2017, Hino said.

The study’s analysis does not take into account missed work days, delayed travel times, or damage to infrastructure. Although the authors note that the 2017 losses are small, their projections of future sea level rise suggest that City Dock could lose more than 37,000 visitors with just a 1-foot (0.3-meter) increase in sea level rise.

Local government officials in Annapolis are actively seeking grants to mitigate the issue, according to the study’s authors. The funds would go to build pumps to siphon away water from downtown. As the city faces more extreme floods due to sea level rise, “there are a range of adaptation options,” said coauthor Samanthe Tiver Belanger, a Stanford University business school graduate student.

“Some of them are as extreme as picking up the businesses and moving them entirely, whereas others are smaller,” she added, such as building walls.

Not Simply a Nuisance

Benjamin Hamlington, a scientist in the Sea Level and Ice Group at NASA’s Jet Propulsion Laboratory, told Eos that the latest study is “one of the first assessments of the effect of high-tide flooding on economic activity.”

“With increasing sea levels, it no longer takes a hurricane or strong storm to cause coastal flooding.”“One of the most important results is that high-tide flooding is already having a measurable impact on coastal populations, beyond simply being a nuisance,” Hamlington noted. “With increasing sea levels, it no longer takes a hurricane or strong storm to cause coastal flooding.”

Thomas Wahl, an assistant professor in coastal engineering at the University of Central Florida, told Eos that coastal planning often focuses on extreme events like hurricanes but misses the “cumulative effects” of small repeated floods. The paper raises a “very important emerging issue,” Wahl noted.

For study coauthor Chris Field, director of the Stanford Woods Institute for the Environment in Stanford, Calif., the latest findings are an example of how humans’ relationship to the coast is shifting.

“Many coastal areas in the U.S. are built as close to sea level as possible to facilitate the interaction between humans and the ocean,” Fields said. “But as the sea has risen, that closeness to the ocean has transitioned from being an asset to being potentially a liability.”

—Jenessa Duncombe (@jrdscience), News Writing and Production Intern

The post Brief, Repetitive Floods in Coastal Cities Cause Economic Losses appeared first on Eos.

Leading Societies Come Together to Address Harassment in STEMM

Fri, 02/15/2019 - 17:00

Built on the idea that professional societies—such as AGU—are standard setters for the science, technology, engineering, mathematics, and medicine (STEMM) fields and that in this role they have a unique responsibility for combating issues such as sexual and gender harassment, an important new partnership was launched today: the Societies Consortium on Sexual Harassment in STEMM.

The consortium was established by AGU, the American Association for the Advancement of Science (AAAS), and the Association of American Medical Colleges (AAMC), but its reach is much broader. With an executive committee that comprises AGU, AAAS, AAMC, the American Chemical Society, the American Educational Research Association, the American Psychological Association, the American Physical Society, the American Society for Cell Biology, the Entomological Society of America, and the Institute of Electrical and Electronics Engineers; policy and law consultation from the EducationCounsel; and more than 50 member societies to date, the consortium is already positioned to be a transformative voice in STEMM.

“This consortium will allow us to collectively use our voice, as leaders of the international science community, to truly transform the workplace culture in ways that allow all to thrive.”“While AGU, and many others, have been working independently to make a difference in areas of harassment, bias, and discrimination, this consortium will allow us to collectively use our voice, as leaders of the international science community, to truly transform the workplace culture in ways that allow all to thrive,” said Billy Williams, vice president for ethics, diversity, and inclusion at AGU. “This work will have an immeasurable impact not just on science, but on its ability to drive the next 100 years of innovations, discoveries, and solutions. We enrich discovery and innovation and strengthen our science when a diverse set of voices feel encouraged and supported in sharing their perspectives and ideas.”

“This consortium provides both leadership for a broad diversity of our societies’ collective voices and actions to advance ethics, equity, inclusion, and excellence in STEMM research, education, and practice,” said Shirley Malcom, senior adviser at AAAS.

“Combating sexual harassment in academic medicine and across the STEMM fields requires a multipronged, ongoing, and sustained approach,” said David Acosta, MD, chief diversity and inclusion officer at AAMC. “The Societies Consortium will help our organizations—and in turn, our respective member institutions—see across the landscape of STEMM as we work together to develop the strategy and tools needed to foster a more inclusive learning and workplace environment.”

Initially, the group will focus on the societies’ honors and awards operations, given the important role they play in everything from professional development to public outreach.“Consortium members are saying loudly and clearly that we need the best scientific output of all talent in STEMM, if these fields are to maximize their potential to drive innovation, economic strength and security, benefiting society across the nation and around the world,” said Jamie Lewis Keith, a partner at EducationCounsel. “And, they stress, that success depends on fully inclusive settings in which all professionals and students are treated with respect.”

Initially, the group will focus on the societies’ honors and awards operations. Given the important role these programs play in everything from professional development to public outreach, the consortium will work to develop model policies and procedures that can help to improve diversity and inclusion and ensure professional and ethical conduct. Ultimately, the group hopes to provide practical research- and evidence-based resources that are informed by social and behavioral science and are applicable to the consortium’s member societies’ own operations.

The consortium is the latest addition to a growing list of efforts AGU is undertaking to build a diverse, inclusive, welcoming, and supportive workforce and workplace—all of which has particular resonance during our Centennial. On 12 February 2019, AGU launched the Ethics and Equity Center. A new hub for comprehensive resources and tools designed to support our community across a range of topics linked to ethics and workplace excellence, the center provides resources to individual researchers, students, department heads, and institutional leaders to promote leading practices on issues ranging from building inclusive environments, to scientific publications and data management, to combating harassment, to example codes of conduct. The center is an outgrowth of the update of AGU’s Scientific Integrity and Professional Ethics Policy in September 2017. In the wake of high-profile cases alleging sexual harassment in the sciences, the updated policy was one of the first steps AGU took to address ongoing issues within the Earth and space science community that have a profound impact in the workplace and on scientists’ individual lives and careers.

—Joshua Speiser (jspeiser@agu.org), Manager of Strategic Communications, AGU

The post Leading Societies Come Together to Address Harassment in STEMM appeared first on Eos.

Can We Predict River Flows from Just a Few Observations?

Fri, 02/15/2019 - 12:32

For water managers, accurately knowing how much water flows in a river is essential for various societal applications ranging from flood defense to water supply allocation. A river’s discharge, however, is rarely measured directly. Instead, relationships known as rating curves are used to calculate discharge time series from continuous observations of water depth. The rating curve is typically inferred from many concurrent measurements of discharge and water depth in the river (gaugings) taken over long periods of time.

But what if we could rapidly and reliably establish rating curves by leveraging hydraulic models based on only a few gaugings?Unfortunately, any uncertainties in the rating curve’s derivation translate directly into uncertainty about water resources. But what if we could rapidly and reliably establish rating curves with well-defined uncertainty estimates by leveraging hydraulic models based on only a few gaugings?

Scientists considered this question at a recent workshop funded by the Swedish Research Council Formas. The workshop was attended by 20 discharge monitoring and water resources management practitioners, bringing together representatives from the Swedish Meteorological and Hydrological Institute, Swedish Agency for Marine and Water Management, The Nature Conservancy, Stockholm University, Swedish University of Agricultural Sciences, Swedish Environmental Research Institute, and Uppsala University. As such, the workshop gathered experts from government, nonprofit, and academic institutes who face data and discharge uncertainty challenges on a daily basis.

Participants discussed results from recently developed methods for obtaining lower discharge monitoring uncertainty for given rivers. This included low-cost gauging strategies that target the most commonly occurring discharges.

Here the low cost comes about as hydraulic modeling and other statistical methods create an “uncertainty framework” that allows users to constrain uncertainty with only a few discharge observations (e.g., three to four gaugings) compared to traditional methods that need numerous gaugings. We also discussed incorporation of prior knowledge about river channel characteristics in addition to information from the few gaugings. Such an approach allows users to define uncertainty ranges similar to those of traditional methods while using fewer discharge observations.

The group highlighted the utility of using hydraulic modeling within uncertainty frameworks for monitoring responsive and remote locations in stream networks. They also highlighted the potential of using drones to find new monitoring locations and map topography that models may need.

Given the observations needed to combine hydraulic modeling and uncertainty frameworks, the workshop considered that there is good opportunity to engage students within modeling and ground-truthing projects. This inclusion creates connections between practitioners and educators.

Attendees concluded there is great potential for establishing rating curves rapidly for ungauged locations.To assess the full potential of such a shift in modeling, especially in issues related to environmental restoration efforts, workshop attendees recommend research and development over a wide range of stream types with different characteristics. A range is necessary since most institutes and practitioners work across diverse geographies. The attendees also note that this recommendation allows for strong connections between research and practice around the assessment of discharge uncertainty. Such strong connections allow for implementation of relevant and realistic strategies for uncertainty characterization, thereby meeting the needs of those that actually work with streams and water resources.

Attendees concluded there is great potential for establishing rating curves rapidly for ungauged locations using hydraulic modeling within an uncertainty framework. This could improve discharge data for water management and environmental restoration in a cost-effective manner.

—Steve W. Lyon (steven.lyon@tnc.org), The Nature Conservancy, Delmont, N.J.; Valentin Mansanarez, Department of Physical Geography, Stockholm University, Sweden; and Ida K. Westerberg, IVL Swedish Environmental Research Institute, Stockholm

The post Can We Predict River Flows from Just a Few Observations? appeared first on Eos.

Baltic Bacterial Blooms Over the Millennia

Fri, 02/15/2019 - 12:31

Eutrophication leading to oxygen depletion in near-bottom water and toxic cyanobacteria blooms is an important contemporary problem of the Baltic Sea and many other coastal waters, with present eutrophication mainly ascribed to anthropogenic activity. Szymczak‐Żyła et al. [2019] compare the present trophic state of the Baltic with that during the past millennia in the southern Baltic Sea, using analysis of phytoplankton pigments (chlorophylls and their derivatives, and carotenoids), grain-size, diatoms and selected metals. The authors deduced that there were high primary production periods during past warm periods, accompanied by oxygen deficiency in the near-bottom water. Cyanobacteria blooms of an intensity similar to or even greater than at present occurred in past millennia, linked to warming. The authors thus conclude that natural factors contribute to eutrophication and low oxygen conditions in the Baltic Sea.

Citation: Szymczak‐Żyła, M., Krajewska, M., Witak, M., Ciesielski, T. M., Ardelan, M. V., Jenssen, B. M., et al. [2019]. Present and past‐millennial eutrophication in the Gulf of Gdańsk (southern Baltic Sea). Paleoceanography and Paleoclimatology, 34. https://doi.org/10.1029/2018PA003474

—Ellen Thomas, Editor in Chief, Paleoceanography and Paleoclimatology

The post Baltic Bacterial Blooms Over the Millennia appeared first on Eos.

When Floods Cross Borders, Satellite Data Can Help

Fri, 02/15/2019 - 12:30

On 23 July 2018, a dam in southernmost Laos collapsed, and the resultant flood left more than 6,000 people homeless. The fractures in the dam that led to the disaster were discovered 2 days earlier. Yet the residents who lived downstream—many across the border in Cambodia—didn’t have access to real-time information about the increased risk of flooding. Such floodwaters that cross borders are often termed “transboundary floods” and are more likely to be catastrophic. News such as dam-driven flooding in Laos underscores the urgency of making information on upstream dams in transboundary regions more accessible to citizens of developing nations.

Currently, numerous observation networks in space can provide routine information on various aspects of flooding such as precipitation [Tapiador et al., 2012], streamflow [Durand et al., 2016], water level in lakes or dams [Birkett et al., 2011], groundwater storage [Rodell et al., 2018], and water quality [Lee et al., 2014]. Such data can be combined to understand how transboundary dams are being operated today and guide management strategies for flood disaster, sedimentation control, irrigation, and ecosystem services. Such valuable data from satellite platforms now need to be made easily accessible in the developing world.

Using Satellites to Make Data More Accessible

In a bid to improve timely access to upstream reservoir information in transboundary river basins of the Red and Mekong rivers, Vietnam recently launched a satellite-based operational system. With support from the U.S. Agency for International Development’s Partnerships for Enhanced Engagement in Research, a team from the University of Washington spent 2 weeks in July 2018 working with the Vietnam National Center for Water Resources Planning and Investigation (NAWAPI), the national water agency that has a mandate for managing the country’s water for its citizens. An advanced water forecasting system was codeveloped and implemented under a permanent budget line for NAWAPI for operational sustainability (Figure 1). We describe below the key steps to building such a transboundary dam monitoring system for water agencies of developing countries.

Fig. 1. Screen shot from the operational water forecasting system maintained by NAWAPI. The inset hydrograph over a blue circle (for dams) shows the time series of reservoir storage change estimated using satellite data for Nuozhadu Dam in China. How Does the Satellite-Based Dam System Work?

By using a simple mass balance approach (Figure 2) and neglecting ground seepage from a dam, satellite data can now be used to yield useful estimates of reservoir storage and outflow. The key inputs to the dam system (precipitation and inflow) can be determined from satellite precipitation data and a hydrologic model that provides estimates of streamflow into the dam. Evaporative losses can often be ignored in the humid climates of South Asia or estimated using standard energy-based methods from publicly available data from global numerical weather prediction models. Daily estimation of evaporation using such publicly available data is in operation in many developing regions, such as in Pakistan. A point to note is that the mass balance approach assumes that irrigation or domestic supply needs are met from reservoir outflows downstream of the dam. Such an assumption may not hold if there is extensive water withdrawal upstream of the dam.

Fig. 2. Water mass balance approach applied to a dam. All the terms in the water balance equation needed to estimate outflow can actually be derived from satellite data. E, evaporative losses; I, inflow; O, outflow; P, precipitation; S, reservoir storage.

By using observations of water elevation or surface area from different satellite sensors, one can also estimate reservoir storage change behind a dam [Song et al., 2013]. Because of its high sampling frequency, visible and near-infrared imagery from satellites is typically useful for estimating the surface area of a reservoir. Examples of such satellites are Landsat, the Moderate Resolution Imaging Spectroradiometer (MODIS), and Sentinel-2, whose reflectance data can be classified for detecting open water using the normalized difference water index. Using publicly available digital elevation model (DEM) data, such as those from the Shuttle Radar Topography Mission (SRTM), or satellite altimetry measurements of reservoir elevations, one can also construct the area-elevation curve for a reservoir without the need for in situ bathymetry. Observed surface areas from satellite data can then be matched with their corresponding elevations on the basis of the area-elevation relationship and vice versa for elevation observations from satellite altimeters. This allows users, including anyone with an interest in knowing if a dam is likely to fail, to calculate storage change between each observation by satellite sensor. A long record of storage change when averaged over time serves as a good proxy for how a dam typically operates (referred to as the “rule curve”) in a given month (Figure 3). Finally, the outflow can be predicted using the mass balance summarized in Figure 2. The step-by-step methodology for deriving the state of a dam using only satellite data is described in detail by Bonnema and Hossain [2017].

Fig. 3. Overall methodology for using satellite data from visible or near-infrared (NIR) imagery to estimate dam surface area (top left panels), the area elevation curve using SRTM DEM (top right panels), and the dam operation pattern (bottom panel; the red line is the average pattern likely to be similar to the official rule curve). Does the Satellite-Based Technique Work?

We put the satellite-based technique for deriving the state of dam operations to the test on two dam sites in the Mekong River basin. The actual dam operating pattern used by the dam operator was publicly available. From Figure 4, we can see quite clearly that the satellite-derived (Landsat) dam operating pattern in the form of monthly storage volumes is captured well within the upper and lower bounds of the dam’s declared operations. There are, however, some challenges posed by extensive cloud cover during the monsoon season and limited Internet bandwidth in developing countries of Asia. These issues can be resolved by using synthetic aperture radar and cloud-based computing services, respectively.

Fig. 4. Testing the satellite-based technique to derive the state of dam operations. The left panels show dam sites Ubol Ratana and Sirindhorn in Thailand; the right panels show the satellite estimated storage pattern (gray line) with the declared range of the dam storage operating pattern (orange and blue lines). Importance of Satellites for Sustainable Development

If local leaders in Cambodia had had access to satellite data that kept them informed of the status of the dam in Laos, they may have been able to prevent the loss of many lives.Monitoring the state of transboundary dams is essential for sustainable development of downstream developing countries by deriving better management strategies for disasters (floods and droughts), ecosystem services, fish migration, sedimentation, and crop production. If local leaders in Cambodia had had access to satellite data that kept them informed of the status of the dam in Laos, they may have been able to prevent the loss of many lives. However, new dams continue to be built at an aggressive pace to secure the water needed for energy and food production. A lot of these dams are being constructed by upstream developing countries that contain transboundary river basins [Zarfl et al., 2015]. Therefore, water availability and the amount that flows farther downstream are now becoming increasingly controlled by storage, withdrawal, and release decisions of upstream nations. Thus, the availability of hydrologic data related to transboundary dam operations will become more crucial for managing the water by downstream nations. As such information is difficult to obtain using in situ networks [Balthrop and Hossain, 2009], satellites will remain the only viable way to monitor the state of transboundary dams. The scientific community needs to work on harnessing the valuable data that are available from satellite remote sensing and converting them into accessible tools for water agencies of developing countries.

The post When Floods Cross Borders, Satellite Data Can Help appeared first on Eos.

Congressional Hearing Considers Paths Forward on Climate Change

Thu, 02/14/2019 - 20:53

The House of Representatives’ Science, Space, and Technology Committee turned over a new leaf on climate change at a hearing Wednesday when Rep. Eddie Bernice Johnson (D-Texas) chaired her first Science Committee hearing since Democrats took control of the House.

“Though this administration has regrettably chosen to ignore the findings of its own scientists in regard to climate change, we as lawmakers have a responsibility to protect the public’s interest.”Largely gone was the climate denialism that often had been on display during the previous chairmanship of Rep. Lamar Smith (R-Texas). In its place was a serious discussion that focused on possible measures to deal with climate change and that hinted at some potential bipartisan paths forward on the issue.

“Though this administration has regrettably chosen to ignore the findings of its own scientists in regard to climate change, we as lawmakers have a responsibility to protect the public’s interest,” said Johnson, whose committee oversees much of the federal climate research portfolio. “I plan to do this by making sure this committee is informed by the most relevant and up-to-date science as we work to conduct our legislative and oversight responsibilities.”

Sparring Over the Green New Deal

Democrats and Republicans sparred over what might be the most effective ways to deal with climate change, but overall, they acknowledged its impacts, the human contribution to it, and the need for a slate of potential remedies.

One area of disagreement was a recently introduced Congressional resolution to support an ambitious Green New Deal. That resolution, already backed by more than 60 House Democrats, calls for achieving net-zero greenhouse gas emissions and other environmental, infrastructure, economic, and equity goals “through a 10-year national mobilization.”

“We’ve led the world in coal, oil, and gas development. Now we need to do it with rapidly growing clean energy markets.”Rep. Steve Cohen (D-Tenn.) and other Democrats called the deal “aspirational.” “Some of the specifics certainly aren’t going to happen anytime soon. Some of them will probably never happen at all,” he said. “But the concept of putting people’s minds and attentions to climate change is important.”

Republicans, however, flinched at what they said are unrealistic timetables, government overreach, and potential financial burdens. “We have seen a lot of aspirational goals lately. I think we need to be very careful about crossing the line from aspirational to outlandish goals that could harm our economy,” said committee member Rep. Michael Waltz (R-Fla.).

Yet Waltz also said that he wants the United States to be a leader in clean energy efforts. “We’ve led the world in coal, oil, and gas development. Now we need to do it with rapidly growing clean energy markets. I think to succeed we need a very broad portfolio of, emphasis here, low-cost technologies to speed the transition to renewable cleaner energy,” Waltz said, adding that nuclear energy should be in the energy mix.

Joseph Majkut of the Niskanen Center (third from left) testifying at the Science Committee hearing. Also pictured (left to right) are Robert Kopp, director of the Rutgers University Institute of Earth, Ocean, and Atmospheric Sciences; Jennifer Francis, senior scientist at the Woods Hole Research Center in Falmouth, Mass.; and Kristie Ebi, director of the Center for Health and the Global Environment at the University of Washington. Natalie Mahowald, professor of engineering at Cornell University, testified via a video link. Credit: House Science Committee Republicans Some Potential Fixes

Natalie Mahowald, professor of engineering at Cornell University in Ithaca, N.Y., and a lead author of the Intergovernmental Panel on Climate Change’s (IPCC) October 2018 Special Report on Limiting Warming to 1.5°  C, testified that the report provides a menu of policy options, technologies, and techniques that could help reduce climate change impacts. Those options, she said, include reducing fossil fuel subsidies, removing regulatory barriers for new energy-producing technology, promoting a stable business environment and low-carbon technologies, and research into carbon dioxide removal and utilization technologies. The IPCC report states that limiting global warming to 1.5°C would require rapid and far-reaching transitions in energy and other systems that “are unprecedented in terms of scale.”

Joseph Majkut, the Republican’s witness at the hearing who is director of climate policy at the Washington, D.C.–based Niskanen Center think tank, also called for a multipronged climate change strategy. He said the strategy includes reducing greenhouses gases, encouraging geoengineering technology research and norms, and placing a priority on adaptation and reducing societal vulnerability to climate change.

“A world aiming for 2°C”—as the increase in temperatures above preindustrial levels—“will require a portfolio of low-carbon energy sources, including carbon capture and storage for fossil fuels,” he said. “In a world aiming for 1.5°C, processes that remove carbon from the atmosphere will need to be deployed at a scale capturing up to one quarter of today’s emissions.” Majkut said “that is a mind-boggling number for an infant technology” and it would need congressional support.

 The Planet Is Running a Fever

“The planet is running a fever.”Robert Kopp, director of the Rutgers University Institute of Earth, Ocean, and Atmospheric Sciences, testified that “the planet is running a fever” and that a wide variety of approaches, including forest sequestration and technological fixes, could help to slow climate impacts. After the hearing, Kopp told Eos that he was “very encouraged” by the committee hearing and said that he heard “some real interest in this issue” from the ranking Republican member and many of the newer Republican committee members.

Majkut told Eos that there is “a lot of interest for bipartisanship,” including on advanced research, among committee members. “Today’s hearing is a real demonstration that ideas on this issue are shifting, and that gives me hope for long-term change,” Majkut said. “This feels like a pretty different world from what we had 6 months ago in the Science Committee. [It’s] not just because of the Democratic majority, but we had members on the Republican side who were saying climate change is real [and] we should do something about it. It’s a question of balance. It’s a question of innovation.”

—Randy Showstack (@RandyShowstack), Staff Writer

The post Congressional Hearing Considers Paths Forward on Climate Change appeared first on Eos.

Estimating the Likelihood of Future Temperature Extremes

Thu, 02/14/2019 - 13:18

Climate change is expected to increase Earth’s average surface temperature as well as boost the frequency of summer heat waves and winter cold snaps, which can have devastating consequences for human life, ecosystems, and the economy. Scientists have hypothesized that shifts in the location and degree of narrow, meandering bands of wind called jet streams could reduce the speed of eddies that drive upper atmosphere circulation. Such changes may play an important role in generating extreme temperature events, but the effects of these proposed mechanisms have been difficult to isolate.

Now Linz et al. have developed a simple model to disentangle how some mechanisms could affect the statistical distribution of future surface temperatures. They used a two-dimensional model stirred by natural, large-scale waves in the atmosphere and the ocean, which are associated with high- and low- pressure systems that drive local weather. With this tool, they explored how variations in the background (equator-to-pole) temperature gradient, the location of the waves that mix the upper atmosphere, and other factors could influence temperatures above the Southern Hemisphere.

A researcher demonstrates the behavior of baroclinic eddies with a simplified DIYnamics model, setting up the gradient by putting a can of ice in the middle and then spinning up the system to show the mixing of a temperature gradient in a rotating fluid system. The instabilities that develop and turn into the eddies are similar to those in the simple computer model used by Linz et al. Credit: TEXTSpencer Hill/DIYnamics

They found that when they varied the location at which midlatitude winds are stirred, it strongly affected the range of resulting temperatures. When they shifted the latitude at which the wind is stirred toward the South Pole, the cold extremes became colder throughout the midlatitudes. By contrast, when they decreased the background temperature gradient, it reduced the range of temperature values across the Southern Hemisphere. This finding agrees with a number of comprehensive climate model predictions.

By offering a physical basis for understanding temperature observations in a warming climate, this model will serve as a powerful new tool for investigating how potential changes in atmospheric circulation may affect the distribution of temperature—and thus the frequency of extreme temperature events—in the Southern Hemisphere. As a next step, the researchers plan to incorporate additional features into the model to enable comparisons with data from the Northern Hemisphere, which is dynamically quite different because of the configuration of the continents and a greater proportion of land compared with the Southern Hemisphere. (Geophysical Research Letters, https://doi.org/10.1029/2018GL079324, 2018)

—Terri Cook, Freelance Writer

The post Estimating the Likelihood of Future Temperature Extremes appeared first on Eos.

Heart-Shaped Valentines, from Nature to You

Thu, 02/14/2019 - 13:17

You show your love for geoscience in thousands of tiny ways. Your eyes might light up when you see unexpected geology in the rockface alongside the road. Maybe you can’t help but puzzle over the mineralogy of a handful of sand at the beach. Or you might know obscure trivia about planets and moons and can’t help sharing it with everyone. This Valentine’s Day, celebrate your love of Earth and space science with these naturally heart shaped features that show that the feeling is mutual.

.

No Barriers Between Our Hearts

We want this barrier—Australia’s Great Barrier Reef, that is—to stick around for a long time.

Credit: alicia3690, CC0

 

You’ve Got Me On Cloud Nine

Watch beautiful and bold lenticular clouds form over New Zealand’s Mount Cook National Park. A special heart-shaped cloud glows red in the video below.



 

Your Love Sends Me to Mars

Mars has shared its heart-shaped craters, mesas, and depressions with many of the missions that study the Red Planet.

Credit: NASA/JPL/Malin Space Science Systems

 

You Melt My Heart

Shimshal Lake, nestled in Hunza Valley in Pakistan, is hard to reach, but when you do reach it, this glacier melt lake will melt your heart.

Credit: Majid dogar, CC BY-SA 4.0

 

You’re the Light in My Skies

The aurora borealis sent its love from the top of the world in October 2016.

 

View this post on Instagram

 

A post shared by Timo Oksanen (@timoksanen) on Feb 14, 2017 at 9:22am PST

 

Pluto Loves You, Too

Planetary scientists love Pluto’s heart for its abundance of scientific potential.

Credit: NASA/APL/SwRI

 

These Are Tears of Joy

Cry only happy tears when you visit Pitugro waterfall in Thailand’s Umphang Wildlife Sanctuary.

Credit: iStock.com/banjongseal

 

You Warm My Heart

In April 2016, the Sun showed us its love with a heart-shaped sunspot as big as Earth.

Credit: NASA/SDO/Goddard

 

Your Love Stopped Me Cold

A love frozen, yet fleeting: This temporary heart froze out of the Minneopa waterfall in Minneopa State Park near Mankato, Minn., in February 2016.

Credit: iStock.com/storkalex

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

The post Heart-Shaped Valentines, from Nature to You appeared first on Eos.

Opportunity Rover Mission Complete

Wed, 02/13/2019 - 23:08

Mars Exploration Rover Opportunity, which has been out of contact for 8 months, failed to respond to NASA’s final attempt to reach it last night. Agency officials and mission scientists announced today that they would not make any more communication attempts.

“Our beloved Opportunity remained silent,” Thomas Zurbuchen, associate administrator of NASA’s Science Mission Directorate, said in today’s press conference. “I’m standing here with a sense of deep appreciation and gratitude and declare the Opportunity mission as complete and, with it, the Mars Exploration Rover mission as complete.”

NASA lost contact with Opportunity on 10 June 2018 during a historic global storm that blanketed Mars with dust for around 3 months. The rover could no longer charge its solar-powered batteries and went into hibernation. Mars-orbiting satellites spotted the rover after the storm ended, but mission scientists sent more than 835 recovery commands to Opportunity without any response.

Opportunity was originally designed for a 90-day mission but survived for nearly 15 years. Its odometer stopped at 45.16 kilometers and marked the off-world driving record. NASA ended the mission for Opportunity’s twin rover, Spirit, in 2011 after losing communication with it for more than a year.

Opportunity explored Meridiani Planum near Mars’s equator and meridian. Among its many accomplishments, Opportunity discovered several types of hydrated minerals and clays that point to flowing water in Mars’s past, explored more than 100 craters, and conducted long-term studies of the Martian environment. Its pioneering work paved the way for missions like Curiosity, the upcoming Mars 2020 and Rosalind Franklin rovers, and possible human exploration.

“Spirit and Opportunity may be gone,” said Jet Propulsion Laboratory director Mike Watkins, “but they leave us a legacy, and that’s a legacy of a new paradigm for solar system exploration.”

Look back on Opportunity’s journey with these photos from the mission’s past:

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

The post Opportunity Rover Mission Complete appeared first on Eos.

Eddies Influence Productivity in the Subtropical Open Ocean

Wed, 02/13/2019 - 12:36

Earth’s five subtropical gyres—large current systems north and south of the tropics—encircle much of the surface water of the open ocean. Known for their low biological activity, these “desert” waters nonetheless contribute significantly to marine productivity because of their vast size. New research by Doddridge and Marshall reveals how eddies might affect nutrient levels within these subtropical surface waters.

The structure of a subtropical gyre includes both a rotating ring of currents and the calmer surface waters within. Winds over the gyres drive a process called Ekman pumping, in which some of the encircled water is drawn deeper into the ocean, out of the gyre system. This vertical flow carries nutrients required for biological activity, contributing to the low nutrient levels often seen in subtropical gyres.

An earlier study that included the current researchers described a previously unrecognized process in which medium-sized (or mesoscale) eddies counteract Ekman pumping and cancel out the associated downward transport of water, which it called “eddy cancellation.” These mesoscale eddies are smaller circular currents, typically less than 100 kilometers across, that may branch off from the main gyre flow and last anywhere from several days to a few months.

The authors have developed a computer model to investigate the impact of eddy cancellation on nutrient transport within an ocean gyre. In a simplified representation of actual gyre structure, the model has an upper water layer representing the euphotic zone, the light-bathed layer where photosynthesis occurs, and a lower mode water layer, an expansive zone with homogeneous properties such as temperature and salinity, characteristic of subtropical gyres.

Using this model, the scientists explored how nutrient concentration within the simulated gyre changed in response to alterations in different model parameters. Nutrients that fell beneath the mode water layer were considered lost to the abyss, no longer contributing to biological productivity in the gyre system.

Their analysis revealed the importance of two parameters: the velocity of Ekman pumping after accounting for eddy cancellation and the thickness of the mode water layer. Initially, increasing the value of either of these two parameters reduced nutrient concentration in the gyre waters. But past a critical threshold, increasing them resulted in higher nutrient levels.

Increasing the Ekman pumping velocity beyond the threshold value increased nutrient concentration by transporting nutrients horizontally into the gyre from adjacent waters. The effect of the mode water layer was less straightforward. In the model, a very thin mode water layer was associated with the diffusion of nutrients up from the abyss and into the gyre system. Thus, increasing the thickness initially reduced nutrient concentration. But past a certain threshold, a thicker mode water layer was associated with reduced flow of nutrients into the abyss and therefore increased biological productivity in the gyre. However, strong Ekman pumping suppressed these effects.

The researchers found support for their model results in the subtropical North Atlantic gyre. Real-world data collected by satellites, free-floating Argo instruments, and research ships showed a correlation between thicker mode water and higher biological productivity, consistent with a small Ekman pumping velocity after accounting for eddy cancelation.

The researchers acknowledge that their model simplifies the structure of gyres, and their observational data have some noisiness. Still, the findings suggest that by countering Ekman pumping, mesoscale eddies may play an important role in setting nutrient concentrations within subtropical gyres and that nutrient recycling within these systems is more effective than expected. (Journal of Geophysical Research: Oceans, https://doi.org/10.1029/2018JC013842, 2018)

—Sarah Stanley, Freelance Writer

The post Eddies Influence Productivity in the Subtropical Open Ocean appeared first on Eos.

Real Time Probing of Shale Cracks in Double Torsion Experiments

Wed, 02/13/2019 - 12:34

Understanding the mechanisms underlying subcritical crack growth in shales is vitally important but data available to date have been scarce. Chandler et al. [2018] provide a significant amount of real-time observations on shales during loading. One of the applications is the assessment of the long-term stability of clayrocks including caprocks and source rocks in sedimentary basins. In addition, this work underlines the role of subcritical crack growth in rocks during the evaluation of the safety of long-term stability of geological storage structures.

Citation: Chandler, M. R., Fauchille, A.‐L., Kim, H. K., Ma, L., Mecklenburgh, J., Rizzo, R., et al. [2018]. Correlative optical and X‐ray imaging of strain evolution during double‐torsion fracture toughness measurements in shale. Journal of Geophysical Research: Solid Earth, 123. https://doi.org/10.1029/2018JB016568

—André Revil, Editor, JGR: Solid Earth

The post Real Time Probing of Shale Cracks in Double Torsion Experiments appeared first on Eos.

Study Suggests Prospect of Recent Underground Volcanism on Mars

Tue, 02/12/2019 - 20:29

A study published last year in the journal Science suggested liquid water is present beneath the south polar ice cap of Mars. Now, a new study in the AGU journal Geophysical Research Letters argues there needs to be an underground source of heat for liquid water to exist underneath the polar ice cap.

The new research does not take sides as to whether the liquid water exists. Instead, the authors suggest recent magmatic activity – the formation of a magma chamber within the past few hundred thousand years – must have occurred underneath the surface of Mars for there to be enough heat to produce liquid water underneath the kilometer-and-a-half thick ice cap. On the flip side, the study’s authors argue that if there was not recent magmatic activity underneath the surface of Mars, then there is not likely liquid water underneath the ice cap.

“Different people may go different ways with this, and we’re really interested to see how the community reacts to it,” said Michael Sori, an associate staff scientist in the Lunar and Planetary Laboratory at the University of Arizona and a co-lead author of the new paper.

Schematic of the case considered in the new study causing a local elevated heat flux beneath Mars’s south polar ice cap. The schematic shows a magma chamber of diameter D buried at a depth of H (to the center of the chamber) beneath the putative liquid water, creating an elevated heat flux Q as itcools. Credit: AGU/GRL/Sori and Bramson

The potential presence of recent underground magmatic activity on Mars lends weight to the idea that Mars is an active planet, geologically speaking. That fact could give scientists a better understanding of how planets evolve over time.

The new study is intended to further the debate around the possibility of liquid water on Mars. The presence of liquid water on the Red Planet has implications for potentially finding life outside of Earth and could also serve as a resource for future human exploration of our neighboring planet.

“We think that if there is any life, it likely has to be protected in the subsurface from the radiation,” said Ali Bramson, a postdoctoral research associate at the Lunar and Planetary Laboratory at the University of Arizona and a co-lead author of the new paper. “If there are still magmatic processes active today, maybe they were more common in the recent past, and could supply more widespread basal melting. This could provide a more favorable environment for liquid water and thus, perhaps, life.”

Examining the environment

Mars has two giant ice sheets at its poles, both a couple of kilometers thick. On Earth, it is common for liquid water to be present underneath thick ice sheets, with the planet’s heat causing the ice to melt where it meets the Earth’s crust.

In a paper published last year in Science, scientists said they detected a similar phenomenon on Mars. They claimed radar observations detected evidence of liquid water at the base of Mars’s south polar ice cap. However, the Science study did not address how the liquid water could have gotten there.

Mars is much cooler than Earth so it was unclear what type of environment would be needed to melt the ice at the base of the ice cap. Although previous research has examined if liquid water could exist at the base of Mars’s ice caps, no one had yet looked at the specific location where the Science study claimed to have detected water.

“We thought there was a lot of room to figure out if [the liquid water] is real, what sort of environment would you need to melt the ice in the first place, what sort of temperatures would you need, what sort of geological process would you need? Because under normal conditions, it should be too cold,” Sori said.

Looking for the heat

The new study’s authors first assumed the detection of liquid water underneath the ice cap was correct and then worked to figure out what parameters were needed for the water to exist. They performed physical modeling of Mars to understand how much heat is coming out of the interior of the planet and if there could be enough salt at the base of the ice cap to melt the ice. Salt lowers the melting point of ice significantly so it was thought that salt could have led to melting at the base of the ice cap.

The model showed salt alone would not raise the temperature high enough to melt the ice. Instead, the authors propose there needs to be additional heat coming from Mars’s interior.

One plausible heat source would be volcanic activity in the planet’s subsurface. The study’s authors argue that magma from the deep interior of Mars rose towards the planet’s surface about 300,000 years ago. It did not break the surface, like a volcanic eruption, but pooled in a magma chamber below the surface. As the magma chamber cooled, it released heat that melted the ice at the base of the ice sheet. The magma chamber is still providing heat to the ice sheet to generate liquid water today.

The idea of volcanic activity on Mars is not new – there is a lot of evidence of volcanism on the planet’s surface. But most of the volcanic features on Mars are from millions of years ago, leading scientists to believe volcanic activity below and above the planet’s surface stopped long ago.

The new study, however, proposes that there could have been more recent underground volcanic activity. And, if there was volcanic activity happening hundreds of thousands of years ago, there’s a possibility it could be happening today, according to the study’s authors.

“This would imply that there is still active magma chamber formation going on in the interior of Mars today and it is not just a cold, sort of dead place, internally,” Bramson said.

Jack Holt, a professor at the at the Lunar and Planetary Laboratory at the University of Arizona, said the question of how water could exist underneath the south polar ice cap immediately came to his mind after the Science paper was published, and the new paper adds an important constraint on the possibility of water being there. He said it will likely add to the debate in the planetary science community about the finding and point out that more research needs to be done to evaluate it.

“I think it was a great idea to do this type of modeling and analysis because you have to explain the water, if it’s there, and so it’s really a critical piece of the puzzle,” said Holt, who was not involved in the new research but did talk to the study’s authors before they submitted the paper. “The original paper just left it hanging. There could be water there, but you have to explain it, and these guys did a really nice job of saying what is required and that salt is not sufficient.”

The post Study Suggests Prospect of Recent Underground Volcanism on Mars appeared first on Eos.

Glacial Census Reveals Ice Thicknesses Around the World

Tue, 02/12/2019 - 17:23

They found that glaciers in southern and central Asia contain, in total, about 50% less ice than previously estimated.There are hundreds of thousands of glaciers worldwide, and many are a major source of fresh water for agriculture. But estimates of both freshwater resources and sea level rise, a by-product of glacial melting, critically hinge on knowing individual glaciers’ thicknesses, data that have been largely lacking. Now researchers have calculated the thicknesses of all of Earth’s nonpolar glaciers on the basis of ice flow dynamics inferred from satellite imagery. They found that glaciers in southern and central Asia contain, in total, about 50% less ice than previously estimated. That’s an unsettling result given the importance of glacial runoff for agriculture in this region, the scientists concluded.

215,000 Glaciers

The thickness of a glacier can be measured using ground-penetrating radar, but this method is laborious and must be applied to individual glaciers. To conduct a census of a large number of glaciers—each of the roughly 215,000 in the Randolph Glacier Inventory—Daniel Farinotti, a glaciologist at Eidgenössische Technische Hochschule Zurich in Switzerland and the Swiss Federal Institute for Forest, Snow and Landscape Research, and his colleagues clearly needed a more efficient technique. The researchers turned to existing models that predicted ice thickness on the basis of satellite-derived glacial topography and ice dynamics: Thicker glaciers tend to flow faster. Farinotti and his collaborators applied up to five different models to each glacier and averaged the results, weighted according to their performance, to reduce the uncertainties associated with relying on just one model.

Farinotti and his colleagues also calculated an ice volume for each glacier by multiplying its area by its thickness. Nonpolar glaciers worldwide have a total ice volume of about 158,000 cubic kilometers, the researchers estimated. That’s enough ice to bury the entire state of California in a layer 400 meters deep.

Less Ice in High Mountain Asia

When the scientists compared their data with previously published values for glaciers in 19 geographical regions, they found striking differences. The largest discrepancy was in High Mountain Asia, a term that encompasses both southern and central Asia and includes countries adjoining the Tibetan Plateau. Farinotti and his colleagues recovered a total ice volume in High Mountain Asia that was 46% lower than the average of previous studies. They attribute this significant difference to advances in satellite imagery, which made it possible to better resolve individual glaciers. “There’s better satellite data,” said Farinotti.

“In light of the importance of glacier melt for the regional water supply, these differences are unsettling.”The implications of a smaller total ice volume in High Mountain Asia will be felt in the coming decades, the researchers suggest. Glacier evolution modeling with these new results suggests that 50% of the glacial area in High Mountain Asia will be gone by the mid-2060s rather than the late 2070s, as predicted by previous estimates. And simulations of glacial discharge with the new data are similarly worrying: Summertime runoff rates near the end of the 21st century will be roughly 6 billion cubic meters lower per month. “In light of the importance of glacier melt for the regional water supply, these differences are unsettling,” the authors concluded in their study, which was published this week in Nature Geoscience.

These new results are important for a variety of calculations ranging from estimates of local and regional water availability to global mean sea level rise, said Georg Kaser, a glaciologist at the University of Innsbruck in Austria not involved in the research. “Knowing the mass of ice stored in glaciers is crucial for projecting any future development of glaciers.”

—Katherine Kornei (hobbies4kk@gmail.com; @katherinekornei), Freelance Science Journalist

The post Glacial Census Reveals Ice Thicknesses Around the World appeared first on Eos.

Tyler Prize Awarded to Climate Scientists Washington and Mann

Tue, 02/12/2019 - 13:45

Climate scientists Michael Mann and Warren Washington are corecipients of this year’s Tyler Prize for Environmental Achievement for their efforts to advance knowledge about climate change, for their “exceptional courage” in working on the issue, and for their commitment to public policy, the prize’s executive committee announced today.

Washington, a distinguished scholar at the National Center for Atmospheric Research, and Mann, a professor of atmospheric science at Pennsylvania State University, are eminent climate scientists who are also experts at communicating the issue to policy makers and the public, the Tyler Prize executive committee stated in its selection of this year’s laureates.

The committee cited Washington’s groundbreaking efforts on climate modeling, which he began working on in 1960 when clunky computers were much slower than today’s computers. The committee stated that “the impact Washington’s climate models have had on improving our understanding of the climate is huge.” Washington, the second African American to receive a Ph.D. in meteorology, “has become an inspiration and a leader to minorities in not only his field, but within the larger science community.”

The Tyler committee applauded Mann for pioneering statistical techniques to reconstruct past global temperatures and for graphically demonstrating through his “hockey stick” graph that “the increase in temperature since the 20th century was both anomalous and historically-unprecedented.” The committee also mentioned attacks on Mann’s science by governments, individuals, and fossil fuel companies and noted that Mann has defended his science and climate science in general while also receiving several awards for his skills in climate communication.

A “Particularly Timely” Recognition

“These two men have done a huge amount to further the science of climate change.”“These two men have done a huge amount to further the science of climate change, to help the public understand the global-scale impact of human actions, and educate the next generation to be interdisciplinary and to tackle this issue so that a sustainable planet can be had,” Tyler Prize executive committee member Rosina Bierbaum told Eos. “We were very happy that the prize has been given to two people who have spent their lifetimes trying to both explain and communicate the short- and long-term impacts of climate change on society.”

The Tyler Award, which comes with a $200,000 prize shared equally between laureates, is considered the premiere international award for environmental science. In 1973 conservationists and philanthropists John and Alice Tyler inaugurated the annual prize, which the University of Southern California administers.

Bierbaum said that “because of the confluence of public interest and attention to climate change,” the award “is particularly timely” this year.

“There has been a genuine tipping point in public opinion in the United States about climate change,” said Bierbaum, who is professor and dean emerita at the University of Michigan’s School of Natural Resources and Environment, which is now the School for Environment and Sustainability. Bierbaum earlier served as acting director of the White House Office of Science and Technology Policy. She said that recent polls show that the American public is growing more concerned about climate change. She also said that recent reports—including the U.S. government’s Fourth National Climate Assessment and the Intergovernmental Panel on Climate Change special report on “Global Warming of 1.5 °C,” both issued in 2018—have helped to crystalize the urgency of dealing with climate change.

Recognizing the Laureates and the Urgency of the Issue

Both laureates told Eos that the prize is important for recognizing not only their own work but the urgency of dealing with climate change. Both also blamed special interests for trying to block action on dealing with climate change.

Washington, who served as the chair of the U.S. National Science Board from 2002 to 2006 and received the National Medal of Science from President Barack Obama in 2010, told Eos that climate modeling has made amazing progress since the late 1950s and early 1960s. Back then, “it took one day of computer time to generate one day of simulation,” he said.

With his many years of studying climate change, Washington said that he is worried about the effects of climate change. Washington said that “people are learning that [climate change] is a serious problem” but that the issue “still hasn’t affected policy makers” as much as he would like.

“We understand that some of the oil and gas and coal supporters have been trying to influence the public about how climate change is not real or it’s a minor effect or that sort of thing,” he said. “We’re making progress [about climate change] but we’re still, on the political side, not solving the problem.”

He said that “it seems like under our system, policy makers are heavily influenced by people who give them money for their campaigns and I think are affecting the resultant policies that come out of Washington and so forth. It’s unfortunate. I think there is a distortion of the priority issues that is actually taking place.”

Washington also expressed concern that President Donald Trump thinks that climate change is fake. “I think that we’ve got to keep pushing back at people like Mr. Trump, unfortunately,” he said. Washington said that if he had an opportunity to speak with Trump, he would tell the president “that climate change is real and happening” but that it’s not too late to take action.

Shining a Light on Climate Change

Climate change is “like a minefield that we are walking out onto and we have to stop walking further out onto that minefield.”Mann told Eos that the Tyler Prize not only recognizes his scientific and communication efforts but helps to shine a light on climate change, which he called “the challenge of our time.” Mann said that he, too, maintains hope that there is still time to slow or mitigate the impacts of climate change.

“By some measures, dangerous climate change has arrived,” and there is a certain amount of damage “that has already happened,” he said. However, Mann emphasized that “it’s not a cliff that we go off” if temperatures increase by 1.5°C or 2°C. “It’s much more like a minefield that we are walking out onto and we have to stop walking further out onto that minefield,” he said. “Every bit of carbon that we don’t burn helps avert further climate changes.”

Mann said that “the only obstacle” to moving forward in dealing with climate change “is political will.” He castigated President Trump for having an “unholy alliance” with “polluting interests” in matters related to energy and climate. Trump “has appointed to cabinet level positions throughout his administration a sort of dream team of fossil fuel lobbyists and climate change deniers who have implemented a deregulatory agenda,” Mann said.

He added, however, that the public’s increasing awareness about climate change coupled with renewed activity in Congress and elsewhere is bringing more focus on climate and is laying the groundwork for action on the issue.

“Dark money outfits”—which contribute money to politicians and others without disclosing the funds’ sources—“have gotten away for too long with very underhanded methods of trying to influence our politics, and I think that they are going to have something to answer for now,” Mann said.

—Randy Showstack (@RandyShowstack), Staff Writer

The post Tyler Prize Awarded to Climate Scientists Washington and Mann appeared first on Eos.

Strengthening Our Science: AGU Launches Ethics and Equity Center

Tue, 02/12/2019 - 13:40

Bias, harassment, and discrimination undermine the entire global scientific enterprise and its ability to benefit humanity.In the next century, our species will face a multitude of challenges. A diverse and inclusive community of researchers ready to lead the way is essential to solving these global-scale challenges. While Earth and space science has made many positive contributions to society over the past century, our community has suffered from a lack of diversity and a culture that tolerates unacceptable and divisive conduct. Bias, harassment, and discrimination create a hostile work climate, undermining the entire global scientific enterprise and its ability to benefit humanity.

As we considered how our Centennial can launch the next century of amazing Earth and space science, we focused on working with our community to build diverse, inclusive, and ethical workplaces where all participants are encouraged to develop their full potential. That’s why I’m so proud to announce the launch of the AGU Ethics and Equity Center, a new hub for comprehensive resources and tools designed to support our community across a range of topics linked to ethics and workplace excellence. The Center will provide resources to individual researchers, students, department heads, and institutional leaders. These resources are designed to help share and promote leading practices on issues ranging from building inclusive environments, to scientific publications and data management, to combating harassment, to example codes of conduct. AGU plans to transform our culture in scientific institutions so we can achieve inclusive excellence.

Resources Including Access to Legal Consultation

The Center includes a pilot initiative to provide free access to consultation with a legal adviser.A key new offering from AGU to be featured through the Center is a pilot initiative to provide free access to consultation with a legal adviser, available to AGU students, postdocs, and untenured faculty members experiencing harassment, bullying, discrimination, retaliation, or other misconduct. Many victims of harassment report feeling alone, scared, ignored, and betrayed. This free legal consultation service is intended to let targets know that they are not alone and to help them chart a course forward. This pilot program is unique in the science community, and we look forward to measuring its benefits.

Overall, the AGU Ethics and Equity Center is designed to help you meet your ethics goals. In addition to the resources described above, visitors will find professional development and ethics-related resources for individual scientists and students, as well as information for organizations and institutions that are looking to implement best practices or update their codes of conduct. The Center will also be a home for information on upcoming ethics- and equity-related workshops, as well as a place where groups can request custom workshops tailored to their own specific needs.

A Partnership Effort

The Center is a natural progression from the update of AGU’s ethics policy recognizing sexual harassment as scientific misconduct.The AGU Ethics and Equity Center is a natural progression from the update of AGU’s ethics policy 2 years ago to recognize sexual harassment as scientific misconduct and our additional AGU policies and practices implemented since then. Led by AGU, the Ethics and Equity Center benefits greatly from partnerships with the National Center for Professional & Research Ethics, the American Geosciences Institute, the Association for Women Geoscientists, the Carnegie Institution for Science, the Earth Science Women’s Network, the Geological Society of America, the International Association for Promoting Geoethics, and the Ecological Society of America. By partnering in this effort, organizations help build and support workplace excellence across the total science community. The ongoing strategic direction of the AGU Ethics and Equity Center will be overseen by an advisory group of ethics experts and experienced leaders from across scientific disciplines and sectors.

Through the AGU Ethics and Equity Center and as a Centennial initiative, we hope to inspire and aggressively support a more vibrant, equitable, and inclusive Earth and space science community into the future. Science is strongest when a diverse set of voices is not simply at the table or in the lab but encouraged to share their perspectives and scientific ideas. We all benefit from more diverse viewpoints to improve our science as we look to another wonderful century of discovery and science for humanity.

—Robin Bell (president@agu.org), President, AGU

The post Strengthening Our Science: AGU Launches Ethics and Equity Center appeared first on Eos.

Unravelling the Past Using Elements and Isotopes

Tue, 02/12/2019 - 13:40

Chemostratigraphy is a comparatively new method for the characterization and interpretation of rock records over different periods of geologic time. A new book, Chemostratigraphy Across Major Chronological Boundaries, recently published by the American Geophysical Union, presents latest applications of chemostratigraphic methods and demonstrates how chemical signatures can decipher past environmental conditions. Here, the editors answer some questions about chemostratigraphy and describe how it can be used to understand the Earth’s past and future.

How does chemostratigraphy differ from, and complement, other stratigraphic methods?

Stratigraphy, in simplest terms, is the study of layers of rock and the processes that created them. The stratigraphic record shows changes in the concentration of certain elements over time caused by fluctuating geological conditions including, but not limited to, tectonic, climatic, redox, oceanographic, biotic, and other processes.

While conventional methods of stratigraphy can identify some of these fluctuations, chemostratigraphy focuses on fine variations in the chemical and isotopic composition of rocks or fossils, thus allowing for a more precise identification of events.

Chemostratigraphy has offered insights where other stratigraphic methods fail or have limitations. For example, the entire subdivision of the Quaternary period is based on oxygen isotope chemostratigraphy. At the other end of the geological record, in the Precambrian, chemostratigraphy is used as a valuable geochronological and correlation tool in strata characterized by a dearth of fossils.

In addition, unlike other methods, the temporal resolution of chemostratigraphy is defined by the sampling interval, which gives a unique edge over all conventional methods.

What are some of the events in Earth’s history that chemostratigraphy has been able to explain?

The Cretaceous-Paleogene boundary of the Højerup section at Stevns Klint, Denmark. Credit: Claudio Gaucher

One example is the causes of mass extinctions. For instance, biostratigraphy (focused on the fossil record found in rock strata) identified the huge Cretaceous-Paleogene boundary extinction, but chemostratigraphy greatly contributed to our understanding of its causes (i.e. asteroid impact versus volcanism), through the identification of heavy-metal enrichments and isotopic shifts in the boundary beds.

Also, the recognition of extreme, near-global glaciations (“Snowball Earth”) in the Neoproterozoic was aided by carbon isotope chemostratigraphy. Likewise, the discovery that the Earth lacked an ozone layer in the Archean, and the identification of its formation in the early Paleoproterozoic, was based mostly on sulphur isotope chemostratigraphy.

What might past geologic events in the chemostratigraphic record be able to tell us about the future?

Rocks are influenced by the environment in which they originated. By definition, any environment can be defined as a set of physical, chemical, and biological conditions. These conditions are all interrelated through the interactions of lithosphere-hydrosphere-atmosphere-biosphere, to which the chemical elements and their isotopes are all sensitive. Hence, through documentation of geochemistry of these geological archives, it is entirely possible to document past environmental variations, such as ocean temperature or ice cap volume, and extrapolate them into the future, enabling the distinction of natural cycles from anthropogenic impacts.

What are some of the major challenges faced by researchers in this field?

Currently, researchers across the world are engaged in documentation of elemental and isotopic variation in stratigraphic successions so that the database can serve as a complement to other stratigraphic methods.

New isotopic systems are being applied and developed every year, demanding new analytical facilities. Furthermore, the meaning of the observed secular variations needs to be understood, presenting researchers with challenges that can only be solved by studying present-day environments and cautiously extrapolating the results to the past.

What are some of the applications of chemostratigraphy?

To date, chemostratigraphy has been used to address geological problems, such as fixation of age, accurate correlation of rocks located in geographically distal regions, identification of climate changes, and hydrocarbon exploration. However, the potential applications are much broader.

They include identification of exact locations of artifacts of ancient cultures through geochemical fingerprinting, understanding the ancient climatic changes, and the reliable identification of ancient catastrophic events, such as meteorite impacts, major volcanic eruptions, ocean chemistry turnover, and extreme glaciations.

Chemostratigraphy is a fascinating and rapidly-evolving field of geoscience. It will continue to shed light into the deep geological past and allow us to reconstruct, in unmatched detail, sudden, catastrophic events.

Chemostratigraphy Across Major Chronological Boundaries, 2018, 320pp., ISBN: 978-1-119-38258-4, list price), $199.95 (hardcover), $159.99 (e-book)

—Alcides N. Sial (email: sial@ufpe.br) and Valderez Pinto Ferreira, Federal University of Pernambuco, Brazil; Claudio Gaucher, University of the Republic, Uruguay; and Muthuvairavasamy Ramkumar, Periyar University, India

Editor’s Note: It is the policy of AGU Publications to invite the authors or editors of newly published books to write a summary for Eos Editors’ Vox.

The post Unravelling the Past Using Elements and Isotopes appeared first on Eos.

Forensic Probe of Bali’s Great Volcano

Tue, 02/12/2019 - 13:39

In November 2017, the world’s eyes were focused on the tourist island of Bali, Indonesia, as Agung erupted for the first time since 1963 [Gertisser et al., 2018] (Figure 1). Locals refer to Gunung Agung, the Bahasa Indonesian term for “great mountain,” as Bali’s “great volcano.” This latest Balinese eruption and the ensuing ashfall required some 150,000 people to evacuate the area and caused airline flight disruptions and widespread anxiety.

Now that Agung has shown signs of reawakening, it is imperative that scientists understand its inner workings.However, this latest eruption was tame compared to the climactic 1963 crisis, in which fast-flowing, glowing hot debris avalanches killed at least 1,100 people. Sulfur-rich gas emitted to the stratosphere during the 1963 event also caused global temperatures to dip by 0.1°C to 0.4°C [Self and Rampino, 2012].

Now that Agung has shown signs of reawakening, it is imperative that scientists understand its inner workings (Figure 1). Our international research team has taken on this challenge. We collected evidence from chemical analysis of volcanic crystals, which now enables us to reconstruct the magma storage network beneath Agung [Geiger et al., 2018].

We found magma storage areas at both mantle (~20 kilometers (km)) and shallow crustal (~5 km) depths beneath Agung. This type of multilevel plumbing system may be typical of Indonesian volcanoes and could cause magma in shallow reservoirs to become enriched in silica and volatile compounds containing sulfur or hydrogen, thus promoting the frequent explosive eruptions observed in the region.

Fig. 1. (a) Agung volcano on Bali peeking out from behind the clouds (right, background) with the Batur crater in the foreground. (b) Eruption of Agung in 2018. Credit: D. Hilton and Ø. Lund Andersen Volcano Forensics

A research team from Sweden, the United States, and Italy collected rock samples from the infamous 1963 lavas of Agung, as well as from the 1963 and 1974 eruptions of Agung’s “twin sister,” Batur. These lava rocks look bland, but when we investigate wafer-thin slices of them under a microscope, a whole world of different crystal types and sizes is revealed (Figure 2).

Fig. 2. Lavas from Agung on Bali contain numerous crystals, such as this pyroxene surrounded by plagioclase feldspar (viewed under a polarizing microscope; field of view is approximately 3 millimeters (mm)). These crystals are held in a groundmass (or matrix) made of tiny, barely perceptible crystals (microlites) and glass (former melt).

Most of the crystals are close to one fifth of a millimeter in size, but some can be as large as 1 millimeter across. These crystals contain a rich archive of information about magmatic processes under and within Agung volcano. The most common minerals in Agung and Batur lavas are pyroxene and plagioclase feldspar, whose chemical composition varies as a function of the pressure and temperature under which they crystallized.

Micrometer-scale chemical data gathered from these minerals can thus be used to calculate their approximate depth of crystallization [Putirka, 2017]. In this way, scientists can make inferences about where magma is stored under a volcano and make predictions about how eruptions are fed, supplied, and, in some cases, sustained for considerable time.

Before the devastating 1963 eruption, magma was stored at multiple levels beneath the volcano, within an interconnected network of melt pockets.“Volcano forensics”—studying minute crystalline components of volcanic rocks—has been very useful for investigating Agung and Batur [see Geiger et al., 2018]. Scientists learned that before the devastating 1963 eruption, magma was stored at multiple levels beneath the volcano, within an interconnected network of melt pockets (Figure 3). One of the main storage levels was at the crust-mantle boundary some 20 km beneath the island’s surface. This is likely the region where magma produced by partial melting of Earth’s mantle meets the lower crust and enters large magma reservoirs. These reservoirs probably form at this boundary level because of the density contrast between the mantle and crust. Mantle-derived magma is basaltic—rich in magnesium and iron and relatively poor in silica—but it is relatively hot, and subduction zone systems often introduce volatiles into the magma. This magma delivers a flush of new volume, heat, and volatiles into the plumbing system, sending shockwaves through the crust, which scientists can detect seismically in the form of deep crustal earthquakes.

Fig. 3. (a) Schematic model of Batur and Agung volcanoes with their underlying magma plumbing systems based on data by Geiger et al. [2018] (map courtesy of NASA). (b) Magma plumbing at Anak Krakatau (Sunda Strait), Merapi (Central Java), Kelut (East Java), and Agung and Batur (Bali) based on literature data presented by Geiger et al. [2018] (map courtesy of Google Earth). Note the ubiquitous presence of shallow arc storage systems (SHARCS) throughout the region. Moho refers to the Mohorovičić discontinuity, the boundary between Earth’s crust and mantle.The other major storage level detected at Agung lies within the top 5 km beneath the volcano. A 2012 study used interferometric synthetic aperture radar (InSAR) to observe deformation indicative of a magma body at just a few kilometers depth [Chaussard and Amelung, 2012], and the existence of a shallow magma body has now been confirmed using petrological methods [Geiger et al., 2018].

When magma is stored in the top portions of Earth’s crust, it cools and crystallizes, changing the composition of the remaining melt so that it becomes more viscous and enriched in alkali elements and silica (e.g., basaltic andesite or andesite composition). Silica-enriched magma, in turn, can dissolve greater amounts of water than basaltic magma, but neither magma type can keep a lot of volatiles in solution under the relatively low pressures of the upper crust. These elemental and volatile enrichments in shallow-level magma reservoirs can be further modified by interaction between magma and hydrous crustal rocks or fluids and, in so doing, promote conditions favorable for explosive eruptions.

Shallow Arc Storage Systems

Crystal-based volcano forensics helps scientists to assess magma storage levels and to evaluate the likelihood of future explosive eruptions. Other studies using thermobarometry and InSAR data have revealed that multilevel plumbing systems are likely also present under other Indonesian volcanoes such as Anak Krakatau, Mount Merapi, and Mount Kelut (Figure 3). These observations suggest that shallow arc storage systems (SHARCS) are a widespread phenomenon in the Sunda subduction system.

The challenge with shallow magma reservoirs is that it remains very difficult to predict when an eruption will occur.The challenge with shallow magma reservoirs is that it remains very difficult to predict when an eruption will occur. It is important to monitor these volcanoes for signs of unrest, such as increased seismicity that might indicate magma or gas movement in the plumbing system. For example, concurrent deep and shallow earthquakes may indicate replenishment of the shallow plumbing system from depth.

In the case of the Agung 2017–2018 events, seismic data from the Indonesian Agency for Meteorology, Climatology and Geophysics (BMKG) initially revealed earthquakes at depths greater than 20 km, which then migrated upward, signaling reactivation of the shallow magma storage system. In 1963, by contrast, the plumbing system at Agung was ripe for a major explosive event, possibly because of the nature of the evolved magma in the shallow crustal magma chamber and the rate and intensity of basaltic injections, which led to a larger and sustained eruption.

In fact, repeated injections of basaltic magma from deep in Earth into high-level andesitic magma bodies might have caused magma mixing and violent expulsion of volatiles from solution prior to the devastating 1963 eruption of Agung [Self and Rampino, 2012] as determined on the basis of evidence from magma chemistry, crystal zoning patterns, and observations of partly dissolved crystals.

Kelut volcano in Eastern Java exhibited only a few days of increased shallow crustal seismicity prior to a short but extremely explosive eruption.However, processes such as cooling, fractionation, and possibly magma-crust interaction can oversaturate the volatiles in SHARCS, which can cause eruptions from shallow reservoirs that are not heralded by deep seismicity. These processes can cause apparently sudden, erratic explosive eruptions, as likely exemplified by the 2014 Valentine’s Day eruption of Kelut volcano in Eastern Java. This volcano exhibited only a few days of increased shallow crustal seismicity prior to a short but extremely explosive eruption [Cassidy et al., 2016]. Another example is the brief but explosive eruption at Merapi in June 2018.

Our research group is currently analyzing recently obtained crystal-scale isotope data. We anticipate that information from these studies and other such emerging volcano forensic techniques will reveal more clues for better understanding the processes and resulting behavior of arc volcanoes like Agung in the near future. Stay tuned!

Acknowledgments

We thank D. Hilton for his earlier contributions to this work and K. Putirka, C. Stein, and an anonymous reviewer for their thoughtful reviews. This work was supported by the Swedish Research Council (Vetenskapsrådet).

The post Forensic Probe of Bali’s Great Volcano appeared first on Eos.

New Research Finds Possible Second Impact Crater Hiding Under Greenland Ice

Mon, 02/11/2019 - 20:42

Scientists have discovered a possible second impact crater buried under more than a mile of ice in northwest Greenland (watch a video about the crater location).

This follows the finding, announced in November 2018, of a 19-mile-wide crater beneath Hiawatha Glacier—the first meteorite impact crater ever discovered under Earth’s ice sheets. Though the newly found impact sites in northwest Greenland are only 114 miles apart, at present they do not appear to have formed at the same time according to the new study, published in AGU’s journal Geophysical Research Letters.

If the second crater, which has a width of over 22 miles, is ultimately confirmed as the result of a meteorite impact, it will be the 22nd largest impact crater found on Earth.

“We’ve surveyed the Earth in many different ways, from land, air and space—it’s exciting that discoveries like these are still possible,” said Joe MacGregor, a glaciologist with NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who participated in both findings.

Before the discovery of the Hiawatha impact crater, scientists generally assumed that most evidence of past impacts in Greenland and Antarctica would have been wiped away by unrelenting erosion by the overlying ice. Following the finding of that first crater, MacGregor checked topographic maps of the rock beneath Greenland’s ice for signs of other craters. Using imagery of the ice surface from the Moderate Resolution Imaging Spectroradiometer instruments aboard NASA’s Terra and Aqua satellites, he soon noticed a circular pattern some 114 miles to the southeast of Hiawatha Glacier. The same circular pattern also showed up in ArcticDEM, a high-resolution digital elevation model of the entire Arctic derived from commercial satellite imagery.

“I began asking myself ‘Is this another impact crater? Do the underlying data support that idea?’,” MacGregor said. “Helping identify one large impact crater beneath the ice was already very exciting, but now it looked like there could be two of them.”

To confirm his suspicion about the possible presence of a second impact crater, MacGregor studied the raw radar images that are used to map the topography of the bedrock beneath the ice, including those collected by NASA’s Operation IceBridge. What he saw under the ice were several distinctive features of a complex impact crater: a flat, bowl-shaped depression in the bedrock that was surrounded by an elevated rim and centrally located peaks, which form when the crater floor equilibrates post-impact. Though the structure isn’t as clearly circular as the Hiawatha crater, MacGregor estimated the second crater’s diameter at 22.7 miles. Measurements from Operation IceBridge also revealed a negative gravity anomaly over the area, which is characteristic of impact craters.

“The only other circular structure that might approach this size would be a collapsed volcanic caldera,” MacGregor said. “But the areas of known volcanic activity in Greenland are several hundred miles away. Also, a volcano should have a clear positive magnetic anomaly, and we don’t see that at all.”

Although the newly found impact craters in northwest Greenland are only 114 miles apart, they do not appear to have been formed at the same time. From the same radar data and ice cores that had been collected nearby, MacGregor and his colleagues determined that the ice in the area was at least 79,000 years old. The layers of ice were smooth, suggesting the ice hadn’t been strongly disturbed during that time. This meant that either the impact happened more than 79,000 years ago or – if it took place more recently– any impact-disturbed ice had long ago flowed out of the area and been replaced by ice from farther inland.

The researchers then looked at rates of erosion: they calculated that a crater of that size would have initially been more half a mile deep between its rim and floor, which is an order of magnitude greater than its present depth. Taking into account a range of plausible erosion rates, they calculated that it would have taken anywhere between roughly a hundred thousand years and a hundred million years for the ice to erode the crater to its current shape – the faster the erosion rate, the younger the crater would be within the plausible range, and vice versa.

“The ice layers above this second crater are unambiguously older than those above Hiawatha, and the second crater is about twice as eroded,” MacGregor said. “If the two did form at the same time, then likely thicker ice above the second crater would have equilibrated with the crater much faster than for Hiawatha.”

To calculate the statistical likelihood that the two craters were created by unrelated impact events, MacGregor’s team used recently published estimates that leverage lunar impact rates to better understand Earth’s harder-to-detect impact record. By employing computer models that can track the production of large craters on Earth, they found that the abundance of said craters that should naturally form close to one another, without the need for a twin impact, was consistent with Earth’s cratering record.

“This does not rule out the possibility that the two new Greenland craters were made in a single event, such as the impact of a well separated binary asteroid, but we cannot make a case for it either,” said William Bottke, a planetary scientist with the Southwest Research Institute in Boulder, Colorado, and co-author of both MacGregor’s paper and the new lunar impact record study.

Indeed, two pairs of unrelated but geographically close craters have already been found in Ukraine and Canada, but the ages of the craters in the pairs are different from one another.

“The existence of a third pair of unrelated craters is modestly surprising but we don’t consider it unlikely,” MacGregor said. “On the whole, the evidence we’ve assembled indicates that this new structure is very likely an impact crater, but presently it looks unlikely to be a twin with Hiawatha.”

The post New Research Finds Possible Second Impact Crater Hiding Under Greenland Ice appeared first on Eos.

Ancient Tsunami Tied to Volcanic Flank Collapse in Italy

Mon, 02/11/2019 - 19:22

The Italian island of Stromboli has long attracted residents and visitors thanks to its mild climate, fertile soils, and picturesque views. But there’s a sinister side to Stromboli—the steep flanks of its active volcano periodically slough off, creating landslides that tumble into the sea and trigger tsunamis. Now, geoscientists and archaeologists have shown that one of these events in the 14th century was likely responsible for the rapid abandonment of the island. An enormous, deadly marine storm reported in Naples in 1343 was also probably due to the same tsunami waves, the researchers proposed. These findings suggest that southern Italy is at a higher risk of tsunamis than previously known.

Something Completely Different

Below 1 meter, we immediately found something that was completely different.Mauro Rosi, a volcanologist at the University of Pisa in Italy, and his colleagues excavated three trenches in the northeastern part of Stromboli to look for signs of ancient tsunamis. Working between 170 and 250 meters from the present-day shoreline, the researchers didn’t have to dig long before their machinery revealed something other than normal soil. “Below 1 meter, we immediately found something that was completely different,” said Rosi. Three clearly defined layers of pebbles and black sand emerged, “closely resembling what you see when you go to the beach,” said Rosi. This material, the researchers surmised, had been swept inland by tsunami waves.

To calculate approximately when these tsunamis occurred, the researchers used carbon-14 dating to age date charcoal fragments buried directly below the tsunami deposits. Rosi and his colleagues estimated that the three tsunamis inundated Stromboli between the 14th and 16th centuries. Focusing on the oldest and largest tsunami, the team found that no large, contemporaneous earthquakes were noted in historical records. The lack of a seismic event, paired with lava records showing a collapse of the volcano’s Sciara del Fuoco (Stream of Fire) lava feature around 1350, pointed to the tsunami waves being triggered by the collapse of the flanks of the volcano, the researchers concluded.

Graves in the Rubble

Rosi and colleagues also used archaeological evidence to show that the tile roof of a medieval church in northeastern Stromboli had collapsed right around the same time. The scientists also found three graves hastily dug in the collapsed tiles that contained human remains. Landslide-induced shaking might have irreparably damaged the church and killed people, the team proposed.This research sheds new light on the persisting hazard of landslide-generated tsunamis in the Tyrrhenian Sea.

Further evidence of this tsunami might also be in literature. In November 1343, the writer Francesco Petrarca recorded a sea storm that pummeled the harbor of Naples, destroyed boats, and killed hundreds of people. It’s entirely conceivable that a tsunami originating on Stromboli could have swept 200 kilometers north and rolled up the shoreline of the Italian mainland, Rosi and his collaborators concluded. Communities in southern Italy may be “exposed to a much higher tsunami hazard than previously thought,” the researchers wrote last month in Scientific Reports.

This research “sheds new light on the persisting hazard of landslide-generated tsunamis in the Tyrrhenian Sea,” said Max Engel, a geomorphologist at the University of Cologne in Germany not involved in the research.

Rosi has a long history with Stromboli—his doctoral thesis in the 1970s focused on the island—and he is looking forward to continuing fieldwork there. In the future, he plans to dig deeper in search of even older tsunami deposits to study how often large waves have struck Stromboli. Extracting history from layers of sediments is hard, however, Rosi admits. “The identification of past tsunami is not an easy task.”

—Katherine Kornei (hobbies4kk@gmail.com; @katherinekornei), Freelance Science Journalist

The post Ancient Tsunami Tied to Volcanic Flank Collapse in Italy appeared first on Eos.

Theme by Danetsoft and Danang Probo Sayekti inspired by Maksimer