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Lobanov Receives 2019 Mineral and Rock Physics Early Career Award

Tue, 04/07/2020 - 12:45
Citation Sergey S. Lobanov

It is my great privilege to honor Dr. Sergey S. Lobanov as the recipient of the 2019 Mineral and Rock Physics (MRP) Early Career Award. Sergey earned his Ph.D. from the Sobolev Institute of Geology and Mineralogy (Novosibirsk, Russia) in 2011 and then moved to the Geophysical Laboratory at the Carnegie Institution for Science in Washington, D.C., as a postdoctoral associate (2012) and a research scientist (2015) to work in my spectroscopy laboratory on the optical properties of planetary materials at high-pressure/temperature conditions. Shortly after moving to Stony Brook University in 2017, where he worked with Prof. John Parise, Sergey received a Helmholtz Young Investigator Group Leaders Award to build his own laboratory at the GFZ German Research Centre for Geosciences in Potsdam, Germany.

Through challenging optical experiments at combined conditions of high pressure and temperature, Sergey identified the mechanisms of light absorption in the mantle and showed that mantle minerals are very opaque at core–mantle boundary conditions. His findings answer a nearly 60-year-long question about the importance of radiative heat transport in the mantle. By identifying specific spectroscopic signatures associated with spin transitions in iron-bearing minerals at mantle conditions, Sergey offered a new recipe to determine the mantle spin state as a function of depth. Another area of his research interests includes the physical and chemical transformation of carbon-bearing minerals and fluids in planetary mantles. After joining GFZ, Sergey constructed a new laboratory for spectroscopic measurements at extreme conditions, and I cannot wait to see the new and exciting results coming out from his research group. Congratulations, Sergey, on your achievements and on your truly deserved award!

—Alexander F. Goncharov, Washington, D.C.



I am honored to receive the 2019 Mineral and Rock Physics Early Career Award and would like to express my deepest gratitude to the AGU MRP section for recognizing my scientific endeavors. I am particularly grateful to Alexander F. Goncharov, who was my postdoc advisor and is a valuable colleague. Alex is by far the most influential figure I have ever worked with. During my time in the Geophysical Lab, he introduced me to the field of high-pressure mineral physics and taught me how to design and perform very challenging experiments. Alex not only has tremendous spectroscopic expertise but also is an endless source of inspiration, creative ideas, and enthusiasm. Where normal humans receive a negative response on a paper and fall into despair, Alex gets excited, beams optimism, and starts new experiments to support the initial research, generating more ideas along the way. This circle is fun to watch but, most important, it promotes discovery and is truly scientific. Alex has contributed greatly to the MRP community and I feel extremely fortunate to be one of his mentees.

I would also like to thank my nominators, the colleagues at Carnegie, Stony Brook University, and GFZ for their friendliness and help, as well as my daughter and wife for being an inspiration and endless source of support.

—Sergey S. Lobanov, GFZ German Research Centre for Geosciences, Potsdam, Germany

Podcast: Paradise Lost

Mon, 04/06/2020 - 17:43


From 1946 to 1958, the U.S. military conducted more than 20 nuclear bomb tests at Bikini Atoll, an idyllic tropical island in the South Pacific Ocean. During the first of these tests, conducted in July 1946, the military anchored nearly 100 warships and submarines within Bikini’s large lagoon to see how a nuclear blast would affect a naval fleet.

The first bomb, in test Able, was detonated in the air and caused a less than expected amount of damage to the fleet. The second bomb, in test Baker, was suspended below a barge and detonated underwater.

Glenn Seaborg, former chairman of the Atomic Energy Commission, called it “the world’s first nuclear disaster.”Baker was far more destructive than the military had planned. It was the first nuclear bomb ever detonated underwater, and chemist Glenn Seaborg, former chairman of the Atomic Energy Commission, called it “the world’s first nuclear disaster.”

The Baker detonation left a crater on the seafloor roughly 800 meters (half a mile) wide and 10 meters (33 feet) deep. The underwater fireball created a supersonic shock wave that expanded outward and crushed the hulls of the closest ships. A colossal column of boiling, radioactive water then poured over the array of target ships, tossing them about like toys in a bathtub.

Three major ships and several small aircraft were sunk within the first few days. The remainder of the fleet was so contaminated with radiation that only 9 of Baker’s original 84 ships were able to be scrapped—the rest were deliberately sunk.

No remnant of the barge from which the bomb was suspended has ever been found. The Baker test was so different from every other detonation that researchers held a conference 2 months later to define all the new phenomena observed in the explosion.

This map of the seafloor in Bikini’s lagoon shows the Baker test crater and various shipwrecks around the site. Credit: Art Trembanis

The original inhabitants of Bikini were evacuated prior to the tests, but the island was so contaminated by radioactivity from the blasts and pollutants released by the sunken ships that they have never been able to return.

University of Delaware professor Art Trembanis spent the summer of 2019 mapping the seafloor around Bikini to see if he could find evidence of the tests all these decades later.

Art and his colleagues have so far discovered the craters from Baker and other tests have left permanent scars on the seafloor around the atoll. The wrecks of sunken ships are still visible and still leaking fuel into the surrounding water, and it is unlikely anyone will be able to inhabit Bikini in the near future.

In the latest episode of AGU’s podcast Third Pod from the Sun, Art tells the story of the Baker test and describes his experience diving through the lagoon’s many shipwrecks. He recounts the mesmerizing sequence of events triggered by the Baker detonation and explains how a tropical paradise became a battleship graveyard.

—Lauren Lipuma (@Tenacious_She), Program Manager, Media Relations, AGU

Different El Niño, Different Paths of North Equatorial Current

Mon, 04/06/2020 - 11:30

The latitude of the North Equatorial Current Bifurcation (NECB) impacts a wide range of large-scale ocean behaviors, such as the Kuroshio, Mindanao Current, and the Indonesian throughflow, with far ranging impacts on the ocean and climate system. It’s been known that the NECB latitude responds to El Niño-Southern Oscillation (ENSO), but the relationship is not rigorous.

Wang et al. [2020] make a meaningful start in detailing the impact of the varied ‘flavors’ of El Niño. Hopefully, it will be helpful to improve the simulation and prediction of the local and global climate, and it will also encourage people to develop a more quantitative study of the coupling of the NECB to larger scale forcing.

Citation: Wang, X., Tong, B., Wang, D., & Yang, L. [2020]. Variations of the North Equatorial Current Bifurcation and the SSH in the western Pacific associated with El Niño flavors. Journal of Geophysical Research: Oceans, 125, e2019JC015733. https://doi.org/10.1029/2019JC015733

—Lei Zhou, Editor, JGR: Oceans

Ancient Impact’s Seismic Waves Reveal Pluto’s Ocean, Core

Mon, 04/06/2020 - 11:07

How do you study the interior of a dwarf planet 5 billion kilometers away? You use an ancient impact.

Millions of years ago, a huge asteroid struck Pluto, creating the landscape we know as Sputnik Planitia, a feature that makes up half of Pluto’s “heart.” A team of scientists now have re-created those ancient waves to study Pluto’s internal structure. They found that Pluto might have a substantially thick internal ocean and a core that hints at an environment potentially habitable to life.

Could Pluto’s ocean be interacting with its rocky floor in a way that produces chemicals necessary to sustain life?“Once you go even a little bit beneath the surface of Pluto, there’s just a lot of question marks,” Adeene Denton, a planetary scientist at Purdue University in West Lafayette, Ind., told Eos. “And the work that I did was trying to remove a few of those question marks.” Denton was scheduled to present the research at the canceled Lunar and Planetary Science Conference on 17 March.

In July 2015, NASA’s New Horizons spacecraft unveiled Pluto to us in unprecedented detail as it zoomed by the dwarf planet at 14 kilometers per second (that’s about 31,000 miles per hour). Scientists discovered a geologically active surface covered in ice mountains, smooth plains, and oozing, nitrogen ice glaciers. There’s even a thin, hazy atmosphere made up of nitrogen, carbon dioxide, and methane.

NASA’s New Horizons spacecraft captured this image of Pluto as it whizzed by on 14 July 2015. Sputnik Planitia, a vast region of ice that makes up part of Pluto’s heart, is thought to be an ancient impact basin. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Alex Parker

Scientists are also fairly certain there’s an ocean sloshing around beneath Pluto’s icy surface, but the details of that ocean remain a mystery. How deep is the ocean? What kind of rock makes up its floor? Could that ocean be interacting with its rocky floor in a way that produces chemicals necessary to sustain life? These are the questions Denton set out to answer.

Pluto’s farside, which New Horizons saw from a distance as it approached the dwarf planet, inspired Denton to investigate further. At almost exactly opposite Sputnik Planitia (at Sputnik’s “antipode”), other scientists had spotted geological features that resemble grabens on Earth. Grabens are extensional rifts that form as a continental plate is split and pulled apart by faults. They look like a series of high plateaus and valleys, striping the surface.

“Curiously, a lot of the weirdest stuff on Pluto’s far side is close to the antipode of Sputnik Planitia,” James Tuttle Keane, a planetary scientist at NASA’s Jet Propulsion Laboratory who has studied these antipodal features, said in an email. “When these seismic waves collide on the opposite side of the body, they can amplify and result in intense surface deformation.”

Denton wondered whether Pluto’s internal structure (namely, its core and subsurface ocean) acted as a lens to focus the impact waves to deform the opposite surface. On Earth, scientists use instruments that measure seismic waves—waves of energy produced by large movements or breaking of rock, either on Earth’s surface or below—to study our planet’s interior. These waves travel faster or slower through different kinds of material, and studying them helped us understand the structure of Earth.

This image of Pluto’s farside was captured by NASA’s New Horizons spacecraft on 11 July 2015, when New Horizons was still 4 million kilometers (2.5 million miles) away from Pluto. Credit: NASA/JHUAPL/SWRI

But we can’t send seismometers to Pluto, so Denton decided to study the waves of the ancient impact that created Sputnik Planitia. Using a computer program that models impacts, Denton tweaked the interior properties of Pluto to see how different combinations of core composition and ocean thickness affected seismic wave propagation.

What Denton found was that a core made primarily of serpentine and a 150-kilometer-thick ocean could act to focus those waves strongly enough to rupture Pluto’s surface antipodal to the impact. Other compositions, like a dunnite core or a thicker or thinner ocean, didn’t focus the waves in the right way, Denton said.

Finding a serpentine core could lead to some exciting new questions. Serpentine is a mineral that forms when seawater reacts with rock. On Earth, these reactions occur deep in the ocean, between seawater and exposed mantle rock, which is primarily made of olivine and pyroxene. When the rock and seawater react, serpentine forms, and those reactions release heat and molecules useful to life. In our oceans, bacteria colonize places where serpentinization occurs, such as in the Lost City hydrothermal field in the northern Atlantic Ocean. Some scientists propose that serpentinization could have occurred—or could be an active process—on other ocean worlds, like Saturn’s moon Enceladus or Jupiter’s moon Europa.

If Pluto does have a serpentine core and a substantial subsurfac­e ocean, then “theoretically, you have an environment that might be conducive to life in some capacity.”If Pluto does have a serpentine core and a substantial subsurface ocean, then “theoretically, you have an environment that might be conducive to life in some capacity,” Denton said.

The new research “sets up a lot of new testable hypotheses for a future Pluto mission, which NASA is actively talking about,” Keane said.

And the research has implications that stretch farther than to just Pluto. “There are a lot more Kuiper Belt objects out there than just Pluto, and if Pluto is geologically active and hosts a potentially habitable location in its interior, that really opens up what’s possible for Kuiper Belt objects in general,” Denton said.

—JoAnna Wendel (@JoAnnaScience), Freelance Writer

The Stuff That Psyche Is Made Of

Mon, 04/06/2020 - 11:03

Psyche is a large, peculiar asteroid that orbits the Sun in our solar system’s asteroid belt. Although most asteroids are made primarily of rock or ice, Psyche is abundant in metal, suggesting that it could be the remnant core of an early planet. Now Elkins-Tanton et al. report that Psyche may have a higher ratio of rock to metal than previously hypothesized.

In preparation for a NASA mission to Psyche set to launch in 2022, the researchers reviewed and analyzed reports on the latest observations of the asteroid, including data from mass and volume calculations, radar measurements, and investigations of Psyche’s spectral signature.

The analysis suggests that Psyche, which is about 226 kilometers in diameter, has a density of 3,400–4,100 kilograms per cubic meter. And although earlier observations suggested that the asteroid consists almost entirely of iron and nickel, it now appears that those metals make up only 30%–60% of its volume, with the rest consisting of silicate rock and pore space.

The origin of Psyche, the details of its structure, and the specific kinds of rock it contains remain mysterious. Is Psyche indeed the core of an early planet that was stripped of its outer layers by impacts with other objects? If so, what did that planet look like, and what kinds of collisions and other conditions shaped its fate? Or did it form in some previously unimagined scenario?

The new findings help constrain the possible answers to these questions, providing valuable context for the upcoming mission to Psyche—the first mission to a metallic asteroid. Observing Psyche up close should provide final answers about the asteroid and could improve understanding of how Earth and other planets formed. (Journal of Geophysical Research: Planets, https://doi.org/10.1029/2019JE006296, 2020)

—Sarah Stanley, Science Writer

Kustas Receives 2019 Hydrologic Sciences Award

Mon, 04/06/2020 - 11:02
Citation William P. Kustas

Dr. William Kustas has achieved groundbreaking results in advancing both the science and the application of remote sensing and the modeling of soil–plant–atmosphere dynamics to address hydrologic and climate problems. His sustained original contributions in hydrology are highly appreciated by scientists internationally.

William Kustas has contributed important advances in the development of techniques, based on atmospheric boundary layer similarity theory and heat and water vapor conservation equations, for computing surface fluxes of latent and sensible heat at regional scales over complex terrain.

He has conceived and designed large-scale multidisciplinary remote sensing field experiments to integrate remote sensing, hydrologic, atmospheric, and biological measurements over a range of temporal and spatial resolutions. He has been a leader in the design and coordination of surface flux measurement networks for joint NASA–U.S. Department of Agriculture (USDA) large-scale multidisciplinary field experiments in various ecosystems and has led numerous cooperative studies to evaluate the utility of micrometeorological measurement techniques.

He has pioneered the development of physically based models to estimate soil and vegetation heat fluxes using remote sensing. His approaches have been major breakthroughs in the application of remotely sensed surface temperature for evapotranspiration modeling over variable surfaces, including the combination of microwave and optical remote sensing information. His methods are now regularly used for the mapping of surface fluxes at basin and regional scales for continuous global-scale evapotranspiration monitoring.

William Kustas is particularly well known for his scholarly generosity. As one of the outstanding leaders in our profession, he has done much to advance and create opportunities for early-career researchers.

—Marc Parlange, Monash University, Australia



I am both honored and humbled to be selected to receive this year’s Hydrologic Sciences Award, especially given the class of past recipients. I would like to thank my nominator, Marc Parlange, and the supporting letter writers, as well as the awards committee members, for my selection.

My 33-year research career, after I earned a Ph.D. under the guidance of Wilfried Brutsaert, has been with the USDA Agricultural Research Service (ARS) conducting basic and applied research on evapotranspiration (ET) modeling using remote sensing. The U.S. Water Conservation Lab had a tremendous impact on my early career, and I am truly indebted to former lab members—the late Ray Jackson and Bob Reginato and Susan Moran.

Throughout my career, I’ve been involved in large-scale remote sensing field experiments focused on the measurement and modeling of land surface fluxes over a wide variety of landscapes both in the United States and abroad. I am very thankful to the many ARS and university colleagues involved in these experiments and need to mention several who significantly contributed to their success: Tom Jackson, John Prueger, Jerry Hatfield, Dave Goodrich, Steve Evett, Larry Hipps, and John Norman.

John Norman had a tremendous impact on my career in the early 1990s collaborating on the development of the two-source energy balance model. This work reestablished the utility of land surface temperature for modeling ET over complex surfaces. Working with ARS and NASA colleagues Martha Anderson and Chris Hain led to the development of a multiscale two-source land surface modeling system that has facilitated the resurgence of thermal remote sensing as the primary tool for ET mapping from field to global scales.

This award also belongs to the many students, postdocs, and research colleagues, as well as ARS science support staff, with whom I have had the privilege of working throughout my career. I am very grateful for their contributions recognized by this award.

—William P. Kustas, Hydrology and Remote Sensing Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Md.

Konar, Long, and Madani Receive 2019 Hydrologic Sciences Early Career Award

Mon, 04/06/2020 - 11:01
Citation for Megan Konar Megan Konar

Megan Konar’s scholarship has transformed our understanding of how economic and social forces influence global hydrologic flows and clarified the effects of these coupled dynamics on water security challenges. She has distinguished herself as a scholar who is exceptionally creative in addressing compelling water resources questions in coupled human–natural systems. Megan can move—seemingly effortlessly—between fundamental contributions to the field and more general synthesis and integrative work that resonates across academia. In my opinion, her capacity to integrate disciplinary expertise and multidisciplinary impact is something that Megan does better than any other young hydrologist working today.

At Princeton University, Megan’s Ph.D. research was the first to quantify the global virtual water trade network and to assess its temporal dynamics. She has continued to build on those efforts at the University of Illinois at Urbana-Champaign, where she is addressing how climate change and trade policies combine to affect water use for the countries of the world. Most recently, she has shown that open trade leads to less water use for nations, on average. These efforts are notable not just for the breadth of their intellectual ambition but also for the depth of rigor with which she addresses such complex, multidisciplinary topics.

In every one of her research manuscripts, Megan asks insightful questions and adopts novel quantitative approaches to reveal the fundamental roles that agricultural water use and food trade play in governing the vulnerability and resiliency of coupled water and food systems. She is conducting trailblazing work and successfully mentoring her students to push the boundaries of what it means to do interdisciplinary water resources science. In all respects, Dr. Konar’s research trajectory has already established her as a world leader in the study of the water–food–trade nexus and the characterization of coupled natural–human water resources systems.

—Kelly Caylor, University of California, Santa Barbara



I am deeply honored to receive the Hydrologic Sciences Early Career Award. This award is particularly meaningful to me because my research is interdisciplinary, yet I have always felt welcomed and encouraged by the AGU hydrology community. First and foremost, I would like to thank Kelly Caylor for his nomination and generous citation. He is my role model and a constant source of inspiration. In addition, I would like to thank Arjen Hoekstra, George Hornberger, Bridget Scanlon, and Eric Wood for their support throughout the nomination process and my career. Murugesu Sivapalan has been an essential mentor and advocate for me during my early faculty career.

I was lucky to have an amazing cohort during my Ph.D. at Princeton. I would not be where I am today without my grad school friends and mentors. Ignacio Rodríguez-Iturbe was a wonderful advisor who pushed me to ask exciting questions and strive for elegant solutions. Carole Dalin and I were in the same group and have been close collaborators and friends ever since. I am also deeply grateful for Tara Troy’s friendship and peer mentoring for more than a decade.

I am especially indebted to my amazing students and collaborators, with whom I share this award. My colleagues in civil and environmental engineering at Illinois have been wonderful to work with. I benefited from camaraderie and weekly lunches with my Hydro colleagues (Ximing Cai, Marcelo Garcia, Praveen Kumar, Gary Parker, Art Schmidt, Ashlynn Stillwell, Rafael Tinoco, and Albert Valocchi). I had two children on the tenure clock and am grateful for the family-friendly atmosphere and policies at Illinois. My children, Sarah, 6, and Sam, 3, are constantly entertaining and a source of motivation. Rus Irani, my husband, has been instrumental to everything and has made it all a wonderfully fun journey.

—Megan Konar, University of Illinois at Urbana-Champaign


Citation for Di Long Di Long

Di Long is receiving the Hydrologic Sciences Early Career Award for pioneering work aimed at monitoring space–time dynamics of the water balance using remote sensing. His major contributions include development of remote sensing methods to retrieve almost every term in the land surface water balance with high accuracy and spatiotemporal resolution. Remote sensing algorithms he has developed have been incorporated into hydrological models to address snow and ice melt contributions to total runoff in alpine regions.

Di Long’s early work focused on evapotranspiration estimation using thermal infrared remote sensing. He developed parameterization schemes of energy balance for dry and wet limits of soil moisture, through interpretations of the relationships among land surface temperature, vegetation cover, and soil moisture, helping to improve earlier generations of models of spatial evapotranspiration. In later work, he expanded his research to the estimation of large-scale changes in groundwater storage using data from gravimetric satellites (Gravity Recovery and Climate Experiment (GRACE)) and to improving the spatial resolution and reliability of water storage changes. Back in China, he developed algorithms to retrieve precipitation, river water levels, and discharge, as well as soil moisture, in the Tibetan Plateau. These have led to major improvements in the understanding of hydrological processes over alpine regions.

Rapid development of satellite remote sensing has provided an unprecedented opportunity to capture spatiotemporal variability in atmospheric and land surface processes and properties and to address scientific questions related to predictions in ungauged basins. Dr Long is positioned at the cutting edge of this exciting area of research and is destined for a stellar career combining hydrological modeling and remote sensing at large scales. Di Long’s outstanding contributions to research, his mentoring of students, and his leadership of and service to the hydrological community merit his receiving the Hydrologic Sciences Early Career Award.

—Murugesu Sivapalan, University of Illinois at Urbana-Champaign



I am honored and delighted to receive this prestigious award. First and foremost, I am grateful to Murugesu Sivapalan for his generous nomination; the honors committee; the AGU Hydrology section; my advisors, Vijay Singh and Bridget Scanlon; and Martyn Clark, for their support. I appreciate all of the people who have helped me with my career.

I was very much inspired by the groundbreaking work of many pioneers who have advanced the field of remote sensing in hydrology. I have been keenly interested in hydrology and remote sensing since my Ph.D. work under Vijay Singh at Texas A&M University. Following that, I enjoyed working with Bridget Scanlon and Laurent Longuevergne at the University of Texas at Austin, who generously helped me expand my expertise to include GRACE and land surface models. Since that time, my vision of remote sensing in hydrology has been broadened by looking at water storage changes from many different angles. This has helped me understand the strengths and limitations of different approaches and to try to capitalize on the distinct advantages of each.

It is my privilege to work with many passionate students and colleagues at Tsinghua University on the hydrology of the Tibetan Plateau, which affects freshwater availability for many downstream Asian countries. The combination of remote sensing, ground measurements, and modeling has great potential for improving our understanding of hydrological processes under a changing environment, which should help to mitigate climate change impacts on society. I plan to continue to pursue this topic throughout my career. As ever more satellites are launched and more cutting-edge observation technology developed, hydrology should exploit data analytics and artificial intelligence to continue our rapid progress into the future.

And last but not least, I am indebted to my parents, my wife, and my son for their strong support and enduring love.

—Di Long, Tsinghua University, Beijing, China


Citation for Kaveh Madani Kaveh Madani

Kaveh Madani receives this award for his fundamental contributions to integrating game theory and decision analysis methods into conventional water resources systems models. His proven dedication to education, outreach, raising public awareness on environmental and climate issues, and selfless service to the hydrologic sciences community has had major societal impacts.

Kaveh is without doubt among the most productive, well-cited, and active members of our community, with exemplary work at the interface of science, policy, and society. His influence on our profession and the real world over the years has been both consistent and striking. The research questions he asks and addresses are creative, provocative, and socially meaningful, a combination that is unique in academia.

The number of Kaveh’s innovative, scientifically rigorous, and interdisciplinary publications in our top professional journals is as impressive as the breadth of his research portfolio, which spans the areas of hydrology, engineering, systems analysis, economics, and human behavior. Kaveh’s pioneering argument that traditional water management models suffer inherently from a full-cooperation and group rationality assumption has spawned new research directions and garnered the attention of thought leaders in the field.

Kaveh’s success in bridging the gap between academic theory and practice is exemplary. He is highly respected in the field for his strong leadership both within (e.g., chair of AGU’s Water and Society Technical Committee) and outside of academia. He has served as a tireless promoter of our scientific community and has been truly dedicated to raising public awareness around key water, environmental, agricultural, and climate change issues.

Other unique accomplishments of Kaveh include his unprecedented societal impacts and contributions as a politician and ambassador of our field in the real world. He is among the few scientists in the AGU community who has had the courage, capacity, and credibility to serve as a high-level environmental decision-maker at national and international levels (e.g., deputy minister of environment in Iran and vice president of the U.N. Environment Assembly Bureau).

Kaveh Madani is indeed an unparalleled early-career role model in our field with an extraordinary record compared with his peers at his career stage. For all his contributions, the Hydrologic Sciences Early Career Award is a richly deserved recognition.

—Rajagopalan Balaji, AGU Fellow; Chair, Department of Civil, Environmental and Architectural Engineering, University of Colorado Boulder



Thank you so much, Balaji, for leading the nomination and for your generous citation. I am also grateful to those colleagues who kindly supported this nomination. As a nontraditional hydrologist who is still having a hard time publishing papers in water resources journals because of talking too much about the human dimension of water and natural resources problems, I am truly humbled and honored to receive this award. I would like to thank AGU and the Hydrology section for this encouraging recognition, which I owe to my remarkable collaborators, students, and mentors.

My deepest gratitude goes to the mentors who have positively affected my life and led me to this point. My professors at the University of Tabriz supported my ambitious plans as the chair of the civil engineering students club and gave me the courage to lead big groups and projects. Rolf Larsson (Lund University) encouraged my move to North America after studies in Iran and Sweden. His positive feedback on an immature work of mine to capture the dynamic feedback relationship between water and society gave me the confidence I needed to pursue my research interests at the interface of engineering, science, and policy. Keith Hipel (University of Waterloo) got me interested in game theory when I spent a semester with him in Canada before moving to the United States. Jay Lund (University of California, Davis), my Ph.D. adviser, was always supportive of my curiosity in taking random courses in law, economics, and political science. He encouraged me to do more work on game theory to develop my own niche of research and independence. Ariel Dinar (University of California, Riverside), my postdoc adviser, gave me the freedom of doing what I liked even though the path was not that clear at the time. Our heated debates over the mathematical sophistication and practical validity of various engineering, economic, and natural science methods certainly made me a better communicator when working with people of other disciplines.

Special thanks go to my students, postdocs, and research group members for their hard work and indispensable contributions to my success. Working with and learning from them have been a true pleasure.

I have benefited from the friendship and wisdom of many colleagues during my unusual career. I wish I could name them all here, but I want to make special mention of Amir AghaKouchak, Ali Alaeipour, Abbas Amanat, Ali Bagheri, Ronny Berndtsson, Michael Campana, Andrea Castelletti, Greg Characklis, Gia Destouni, Julien Harou, Zahra Kalantari, Mohammad Karamouz, Joe Kasprzyk, Björn Klöve, Hugo Loaiciga, Pete Loucks, Arash Marashi, Miguel Mariño, Josue Medellin-Azuara, Ali Mirchi, Amin Moazedi, Hamid Moradkhani, Sarah Null, Marcelo Olivares, Laura Read, Pat Reed, Debra Reinhart, Omid Rouhani, David Rosenberg, Soroosh Sorooshian, and Cintia Uvo for their generous support and for making my academic journey memorable and exciting.

Last but not least, I would like to thank my family for their unconditional love and support throughout my life. They have made and continue to make many sacrifices for me to realize my goals and aspirations.

—Kaveh Madani, Yale University, New Haven, Conn.

Finding Natural Solutions to Man-Made Problems in River Deltas

Fri, 04/03/2020 - 13:34

River deltas are dynamic systems, fed by sediment flows and shaped by tides and wave action over long timescales. They’ve long proved fertile ground for human civilization. Many of the world’s biggest cities are located on river deltas, where easy access to marine transport, fishing, and coastal soils gives them an economic boost. But human activities and climate change have led to the instability of deltas around the globe, threatening the ecosystem services they provide. Reservoirs and demand for sand, for example, have left many deltas starved of sediment: The Nile Delta, the Mississippi Delta, and the Yellow River Delta are all experiencing shoreline erosion as sea level rise, land subsidence, and dwindling sediment supply interact.

Coastal communities have a vested interest in promoting delta resilience, but there’s growing understanding that our conventional and inflexible strategies for managing deltas—including storm surge barriers and river embankments—are unsustainable in the face of climate change. Managers are turning to nature-based solutions, but those solutions require deep knowledge of stable delta behavior. There is almost no place on Earth left undisturbed by human activities, which makes modeling and predicting modern delta behavior all the more challenging. It’s critical to develop natural solutions to contest the challenges deltas face.

Here Hoitink et al. synthesize recent research on river deltas to identify the ways that human activities interact with natural processes to create instability and discuss the tools that researchers can use to better understand those processes and render deltas resilient. The study area spanned the globe, using the best-studied delta systems, such as the Mississippi in the United States, the Rhine-Meuse in the Netherlands, and the Yellow River of China, to inform about process evolution of deltas.

The team identified four main processes revealing delta instability that relate to both natural dynamics and human activities: riverbank failure, channel incision and siltation, river avulsions, and a shift to hyperturbidity. These processes take place over a wide range of spatial and temporal scales. Riverbank failure, or a dredging-induced hyperconcentration of suspended sediment, can occur over relatively short timescales (years to decades), whereas channel bed erosion and the formation of a new deltaic landscape may require centuries.

The authors call for the development and improvement of a host of analysis tools to better understand these complex processes, including numerical modeling, network and dynamic system theory, and direct and continuous observations. Empirical data sets on the behavior of past and present river delta systems can help inform predictions of delta behavior in the future.

The major challenges that remain, according to the authors, are determining the annual sediment balance, predicting the impacts of dwindling sediment supply and sea level rise, and combining approaches to monitoring and modeling river deltas to optimize our understanding of river delta resilience in our rapidly changing world. (Journal of Geophysical Research: Earth Surface, https://doi.org/10.1029/2019JF005201, 2020)

—Kate Wheeling, Science Writer

This Week: From EPA Enforcement to Underwater Eruptions

Fri, 04/03/2020 - 13:33

EPA Suspends Enforcement of Environmental Laws Amid Coronavirus. In case you missed the news: The U.S. Environmental Protection Agency (EPA) is no longer telling companies they must adhere to environmental laws. The temporary policy has no end date, and as Rebecca Beitsch reports for The Hill, it came after calls from industries to relax environmental goals amid coronavirus uncertainty. —Jenessa Duncombe, Staff Writer


A Decade of Science Since Deepwater Horizon.

Ten years ago, the worst oil spill in recorded history happened in the Gulf of Mexico, but from that tragedy also came enormous funding and support for science. Our April issue of Eos is dedicated to those who worked under pressure to stop the spill and who came together afterward to build huge support networks, like the Gulf Research Project and the Gulf of Mexico Research Initiative, to create a scientific movement. —Heather Goss, Editor in Chief



Coronavirus Lockdowns Have Changed the Way Earth Moves. Yet another way COVID-19 is affecting science, but this time it’s good. The drop in traffic—by foot, car, bus, train, and truck—is giving seismologists a clearer picture of the subtle movements of the Earth. The reduction of anthropogenic seismic noise is boosting the sensitivity of instruments designed to locate earthquake aftershocks and study the crashing of ocean waves. —Kimberly Cartier, Staff Writer


Satellite Sleuthing Detects Underwater Eruptions.

This satellite imagery shows the sea surface on 6 August 2019 following the eruption of Volcano F. UTC = coordinated universal time; Bft 5 = Beaufort scale category 5 winds, corresponding to 29–38 kilometers per hour. Credit: European Space Agency, Copernicus Sentinel-2, modified by Philipp Brandl

Underwater volcanoes may be out of sight, but just like their terrestrial kin, they can still be extremely hazardous, releasing plumes of gas and floating debris and sometimes triggering landslides and tsunamis. Tracking underwater eruptions is tricky because it’s difficult to monitor what we can’t readily see or reach. This piece highlights research into the (initially unknown) volcanic origins of a vast raft of floating pumice ejected during an eruption last summer in the South Pacific Ocean and discusses how combining remote sensing and other emerging methods with existing techniques like seismic monitoring could give us a better handle on these submarine hazards. —Timothy Oleson, Science Editor


Coronavirus Concerns Force Arctic Mission to Cancel Research Flights. The reach of COVID-19 stretches everywhere, including to the R/V Polarstern, which has been locked in Arctic sea ice. The Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition now faces questions about how to rotate scientists on and off the ship and keep the virus from making its way on board. Some research has already been canceled. —Tshawna Byerly, Copy Editor


Armageddon at 10,000 BCE.

The Paleolithic settlement of Abu Hureyra, in what is now Syria, may have been destroyed by the airburst of an impacting comet about 12,800 years ago. Credit: Jennifer Rice, CometResearchGroup.org

Do you need a better recommendation than that headline? —Caryl-Sue, Managing Editor


Keppel-Aleks, Swann, and Xu Receive 2019 Global Environmental Change Early Career Award

Fri, 04/03/2020 - 13:25
Citation for Gretchen Keppel-Aleks Gretchen Keppel-Aleks

Dr. Keppel-Aleks is a rising leader in the carbon cycle community. Her research uniquely combines observational and modeling tools to increase understanding of the effects of climate variability on the carbon cycle. She has made notable contributions to our understanding of the role of the terrestrial land sink in a very short period of time and has linked a range of disciplines that represent the Global Environmental Change community.

To provide constraints from atmosphere and space-based observations, Dr. Keppel-Aleks has integrated remote sensing and ground-based observations to understand the flux of carbon from the terrestrial biosphere, including remote sensing data sets (such as NASA’s Orbiting Carbon Observatory (OCO-2)) and solar-induced chlorophyll fluorescence (SIF). In addition, Keppel-Aleks is part of a team to develop and deploy tower-based spectrometer systems to connect satellite-derived SIF and ecosystem models. Her research combines a suite of various and disparate observations and tools to improve our understanding of the terrestrial carbon sink. Further, Keppel-Aleks has linked this observational framework with that of the Earth system modeling community to improve our understanding of climate-driven variations in the global carbon cycle, using modeling tools such as the Community Earth System model.

Dr. Keppel-Aleks has already taken on several leadership positions in the field, including her participation on the OCO-2 science team, as a coauthor on the U.S. State of the Carbon Cycle Report (SOCCR-2), as a cochair for the Biogeochemistry Working Group for the National Center for Atmospheric Research Community Earth System model, and as a member of the Department of Energy’s International Land Model Benchmarking (ILAMB) team. Her nominators also cite her excellent mentoring of students in the community, and I have seen this firsthand at Michigan. Dr. Keppel-Aleks has developed a diverse group and provides the support to produce excellent science in her research team.

Dr. Keppel-Aleks is an outstanding young scientist who has developed a deep and broad approach to address one of the greatest environmental conundrums of this generation.

—Allison Steiner, University of Michigan, Ann Arbor



Thank you, Allison, for your kind words. It is humbling to have been nominated by a colleague who inspires me with her interdisciplinary research approach and with her commitment to forging a more equitable and inclusive scientific community. Both of these facets—interdisciplinarity and inclusivity—are necessary to confront the scientific and social challenges posed by climate change. The research that falls under the AGU Global Environmental Change section addresses the most pressing scientific questions faced by my generation, and it is an honor to receive this section award.

This award is a reminder of how privileged I am to engage in interesting and thought-provoking work each day. Much of the joy in doing science stems from the opportunity to collaborate with and learn from other scientists. This award reflects the outstanding mentorship from which I have benefited over the course of my career. I especially acknowledge senior scientists who have taught me how to think creatively and deeply about the Earth system and the tools we use to understand it, especially Scott Doney, Jim Randerson, Tapio Schneider, Geoffrey Toon, and Paul Wennberg. It has been a pleasure to have friends from my graduate and postdoctoral programs turn into collaborators and sounding boards, especially Dan Feldman, Tim Merlis, Brendan Rogers, Rebecca Washenfelder, and Debra Wunch. This award also affirms the efforts of the next generation of scientists whom I have been fortunate to teach and advise at the University of Michigan.

Finally, I want to thank my family, especially Aaron Wolf, for their support. On the days that I am not optimistic that human civilization is up to the challenge, the people I love keep me going.

—Gretchen Keppel-Aleks, University of Michigan, Ann Arbor


Citation for Abigail L. S. Swann Abigail L. S. Swann

Abigail L. S. Swann is being recognized with the Global Environmental Change Early Career Award for her innovative, interdisciplinary research coupling vegetation and the atmosphere. Dr. Swann has appointments in the Department of Atmospheric Sciences and the Department of Biology at the University of Washington. Her contributions lie within three overlapping areas: (1) She focuses on an obvious but amazingly overlooked set of processes: how vegetation change affects climate, both locally and elsewhere, subsequently affecting vegetation elsewhere—termed an “ecoclimate teleconnection.” (2) She possesses an extremely rare skill set enabling her to run Earth system models focusing on the atmosphere as well as running relevant linked ecological models. (3) She is rapidly, creatively demonstrating the relevance of ecoclimate teleconnections for a variety of vegetation response types, at a variety of spatial scales, and for a variety of applied problems.

Dr. Swann evaluated the consequences of afforestation (adding forests) to Northern Hemisphere grasslands, a commonly discussed carbon sequestration strategy, and showed that such vegetation change could alter the position of the Intertropical Convergence Zone. Dr. Swann also focused on the converse of regional-scale afforestation—regional-scale loss of tree cover from die-off or deforestation. Her simulations reveal important cross-hemisphere impacts of tree loss from western North America or the Amazon Basin.

The potential importance of ecoclimate teleconnections is profound. On the basis of the Paris Agreement, there is now an attempt to move toward globally coordinated carbon management. Dr. Swann’s work reveals how forest changes in one continent (e.g., either increasing or decreasing forest area) could affect another. Consequently, carbon gains in one area could have a negative impact on the productivity and associated carbon dynamics in another. This has profound implications for carbon management.

Abby is making enormous contributions to science, and I am extremely privileged to have had opportunities to collaborate with her.

—David D. Breshears, University of Arizona, Tucson



I am honored to receive the Global Environmental Change Early Career Award. Thank you, Dave, for nominating me and for your kind words. Collaborating with you has been a productive, educational, and thoroughly enjoyable experience.

I am lucky to have had the opportunity to work with many people who have broadened my scientific and academic thinking and helped me to tackle problems at the boundaries between traditional academic disciplines. I am grateful for my colleagues and collaborators who have provided both formal and informal mentorship. Inez Fung has played the central role in teaching me how to do science and be a scientist, serving as a mentor since I was an undergraduate. Becky Alexander, Cecilia Bitz, Gordon Bonan, Dave Breshears, Emily Fischer, Charlie Koven, Jim Randerson, Scott Saleska, and LuAnne Thompson have all provided critical support in science and beyond. I am so appreciative to have had the opportunity to work with graduate students and postdocs Greg Quetin, Marlies Kovenock, Marysa Laguë, Elizabeth Garcia, Jennifer Hsiao, Claire Zarakas, and Greta Shum. My peer support group of women scientists at the University of Washington has been invaluable in helping me through the day-to-day challenges of research and academia. I also owe a huge debt of gratitude to my partner and our two children for their love and support.

Finally, I am happy to join Gretchen Keppel-Aleks in the 2019 cohort for this early-career award; however, I strongly believe that as a community we can and must do more to increase nominations of and awards to women and scientists from underrepresented groups for all honors, but especially for early-career awards. In failing to represent all members of our community in awards and honors, we perpetuate a history of unequal opportunities for success in our field.

—Abigail L. S. Swann, University of Washington, Seattle


Citation for Yangyang Xu Yangyang Xu

Yangyang Xu’s research has provided vital insights into major issues related to both the science of climate change and the mitigation of climate change. While still a graduate student, Xu led and completed a multi-institutional study on hydrofluorocarbon (HFC) forcing and its mitigation potential for 21st-century projected trends. This had a major impact on U.S. policy toward eliminating HFCs in refrigeration and helped provide the scientific basis for the Kigali Amendment to the Montreal Protocol.

Xu was also one of the first to show that black carbon heating contributed as much as half of the observed large warming over the elevated regions of the Himalayan–Tibetan region. A series of model-based investigations by Xu and his students and collaborators have shown aerosols from industrial activities to be an important influence on changes observed in the past few decades. These studies consistently demonstrate a more significant impact than was previously suspected for changes in precipitation extremes, latitudinal temperature gradient, drought indices, and snow cover.

In view of his significant contributions to our understanding of the physical mechanisms of climate change, their impacts, and their implications for national and international climate policies, Yangyang Xu is a highly deserving recipient of the 2019 Global Environmental Change Early Career Award.

—V. Ramanathan, Scripps Institution of Oceanography, University of California, San Diego, La Jolla



I deeply appreciate Ram for the nomination and a few of my colleagues at Texas A&M University for starting the process. I benefited greatly from the kind support and inspiration since I started working with Ram 10 years ago at the Scripps Institution of Oceanography. Ram has supplied me a flexible environment in which to explore various research topics and, more important, led me to do society-relevant climate research, which has become my main aspiration today. Through Ram, I had the chance to work with researchers in a multidisciplinary setting and have learned so much from them, especially David Victor (School of Global Policy and Strategy, University of California, San Diego) and Durwood Zaelke (Institute for Governance and Sustainable Development).

My gratitude needs to be extended to many scientists at the National Center for Atmospheric Research, where I worked for several years as a visiting student, postdoc fellow, and project scientist. The too-long-to-complete list particularly includes Warren Washington, Jean-François Lamarque, Jerry Meehl, Aixue Hu, Claudia Tebaldi, Simone Tilmes, Mary Barth, and Rajesh Kumar. The career mentoring and research advice from them continue to drive my research forward.

Since moving to Texas A&M, I have received tremendous support from many colleagues in the department as well as at the university, especially Andy Dessler, Ping Yang, Jerry North, Ken Bowman, John Nielsen-Gammon, Sarah Brooks, R. Saravanan, and Bruce McCarl. It has been a very productive and enjoyable 3 years in Aggieland.

Last and most important, I thank my family, especially my wife, Xiaoshan Gao, for her continuous sacrifice to support my (flexible) work schedule.

I’m honored by this award from the AGU Global Environmental Change section, and it will provide encouragement to my future research. Further motivation comes from the grand challenge imposed by the unprecedented rate of global and environmental change, to which I plan to devote my career. I hope the younger generations, my pre-K son and newborn daughter included, can testify (in 2100?) that we tried our best.

—Yangyang Xu, Texas A&M University, College Station

Calvin Receives 2019 Piers J. Sellers Global Environmental Change Mid-Career Award

Fri, 04/03/2020 - 13:25
Citation Katherine Calvin

Dr. Katherine Calvin has made outstanding research contributions in the area of global environmental change. Dr. Calvin’s research focuses on the interactions between human socioeconomic activity and Earth system changes. She has worked extensively in developing international scenarios for climate change research and is a leading expert in integrated assessment modeling, combining quantitative and coding expertise with broad training across Earth sciences, socioeconomics, and land use change.

Dr. Calvin’s scientific findings have been used and cited by all three working groups of the Intergovernmental Panel on Climate Change (IPCC). Her expertise has led to international recognition and community involvement as a contributing author to the IPCC Working Group III Fifth Assessment Report (AR5), lead author for the Working Group III AR6, and the coordinating lead author for the IPCC Special Report on Climate Change and Land. The IPCC reports span sectors and national boundaries to provide the scientific information and basis for understanding climate change and its impacts on natural and human systems and for informing pathways to mitigate and adapt to those changes. Kate’s diverse background and skills make her an ideal person to lead these efforts. Dr. Calvin is also the biogeochemistry group lead for the Department of Energy’s Energy Exascale Earth System Model (E3SM), coordinating model development and interacting with the other modeling groups to ensure seamless coupling and performance. With her outstanding career thus far, we look forward to the next decade of exceptional research from Dr. Calvin.

—Corinne Hartin and Ben Bond-Lamberty, Pacific Northwest National Laboratory, College Park, Md.



I am humbled and honored to receive the Piers J. Sellers Global Environmental Change Mid-Career Award this year. I had the pleasure of hearing Piers Sellers talk a few times and always found his stories of carbon and space travel inspiring. I’m also honored to be the third awardee, following the amazing Jim Randerson and Markus Reichstein. Thank you, Corinne, for nominating me!

Several people have helped mentor me and shaped my career. First, I’d like to thank my Ph.D. advisor, John Weyant, for introducing me to climate change and teaching me how to do research. The breadth of John’s knowledge and the encouragement he provides his students had a tremendous influence on me, in terms of both my field of study and the way I engage with others. Next, I’d like to thank Jae Edmonds and Leon Clarke for hiring me and teaching me about integrated assessment. The opportunities Jae and Leon gave me as an early-career researcher, from coordinating model intercomparison projects to working on next-generation emissions scenarios, helped me hone my technical skills and introduced me to leadership. I’d like to thank Tony Janetos for teaching me about land and the Earth system and steering me toward more interdisciplinary research; I will always be grateful for the chats I had with him on agriculture and the Global Change Assessment Model, and sports. Last, I’d like to thank all of the colleagues, collaborators, and coauthors with whom I’ve interacted over the years. I couldn’t have done the research I have, and certainly wouldn’t have enjoyed it as much, without them. I hope that I can provide as much to the Global Environmental Change community as it has provided to me.

—Katherine Calvin, Pacific Northwest National Laboratory, College Park, Md.

Leung Receives 2019 Bert Bolin Global Environmental Change Award

Thu, 04/02/2020 - 12:35
Citation L. Ruby Leung

Dr. Lai-Yung (Ruby) Leung has been a real force advancing the science and modeling frontiers of environmental change. She is an influential researcher and an outstanding community leader. She has pioneered modeling of regional and global climate change using innovative approaches to represent such fine-scale processes as orographic precipitation and mountain snowpack and to integrate natural and human system processes in Earth system models. Using models and observations, her research has advanced understanding of the water cycle and its interactions with anthropogenic forcings. She has demonstrated exemplary leadership in advancing community research in extreme weather and climate through field campaigns, data analysis, and modeling of such phenomena as atmospheric rivers, mesoscale convective systems, tropical cyclones, extreme precipitation, and floods and droughts. In addition to organizing workshops for U.S. climate agencies to identify gaps and priorities in climate and hydrological research, she has been serving as the chief scientist for the U.S. Department of Energy’s Energy Exascale Earth System Model (E3SM). This activity pushes the cutting edge of high-resolution climate modeling and develops unique capabilities to represent human–Earth system interactions. In sum, she exemplifies the spirit of Bolin’s legacy by advancing both science and modeling to address environmental change problems of high societal impacts.

—Rong Fu, University of California, Los Angeles



It is an honor for me to be selected for the Bert Bolin Award and Lecture of the AGU Global Environmental Change section. I am grateful for the nomination and for the committee’s selecting me for the award. I have been fascinated by water for its life-supporting function, the beauty it creates in our environment, and its mysterious ways in connecting the various parts of the Earth system. Hence, water weaves through my journey as a scientist from modeling orographic clouds and precipitation and snowpack in mountainous areas, to collecting data from a research aircraft flying through atmospheric rivers, to modeling storms and land and river processes, to exploring the mechanisms of how precipitation may respond to warming and other human perturbations. I have been blessed with many opportunities to collaborate with wonderful colleagues in my institution and scientists across the community sharing the same passion about water in its various forms in the Earth system. I thank them for being an inspiration and for sharing their ideas and expertise. I am also grateful to the U.S. Department of Energy’s Biological and Environmental Research program for its foresight and continued support of cutting-edge Earth system research and its user facilities enabling the research. Through national and international efforts, we now have an explosion of data from different observing systems and computational models capable of simulating clouds in their glorious details or connecting human and Earth system processes, providing data and tools to test our understanding and predict Earth system evolution. Continued advances in understanding and predicting regional and global environmental change will equip us with powerful knowledge to improve societal resilience to extremes and variability and change.

—L. Ruby Leung, Pacific Northwest National Laboratory, Richland, Wash.

New Classification System for Lakes Forecasts a Warming Trend

Thu, 04/02/2020 - 12:32

Elevated water levels and flooding around the Great Lakes have generated recent debate about the role of global warming, but researchers have known for years that lake temperatures are rising. To illustrate how lakes are changing, scientists have created a lake thermal classification system and noted that a significant proportion of lakes could be reclassified as warmer types as global temperatures rise.

Changing Thermal Classifications

Temperature plays a key role in lake ecology and affects phenomena such as species distribution and organism growth rate. But although there are lake classification systems for characteristics such as trophic state, which measures biological activity, there has been no temperature-based system.

“The thermal classification allows any lake in the world to be allocated to a thermal type. This will allow the responses of lakes with similar thermal characteristics to be compared or lakes with different characteristics to be contrasted.”Writing in Nature Communications, researchers have proposed a classification of lakes into nine thermal regions based on surface water temperatures. Corresponding roughly with latitude, the nine regions are, from north to south, northern frigid, northern cool, northern temperate, northern warm, northern hot, tropical hot, southern hot, southern warm, and southern temperate.

“The thermal classification allows any lake in the world to be allocated to a thermal type,” said Stephen Maberly, a limnologist and ecophysiologist at the UK Centre for Ecology & Hydrology who was the lead author of the study. “This will allow the responses of lakes with similar thermal characteristics to be compared or lakes with different characteristics to be contrasted. For example, the growing interest in effects of warming could be described for lakes from different thermal regions. It will also help work at one particular site to be contextualized at a global scale.”

Maberly and collaborators from U.K. universities in Dundee, Glasgow, Reading, and Stirling, as well as the Dundalk Institute of Technology in Ireland, used satellite data from over 700 lakes around the world collected twice a month for more than 16 years. They performed a statistical analysis of the data and established a classification system, which they applied to all areas of the world with a lake model.

Researchers studied data from 700 lakes around the world to create the new classification system. Credit: Maberly et al., 2020, https://doi.org/10.1038/s41467-020-15108-z, CC BY 4.0

Researchers applied different future climate scenarios to project how the distribution of the thermal regions could change. They found that 12%, 27%, and 66% of lakes would be reclassified to a lower-latitude thermal region under scenarios of low, medium, and high greenhouse gas concentrations, respectively. Under the last scenario, the number of northern frigid lakes will drop by 79%, whereas northern temperate and northern warm lakes will increase by 166% and 228%, respectively.

Warmer surfaces can generate a host of direct and indirect effects on lakes. These effects range from impacts on species (including fish such as salmon, trout, and arctic char that require cool water) to changes in ice cover, which may affect how people use lakes.

“Indirect effects will be linked to changes in the critical physical structure of lakes where typically, in summer warm surface water is less dense and floats on top of cooler, more dense water at depth—so-called stratification,” said Maberly. “This creates two very different environments with consequences for algal growth, deoxygenation at depth, and cycling of nutrients within the lake. Warming will increase the strength and duration of stratification, promoting development of cyanobacterial (blue-green algal) blooms, especially in nutrient-rich lakes and promoting deoxygenation at depth.”

Teasing Out the Effects of Warming

Although lakes can act as sentinels of change, they are the result of complex forces at play that make determining the effects of climate change very difficult, said John D. Lenters, an honorary fellow at the University of Wisconsin–Madison’s Center for Limnology who was not involved in the study. He called the work a robust and intensive analysis of lake surface water temperature (LSWT) data and model output but said it fails to make the case for the merits of its new approach over climate or air temperature classifications.

“There wasn’t anything that was all that surprising in the results, e.g., LSWT varies according to (mostly) latitude and elevation,” said Lenters. “And so why not just classify LSWT according to these and other more easy-to-relate-to geographic and/or climatic variables? I would think that would be of more interest to readers.”

Meanwhile, Maberly and his collaborators plan to expand their lake temperature modeling work to analyze other global aspects of future temperature in lakes. They also want to widen their analysis from temperature to other variables that can be detected with satellites.

“Ultimately, by bringing different global data sets together for lakes and their catchments we hope to define different lake biomes and the variables that control them,” said Maberly.

—Tim Hornyak (@robotopia), Science Writer

Reforestation as a Local Cooling Mechanism

Thu, 04/02/2020 - 12:28

Temperate forests have a reputation as crucial global carbon sinks. In fact, research suggests that American forests alone suck up the equivalent to 14% of annual carbon dioxide emissions in the United States. And after decades of net global forest loss, reestablishing forests worldwide is viewed as a viable option for mitigating the effects of climate change.

Beyond the carbon sequestration potential of reforestation, in many parts of the world, forests offer the added benefit of reducing surface temperatures by drawing water from the atmosphere and increasing heat transfer away from the surface. At a local level, restoring forests may help alleviate the effects of climate warming.

There is a distinction, however, between surface temperature and air temperature, and the science remains unclear as to whether reforestation also successfully lowers the air temperature. Whereas surface temperature is measured only at the surface, air temperature changes with height and may be influenced by changes in wind patterns caused by the forest canopy.

In a new study, Novick and Katul describe a novel approach to investigating both surface and air temperature on the basis of flux tower observations. The method accounts for canopy effects and uses tower measurements to estimate multiple metrics that link surface and air temperature. The research was conducted using data from three AmeriFlux sites in the Duke Forest in North Carolina. The researchers compared observations from colocated grassland, pine forest, and hardwood forest ecosystems, which represent the three phases of ecological succession in the region.

The study found that although air cooling from forests is not as significant as cooling on the surface, forest canopies still reduce air temperature near the surface by 0.5°C–1°C over a year. During the growing season, the warmest time of the year, forests reduce daytime near-surface air temperatures by 2°C–3°C. However, the effect was minimal at night.

By focusing on air and surface temperature, the study offers a more complete picture of how forests regulate temperature and cool landscapes than previous studies. The results should help communities better understand the benefits of reforestation and its upside as a climate mitigation tool. (Journal of Geophysical Research: Biogeosciences, https://doi.org/10.1029/2019JG005543, 2020)

—Aaron Sidder, Freelance Writer

Chinese Swamp Core Reveals 47,000 Years of Monsoon History

Thu, 04/02/2020 - 12:27

Every summer, one third of the world’s population receives rainfall from the East Asian monsoon. Variations in monsoon behavior can pose flood or drought risk, so understanding how it has changed over time could help clarify future risks. Wei et al. now provide new insights into 47,000 years of East Asian monsoon history.

The new research addresses a lack of long-term, high-resolution data on past monsoon variability from southern China. To help fill this gap, the researchers collected an 8.6-meter-long sediment core from Dahu Swamp in the Nanling Mountains of southern China; the region’s topography makes it particularly sensitive to shifts in monsoon rainfall patterns.

The research team took samples of material every 2 centimeters along the length of the core and analyzed each sample’s magnetic properties to produce snapshots of mineral composition in the swamp at different time periods. These snapshots provided clues to the hydrologic and climatic processes in play when the materials were deposited.

Findings from the mineral-magnetic analysis enabled the scientists to reconstruct patterns of fluctuation between relatively wet and dry periods in the region over the past 47,000 years. These monsoonal rainfall patterns are consistent with data from northern China and are in line with past climate changes resulting from gradual shifts in Earth’s orbit and orientation.

The results also add to mounting evidence against a traditional view that climate processes at high latitudes were the primary driver of paleoclimate monsoon trends. The new findings suggest that tropical climate patterns associated with the El Niño–Southern Oscillation have played an important role in driving long-term monsoon rainfall patterns.

This research could help refine climate models and improve predictions of future shifts in monsoon rainfall patterns as climate change progresses. (Paleoceanography and Paleoclimatology, https://doi.org/10.1029/2019PA003796, 2020)

—Sarah Stanley, Freelance Writer

Floating Patches of Soil Nutrients in Soil Help Explain Arctic Thawing

Thu, 04/02/2020 - 12:25

The Arctic is warming at a rate that outstrips any other region of the planet, and the rapidly thawing permafrost houses an estimated 1,400 gigatons of carbon, which is nearly triple the total amount of carbon circulating in the atmosphere. Understanding soil dynamics and their feedbacks is vital to understanding how Earth’s climate will change in the future.

To understand what will happen as permafrost continues to thaw, scientists look to Arctic environments where the soils already undergo regular freeze-thaw cycles. About a quarter of the Arctic is made up of High Arctic polar deserts. In these regions, the soil thaws in the summer as temperatures average in the single digits on the Celsius scale. During this time, polar desert plants—mostly mosses, algae, lichens, and small shrubs—and soil microbes come out of hibernation and perform all the chemistries of life that cycle carbon and nitrogen through the environment.

The freeze-thaw cycle also produces unique physics within the soil itself, creating frost boils, which churn nutrients vertically through the ground. In some instances, this process can create nutrient-rich soil layers called diapirs. Diapirism can occur in viscous soils and is expected to increase with soil moisture caused by permafrost thaw in a warming climate. Scientists have previously observed that some plants, especially Salix arctica, preferentially target diapirs with their roots, making the soils a potential nutrient source for greenhouse gas production. However, the biological processes at play in diapirs are still quite poorly understood.

Here Ota et al. compare the soil in frost boils with diapirs to the soil in frost boils without diapirs. The study took place in two different types of polar deserts near Alexandra Fjord, Ellesmere Island, Nunavut, Canada, during July and August of 2013. Diapirs were 29% richer in nitrogen. The scientists also found that diapirism increased the concentration of low-quality carbon—carbon contained in molecules that are challenging to microbial decomposition. Although the lower-quality carbon reduced microbial activity, the researchers confirmed that Salix arctica does increase its root density in diapirs, a finding they say suggests a mutualistic relationship between the plant and the microbe, with both benefiting from diapirism overall.

The researchers also found an abundance of polysaccharides in the frost boils that contained diapirs. Polysaccharides are sugar molecules common in both plant and microbial chemistry. What’s interesting about the presence of polysaccharides is that they make the soil more viscous, which should make it more prone to diapirism. One hypothesis the researchers have is that the plants or the microbes (or both) are secreting these sugars into the ground to promote diapirism.

This complex interplay between soil physics, plant, and microbes—what the scientists call “geomorphologic-plant-microbe interactions”—might even explain why only 30% of the frost boils in the study region contained diapirs in the first place. Because these nutrient-rich soil layers are a hotbed for Arctic greenhouse gas production, understanding how they form could greatly improve our knowledge of just how quickly the planet warms and the Arctic thaws. (Journal of Geophysical Research: Biogeosciences, https://doi.org/10.1029/2019JG005263, 2020)

—David Shultz, Science Writer

Fresh Approaches to Protecting Human Health from Pollution

Thu, 04/02/2020 - 11:30

Historical and current pollution from numerous sources causes disease and death throughout the world. To reduce the impact of this pollution on human health, comprehensive and cost-effective methods are needed to identify these sources.

Filippelli et al. [2020] give an excellent overview of new ways to identify and reduce pollution-related health burdens. These new approaches include low-cost monitoring of air pollution using satellite reflectance data to measure metal contamination of soils and incorporating citizen science for data collection.

The paper stresses the need for policy makers and scientists to work together to protect human health into the 21st century. The case studies provided show how pollution science can be combined with real applications for global communities to safeguard human health.

Citation: Filippelli, G., Anenberg, S., Taylor, M., van Geen, A., & Khreis, H. [2020]. New approaches to identifying and reducing the global burden of disease from pollution. GeoHealth, 4, e2018GH000167. https://doi.org/10.1029/2018GH000167

—Karen Hudson-Edwards, Editor, GeoHealth

During a Pandemic, Is Oceangoing Research Safe?

Wed, 04/01/2020 - 17:43

Oceanographer Rainer Lohmann from the University of Rhode Island was on a research cruise near Barbados when the coronavirus spread rapidly into a pandemic.

“When we left, everything was normal.”“When we left, everything was normal,” Lohmann said, speaking by phone while his ship, the R/V Endeavor, waited to dock in the city of Praia in Cape Verde on 17 March. “Now what we’re hearing and seeing is that we’re coming back to a country where we have to fight for toilet paper, where there are no hand sanitizers left, and you can’t go out to restaurants.”

The Endeavor left the Caribbean island of Barbados in late February and set off toward Cape Verde near West Africa, collecting sediment cores as it went. Lohmann and his team were investigating whether ocean sediments thousands of meters below the surface contained traces of atmospheric black carbon. After traversing much of the Atlantic Ocean, they had all the samples they needed and planned to fly home via Europe in mid-March.

But they faced a problem: The United States had just imposed strict travel restrictions through Europe. They needed a new way home.

Past Plans Scrapped…

Scientists around the world are scrambling to adjust to a rapidly changing environment. Researchers are shuttering their labs, switching to remote observing on telescopes, and learning to present their work virtually. A confirmed case of coronavirus disease 2019 (COVID-19) among the aircraft team of the Arctic expedition Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) quarantined about 20 of its members. Universities around the world have closed, some for months.

“It’s just one domino falling after the other, and you realize that you’re just in the middle of this geopolitical crisis.”Research teams and oceangoing scientists who work in the field, often in remote locations, are facing new questions about how to conduct science safely. The organization that coordinates oceanographic research vessels across 59 academic institutions, University-National Oceanographic Laboratory System (UNOLS), paused operations on its vessels for 30 days on 13 March. This week, the group extended the pause until July.

R/V Endeavor, one of the UNOLS fleet, is one of the few vessels that were midvoyage when the situation worsened. Endeavor barely made it to Cape Verde before its ports closed to ships, Lohmann said. Their flights through Europe blocked, he and five other scientists who live in the United States decided to stay on board the ship as it travels back to its homeport in Rhode Island. Two scientists on the cruise from Spain departed at Cape Verde to catch one of the few remaining flights back home.

“It’s just one domino falling after the other, and you realize that you’re just in the middle of this geopolitical crisis,” Lohmann said.

…And Future Plans Dashed

UNOLS chair Craig Lee said that the group postponed cruises partly because it’s not known how expeditions can mitigate the risks of transmission of COVID-19 while at sea. “In the U.S. it is clear that the peak of the outbreak and any beginnings of a reduction or flattening of ‘the curve’ are still weeks away, and are based on successful social distancing efforts,” UNOLS wrote in a statement.

Social isolation and physical distancing are “difficult to impossible” on a ship.But on a ship, social isolation and physical distancing are “difficult to impossible,” said Lee. Crew, technicians, and scientists may come from many locations for the same cruise, making it challenging to limit geographic risk. Putting a group in small quarters runs a higher risk of transmission, especially since testing participants for COVID-19 before the cruise isn’t possible, according to Lee. While each cruise has at least one person trained in emergency medicine and significant medical supplies, ships have “far short of an ICU [intensive care unit],” said Lee, and it could take days to get to port.

Oceanographer Jonathan Fram at Oregon State University had a local cruise scheduled in late March to replace equipment in a long-term array installed off the coast. “We have a parking lot full of wonderful moorings, clean and ready to go,” he said. Usually, the team services the array every 6 months to monitor, among other things, ocean acidification and low-oxygen conditions that can be harmful to marine life.

Their cruise is now canceled, and Fram is concerned about their equipment left at sea. The moorings will “go dark” after a while, he said, and the autonomous, torpedo-shaped underwater vehicles (gliders) that traverse the array will run out of batteries in May.

“Our hope, at least, is that we can find a way forward for some of the more local endeavors.”Pushing back the cruise means that the team will miss recording data during the coastal ocean’s transition from winter to spring, when ocean upwelling brings nutrient-rich waters along the Pacific Coast. “It’s important to get a measure of that transition. And we’re not going to be able to do that as well this year,” Fram said.

Local cruises like Fram’s may get some respite, according to UNOLS leadership.

“Our hope, at least, is that we can find a way forward for some of the more local endeavors,” Lee said. “And again, it depends on how things evolve.” UNOLS is working with federal agencies to roll out guidelines in the coming days to help operators assess risks. Cancelations can be particularly hard on students and early-career scientists who have a “short, but critical, phase of their research careers,” said Lee.

As for the R/V Endeavor on its international cruise, Lohmann said that the crew took precautions to limit any transmission risk while in port in Cape Verde. Food was handed over the raised platform connecting the ship to the dock, people did not leave the ship if they intended to get back on, and no new passengers joined for the voyage home. During their 2-week journey back, those on board are taking their temperatures daily and using disposable cutlery and dishware. Lohmann hopes that their transit time will count toward any required quarantine when they get back to Rhode Island.

“We couldn’t foresee that those 3 days were going to make the difference for most of us.”Until then, Lohmann said, the people on board are playing cards, watching movies, and joking around. “We realized that we will face social distancing once home and will long for group activities.”

Lohmann said the expedition was laid over for 3 days in Barbados at the start of the cruise, meaning they missed the window to catch flights back to the United States. “We couldn’t foresee that those 3 days were going to make the difference for most of us,” Lohmann said.

—Jenessa Duncombe (@jrdscience), Staff Writer

La Violencia Aumenta con el Cambio Climático

Wed, 04/01/2020 - 11:56

This is an authorized translation of an Eos article. Esta es una traducción al español autorizada de un artículo de Eos.

El cambio climático y la degradación ambiental están incrementando la violencia contra las mujeres y obstaculizando el cumplimiento de los objetivos de desarrollo sostenible, según un nuevo informe publicado por la Unión Internacional para la Conservación de la Naturaleza (UICN). El empeoramiento de las condiciones en todo el mundo podría conducir a un incremento de la violencia en medida que los recursos naturales comiencen a escasear.

Los más vulnerables a menudo se ven afectados de manera desproporcionada por problemas ambientales: un informe del grupo de investigación Lancet Countdown encontró que los niños y las mujeres embarazadas sufrirán el aumento de las temperaturas y la contaminación del aire en las próximas décadas; las comunidades afroamericanas están más expuestas a la contaminación del aire; y las personas de color, particularmente los nativos americanos, están más expuestos a los incendios forestales.

En el último reporte, los investigadores estudiaron los vínculos entre los problemas ambientales (incluida la deforestación, la minería ilegal, los desastres relacionados con el clima, la sequía y el cambio climático) y los casos de violencia de género. Las personas de cualquier género pueden experimentar violencia, incluyendo violencia doméstica, agresión sexual, prostitución forzada y otros actos de abuso. Debido a las normas sociales y culturales, las mujeres y las minorías de género suelen estar en mayor riesgo.

Combinando información de investigaciones publicadas en revistas arbitradas, informes organizacionales, artículos de noticias, casos de estudio y la encuesta de la UICN, los autores encontraron estrechos vínculos entre el empeoramiento de los factores de estrés ambientales y un aumento en la violencia de género.

“La precedencia, la vulnerabilidad, la probabilidad y las tasas reales de violencia ya están aumentando claramente en algunos contextos”, dijo Cate Owren, gerente senior de en UICN y autora principal del informe. “Estamos en una trayectoria peligrosa”.

La Violencia Como Control

Las estrictas normas y reglas de género, así como las leyes, limitan a quienes tienen acceso a los recursos, como las mujeres agricultoras que no pueden vender alimentos en el mercado debido a su género. La violencia, dijo Owren, “se usa de manera generalizada como una herramienta para negociar el poder, para mantener el desequilibrio de poder y mantener intacta la desigualdad”. El informe estima que una de cada tres mujeres experimenta violencia de género en su vida.

En un caso de estudio en Vanuatu, la violencia de pareja aumentó en un 300% después de dos ciclones tropicales. Owrens señaló que la violencia doméstica también aumentó en Australia después de varios años de sequía, y en general, el informe describe cómo aumenta la violencia de pareja cuando los hombres intentan controlar recursos limitados bajo las presiones y amenazas ambientales.

Las tensiones por la escasez de recursos también pueden reforzar las desigualdades de género, como las familias que fuerzan a sus hijas a casarse a una edad temprana. Ntoya Sande, una mujer que se casó a los 13 años en la aldea de Kachaso, Malawi, dijo en el informe que antes de su matrimonio, las tierras de su familia habían sufrido inundaciones. “Me enviaron a casarme por la escasez de comida en la casa. De lo contrario, habrían esperado.” Malawi ahora enumera el matrimonio infantil como un riesgo mayor en su documento de 2015 acerca de evaluación de necesidades posteriores al desastre.

Un estado de derecho débil puede llevar a las autoridades a hacer la vista gorda ante el abuso. La minería ilegal, la pesca, la tala y otras prácticas pueden conducir a la explotación sexual. El informe señala que en África oriental y meridional, los vendedores de pescado exigen sexo a las mujeres a cambio de los peces, y se estima que 1,000 hombres y niños, la mayoría de los cuales tenían 14 años o menos, fueron traficados solo en 2015 en la industria pesquera ilegal cerca de Indonesia.

“Necesitamos Abrir los Ojos”

Dado que el cambio climático acelerará los desastres como sequías, eventos meteorológicos extremos y otras consecuencias, los autores del informe advierten que estas situaciones conducirán a mayores tasas de violencia. “Concluimos que esta es una trayectoria muy preocupante”, dijo Owren.

Los defensores del medio ambiente corren un riesgo particular. Según la investigación publicada el año pasado, los activistas en la línea de defensa de la tierra y los recursos naturales son cada vez más asesinados, y las mujeres, en particular las indígenas, enfrentan amenazas crecientes, como se describe en el último informe.

Las organizaciones que abordan los impactos ambientales deben considerar cómo sus esfuerzos impactan la violencia de género; de lo contrario, las soluciones pueden hacer más daño que bien, según el informe. Las personas LGBTQ+ pueden enfrentar amenazas en los centros de evacuación después de un desastre o encontrar problemas con los esfuerzos de ayuda cuando los documentos oficiales no coinciden con su identidad o presentación de género.

La planificación de la gestión del riesgo de desastres debe mitigar estos desafíos, según Owren. “Tenemos que abrir los ojos”, dijo. “Esperamos que esta publicación contribuya como … un verdadero llamado a la acción”.

—Jenessa Duncombe, escritora de Eos

This translation was made possible by a partnership with Planeteando. Esta traducción fue posible gracias a una asociación con Planeteando. Traducción de Luis David Coazozon García.

Florida Coastlines Respond to Sea Level Rise

Wed, 04/01/2020 - 11:56

Sea level rise is one of climate change’s hallmarks. Rising seas threaten coastal populations and can damage coastal ecosystems. Some ecosystems, though, appear to be building themselves up as the water rolls in.

In coastal mangroves and marshes, dead plant matter like leaves and roots does not decompose as it does in drier environments. Instead, it is “buried” in the wet ground. For some of these coastal wetlands, the burial rates seem to be increasing.

Breithaupt et al. noticed this pattern. They took soil core samples from different coastal systems in southwestern Florida to determine whether this trend was genuine or merely an illusion arising from the most common methods used.

The scientists compared several measures, focusing primarily on the degradation of different types of organic carbon and the different tools used to quantify sediment accumulation rates. They determined that the apparent increase was not an artifact of a particular method or an illusion caused by old carbon washing away or degrading over time.

Further examination confirmed that the additional carbon was not merely washed into the study areas from other parts of the coastline or deposited by major storms. Local factors, such as the type of vegetation and the availability of nutrients, played a larger role in the carbon burial increase.

The scientists surmised that sea level rise may drive the increasing accumulation of soil carbon. Longer flood periods encourage mangrove and marsh vegetation to expand their belowground systems, producing and storing more carbon there. Rising sea levels may also allow more space for carbon to be buried and preserved.

This means these coastal areas are both responding well to sea level rise and pulling more carbon from the atmosphere. In the past 120 or so years, organic carbon burial rates have increased by factors of 1.4–6.2 in marshes and mangroves, with mangroves having the greatest gains. As a result, stored carbon stocks have increased by about 4–8 kilograms per square meter in the past century in these study areas.

However, rising sea levels still pose a threat to these systems. Rapid, heavy sediment deposits from hurricanes can smother and kill mangrove trees and other vegetation. Further, the waters are rising faster over time. Though these ecosystems are handling the change now, it remains to be seen how high sea level rise rates can go before adverse effects threaten to drown them.

This dynamic relationship between coastal ecosystems and the sea is an important factor both in carbon estimates and in predicting the effects of sea level rise. As the climate continues to change, more research is needed to estimate how widespread this phenomenon is and to inform coastal decision-making about the best ways to manage ecosystem responses. (Journal of Geophysical Research: Biogeosciences, https://doi.org/10.1029/2019JG005349, 2020)

—Elizabeth Thompson, Science Writer

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