Surprising news: drylands are not getting drier

New study--first to investigate the long-term effect of soil moisture-atmosphere feedbacks in drylands--finds that soil moisture exerts a negative feedback on surface water availability in drylands, offsetting some of the expected decline

COLUMBIA UNIVERSITY SCHOOL OF ENGINEERING AND APPLIED SCIENCE

Research News

 

IMAGE: A DRYLAND ECOSYSTEM IN NORTHERN CALIFORNIA SHOWS DECREASING SOIL MOISTURE BUT LITTLE CHANGES IN SURFACE WATER AVAILABILITY. view more 

CREDIT: COLUMBIA ENGINEERING

New Columbia Engineering study--first to investigate the long-term effect of soil moisture-atmosphere feedbacks in drylands--finds that soil moisture exerts a negative feedback on surface water availability in drylands, offsetting some of the expected decline

New York, NY--January 4, 2021--Scientists have thought that global warming will increase the availability of surface water--freshwater resources generated by precipitation minus evapotranspiration--in wet regions, and decrease water availability in dry regions. This expectation is based primarily on atmospheric thermodynamic processes. As air temperatures rise, more water evaporates into the air from the ocean and land. Because warmer air can hold more water vapor than dry air, a more humid atmosphere is expected to amplify the existing pattern of water availability, causing the "dry-get-drier, and wet-get-wetter" atmospheric responses to global warming.

A Columbia Engineering team led by Pierre Gentine, Maurice Ewing and J. Lamar Worzel professor of earth and environmental engineering and affiliated with the Earth Institute, wondered why coupled climate model predictions do not project significant "dry-get-drier" responses over drylands, tropical and temperate areas with an aridity index of less than 0.65, even when researchers use the high emissions global warming scenario. Sha Zhou, a postdoctoral fellow at Lamont-Doherty Earth Observatory and the Earth Institute who studies land-atmosphere interactions and the global water cycle, thought that soil moisture-atmosphere feedbacks might play an important part in future predictions of water availability in drylands.

The new study, published today by Nature Climate Change, is the first to show the importance of long-term soil moisture changes and associated soil moisture-atmosphere feedbacks in these predictions. The researchers identified a long-term soil moisture regulation of atmospheric circulation and moisture transport that largely ameliorates the potential decline of future water availability in drylands, beyond that expected in the absence of soil moisture feedbacks.

"These feedbacks play a more significant role than realized in long-term surface water changes," says Zhou. "As soil moisture variations negatively impact water availability, this negative feedback could also partially reduce warming-driven increases in the magnitudes and frequencies of extreme high and extreme low hydroclimatic events, such as droughts and floods. Without the negative feedback, we may experience more frequent and more extreme droughts and floods."

The team combined a unique, idealized multi-model land-atmosphere coupling experiment with a novel statistical approach they developed for the study. They then applied the algorithm on observations to examine the critical role of soil moisture-atmosphere feedbacks in future water availability changes over drylands, and to investigate the thermodynamic and dynamic mechanisms underpinning future water availability changes due to these feedbacks.

They found, in response to global warming, strong declines in surface water availability (precipitation minus evaporation, P-E) in dry regions over oceans, but only slight P-E declines over drylands. Zhou suspected that this phenomenon is associated with land-atmosphere processes. "Over drylands, soil moisture is projected to decline substantially under climate change," she explains. "Changes in soil moisture would further impact atmospheric processes and the water cycle."

Global warming is expected to reduce water availability and hence soil moisture in drylands. But this new study found that the drying of soil moisture actually negatively feeds back onto water availability--declining soil moisture reduces evapotranspiration and evaporative cooling, and enhances surface warming in drylands relative to wet regions and the ocean. The land-ocean warming contrast strengthens the air pressure differences between ocean and land, driving greater wind blowing and water vapor transport from the ocean to land.

"Our work finds that soil moisture predictions and associated atmosphere feedbacks are highly variable and model dependent," says Gentine. "This study underscores the urgent need to improve future soil moisture predictions and accurately represent soil moisture-atmosphere feedbacks in models, which are critical to providing reliable predictions of dryland water availability for better water resources management."

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About the Study

The study is titled "Soil moisture-atmosphere feedbacks mitigate declining water availability in dryland."

Authors are: Sha Zhou 1,2,3,4,5; A. Park Williams 1; Benjamin R. Lintner 6; Alexis M. Berg 7; Yao Zhang 4,5; Trevor F. Keenan 4,5; Benjamin I. Cook 1,8; Stefan Hagemann 9; Sonia I. Seneviratne 10; Pierre Gentine 2,3
1 Lamont-Doherty Earth Observatory, Columbia University
2 Earth Institute, Columbia University
3 Department of Earth and Environmental Engineering Columbia University
4 Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory
5 Department of Environmental Science, Policy and Management UC
6 Department of Environmental Sciences Rutgers, The State University of New Jersey
7 Department of Earth and Planetary Sciences, Harvard University
8 NASA Goddard Institute for Space Studies
9 Helmholtz-Zentrum Geesthacht Institute of Coastal Research, Germany
10 Institute for Atmospheric and Climate Science ETH Zurich

The study was supported by NASA ROSES Terrestrial hydrology (NNH17ZDA00IN-THP) and NOAA MAPP NA17OAR4310127, Lamont-Doherty Postdoctoral Fellowship, and the Earth Institute Postdoctoral Fellowship.

The authors declare no competing interests.

LINKS:

Paper:
https://www.nature.com/articles/s41558-020-00945-z

DOI: 10.1038/s41558-020-00945-z

http://engineering.columbia.edu/
https://engineering.columbia.edu/faculty/pierre-gentine
https://eee.columbia.edu/
http://ei.columbia.edu/

Columbia Engineering

Columbia Engineering, based in New York City, is one of the top engineering schools in the U.S. and one of the oldest in the nation. Also known as The Fu Foundation School of Engineering and Applied Science, the School expands knowledge and advances technology through the pioneering research of its more than 220 faculty, while educating undergraduate and graduate students in a collaborative environment to become leaders informed by a firm foundation in engineering. The School's faculty are at the center of the University's cross-disciplinary research, contributing to the Data Science Institute, Earth Institute, Zuckerman Mind Brain Behavior Institute, Precision Medicine Initiative, and the Columbia Nano Initiative. Guided by its strategic vision, "Columbia Engineering for Humanity," the School aims to translate ideas into innovations that foster a sustainable, healthy, secure, connected, and creative humanity.

Gas pressure depletion and seismicity

New study published in Geology

GEOLOGICAL SOCIETY OF AMERICA

Research News

 

IMAGE: A SECTIONED QUARTZ-QUARTZ GRAIN CONTACT REVEALING A THIN CLAY FILM (RIBBON-LIKE STRUCTURE). COMPACTION AND SHEAR OF THESE THIN CLAY FILMS HAS PLAYED A KEY ROLE IN CONTROLLING COMPACTION OF THE... view more 

CREDIT: MICROSTRUCTURES WERE OBTAINED BY B.A. VERBERNE.

Boulder, Colo., USA: Europe's largest gas field, the Groningen field in the Netherlands, is widely known for induced subsidence and seismicity caused by gas pressure depletion and associated compaction of the sandstone reservoir. Whether compaction is elastic or partly inelastic, as implied by recent experiments, is key to forecasting system behavior and seismic hazard.

Bart Verberne and colleagues sought evidence for a role of inelastic deformation through comparative microstructural analysis of unique drill-core, recovered from the seismogenic center of the field in 2015, 50 years after gas production started, versus core recovered before production (1965). Quartz grain fracturing, crack healing, and stress-induced Dauphiné twinning are equally developed in the 2015 and 1965 cores, with the only measurable effect of gas production being enhanced microcracking of sparse K-feldspar grains in the 2015 core.

Interpreting these grains as strain markers, Verberne and colleagues suggest that reservoir compaction involves elastic strain plus inelastic compression of weak clay films within grain contacts.

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FEATURED ARTICLE
Drill core from seismically active sandstone gas reservoir yields clues to internal deformation mechanisms
Berend A. Verberne; Suzanne J.T. Hangx; Ronald P.J. Pijnenburg; Maartje F. Hamers; Martyn R. Drury; Christopher J. Spiers

Paper URL:
https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G48243.1/593344/Drill-core-from-seismically-active-sandstone-gas

GEOLOGY articles are online at http://geology.geoscienceworld.org/content/early/recent. Representatives of the media may obtain complimentary articles by contacting Kea Giles at the e-mail address above. Please discuss articles of interest with the authors before publishing stories on their work, and please make reference to GEOLOGY in articles published. Non-media requests for articles may be directed to GSA Sales and Service, gsaservice@geosociety.org.
https://www.geosociety.org

 

CAPTION

Idealized volume of reservoir sandstone undergoing vertical compaction with zero horizontal strain, typical of producing gas reservoirs. Note, in this simplification, all grain surfaces are coated with uniform clay films. In a real sandstone reservoir, clay films are discontinuous and locally absent, especially in distal regions of the field (orange--load-supporting quartz framework; blue--sparse feldspar grains; red--clay films).

CREDIT

The conceptual model was developed by B.A. Verberne, S. Hangx, and C. Spiers.

USAGE RESTRICTIONS

Credit B.A. Verberne, S. Hangx, and C. Spiers.

Reawakened geyser does not foretell Yellowstone volcanic eruptions, study shows

UNLIKE FAKE TERROR STORIES 

IN RT AND UK TABS

Analysis of Steamboat Geyser also finds relationship between column height and reservoir depth

UNIVERSITY OF CALIFORNIA - BERKELEY

Research News

 

IMAGE: A 2019 ERUPTION OF STEAMBOAT GEYSER IN THE NORRIS GEYSER BASIN OF YELLOWSTONE NATIONAL PARK. THE GEYSER'S FIRST DOCUMENTED ACTIVITY WAS IN 1878, AND IT HAS TURNED OFF AND ON... view more 

CREDIT: UC BERKELEY PHOTO BY MARA REED

When Yellowstone National Park's Steamboat Geyser -- which shoots water higher than any active geyser in the world -- reawakened in 2018 after three and a half years of dormancy, some speculated that it was a harbinger of possible explosive volcanic eruptions within the surrounding geyser basin. These so-called hydrothermal explosions can hurl mud, sand and rocks into the air and release hot steam, endangering lives; such an explosion on White Island in New Zealand in December 2019 killed 22 people.

A new study by geoscientists who study geysers throws cold water on that idea, finding few indications of underground magma movement that would be a prerequisite to an eruption. The geysers sit just outside the nation's largest and most dynamic volcanic caldera, but no major eruptions have occurred in the past 70,000 years.

"Hydrothermal explosions -- basically hot water exploding because it comes into contact with hot rock -- are one of the biggest hazards in Yellowstone," said Michael Manga, professor of earth and planetary sciences at the University of California, Berkeley, and the study's senior author. "The reason that they are problematic is that they are very hard to predict; it is not clear if there are any precursors that would allow you to provide warning."

He and his team found that, while the ground around the geyser rose and seismicity increased somewhat before the geyser reactivated and the area currently is radiating slightly more heat into the atmosphere, no other dormant geysers in the basin have restarted, and the temperature of the groundwater propelling Steamboat's eruptions has not increased. Also, no sequence of Steamboat eruptions other than the one that started in 2018 occurred after periods of high seismic activity.

"We don't find any evidence that there is a big eruption coming. I think that is an important takeaway," he said.

The study will be published this week in Proceedings of the National Academy of Sciences.

Manga, who has studied geysers around the world and created some in his own laboratory, set out with his colleagues to answer three main questions about Steamboat Geyser: Why did it reawaken? Why is its period so variable, ranging from 3 to 17 days? and Why does it spurt so high?

The team found answers to two of those questions. By comparing the column heights of 11 different geysers in the United States, Russia, Iceland and Chile with the estimated depth of the reservoir of water from which their eruptions come, they found that the deeper the reservoir, the higher the eruption jet. Steamboat Geyser, with a reservoir about 25 meters (82 feet) below ground, has the highest column -- up to 115 meters, or 377 feet -- while two geysers that Manga measured in Chile were among the lowest -- eruptions about a meter (3 feet) high from reservoirs 2 and 5 meters below ground.

"What you are really doing is you are filling a container, it reaches a critical point, you empty it and then you run out of fluid that can erupt until it refills again," he said. "The deeper you go, the higher the pressure. The higher the pressure, the higher the boiling temperature. And the hotter the water is, the more energy it has and the higher the geyser."

To explore the reasons for Steamboat Geyser's variability, the team assembled records related to 109 eruptions going back to its reactivation in 2018. The records included weather and stream flow data, seismometer and ground deformation readings, and observations by geyser enthusiasts. They also looked at previous active and dormant periods of Steamboat and nine other Yellowstone geysers, and ground surface thermal emission data from the Norris Geyser Basin.

They concluded that variations in rainfall and snow melt were probably responsible for part of the variable period, and possibly for the variable period of other geysers as well. In the spring and early summer, with melting snow and rain, the underground water pressure pushes more water into the underground reservoir, providing more hot water to erupt more frequently. During winter, with less water, lower groundwater pressure refills the reservoir more slowly, leading to longer periods between eruptions. Because the water pushed into the reservoir comes from places even deeper than the reservoir, the water is decades or centuries old before it erupts back to the surface, he said.

In October, Manga's team members demonstrated the extreme impact water shortages and drought can have on geysers. They showed that Yellowstone's iconic Old Faithful Geyser stopped erupting entirely for about 100 years in the 13th and 14th centuries, based on radiocarbon dating of mineralized lodgepole pine trees that grew around the geyser during its dormancy. Normally the water is too alkaline and the temperature too high for trees to grow near active geysers. The dormancy period coincided with a lengthy warm, dry spell across the Western U.S. called the Medieval Climate Anomaly, which may have caused the disappearance of several Native American civilizations in the West.

"Climate change is going to affect geysers in the future," Manga said.

Manga and his team were unable to determine why Steamboat Geyser started up again on March 15, 2018, after three years and 193 days of inactivity, though the geyser is known for being far more variable than Old Faithful, which usually goes off about every 90 minutes. They could find no definitive evidence that new magma rising below the geyser caused its reactivation.

The reactivation may have to do with changes in the internal plumbing, he said. Geysers seem to require three ingredients: heat, water and rocks made of silica -- silicon dioxide. Because the hot water in geysers continually dissolves and redeposits silica -- every time Steamboat Geyser erupts, it brings up about 200 kilograms, or 440 pounds of dissolved silica. Some of this silica is deposited underground and may change the plumbing system underneath the geyser. Such changes could temporarily halt or reactivate eruptions if the pipe gets rerouted, he said.

Manga has experimented with geysers in his lab to understand why they erupt periodically, and at least in the lab, it appears to be caused by loops or side chambers in the pipe that trap bubbles of steam that slowly dribble out, heating the water column above until all the water can boil from the top down, explosively erupting in a column of water and steam.

Studies of water eruptions from geysers could give insight into the eruptions of hot rock from volcanoes, he said.

"What we asked are very simple questions and it is a little bit embarrassing that we can't answer them, because it means there are fundamental processes on Earth that we don't quite understand," Manga said. "One of the reasons we argue we need to study geysers is that if we can't understand and explain how a geyser erupts, our hope for doing the same thing for magma is much lower."

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The research, led by UC Berkeley graduate student and first author Mara Reed, resulted from a collaboration that started in one of the annual summer workshops put on by the Cooperative Institute for Dynamic Earth Research, or CIDER. Other co-authors are Carolina Munoz-Saez of the University of Chile and Rice University in Texas, Sahand Hajimirza of Rice University, Sin-Mei Wu of the University of Utah, Anna Barth of Columbia University in New York, Társilo Girona of the University of Alaska, Majid Rasht-Behesht of Brown University in Rhode Island, Erin White of Yellowstone National Park in Wyoming, Marianne Karplus of the University of Texas and Shaul Hurwitz of the U.S. Geological Survey in California.

Pollutants rapidly changing the waters near Ieodo Island

POHANG UNIVERSITY OF SCIENCE & TECHNOLOGY (POSTECH)

Research News

 

There has been frequent occurrence of red tide in coastal waters around Korea where the sea turns red. Red tide is a phenomenon in which phytoplankton proliferate as nutrient or sewage flow into seawater, making it appear red. This not only causes damage to the fisheries industry but also affects the marine ecosystem.

Professor Kitack Lee and Ph.D. candidate Ji-Young Moon (first author) of POSTECH's Division of Environmental Science and Engineering have confirmed that the inflow of nitrogen pollutants since the 1980s has disturbed the nutrient balance in the northeast Asian waters and is changing the species of phytoplankton responsible for red tide. The team also found that the fastest change in the oceanic conditions caused by this inflow of nitrogen pollutants is happening in the waters near the Ieodo Ocean Research Station, located downstream of the Changjiang River of China. These findings were recently introduced in the journal Limnology and Oceanography.

The Northeast Asia region, including Korea, China, and Japan, has seen an increase of nitrogen pollutants because of the rapid population growth and industrialization in modern times. As the nitrogen pollutant flows into the sea as a result of floods and monsoons, northeast Asian waters have experienced an unexpected massive fertilization. Many scientists have warned that these nitrogen pollutants not only increase harmful algae bloom in the coastal waters, but also lead to deterioration of water quality and changes in the formation of marine ecosystem species.

The researchers analyzed the nutrient concentration data and the occurrence of red tide in the East China seas and coastal waters of the Korean Peninsula in the past 40 years since the 1980s. The results show that a wide range of oceans in this region have changed from being nitrogen deficient to phosphorus (P) deficient, while at the same time the concentration of nitrate (N) has been higher than that of silicate (Si). In particular, it has been confirmed that the major phytoplankton in Korea's coastal waters are also changing from diatoms to dinoflagellates.

The research team explained that this is direct evidence that the nutrient regime in the northeast Asian marginal sea is changing as the amount of nitrogen pollutants is increasing, which is further creating phytoplankton species and disrupting the marine ecosystem.

At the same time, the team verified that the fastest place to see these oceanic changes due to the inflow of nitrogen pollutants was in the waters around Ieodo Ocean Research Station.

"Since the changes in the waters near Ieodo Ocean Research Station will soon occur in the waters near the Korean Peninsula, long-term observation of the concentration of nutrient in the coastal waters and changes in the ecosystem are necessary," proposed Professor Kitack Lee who led the study. He added, "The findings can be used as important scientific evidence for establishing environmental policies, such as setting nitrogen pollutant emissions."

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This study was conducted as part of the National Institute of Fisheries Science's Impact and Prediction of Oceanic Acidification due to Climate Change and the Korea Hydrographic and Oceanographic Agency's Ocean Carbon Circulation Response with Climate Change and the Interrelationship Study (I

 

Risk of extinction cascades from freshwater mussels to a bitterling fish

Decline of unionid mussels heightens hybridisation of native and introduced bitterling fish

EHIME UNIVERSITY

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IMAGE: FRESHWATER FISH DISTRIBUTED IN JAPAN, SOUTH KOREA, AND CHINA. LISTED AS NEAR THREATENED IN JAPANESE RED LIST. view more 

CREDIT: HIROKI HATA (EHIME UNIVERSITY)

Bitterling fishes (Subfamily: Acheilognathinae) spawn in the gills of living freshwater mussels obligately depending on the mussels for reproduction. On the Matsuyama Plain, Japan, populations of unionid mussels--Pronodularia japanensis, Nodularia douglasiae, and Sinanodonta lauta--have decreased rapidly over the past 30 years. Simultaneously, the population of a native bitterling fish, Tanakia lanceolata, which depends on the three unionids as a breeding substrate, has decreased. Furthermore, a congeneric bitterling, Tanakia limbata, has been artificially introduced, and hybridisation and genetic introgression occur between them. Here, we surveyed the reproduction and occurrence of hybridisation between native and invasive species of bitterling fishes. We collected mussels in which these bitterlings lay their eggs, kept them separately in aquaria, collected eggs and larvae ejected from the mussels, and genotyped them using six microsatellite markers and mitochondrial cytochrome b sequences.

The introduced T. limbata was more abundant, had a longer breeding period, and produced more juveniles than the native T. lanceolata. Hybrids between the two species occurred frequently, and in total 101 of the 837 juveniles genotyped were hybrids. The density of P. japanensis was low, at most 0.42 individuals/m2. Nodularia douglasiae and S. lauta have nearly or totally disappeared from these sites. Hybrid clutches of the Tanakia species occurred more frequently where the local density of P. japanensis was low. The mussels were apparently overused and used simultaneously by three species of bitterlings.

The decline of freshwater unionid populations has heightened hybridisation of native and invasive bitterling fishes by increasing the competition for a breeding substrate. We showed that a rapid decline of host mussel species and an introduction of an invasive congener have interacted to cause a rapid decline of native bitterling fish. The degradation of habitat and the introduction of invasive species interact to cause a cascade of extinctions in the native species. In our study, obligate parasite species are threatened because the host species are disappearing, resulting in a serious threat of coextinction.

CAPTION

Freshwater unionid species endemic in Japan.

CAPTION

Excessive crowding of a native Tanakia lanceolata (orange fin) and invasive Tanakia limbata (olive brown body) of a mussel, Pronodularia japanensis, seen at the bottom center in the image.

Researchers discover a new tool for reconstructing ancient sea ice to study climate change

BROWN UNIVERSITY

 NEWS RELEASE 4-JAN-2021

Research News

 

IMAGE: A COMPOUND THAT WAS NOTORIOUS FOR THROWING OFF RECONSTRUCTIONS OF SEA SURFACE TEMPERATURE TURNS OUT TO BE A GOOD PROXY FOR RECONSTRUCTING PAST SEA ICE, A NEW STUDY FINDS. view more 

CREDIT: KAREN WANG

PROVIDENCE, R.I. [Brown University] -- Sea ice is a critical indicator of changes in the Earth's climate. A new discovery by Brown University researchers could provide scientists a new way to reconstruct sea ice abundance and distribution information from the ancient past, which could aid in understanding human-induced climate change happening now.

In a study published in Nature Communications, the researchers show that an organic molecule often found in high-latitude ocean sediments, known as tetra-unsaturated alkenone (C37:4), is produced by one or more previously unknown species of ice-dwelling algae. As sea ice concentration ebbs and flows, so do the algae associated with it, as well as the molecules they leave behind.

"We've shown that this molecule is a strong proxy for sea ice concentration," said Karen Wang, a Ph.D. student at Brown and lead author of the research. "Looking at the concentration of this molecule in sediments of different ages could allow us to reconstruct sea ice concentration through time."

Other types of alkenone molecules have been used for years as proxies for sea surface temperature. At different temperatures, algae that live on the sea surface make differing amounts of alkenones known as C37:2 and C37:3. Scientists can use the ratios between those two molecules found in sea sediments to estimate past temperature. C37:4 -- the focus of this new study -- had been long considered a bit of problem for temperature measurements. It turns up in sediments taken from closer to the Arctic, throwing off the C37:2/C37:3 ratios.

"That was mostly what the C37:4 alkenone was known for -- throwing off the temperature ratios," said Yongsong Huang, principal investigator of the National Science Foundation-funded project and a professor in Brown's Department of Earth, Environmental and Planetary Science. "Nobody knew where it came from, or whether it was useful for anything. People had some theories, but no one knew for sure."

To figure it out, the researchers studied sediment and sea water samples containing C37:4 taken from icy spots around the Arctic. They used advanced DNA sequencing techniques to identify the organisms present in the samples. That work yielded previously unknown species of algae from the order Isochrysidales. The researchers then cultured those new species in the lab and showed that they were indeed the ones that produced an exceptionally high abundance of C37:4.

The next step was to see whether the molecules left behind by these ice-dwelling algae could be used as a reliable sea ice proxy. To do that, the researchers looked at concentrations of C37:4 in sediment cores from several spots in the Arctic Ocean near the present-day sea ice margins. In the recent past, sea ice in these spots is known to have been highly sensitive to regional temperature variation. That work found that the highest concentrations of C37:4 occurred when climate was coldest and ice was at its peak. The highest concentrations dated back to the Younger-Dryas, a period of very cold and icy conditions that occurred around 12,000 years ago. When climate was at its warmest and ice ebbed, C37:4 was sparse, the research found.

"The correlations we found with this new proxy were far stronger than other markers people use," said Huang, a research fellow at the Institute at Brown for Environment and Society. "No correlation will be perfect because modeling sea ice is a messy process, but this is probably about as strong as you're going to get."

And this new proxy has some additional advantages over others, the researchers say. One other method for reconstructing sea ice involves looking for fossil remains of another kind of algae called diatoms. But that method becomes less reliable further back in time because fossil molecules can degrade. Molecules like C37:4 tend to be more robustly preserved, making them potentially better for reconstructions over deep time than other methods.

The researchers plan to further research these new algae species to better understand how they become embedded in sea ice, and how they produce this alkenone compound. The algae appear to live in brine bubbles and channels inside sea ice, but it may also bloom just after the ice melts. Understanding those dynamics will help the researchers to better calibrate C37:4 as a sea ice proxy.

Ultimately, the researchers hope that the new proxy will enable better understanding of sea ice dynamics through time. That information would improve models of past climate, which would make for better predictions of future climate change.

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Other coauthors on the study were Markus Majaneva, Simon Belt, Sian Liao, Joseph Novak, Tyler R. Kartzinel, Timothy Herbert, Nora Richter and Patricia Cabedo-Sanz. The work was supported by the National Science Foundation (EAR-1762431).

New data-driven global climate model provides projections for urban environments


UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN, NEWS BUREAU
Research News

AT MAKES PROJECTIONS SPECIFIC TO URBAN AREAS PREDICTS THAT BY THE END OF THIS CENTURY, WARMING ACROSS GLOBAL CITIES WILL INCREASE BY 1.9 DEGREES CELSIUS... view more
CREDIT: GRAPHIC BY MICHAEL VINCENT

CHAMPAIGN, Ill. -- Cities only occupy about 3% of the Earth's total land surface, but they bear the burden of the human-perceived effects of global climate change, researchers said. Global climate models are set up for big-picture analysis, leaving urban areas poorly represented. In a new study, researchers take a closer look at how climate change affects cities by using data-driven statistical models combined with traditional process-driven physical climate models.

The results of the research led by University of Illinois Urbana Champaign engineer Lei Zhao are published in the journal Nature Climate Change.

Home to more than 50% of the world's population, cities experience more heat stress, water scarcity, air pollution and energy insecurity than suburban and rural areas because of their layout and high population densities, the study reports.

"Cities are full of surfaces made from concrete and asphalt that absorb and retain more heat than natural surfaces and perturb other local-scale biophysical processes," said Zhao, a civil and environmental engineering professor and National Center for Supercomputing Applications affiliate. "Incorporating these types of small-scale variables into climate modeling is crucial for understanding future urban climate. However, finding a way to include them in global-scale models poses major resolution, scale and computational challenges."

Global climate models project future scenarios by modeling how broader-scale processes like greenhouse gas emissions force the global climate to respond. By combining this technique with a statistical model that emulates a complex and detailed climate model for urban landscapes, Zhao's team confronted the urban-to-global information gap.

The team applied its urban climate emulation technique to data from 26 global climate models under intermediate- and high-emissions scenarios. This approach allowed researchers to model outputs into city-level projections of temperature and relative humidity through the year 2100, permitting climate change and uncertainty quantification.

The model predicts that by the end of this century, average warming across global cities will increase by 1.9 degrees Celsius with intermediate emissions and 4.4 C with high emissions, with good agreement among existing climate models over certain regions, Zhao said.

The projections also predicted a near-universal decrease in relative humidity in cities, making surface evaporation more efficient and implying that adaptation strategies like urban vegetation could be useful.

"Our findings highlight the critical need for global projections of local urban climates for climate-sensitive urban areas," Zhao said. "This could give city planners the support they need to encourage solutions such as green infrastructure intervention to reduce urban heat stress on large scales."

Currently, the projections do not account for the effects of future urban development. However, the researchers hypothesize that they can extend their strategy to make up for this. "The methodology, overall, is very flexible and can be adjusted to capture things like finer time scales and can even be applied to other ecosystems, like forests and polar regions, for example," Zhao said.

The National Science Foundation and the Army Research Office supported this study.

Editor's notes:

To reach Lei Zhao, call 217-300-9546; email leizhao@illinois.edu.

The paper "Global multi-model projections of local urban climates" is available from the U. of I. News Bureau. DOI: 10.1038/s41558-020-00958-8.

A robotic revolution for urban nature

UNIVERSITY OF LEEDS

Research News

 

Drones, robots and autonomous systems can transform the natural world in and around cities for people and wildlife.

International research, involving over 170 experts and led by the University of Leeds, assessed the opportunities and challenges that this cutting-edge technology could have for urban nature and green spaces.

The researchers highlighted opportunities to improve how we monitor nature, such as identifying emerging pests and ensuring plants are cared for, and helping people engage with and appreciate the natural world around them.

As robotics, autonomous vehicles and drones become more widely used across cities, pollution and traffic congestion may reduce, making towns and cities more pleasant places to spend time outside.

But the researchers also warned that advances in robotics and automation could be damaging to the environment.

For instance, robots and drones might generate new sources of waste and pollution themselves, with potentially substantial negative implications for urban nature. Cities might have to be re-planned to provide enough room for robots and drones to operate, potentially leading to a loss of green space. And they could also increase existing social inequalities, such as unequal access to green space.

Lead author Dr Martin Dallimer, from the School of Earth and Environment at the University of Leeds, said: "Technology, such as robotics, has the potential to change almost every aspect of our lives. As a society, it is vital that we proactively try to understand any possible side effects and risks of our growing use of robots and automated systems.

"Although the future impacts on urban green spaces and nature are hard to predict, we need to make sure that the public, policy makers and robotics developers are aware of the potential pros and cons, so we can avoid detrimental consequences and fully realise the benefits."

The research, published today in Nature Ecology & Evolution, is authored by a team of 77 academics and practitioners.

The researchers conducted an online survey of 170 experts from 35 countries, which they say provides a current best guess of what the future could hold.

Participants gave their views on the potential opportunities and challenges for urban biodiversity and ecosystems, from the growing use of robotics and autonomous systems. These are defined as technologies that can sense, analyse, interact with and manipulate their physical environment. This includes unmanned aerial vehicles (drones), self-driving cars, robots able to repair infrastructure, and wireless sensor networks used for monitoring.

These technologies have a large range of potential applications, such as autonomous transport, waste collection, infrastructure maintenance and repair, policing and precision agriculture.

The research was conducted as part of Leeds' Self Repairing Cities project, which aims to enable robots and autonomous systems to maintain urban infrastructure without causing disruption to citizens.

First author Dr Mark Goddard conducted the work whilst at the University of Leeds and is now based at the Northumbria University. He said: "Spending time in urban green spaces and interacting with nature brings a range of human health and well-being benefits, and robots are likely to transform many of the ways in which we experience and gain benefits from urban nature.

"Understanding how robotics and autonomous systems will affect our interaction with nature is vital for ensuring that our future cities support wildlife that is accessible to all."

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This work was funded by the Engineering and Physical Sciences Research Council (EPSRC).

Notes to editors

For interview requests please contact press officer Simon Moore in the University of Leeds press office on s.i.moore@leeds.ac.uk

The paper is titled 'A global horizon scan of the future impacts of robotics and autonomous systems on urban ecosystems' and is published today in Nature Ecology & Evolution.

The paper will be available online here: https://www.nature.com/articles/s41559-020-01358-z

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.

Psychological distress during first months of pandemic equal to that during prior year

First longitudinal study of psychological distress during the pandemic shows big spike during early months

RAND CORPORATION

Research News

 

The coronavirus pandemic is creating a large spike in significant psychological distress among Americans, with the first month of the pandemic causing as much distress in the same number of individuals that experienced it during the whole previous year, according to a new RAND Corporation study.

Findings from the first longitudinal study of psychological distress during the pandemic show that among a representative sample of Americans, more than 10% reported experiencing symptoms of significant psychological distress during April and May of 2020 -- the same amount they reported experiencing over an entire year during a survey conducted a year earlier.

The study also found that people with distress prior to the pandemic were more likely to report distress during the pandemic. Among people with severe distress prior to the pandemic, 48% reported distress during the pandemic while among people with low or no distress prior to the pandemic, just 3% reported distress during the pandemic.

The findings are published online by the journal Preventive Medicine.

"We found equal numbers of people experienced serious psychological distress over 30 days during the pandemic as did over an entire year prior to the pandemic," said Joshua Breslau, the study's lead author and a senior behavioral scientist at RAND, a nonprofit research organization.

The study found there was a higher risk of an increase in psychological distress among people younger than age 60, suggesting that the distress may be driven more by economic stressors than fears specific to the disease, since older individuals are at higher risk of serious illness and death from the virus.

The survey was fielded using the RAND American Life Panel, a nationally representative internet panel. Participants were surveyed in February 2019 and again in May 2020, about 8 weeks after the declaration of a national emergency. There were 2,555 respondents to the first wave of the survey and 1,870 respondents to the second wave.

During each survey, participants were asked about their level of psychological distress at various points over the prior year using standard research assessment tools.

Researchers found that the past-month prevalence of serious psychological distress reported by participants of the second survey was as high (10.9%) as the past-year prevalence reported by individuals in the first survey (10.2%). Previous research has found that the 30-day prevalence of significant distress typically is about half the 12-month prevalence when both are assessed at the same time.

More than 12% of the participants reported higher levels of psychological distress during the second survey as compared to the first. Increases in distress were more common among women compared with men, those under 60 compared with those over 60, and Hispanic people compared with people of other racial/ethnic groups.

"Elevated psychological distress has been observed during prior disasters, but it has never before been seen as a persistent and complex stressor affecting the entire U.S. population," Breslau said. "Policymakers should consider targeting services to population groups at high risk for elevated psychological distress during the pandemic, including people vulnerable to the economic consequences of social distancing."

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Support for the study was provided by the National Institute on Minority Health and Health Disparities, and the National Institute of Mental Health. Other authors of the study are Melissa L. Finucane, Alicia R. Locker, Matthew Baird, Elizabeth Roth and Rebecca L. Collins.

RAND Health Care promotes healthier societies by improving health care systems in the United States and other countries.