Scientists discover how birds navigate crosswinds

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Scientists discover how birds navigate crosswinds

Study of lovebirds’ flight could lead to better visual control algorithms for autonomous aerial robots

Lovebird during flight training in wind tunnel

Ferrari the lovebird during flight training in a laboratory bird wind tunnel.

July 16, 2019

While pilots rely on radio signals, advanced computations and other tools to keep them on course during strong crosswinds, birds can naturally navigate these demanding conditions — in environments with little visibility.

To understand how, Stanford University mechanical engineer David Lentink and colleagues studied lovebirds flying in a crosswind tunnel that features customizable wind and light settings.

The results, published in Proceedings of the National Academy of Science, could inspire more robust and computationally efficient visual control algorithms for autonomous aerial robots.

This is the first study of how birds orient their bodies, necks and heads to fly through extreme 45-degree crosswinds over short ranges — both in bright visual environments and in dark, cave-like environments, where faint points of light are the only beacons. The lovebirds navigated all environments equally well.

The researchers found that lovebirds navigate by stabilizing and fixating their gaze on the goal, while yawing their bodies into a crosswind. Staying on course requires them to contort their necks by 30 degrees or more. A computer-simulated model indicated that, while neck control is active, body reorientation into the wind is achieved passively.

“Airplanes have a vertical tail to orient stably into the wind,” said Lentink. “We discovered why birds don’t need one: their flapping wings don’t only offer propulsion — they also orient into the wind passively like a weathervane.”

Added Kathy Dickson, a program officer in NSF’s Division of Integrative Organismal Systems, which funded the study, “This integrative research used innovative technological advancements to bring studies of animal movement from closely controlled conditions in the laboratory into the field, where unsteady and intermittent flows are more the norm. The work provides unexpected insights into how birds adjust their bodies when encountering crosswinds and navigate through unstable air flows, even at night with limited visual cues.”

—  NSF Public Affairs, (703) 292-8070 media@nsf.gov

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Instability in Antarctic ice projected to increase likelihood of worst-case sea level rise projectio

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Instability in Antarctic ice projected to increase likelihood of worst-case sea level rise projectio

Thwaites Glacier, modeled for new study, likely to succumb to instability

Antarctic ice

Instability in Antarctic ice is likely to rapidly increase sea level rise.

July 12, 2019

Images of vanishing Arctic ice are jarring, but the region’s potential contributions to sea level rise are no match for Antarctica’s. Now, a study says that instability hidden in Antarctic ice increases the likelihood of worst-case scenarios for the continent’s contribution to global sea level.

In the last six years, five closely observed Antarctic glaciers have doubled their rate of ice loss. At least one, Thwaites Glacier, modeled for the new study, will likely succumb to this instability, a volatile process that pushes ice into the ocean fast.

How much ice the glacier will shed in the coming 50 to 800 years can’t be projected exactly, scientists say, due to unpredictable fluctuations in climate and the need for more data. But researchers at the Georgia Institute of Technology and other institutions have factored the instability into 500 ice flow simulations for Thwaites.

The scenarios together point to the eventual triggering of the instability. Even if global warming were to stop, the instability would keep pushing ice out to sea at an accelerated rate over the coming centuries.

“This study underscores the sensitivity of key Antarctic glaciers to instability,” says Paul Cutler, director of NSF’s Antarctic Glaciology Program. “The warping influence of these instabilities on the uncertainty distribution for sea level predictions is of great concern, and is a strong motivator for research that will tighten the error bars on predictions of Antarctica’s contribution to sea level rise.”

The research was funded by NSF’s Office of Polar Programs.

—  NSF Public Affairs, (703) 292-8070 media@nsf.gov

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Coral reefs shifting away from equatorial waters

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Coral reefs shifting away from equatorial waters

Number of young corals on tropical reefs has declined

Corals settled on a reef

In the study, researchers counted the number of baby corals that settled on a reef.

July 12, 2019

Coral reefs are retreating from equatorial waters and establishing new reefs in more temperate regions, according to NSF-funded research published in the journal Marine Ecology Progress Series. Scientists found that the number of young corals on tropical reefs has declined by 85 percent – and doubled on subtropical reefs – over the last four decades.

The research was conducted in part at NSF’s Moorea Coral Reef Long-Term Ecological Research site in French Polynesia, one of 28 such NSF long-term research sites across the country and around the globe.

“Climate change seems to be redistributing coral reefs, the same way it is shifting many other marine species,” said Nichole Price, a senior research scientist at the Bigelow Laboratory for Ocean Sciences and lead author of the paper. “The clarity in this trend is stunning, but we don’t yet know whether the new reefs can support the incredible diversity of tropical systems.”

As oceans warm, cooler subtropical environments are becoming more favorable for corals than the equatorial waters where they traditionally thrived. That’s allowing drifting coral larvae to settle and grow in new regions.

The scientists, who are affiliated with more than a dozen institutions, believe that only certain types of coral are able to reach these new locations, based on how far their microscopic larvae can drift on currents before they run out of limited fat stores.

“This report addresses the important question of whether warming waters have resulted in increases in coral populations in new locations,” said David Garrison, a program director in NSF’s Division of Ocean Sciences, which funded the research. “Whether it offers hope for the sustainability of coral reefs requires more research and monitoring.”

—  NSF Public Affairs, (703) 292-8070 media@nsf.gov

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Research reveals exotic quantum states in double-layer graphene

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Research reveals exotic quantum states in double-layer graphene

Findings establish a potential new platform for future quantum computers

composite fermion consisting of one electron and two different types of magnetic flux

A new type of quasiparticle is discovered in graphene double-layer structure.

July 8, 2019

NSF-funded research by scientists at Brown and Columbia Universities has demonstrated the existence of previously unknown states of matter that arise in double-layer stacks of graphene, a two-dimensional nanomaterial. These new states, known as the fractional quantum Hall effect, arise from the complex interactions of electrons both within and across graphene layers.

“The findings show that stacking 2D materials together in close proximity generates entirely new physics,” said Jia Li, a physicist at Brown University. “In terms of materials engineering, this work shows that these layered systems could be viable in creating new types of electronic devices that take advantage of these new quantum Hall states.”

The research is published in the journal Nature Physics.

The Hall effect emerges when a magnetic field is applied to a conducting material in a direction perpendicular to a current flow. The magnetic field causes the current to deflect, creating a voltage in the transverse direction, called the Hall voltage. 

Importantly, researchers say, several of these new quantum Hall states may be useful in making fault-tolerant quantum computers.

“The full implications of this research are yet to be understood,” said Germano Iannacchione, a program director in NSF’s Division of Materials Research, which funded the project. “However, it’s not hard at all to foresee significant advances based on these discoveries emerging in traditional technologies such as semiconductors and sensors.”

—  NSF Public Affairs, (703) 292-8070 media@nsf.gov

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Artificial intelligence controls robotic arm to pack boxes and cut costs

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Artificial intelligence controls robotic arm to pack boxes and cut costs

Researchers used software, algorithms to automate packing of boxes, a critical part of warehouse efficiency

robotic arm packs items into a box

A robotic arm tightly packs items into a box for shipment.

July 5, 2019

An NSF-funded team of computer scientists at Rutgers University used artificial intelligence to control a robotic arm, thereby providing a more efficient way to pack boxes that will save businesses time and money.

Deploying robots to perform logistics, retail and warehouse tasks is a growing trend in business, but tightly packing products picked from an unorganized pile remains largely a manual task, even though it is critical to warehouse efficiency. Automating such tasks is important for companies’ competitiveness and allows people to focus on less menial and physically taxing work.

For the study, the team used a robotic arm to move objects from a bin into a small shipping box and tightly arrange them. The researchers developed software and algorithms for the robotic arm and used visual data and a simple suction cup that doubles as a finger for pushing objects. The resulting system can topple objects to get a desirable surface for grabbing them and use sensor data to pull objects toward a targeted area and push objects together. It is designed to overcome errors during packing.

The scientists’ peer-reviewed study was published recently at the IEEE International Conference on Robotics and Automation, where it was a finalist for the Best Paper Award in Automation.

The research was supported by the Robust Intelligence program in NSF’s Division of Information and Intelligent Systems. RI encompasses the broad spectrum of foundational computational research needed to understand and enable intelligent systems in complex, realistic contexts.

—  NSF Public Affairs, (703) 292-8070 media@nsf.gov

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Does limited underground water storage make plants less susceptible to drought?

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Does limited underground water storage make plants less susceptible to drought?

Plants adapted to Mediterranean climate may be more flexible in face of unpredictable rains

researchers track underground water

Researchers at NSF’s Eel River CZO track underground water to explain plant drought response.

July 2, 2019

You might expect that plants hoping to thrive in California’s boom-or-bust rain cycle would choose to set down roots in a place that can store lots of water underground to last through drought years.

But some of the most successful plant communities in the state — and probably in Mediterranean climates worldwide, with their wet winters and dry summers — have taken a different approach. They’ve learned to thrive in areas with a below-ground water storage capacity barely large enough to hold the water that falls even in lean years.

Surprisingly, these plants do well in both low-water and rainy years precisely because the soil and weathered rock below ground store so little water relative to the rain delivered, NSF-funded scientists at UC Berkeley have found.

As a result, the plants are much more resilient in drought years, as evidenced by California’s relatively unscathed North Coast during recent droughts that killed hundreds of millions of trees in the Sierra Nevada.

The insights about rock moisture emerged from a long-term project at NSF’s Eel River Critical Zone Observatory, where scientists charted the life cycle of water in the environment — from sky through vegetation, soil and rock into streams, and back up into the atmosphere by evaporation and transpiration.

The researchers describe their findings in a paper recently published in the journal Geophysical Research Letters.

The research is funded by NSF’s Division of Earth Sciences.

—  NSF Public Affairs, (703) 292-8070 media@nsf.gov

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Cicada fungus may foster new drug discoveries

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Cicada fungus may foster new drug discoveries

Fungus contains chemicals similar to those found in hallucinogenic mushrooms

Cicada on a leaf

Cicadas can carry a fungus similar to those found in hallucinogenic mushrooms.

July 2, 2019

If cicadas made horror movies, they’d probably film the actions of their counterparts plagued by a psychedelic fungus.

West Virginia University researchers funded by NSF have discovered that a cicada fungus called Massopora contains chemicals similar to those found in hallucinogenic mushrooms.

The fungus causes cicadas to lose their limbs, then eccentric behavior sets in. Despite the cicadas’ physical state, they continue to roam around freely, infecting other cicadas with their disease.

You’ve heard of “The Walking Dead.” This research reports the existence of “The Flying Dead.” The results are published in the journal Fungal Ecology.

“They’re zombies in the sense that the fungus is in control of their bodies,” said Matt Kasson, a WVU forest pathologist and study author.

Cicadas first encounter the fungus underground, where they spend 13 to 17 years before emerging as adults. Within seven to 10 days above ground, their abdomens begin to slough off, revealing the fungal infection.

The scientists plan to re-sequence the genome of the fungus and analyze the gene expression in both healthy and infected cicadas to better understand the genetic aspects of the discovery. 

The results will foster a renewed interest in early diverging fungi and their pharmacologically important secondary metabolites, the researchers believe, which may serve as the next frontier for drug discovery.

The study was funded by NSF’s Divisions of Biological Infrastructure and Environmental Biology. “Many important drugs are discovered by accident while looking for something else,” says Sam Scheiner, an environmental biology program director at NSF. “This study of insects and their fungi may end up leading to new medicines.”

—  NSF Public Affairs, (703) 292-8070 media@nsf.gov

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New research shows an iceless Greenland may be in the future

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New research shows an iceless Greenland may be in the future

Island could be ice-free by year 3000, says new estimate

Ilulissat, known as the city of icebergs

Scientists believe that Greenland may be ice-free by the year 3000.

June 26, 2019

New research shows that an iceless Greenland may be in the future. If worldwide greenhouse gas emissions remain on their current trajectory, Greenland may be ice-free by the year 3000. By the end of the century, the island could lose 4.5% of its ice, contributing up to 13 inches of sea level rise.

“How Greenland will look in the future — in a couple hundred years or in 1,000 years — whether there will be Greenland, or at least a Greenland similar to today, is up to us,” said NSF-supported researcher Andy Aschwanden of the University of Alaska Fairbanks Geophysical Institute.

Aschwanden is lead author of a new study published in the June issue of Science Advances.

Greenland’s ice sheet is huge, spanning more than 660,000 square miles. Today, the ice sheet covers 81% of Greenland and contains 8% of Earth’s fresh water.

If greenhouse gas concentrations remain on their current trajectory, melting ice from Greenland alone could contribute as much as 24 feet to global sea level rise by the year 3000, which would place much of San Francisco, Los Angeles, New Orleans and other coastal cities underwater.

However, if greenhouse gas emissions are cut significantly, ice losses would be reduced. Instead, by 3000, Greenland may lose 8% to 25% of its ice and contribute up to 6.5 feet of sea level rise.

“Modeling studies like this show us the future of the Greenland Ice Sheet, which in turn can help us predict and plan for rising sea levels,” said Cynthia Suchman, Arctic Natural Sciences Program Director in NSF’s Office of Polar Programs, which funded the research.

—  NSF Public Affairs, (703) 292-8070 media@nsf.gov

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Scientists find no direct link between North Atlantic Ocean currents, New England coast sea level

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Scientists find no direct link between North Atlantic Ocean currents, New England coast sea level

New study clarifies influence of major ocean currents on sea level

New England coast

Scientists report new results on the link between ocean currents and sea level in New England.

June 26, 2019

A new study by NSF-funded scientists at the Woods Hole Oceanographic Institution clarifies the influence of major currents in the North Atlantic Ocean on sea level along the coast of the northeastern United States.

The results, published in the American Geophysical Union journal Geophysical Research Letters, consider the strength of the Atlantic Meridional Overturning Circulation — a conveyor belt of currents that moves warmer waters north and cooler waters south in the Atlantic — and historical records of sea level in coastal New England.

“Scientists had previously noticed that if the AMOC is stronger in a given season or year, sea levels in the northeast U.S. go down, but if the AMOC weakens, average sea levels rise considerably,” says Chris Piecuch, a physical oceanographer at WHOI and lead author of the paper. “A half-foot of sea level rise, held for months, can have serious coastal impacts. It’s been unclear whether those two things—coastal sea level and the AMOC—are linked by cause and effect.” 

Although the study confirmed that AMOC intensity and sea level seem to change at the same time, it found that neither directly causes changes in the behavior of the other. According to Piecuch, a study like this was not possible until recently. In 2004, an international team of scientists began maintaining a chain of instruments that stretch across the Atlantic. The instruments, which are collectively called the RAPID array, hold sensors that measure currents, salinity, and temperature.

“This study looked at variability in water sloshing around the Atlantic Basin, which is limited to several inches, whereas the melting of glaciers could add many feet of new water,” said Mete Uz, a program director in NSF’s Division of Ocean Sciences, which funded the research. “Still it is very important to understand this signal. Melting will happen over many years, during which we will constantly be watching for signs of acceleration or slow down. Understanding what drives local sea level variability will help us avoid misinterpreting limited observations.”

—  NSF Public Affairs, (703) 292-8070 media@nsf.gov

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In search of an undersea kelp forest’s missing nitrogen

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In search of an undersea kelp forest’s missing nitrogen

Ocean plants need nutrients to grow

California spiny lobster

Lobsters and sea stars are important contributors to the kelp forest nitrogen cycle.

June 24, 2019

Plants need nutrients to grow. So scientists were surprised to learn that giant kelp maintains its impressive growth rates year-round, even in summer and early fall when ocean currents along the California coast stop delivering nutrients. Clearly something else is nourishing the kelp, but what?

A team of NSF-supported scientists at UC Santa Barbara has made a breakthrough in identifying one of those sources. Their research suggests that the invertebrate residents of kelp forests provide at least some of the nutrients the giant algae need. The findings appear in the journal Global Change Biology.

To sustain growth rates, kelp requires many nutrients, especially nitrogen, but changes in ocean currents reduce the availability of such nutrients each year beginning in May. As a result, kelp forests face a potential shortage of nitrogen just as long summer days are poised to fuel algal growth, said lead author Joey Peters.

Peters and his co-authors, UC Santa Barbara marine ecologists Dan Reed and Deron Burkepile, saw the local community of sea-bottom invertebrates as a likely additional nitrogen source. Indeed, it turned out that these invertebrates, especially lobsters and sea stars, are an important part of the nitrogen cycle in coastal ecosystems. Waste from the invertebrates is a consistent component of the “missing nitrogen.”

The scientists made the discovery thanks to nearly two decades of data from the Santa Barbara Coastal Long-Term Ecological Research site, part of a network of sites funded by NSF to conduct long-term ecological research.

This study reveals how environmental change can affect subtle ecosystem dynamics in kelp forests,” said David Garrison, a program director in NSF’s Division of Ocean Sciences, which funded the research. “This work would only be possible where long-term studies are underway.”

—  NSF Public Affairs, (703) 292-8070 media@nsf.gov

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Fishing communities from Maine to North Carolina may need to change catch species

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Fishing communities from Maine to North Carolina may need to change catch species

Fishing communities require new approaches to fishing, studies find

fishing harbor at Matinicus Isle, Maine

The fishing harbor at Matinicus Isle, Maine. Some communities risk losing current fishing options.

June 19, 2019

Most fishing communities from Maine to North Carolina are projected to face declining fishing options unless they adapt to climate change by catching different species or fishing in different areas, according to a study in the journal Nature Climate Change.

Some Maine fishing communities are at greatest risk of losing their current fishing options, according to the work by scientists at Rutgers University and other institutions.

Communities like Portland, Maine, are on track to lose out, while others like Mattituck, New York, or Sandwich, Massachusetts, may do better as waters warm, the scientists said. Adapting to climate change for many communities will require new approaches to fishing, the researchers believe.

Fishing has been the economic and cultural lifeblood for many coastal towns and cities along the Northeast coast, in some cases for hundreds of years. But climate change is expected to have a major impact on the distribution, abundance and diversity of marine species worldwide, the study notes.

The researchers used 13 global climate models to project how ocean temperatures are likely to change. They also looked at whether the species caught by fishing communities are likely to become more, or less, abundant in the ocean regions where they typically fish.

This new approach to mathematical modeling — using vast data sets of fishing practices, fish populations, and projected ocean change — can build scenarios that enable fishing communities to think about and plan for adapting to possible futures,” says Mike Sieracki, a program director in NSF’s Division of Ocean Sciences, which funded the research.

—  NSF Public Affairs, (703) 292-8070 media@nsf.gov

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NSF-supported Frontera named 5th fastest supercomputer in the world

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NSF-supported Frontera named 5th fastest supercomputer in the world

Leadership-class system tops all academic supercomputers

view between two rows of Frontera servers in the TACC data center

A view between two rows of Frontera servers in the TACC data center.

June 19, 2019

The NSF-supported Frontera supercomputer at the Texas Advanced Computing Center earned the number-five spot on the Top500 list, which ranks the world’s most powerful non-distributed computer systems twice a year.

Located at The University of Texas at Austin, Frontera is the fastest university supercomputer in the world. To match what Frontera can compute in just one second, a person would have to perform one calculation every second for about a billion years.

“Many of the frontiers of research today can only be advanced using computing,” said TACC Executive Director Dan Stanzione. “Frontera will be an important tool to solve Grand Challenges that will improve our nation’s health, well-being, competitiveness, and security.”

Supported by a $60 million NSF award, Frontera will provide researchers with the most advanced capabilities for science and engineering when it goes into full operation later this summer.

“Frontera will provide scientists across the country with access to unprecedented computational modeling, simulation, and data analytics capabilities,” said Jim Kurose, NSF assistant director for Computer and Information Science and Engineering. “Frontera represents the next step in NSF’s more than three decades of support for advanced computing capabilities to ensure that the U.S. retains its global leadership in research frontiers.”

—  NSF Public Affairs, (703) 292-8070 media@nsf.gov

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Scientists solve long-standing mystery: Why atmospheric carbon dioxide was lower during ice ages

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Scientists solve long-standing mystery: Why atmospheric carbon dioxide was lower during ice ages

Carbon dioxide as much as one-third lower during ice ages

cooling ocean surface waters and more dust from Southern Hemisphere continents

Cooling waters and Southern Hemisphere dust decreased atmospheric CO2 during the last ice age.

June 17, 2019

Since scientists first determined that atmospheric carbon dioxide was lower during ice ages than during warm phases, they have looked at why, theorizing that it may be a function of ocean circulation, sea ice, iron-laden dust or temperature.

Yet no computer model has been able to explain why CO2 levels were as much as one-third lower when an ice age settled in.

A new study published in Science Advances offers a compelling answer — a  combination of temperature variation in sea water and iron from dust off Southern Hemisphere continents.

“Many past studies that analyzed ocean temperatures made the assumption that they cooled at the same rate over the entire globe,” said Andreas Schmittner, a scientist at Oregon State University and co-author of the study. “We now know that the oceans cooled much more in some regions. Cold water has the potential to soak up a lot more carbon from the atmosphere than past studies accounted for.” 

Schmittner and his colleagues estimate that colder ocean temperatures would account for about half the decrease in CO2 during the last glacial maximum — or peak of the last ice age.

“These researchers have come up with an elegant yet straightforward solution to a problem that has stumped generations of scientists,” said Candace Major, a program director in NSF’s Division of Ocean Sciences, which funded the research.

—  NSF Public Affairs, (703) 292-8070 media@nsf.gov

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Community impacts from extreme weather can shape climate beliefs

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Community impacts from extreme weather can shape climate beliefs

Community impacts from extreme weather may have stronger effects on climate beliefs than individual losses

community damage caused by extreme weather

Community damage from extreme weather may shape climate beliefs more strongly than individual losses

June 14, 2019

Recent studies suggest that people who experience hurricanes, catastrophic flooding or other severe weather events are more likely to believe in, and be concerned about, climate change in the wake of the disaster. But a new, NSF-supported study by researchers at Duke University and the University of Colorado Denver finds that not all severe weather impacts have the same effect.

“How our community or neighborhood fares — the damages it suffers — may have a stronger and more lasting effect on our climate beliefs than individual impacts do,” said Elizabeth Albright, assistant professor at Duke’s Nicholas School of the Environment.

People who perceived that damage occurred at a broad scale were more likely to believe that climate change poses a problem and causes harm, she explained. They were also more likely to perceive a greater risk of future flooding in their community.

In contrast, individual losses such as damage to one’s home appeared to have a negligible long-term impact on climate change beliefs and perceptions of future risks.

“The NSF Directorate for Engineering supports such research to learn how communities can adapt to flooding and other disasters and become more resilient,” said Robin Dillon-Merrill, NSF program director for Humans, Disasters, and the Built Environment.

—  NSF Public Affairs, (703) 292-8070 media@nsf.gov

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