As glaciers melt, huge chunks of ice break free and splash into the sea, generating tsunami-size waves and leaving behind a powerful wake as they drift away. This process, called calving, is important for researchers to understand. But the front of a glacier is a dangerous place for data collection.

To solve this problem, a team of researchers from the 91̽�� and collaborating institutions used a fiber-optic cable to capture calving dynamics across the fjord of the Eqalorutsit Kangilliit Sermiat glacier in South Greenland. This allowed them to document — without getting too close — one of the key processes that is accelerating the rate of glacial mass loss and in turn, threatening the stability of ice sheets, with consequences for global ocean currents and local ecosystems.

“We took the fiber to a glacier, and we measured this crazy calving multiplier effect that we never could have seen with simpler technology,” said co-author, a 91̽��assistant professor in Earth and space sciences. “It’s the kind of thing we’ve just never been able to quantify before.”

in Nature on Aug. 13.

The Greenland ice sheet — a frozen cap about three times bigger than Texas ­­­— is shrinking. Scientists have documented its retreat years as they scramble to understand the consequences of continued mass loss. If the Greenland ice sheet were to melt, it would release enough water to raise global sea levels by about 25 feet, inundating coastlines and displacing millions of people.

Researchers also speculate that ice loss is, a global current system that controls the climate and nutrient distribution by circulating water between northern and southern regions.

“Our whole Earth system depends, at least in part, on these ice sheets,” said lead author, a postdoctoral researcher in Earth and space sciences. “It’s a fragile system, and if you disturb it even just a little bit, it could collapse. We need to understand the turning points, and this requires deep, process-based knowledge of glacial mass loss.”

For the researchers, that meant taking a field trip to South Greenland — where the Greenland ice sheet meets the Atlantic Ocean — to deploy a fiber-optic cable. In the past decade, researchers have been exploring how these cables can be used for remote data collection through technology called Distributed Acoustic Sensing, or DAS, that records ground motion based on cable strain. Before this study, no one had attempted to record glacial calving with a submarine DAS cable.

“We didn’t know if this was going to work,” said Lipovsky. “But now we have data to support something that was just an idea before.”

Researchers dropped a 10-kilometer cable from the back of their boat near the mouth of the glacier. They connected it to a small receiver and collected ground motion data and temperature readings along the length of the cable for three weeks.

The backscatter pattern from photons passing through the cable gave researchers a window beneath the surface. They were able to make nuanced observations about the enormous chunks of ice speeding past their boat. Some of which, said Lipovsky, were the size of a stadium and humming along at 15 to 20 miles per hour.

Glaciers are huge, and most of their mass sits below the surface of the water. Mass loss proceeds faster underwater, eating away at the base and creating an unstable overhang. During a calving event, the overhanging portion breaks off and splashes into the sea. Gradual calving chips away at the glacier, but every so often, a large event occurs. During the experiment, the researchers witnessed a large event every few hours.

“Icebergs are breaking off and exciting all sorts of waves,” said.

Following the initial impact, surface waves — called calving-induced tsunamis — surged through the fjord. This stirs the upper water column, which is stratified. Seawater is warmer and heavier than glacial melt and thus settles at the bottom. But long after the splash, when the surface had stilled, researchers observed other waves, called internal gravity waves, propagating between density layers.

Although they were not visible from the surface, the researchers recorded internal waves as tall as skyscrapers rocking the fjord. The slower, more sustained motion created by these waves prolonged water mixing, bringing a steady supply of warmer water to the surface while driving cold water down to the fjord bottom.

�Ұ�ä�ڴ� compared this process to ice cubes melting in a warm drink. If you don’t stir the drink, a cool layer of water forms around the ice cube, insulating it from the warmer liquid. But if you stir, that layer is disrupted, and the ice melts much faster. In the fjord, researchers hypothesized that waves, from calving, were disrupting the boundary layer and speeding up underwater melt.

Researchers also observed disruptive internal gravity waves emanating from the icebergs as they moved across the fjord. This type of wave is not new, but documenting them at this scale is. Previous work relied on site specific measurements from ocean bottom sensors, which capture just a snapshot of the fjord, and temperature readings from vertical thermometers. The data could help improve forecasting models and support early warning systems for calving-induced tsunamis.

“There is a fiber-sensing revolution going on right now,” said Lipovsky. “It’s become much more accessible in the past decade, and we can use this technology in these amazing settings.”

Other authors include, a 91̽��graduate student in Earth and space science; a 91̽��postdoctoral researcher in Earth and space science,,, , , of University of Zurich; , ,, of ETH Zurich;,, and of the Université Côte d’Azur; and of GEOMAR | Helmholtz Centre for Ocean Research Kiel; of Tufts University;, of École Polytechnique Fédérale de Lausanne; of Stanford University; and of the Université Paris Cité.

This research was funded by the U.S. National Science Foundation, the 91̽��’s FiberLab, the Murdock Charitable Trust, the Swiss Polar Institute, the University of Zurich, ETH Zurich, and the German Research Center for Geosciences GFZ.

For more information, contact Dominik �Ұ�ä�ڴ� at graeffd@uw.edu.

There’s enough water frozen in Greenland and Antarctic glaciers that if they melted, global seas would rise by many feet. What will happen to these glaciers over the coming decades is the biggest unknown in the future of rising seas, partly because glacier fracture physics is not yet fully understood.

A critical question is how warmer oceans might cause glaciers to break apart more quickly. 91̽�� researchers have demonstrated the fastest-known large-scale breakage along an Antarctic ice shelf. The , recently published in AGU Advances, shows that a 6.5-mile (10.5 kilometer) crack formed in 2012 on Pine Island Glacier — a retreating ice shelf that holds back the larger West Antarctic ice sheet — in about 5 and a half minutes. That means the rift opened at about 115 feet (35 meters) per second, or about 80 miles per hour.

“This is to our knowledge the fastest rift-opening event that’s ever been observed,” said lead author , who did the work as part of her doctoral research at the 91̽��and Harvard University and is now a postdoctoral researcher at Stanford University. “This shows that under certain circumstances, an ice shelf can shatter. It tells us we need to look out for this type of behavior in the future, and it informs how we might go about describing these fractures in large-scale ice sheet models.”

A rift is a crack that passes all the way through the roughly 1,000 feet (300 meters) of floating ice for a typical Antarctic ice shelf. These cracks are the precursor to ice shelf calving, in which large chunks of ice break off a glacier and fall into the sea. Such events happen often at Pine Island Glacier — the iceberg observed in the study has long since separated from the continent.

“Ice shelves exert a really important stabilizing influence on the rest of the Antarctic ice sheet. If an ice shelf breaks up, the glacier ice behind really speeds up,” Olinger said. “This rifting process is essentially how Antarctic ice shelves calve large icebergs.”

In other parts of Antarctica, rifts often develop over months or years. But it can happen more quickly in a fast-evolving landscape like Pine Island Glacier, where researchers believe the West Antarctic Ice Sheet has already passed a tipping point on its collapse into the ocean.

Satellite images provide ongoing observations. But orbiting satellites pass by each point on Earth only every three days. What happens during those three days is harder to pin down, especially in the dangerous landscape of a fragile Antarctic ice shelf.

For the new study, the researchers combined tools to understand the rift’s formation. They used seismic data recorded by instruments placed on the ice shelf by other researchers in 2012 with radar observations from satellites.

Glacier ice acts like a solid on short timescales, but it’s more like a viscous liquid on long timescales.

“Is rift formation more like glass breaking or like Silly Putty being pulled apart? That was the question,” Olinger said. “Our calculations for this event show that it’s a lot more like glass breaking.”

If the ice were a simple brittle material, it should have shattered even faster, Olinger said. Further investigation pointed to the role of seawater. Seawater in the rifts holds the space open against the inward forces of the glacier. And since seawater has viscosity, surface tension and mass, it can’t just instantly fill the void. Instead, the pace at which seawater fills the opening crack helps slow the rift’s spread.

“Before we can improve the performance of large-scale ice sheet models and projections of future sea-level rise, we have to have a good, physics-based understanding of the many different processes that influence ice shelf stability,” Olinger said.

The research was funded by the National Science Foundation. Co-authors are and , both 91̽��faculty members in Earth and space sciences who began advising the work while at Harvard University.

For more information, contact Olinger at solinger@stanford.edu.

An international team of researchers has combined satellite imagery and climate and ocean records to obtain the most detailed understanding yet of how the West Antarctic Ice Sheet — which contains enough ice to raise global sea level by 11 feet, or 3.3 meters — is responding to climate change.

The researchers, from the 91̽��, the University of Cambridge and the University of Edinburgh, found that the pace and extent of ice destabilization along West Antarctica’s coast varies according to differences in regional climate.

The , published Jan. 16 in Nature Communications, shows that while the West Antarctic Ice Sheet continues to retreat, the pace of retreat slowed in a key region between 2003 and 2015. This slowdown was driven by ocean temperatures, which were in turn caused by variations in offshore winds.

The marine-based West Antarctic Ice Sheet, home to the vast and unstable Pine Island and Thwaites glaciers, sits on an underwater landmass peaking  1.5 miles, or 2.5 kilometers, below the ocean’s surface. Since the early 1990s, scientists have observed an abrupt acceleration in ice melt, retreat and speed in this area, which is attributed in part to human-induced climate change over the past century.

Previous studies, including from the UW, indicated that the observed changes could be the onset of an irreversible, ice-sheet-wide collapse, which would continue independently of any further climate-driven influence.

“The idea that once a marine-based ice sheet passes a certain tipping point it will cause a runaway response has been widely reported,” said lead author Frazer Christie at Cambridge University. “Despite this, questions remain about the extent to which ongoing changes in climate still regulate ice losses along the entire West Antarctic coastline.”

Using observations collected by an array of satellites, the new study found pronounced regional variations in how the West Antarctic Ice Sheet has changed since 2003 due to climate change, with the pace of retreat in the Amundsen Sea Sector, an area of West Antarctica facing the Pacific Ocean, having slowed significantly. That’s in contrast to the neighboring Bellingshausen Sea Sector, closer to the tip of the Antarctic Peninsula, where glacier retreat accelerated during that time.

By analyzing climate and ocean records, the researchers linked these regional differences to changes in the strength and direction of offshore surface winds. When the prevailing westerly winds are stronger, more of the deeper, warmer ocean water reaches the surface and increases the rate of ice melt.

Winds near the Amundsen Sector slackened between 2003 and 2015, researchers found, because of a deepening of the pressure system. This system is the key atmospheric circulation pattern in the region, and its center — near which changes in offshore wind strength are greatest — typically sits offshore of its namesake coast for most of the year.

Researchers found that the accelerated response of the glaciers flowing from the Bellingshausen Sea Sector can be explained by more constant winds there, causing more persistent ocean-driven melt.

Ultimately, the study illustrates the complexity of the competing ice, ocean and atmosphere interactions driving shorter-term changes across West Antarctica, and raises important questions about how quickly the icy continent will evolve in a warming world.

“Ocean and atmospheric forcing mechanisms still really, really matter in West Antarctica,” said co-author , a 91̽��professor of Earth and space sciences. “That means that ice-sheet collapse is not inevitable. It depends on how climate changes over the next few decades, which we could influence in a positive way by reducing greenhouse gas emissions.”

And while the strength of the low-pressure cell in the Amundsen Sea is not necessarily tied to levels of greenhouse gases — itself an active area of study — the system’s influence shows that even the West Antarctic Ice Sheet is sensitive to weather and climate shifts.

Results show that changes in ocean, driven by changes in the winds, can slow down and even reverse the loss of ice, Steig says. But he points out that the effect is local and unlikely to last for more than a few decades.

“Only the most aggressive reductions in greenhouse gas emissions can plausibly turn the situation around in the long term,” Steig said.

Other co-authors are Noel Gourmelen and Simon Tett at the University of Edinburgh. The study was supported by the Carnegie Trust for the Universities of Scotland; the Scottish Alliance for Geoscience, Environment and Society; the Prince Albert II of Monaco Foundation; the U.K. Natural Environment Research Council; the U.S. National Science Foundation; the joint U.K./U.S. International Thwaites Glacier Collaboration project; and the European Space Agency.

Adapted from a University of Cambridge . For more information, contact Steig at steig@uw.edu

As glaciers worldwide retreat due to climate change, managers of national parks need to know what’s on the horizon to prepare for the future. A new study from the 91̽�� and the National Park Service measures 38 years of change for glaciers in Kenai Fjords National Park, a stunning jewel about two hours south of Anchorage.

The , published Aug. 5 in The Journal of Glaciology, finds that 13 of the 19 glaciers show substantial retreat, four are relatively stable, and two have advanced. It also finds trends in which glacier types are disappearing fastest. The nearly 670,000-acre park hosts various glaciers: some terminate in the ocean, others in lakes or on land.

“These glaciers are a big draw for tourism in the park — they’re one of the main things that people come to see,” said lead author , a 91̽��doctoral student in Earth and space sciences. “Park managers had some information from satellite images, aerial photos, and repeat photography but they wanted a more complete understanding of changes over time.”

The data show that lake-terminating glaciers, which include the popular and , are retreating fastest. Bear Glacier retreated by 5 kilometers (3 miles) between 1984 to 2021, and Pedersen Glacier retreated by 3.2 kilometers (2 miles) during that period.

“In Alaska, much glacier retreat is being driven by climate change,” said Black, who will complete her doctoral degree at the 91̽��this month. “These glaciers are at really low elevation. It’s possibly causing them to get more rain in the winter rather than snow in addition to warming temperatures, which is consistent with other climate studies in this region.”

One surprising finding was that , which as a tidewater glacier terminates at the ocean, has advanced in recent years. Local boat operators had reported seeing newly exposed land near the glacier’s edge in 2020. But the new analysis shows that the overall glacier has been advancing for about 5 years, and appears to go through regular cycles of advance and retreat. The edges of most of the other tidewater glaciers were relatively stable over the study period.

The six land-terminating glaciers all showed intermediate response, with most retreating, especially in summer months, but at a slower rate than the lake-terminating glaciers. The only other glacier that advanced during the study period was land-terminating Paguna Glacier, which is covered in rock debris from a landslide caused by the 1964 Alaska earthquake. This debris insulates the glacier surface from melting.

To make the calculations, Black used 38 years of images captured by satellites in fall and spring to trace outlines for each of the 19 glaciers — a total of about 600 outlines. She visually inspected each image to map the position of the glacier’s edge. Black used a similar approach in recent to calculate the rate of retreat of marine-terminating glaciers in west Greenland.

The new data for Alaska provide a baseline to study how climate change — including warmer air temperatures, as well as changes in both the types and amount of precipitation — will continue to affect these glaciers. All the glaciers in the study are considered maritime glaciers because they are subject to the warm, wet maritime climate.

The study has immediate application for park managers. These numbers help to quantify the changes that have been occurring and will continue for the glaciers and their immediate environments.

“We can’t manage our lands well if we don’t understand the habitats and processes occurring on them,” said co-author Deborah Kurtz at the U.S. National Park Service in Seward, Alaska.

As the park’s Physical Science Program Manager, Kurtz is also interested in the changes to the surrounding river, lake and landscape ecosystems, and how to communicate those changes to the public.

“Interpretation and education are also an important part of the National Park Service mission,” Kurtz said. “These data will allow us to provide scientists and visitors with more details of the changes occurring at each specific glacier, helping everyone to better understand and appreciate the rate of landscape change we are experiencing in this region.”

This study was done as part of an internship originally intended to take place at Kenai Fjords National Park. Black instead did the research remotely from Seattle and visited local glaciers at Mount Rainier. Part of this research was funded by the National Park Service’s Future Park Leaders program, a partnership between the Ecological Society of America and the U.S. National Park Service.

For more information, contact Black at teblack@uw.edu and Kurtz at Deborah_kurtz@nps.gov.

Glacier ice is usually thought of as brittle. You can drill a hole in an ice sheet, like into a rock, and glaciers crack and calve, leaving behind vertical ice cliffs.

But new 91̽�� research shows that glaciers are also slightly compressible, or squishy. This compression over the huge expanse of an ice sheet — like Antarctica or Greenland — makes the overall ice sheet more dense and lowers the surface by tens of feet compared to what would otherwise be expected, according to published Jan. 19 in the Journal of Glaciology.

“It’s like finding hidden ice,” said author , a 91̽��assistant professor of Earth and space sciences. “In a sense, we discovered a big piece of missing ice that wasn’t accounted for correctly.”

Compression of the ice lowers the surface by up to 37 feet (11.3 meters) on the Antarctic ice sheet and by up to 19 feet (5.8 meters) on the Greenland ice sheet. Averaged across the entire Antarctic ice sheet, the surface is lower by 2.3 feet (0.7 meters), which represents 30,200 gigatons of additional ice. For Greenland, the surface of the ice sheet is lowered by an average of 2.6 feet (0.8 meters), which represents 3,000 gigatons of ice.

The mass of the ice sheet is only partly to blame: Since a glacier’s temperature increases with depth, thermal compression makes the colder ice, near the surface of the ice sheet, denser, squishing the ice almost as much as its weight.

Together, the combined effects of gravitational and thermal compression add about 0.2% to the total mass of the ice sheet. Though that sounds small, including this effect will help improve calculations of glacier changes over time — especially as the newest satellites can make precise measurements of glaciers’ elevation to monitor their responses to climate change.

“The long-term behavior of the ice is that it flows, and it also slides a bit. But at the same time, if you hit the ice with a hammer, it goes bing, bing, bing,” Lipovsky said. “On short timescales the glacier is a solid, and on long timescales it’s a fluid.”

Currently even the long-term climate models don’t account for the compression, which becomes a bigger effect for large ice sheets like in Antarctica and Greenland.

“In the long-term flow models, ice is always treated as incompressible. I think if you had really pressed people, and said, ‘There’s seismic pressure waves in glaciers, they must be compressible,’ they would have agreed. But it’s not something people have been thinking about,” Lipovsky said.

The additional water content probably doesn’t matter to future sea-level rise — the new results might add 8 inches (20 centimeters) to the projected 260 feet (80 meters) of sea level rise in the very unlikely event of all the planet’s glaciers melting, Lipovsky said.

But compressibility affects measurements of the difference in glacier elevation between winter, when they are weighted with fresh snow, and summer, when much of that snow has drained off. These seasonal measurements are used to monitor how the glacier is changing over time. The new study estimates that adding ice compressibility could eliminate about one-tenth of the error around these estimates, improving the monitoring of large ice sheets as they respond to climate change.

“Going forward, I hope this will become a correction that’s more commonly accounted for,” Lipovsky said.

For more information, contact Lipovsky at bpl7@uw.edu.

91̽�� glaciologists will join colleagues from around the country in a new effort to discover Antarctica’s oldest ice and learn more about the history of our planet’s climate.

The new Center for Oldest Ice Exploration, or COLDEX, will be created under a five-year, $25 million National Science Foundation grant on Sept. 9. Roughly $5 million of that grant will go to the UW.

91̽��researchers will lead in aspects of Antarctic fieldwork and modeling to identify the drilling location, deploy new technologies to scan the ice, and use new ways to analyze the ice once it is retrieved. The center will bring together experts from across the United States to generate knowledge about Earth’s climate system and share this knowledge to advance efforts to address climate change and its impacts.

“Establishing a center makes it possible to go after the big scientific goal of finding and analyzing the oldest ice remaining on Earth to address fundamental questions about the climate system,” said co-principal investigator , a 91̽��research associate professor of Earth and space sciences. “This is a tremendous opportunity that will bring together an ambitious research program with coordinated education, outreach and knowledge transfer programs as part of a new center that is founded on broadening participation in ice and climate science.”

The oldest existing ice cores currently go back 130,000 years in Greenland and 800,000 years in Antarctica. The newly funded effort aims to find a continuous ice core that goes back 1.5 million years, and to recover chunks that are even older. Previous 91̽��research has explored a possible location for this oldest ice record, in the Allan Hills region of East Antarctica.

A continuous record longer than 1 million years could offer new information about past climate transitions to help understand and predict current changes in the Earth’s climate.

“This ice and the ancient air trapped in it will offer an unprecedented record of how greenhouse gases and climate are linked in warmer climates and will help to advance our understanding of what controls the long-term rhythms of Earth’s climate system,” said principal investigator at Oregon State University.

91̽��researchers will help study potential drilling sites and model ice flow to find a location where the oldest ice-core climate record is preserved in Antarctica; apply new radar techniques for the first time on a large scale; and help develop novel methods for analyzing the ice that will eventually be recovered.

One aspect of COLDEX will involve new development of a probe, the 91̽�� , that melts through layers of ice and provides information about the age of the ice and other data without having to lift a core back up to the surface. The technology is being developed by COLDEX participant , a 91̽��research professor in Earth and Space Sciences and senior physicist at the 91̽��Applied Physics Laboratory, in collaboration with Ryan Bay at the University of California, Berkeley.

“This is something that has never been done before. The idea is that it would have an optical device that could detect the amount of dust in the ice,” Brook said — without the need for a preexisting borehole.

Because the atmosphere tends to be dustier during colder periods and after big volcanic eruptions, the researchers expect to be able to count the dust cycles to estimate the age of the ice, even before the ice is recovered and brought back to the laboratory for more detailed analysis.

“The Ice Diver allows us to reach great depths in the ice for logging dust levels at costs low enough to sample in many places,” Winebrenner said.

The first fieldwork season is in the planning stages for 2022-2023. Initial on-the-ground work will be done in the Allan Hills region of Antarctica and airborne campaigns across a target sector of East Antarctica, Koutnik said. After that, ground surveying will be done in East Antarctica to help target the specific deep drill site. The deep ice core would be extracted in a second five-year phase of COLDEX.

Other researchers leading the COLDEX effort at the 91̽��are Knut Christianson, T.J. Fudge, Eric Steig, Howard Conway, Ed Waddington and Andrew Schauer in Earth and space sciences.

“Many researchers at UW, including new young scientists, will come together and contribute to the ambitious center goals of understanding the ice sheet and the climate history,” Koutnik said. “This is really exciting science and a fantastic opportunity for our community of researchers at 91̽��to work together and to collaborate across institutions and across disciplines to address major questions in ice core and cryosphere science.”

Other institutional partners on COLDEX include Amherst College; Brown University; Dartmouth College; Princeton University; Scripps Institution of Oceanography; the University of California, Berkeley; UC Irvine; the University of Kansas; University of Maine; University of Minnesota, Duluth; University of Minnesota, Twin Cities; and the University of Texas.

Additional partners include the American Meteorological Society, Inspiring Girls Expeditions, the Earth Science Women’s Network and the Alaska Native Science and Engineering Program, helping to meet a program goal of enhancing diversity in Earth science fields. The center will work with the American Meteorological Society’s educational arm to develop a summer program on ice cores for K-12 teachers who work with students from underrepresented backgrounds.

Funding will be available to support research experiences for undergraduate and graduate students and postdoctoral scholars, with the aim of recruiting diverse pools of candidates for those opportunities.

COLDEX is one of six new science and technology centers announced this month by the National Science Foundation. NSF currently supports 12 centers, with the last group funded in 2016. The objective of the program, established in 1987, is to support transformative, complex research programs in fundamental areas of science that require large-scale, long-term funding.

For more information, contact Koutnik at mkoutnik@uw.edu.

The Uttarakhand region of India experienced a humanitarian tragedy on Feb. 7, 2021, when a wall of debris and water barreled down the Ronti Gad, Rishiganga and Dhauliganga river valleys.

The event began when a wedge of rock carrying a glacier broke off of a steep ridge in the Himalayan mountain range. The resulting debris flow destroyed two hydropower facilities and left more than 200 people dead or missing.

A self-organized coalition of 53 scientists came together in the days following the disaster to investigate the cause, scope and impacts. The team determined that the flood was caused by falling rock and glacier ice that melted on its descent — not by a lake or diverted river — which will help researchers and policymakers better identify emerging hazards in the region.

The study, which used satellite imagery, seismic records and eyewitness videos to produce computer models of the flow, in Science.

“On the morning of the event, I was reading the news over coffee, and saw a headline about a disaster in the Himalayas,” said co-author , a 91̽�� assistant professor of civil and environmental engineering. “I sat down at the computer and pulled up the satellite images that had been acquired that morning. When I saw the dust cloud moving down the valley, I started writing emails to other scientists asking if they were working on this. One email thread quickly became five, then 10, and the response effort consumed most of our waking hours for the next two weeks.”

Initial hypotheses for the cause of the event suggested a glacial lake outburst flood. But there are no glacial lakes large enough to produce a flood anywhere near the site, the team determined.

“Our access to high-resolution satellite imagery and research software, and our expertise in satellite remote sensing were crucial to get a bird’s-eye view of how the event unfolded,” said co-author , a 91̽��doctoral student in civil and environmental engineering. “We worked with our French collaborators to coordinate satellite collections within days of the event and rapidly process the images to derive detailed topographic maps of the site.”

The researchers compared the images and topographic maps from before and after the event to document all of the changes and reconstruct the sequence of events.

“We tracked a plume of dust and water to a conspicuous dark patch high on a steep slope,” said lead author , associate professor at the University of Calgary.

The dark patch turned out to be the scar left by the 35 million cubic yards of missing rock and glacier ice — enough material to cover Washington, D.C., with a half-foot-deep layer.

“This was the source of a giant landslide that triggered the cascade of events, and caused immense death and destruction,” said Shugar, who was previously an assistant professor at 91̽��Tacoma.

The researchers also used the maps to determine how far the block of ice and rock fell.

“The failed block fell over a mile before impacting the valley floor. To put this height in context, imagine vertically stacking up 11 Space Needles or six Eiffel Towers,” Bhushan said.

Then the larger team was able to quantify how the pulverized rock and ice were redistributed over the downstream areas.

“As the block fell, most of the glacier ice melted within minutes. This resulted in a huge volume of water associated with the flooding,” Bhushan said. “This is highly unusual — a normal rock landslide or snow/ice avalanche could not have produced such huge volumes of water.”

For Bhushan, the work was personal.

“In general, doctoral research projects are very niche. I sometimes have a hard time explaining to my parents why measuring glacier dynamics is important,” Bhushan said. “But due to the scale of this disaster, my family and friends back in India were very curious to know how this event unfolded, and they were expecting me to come up with an answer. These interactions provided me with a sense of belonging and motivation that some of my research can be of such immediate use to society.”

The team also used satellite image archives to show that previous large ice masses had been dislodged from the same ridge and struck the same valley in recent years. The researchers suggest that climate change is likely increasing the frequency of such events, and that the greater magnitude of the latest disaster should be considered before further infrastructure development in the area.

“These high-mountain rivers are appealing for hydropower projects, and we need a better understanding of the full spectrum of potential high-mountain hazards,” Shean said. “We hope that lessons learned from this effort will improve our ability to respond to future disasters and guide policy decisions that will save lives.”

Shean, Bhushan and Shugar are joined by 50 additional co-authors from 14 countries. In addition to geoscientists, the co-authors list includes water policy experts and a social scientist. Shean and Bhushan were funded by the NASA High Mountain Asia Team and the Future Investigators in NASA Earth and Space Science Technology fellowship. Other co-authors received funding from a variety of government agencies including those in India, Canada, France, Germany and Switzerland. The satellite imagery the 91̽��team used was provided by MAXAR, Planet, ISRO and CNES, the French government space agency.

For more information, contact Shean at dshean@uw.edu and Bhushan at sbaglapl@uw.edu.

Grant numbers for the 91̽��team: 80NSSC20K1595, 80NSSC19K1338

As the planet warms, glaciers are retreating and causing changes in the world’s mountain water systems. For the first time, scientists at the University of Oxford and the 91̽�� have directly linked human-induced climate change to the risk of flooding from a glacial lake known as one of the world’s greatest flood risks.

The study examined the case of in the Peruvian Andes, which could cause flooding with devastating consequences for 120,000 residents in the city of Huaraz. The , published Feb. 4 in Nature Geoscience, provides new evidence for an ongoing that hinges on the link between greenhouse gas emissions and particular climate change impacts.

“The scientific challenge was to provide the clearest and cleanest assessment of the physical linkages between climate change and the changing flood hazard,” said co-author , a 91̽��professor of Earth and space sciences.

In 2016, Roe and colleagues developed a method to determine whether an individual glacier’s retreat can be linked to human-induced climate change. The retreat of mountain glaciers has several consequences, including creating basins in the space left by the retreating glacier. Precipitation and meltwater collects in these basins to form glacial lakes. Recent work has shown a rapid of high-elevation glacial lakes.

“We believe our study is the first to assess the full set of linkages between anthropogenic climate change and the changing glacial lake outburst flood hazard,” Roe said. “The methods used in our study can certainly be applied to other glacial lakes around the world.”

The new study first calculated the role of human emissions in the observed temperature increase since the start of the industrial era around Palcaraju Glacier. It finds that human activity is responsible for 95% of the observed 1 degree Celsius (1.8 degrees Fahrenheit) warming in this region since 1880.

The authors then used the UW-developed technique to assess the relationship between these warming temperatures and the observed long-term retreat of the glacier that has caused Lake Palcacocha to expand. Results show it is virtually certain, with greater than 99% probability, that human-induced climate change has caused Palcaraju Glacier’s retreat.

Lead author Rupert Stuart-Smith, a doctoral student at Oxford, then used two methods to assess the hazard of glacial lake outburst flooding, in which an avalanche, landslide or rockfall induces a tsunami wave that overtops the lake’s banks, to pinpoint how Lake Palcacocha’s growth affects the flood risk faced by the city of Huaraz below.

“We found that human influence on climate — through greenhouse-gas emissions — is responsible for virtually all of the warming that has been observed in the region,” said Stuart-Smith, who spent the summer of 2019 at the UW. “The study shows that warming has caused the retreat of the Palcaraju Glacier, which in turn has greatly increased the flood risk.”

The study provides new evidence for an in which Saúl Luciano Lliuya, a farmer from Huaraz, has sued RWE, Germany’s largest electricity producer, for its role in creating global warming. The suit seeks reimbursement for current and future flood-risk reduction measures.

“Crucially, our findings establish a direct link between emissions and the need to implement protective measures now, as well as any damages caused by flooding in the future,” Stuart-Smith said.

This is not the first time Huaraz has been threatened by climate change. In 1941, an outburst flood from Lake Palcacocha, resulting from an ice and rock slide, killed at least 1,800 people. The study also found this flood to be influenced by human-induced climate change — making it one of the earliest identified fatal impacts of climate change.

The lake’s recent growth strains since the 1970s to contain the lake’s water.

“Around the world, the retreat of mountain glaciers is one of the clearest indicators of climate change,” Roe said. “Outburst floods threaten communities in many mountainous regions, but this risk is particularly severe in Huaraz, as well as elsewhere in the Andes and in countries like Nepal and Bhutan, where vulnerable populations live in the path of the potential floodwaters.”

Other co-authors are Myles Allen and Sihan Li at the University of Oxford. The study was funded by the U.K. Natural Environment Research Council, the U.S. National Science Foundation and a from the University of Oxford.

For more information, contact Roe at groe@uw.edu or Stuart-Smith at rupert.stuart-smith@ouce.ox.ac.uk.

Adapted from a University of Oxford .

Antarctica’s next deep ice core, drilling down to ice from 130,000 years ago, will be carried out by a multi-institutional U.S. team at Hercules Dome, a location hundreds of miles from today’s coastline and a promising site to provide key evidence about the possible last collapse of the West Antarctic Ice Sheet.

The National Science Foundation has funded the roughly five-year, $3 million involving the 91̽��, the University of New Hampshire, the University of California, Irvine and the University of Minnesota. Work has been delayed by the novel coronavirus, but drilling the 1.5-mile ice core likely will begin in 2024.

“The ice at this site goes back to a time when sea level was about 6 meters (20 feet) higher than it is now,” said project leader , a 91̽��professor of Earth and space sciences. “One of the most likely reasons that sea level was higher is that a large area of Antarctic, known as the West Antarctic Ice Sheet, was gone.”

Scientists hope to understand the most recent collapse of the West Antarctic Ice Sheet in order to better gauge its . Deeper ice layers at this site reach back to times — the most recent period that, like now, was between ice ages. The Eemian was even warmer than today’s climate and oceans were higher.

“This location, which is now hundreds of miles from the ocean, may have been waterfront property 125,000 years ago,” Steig said. “We should be able to determine this from the chemistry of the ice — for example, the salt concentration may be higher if there was open water nearby, instead of more than a thousand miles away. Understanding that event will help guide our understanding of how quickly sea level may rise in the future due to ongoing anthropogenic climate change.”

The Hercules Dome site, remote even by Antarctic standards, lies near a mountain range that divides East and West Antarctica. 91̽��researchers to survey potential locations for drilling. They used ice-penetrating radar to find places where the layers of ice are uninterrupted back more than 125,000 years, when oceans rose dramatically.

Ice and air bubbles trapped in the ice layers can provide researchers with various information about past conditions The most recent deep ice core in Antarctica was completed in 2016 at the South Pole by many of the same team members.

“The Hercules Dome ice core will be the first U.S. ice core with the potential to yield a detailed climate record during the last interglacial period,” said principal investigator at the University of California, Irvine.

The project will begin with online workshops over the next year to seek new collaborators and work to broaden participation in polar science. The initial investment by the National Science Foundation covers the costs of the drilling project, but over the next few years, many more scientists can seek additional funding to analyze the core. The delays caused by the pandemic offer more time to try to bring new people into the discipline.

“Earth sciences is known for being particularly white and male, and polar Earth sciences is even more that way,” Steig said. “It’s well established that having a more diverse community leads to better outcomes — that is, we’ll do better science with more kinds of people involved. But also it’s the right thing to do. Anyone who is interested in being involved in this science should have the opportunity to do it.”

The University of New Hampshire will provide logistics and science support planning for the field project. Researchers will live in tents on the ice sheet hundreds of miles from any inhabited areas for the months-long field seasons.

“Our planning will detail, for example, how we will get ourselves and all of the required science cargo and camp materials to Hercules Dome, likely through a combination of overland traverse and aircraft support; specifics on the field camp, such as camp population, camp structures and layout, power and fuel requirements, camp equipment; and the fieldwork schedule,” said , research project manager at the University of New Hampshire.

The project has plans to coordinate with artists, computer scientists, media outlets, educational organizations and museums to share the effort and the science of climate change.

, a climate scientist at the University of Minnesota, will lead the engagement programming and will work to connect the science through this project to different audiences including those who are actively planning and preparing for the impacts sea level rise — from coastal planners and water utility engineers to homeowners and elected officials.

“This is the first U.S. deep ice core drilling project with a lead researcher dedicated to the integration of community engagement and communication across the full lifespan of the project,” Roop said. “With this investment by NSF, we are confident we can more effectively connect this science to action.”

For more information, contact Steig at steig@uw.edu, Aydin at maydin@uci.edu, Souney at joe.souney@unh.edu and Roop at hroop@umn.edu. More information about the project is at .

Using the most advanced Earth-observing laser instrument NASA has ever flown in space, a team of scientists led by the 91̽�� has made precise measurements of how the Greenland and Antarctic ice sheets have changed over 16 years.

In a published April 30 in the journal Science, researchers found the net loss of ice from Antarctica, along with Greenland’s shrinking ice sheet, has been responsible for 0.55 inches (14 millimeters) of sea level rise to the global ocean since 2003. In Antarctica, sea level rise is being driven by the loss of the floating ice shelves melting in a warming ocean. These ice shelves help hold back the flow of land-based ice.

The findings come from the Ice, Cloud and land Elevation Satellite 2 (ICESat-2), and began taking detailed global elevation measurements, including over Earth’s frozen regions. By comparing the new data with measurements taken by the original ICESat from 2003 to 2009, researchers have generated a comprehensive portrait of the complexities of ice sheet change — and insights into the future of Greenland and Antarctica.

“If you watch a glacier or ice sheet for a month, or a year, you’re not going to learn much about what the climate is doing to it,” said lead author , a glaciologist at the 91̽��Applied Physics Laboratory. “We now have a 16-year span between ICESat and ICESat-2 and can be much more confident that the changes we’re seeing in the ice have to do with the long-term changes in the climate.��And ICESat-2 is a really remarkable tool for making these measurements. We’re seeing high-quality measurements that carpet both ice sheets, which let us make a detailed and precise comparison with the ICESat data.”

Previous studies of ice loss or gain often analyze data from multiple satellites and airborne missions. The new study takes a single type of measurement — height as measured by an instrument that bounces laser pulses off the ice surface — providing the most detailed and accurate picture of ice sheet change to date.

The researchers took tracks of ICESat measurements and overlaid the denser tracks of ICESat-2 measurements from 2019. Where the two data sets intersected — tens of millions of sites — they ran the data through computer programs that accounted for the snow density and other factors, and then calculated the mass of ice lost or gained.

“The new analysis reveals the ice sheets’ response to changes in climate with unprecedented detail, revealing clues as to why and how the ice sheets are reacting the way they are,” said co-author , a glaciologist at NASA’s Jet Propulsion Laboratory in Pasadena, California.

The study found that Greenland’s ice sheet lost an average of 200 gigatons of ice per year, and Antarctica’s ice sheet lost an average of 118 gigatons of ice per year. One gigaton of ice is enough to fill 400,000 Olympic-sized swimming pools.

Of the sea level rise that resulted from ice sheet meltwater and iceberg calving, about two-thirds of it came Greenland, the other third from Antarctica, Smith said.

“It was amazing to see how good the ICESat-2 data looked, right out of the gate,” said co-author at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “These first results looking at land ice confirm the consensus from other research groups, but they also let us look at the details of change in individual glaciers and ice shelves at the same time.”

In Greenland, there was a significant amount of thinning of coastal glaciers, Smith said. The Kangerlussuaq and Jakobshavn glaciers, for example, have lost 14 to 20 feet (4 to 6 meters) of elevation per year. Warmer summer temperatures have melted ice from the surface of the glaciers and ice sheets, and in some places warmer ocean water erodes away the ice at their fronts.

In Antarctica, the dense tracks of ICESat-2 measurements showed that the ice sheet is getting thicker in parts of the continent’s interior, likely as a result of increased snowfall, Smith said. But the loss of ice from the continent’s margins, especially in West Antarctica and the Antarctic Peninsula, far outweighs any gains in the interior. In those places, the ocean is also likely to blame.

“In West Antarctica, we’re seeing a lot of glaciers thinning very rapidly,” Smith said. “There are ice shelves at the downstream end of those glaciers, floating on water. And those ice shelves are thinning, letting more ice flow out into the ocean as the warmer water erodes the ice.”

These ice shelves, which rise and fall with the tides, can be difficult to measure, said co-author , a glaciologist at Scripps Institution of Oceanography at the University of California, San Diego. Some of them have rough surfaces, with crevasses and ridges, but the precision and high resolution of ICESat-2 allows researchers to measure overall changes, without worrying about these features skewing the results.

This is one of the first times that researchers have measured loss of the floating ice shelves around Antarctica simultaneously with loss of the continent’s ice sheet.

Ice that melts from ice shelves doesn’t raise sea levels, since it’s already floating — just like an ice cube melting in a full cup of water doesn’t overflow the glass. But the ice shelves do provide stability for the glaciers and ice sheets behind them.

“It’s like an architectural buttress that holds up a cathedral,” Fricker said. “The ice shelves hold the ice sheet up. If you take away the ice shelves, or even if you thin them, you’re reducing that buttressing force, so the grounded ice can flow faster.”

The researchers found ice shelves in West Antarctica, where many of the continent’s fastest-moving glaciers are located, are losing mass. Patterns of thinning show that Thwaites and Crosson ice shelves have thinned the most, an average of about 5 meters (16 feet) and 3 meters (10 feet) of ice per year, respectively.

The study was funded by NASA. Other co-authors are Johan Nilsson and Fernando Paolo at NASA’s Jet Propulsion Laboratory; Brooke Medley, Thorsten Markus and H. Jay Zwally at NASA’s Goddard Space Flight Center; Nicholas Holschuh at Amherst College; Susheel Adusumilli at the University of California, San Diego; Kelly Brunt at the University of Maryland; Bea Csatho at the University of Buffalo; Kaitlin Harbeck at KBR; and Matthew Siegfried at the Colorado School of Mines. Smith and Neumann are both affiliate faculty members in the 91̽��Department of Earth & Space Sciences.

For more information contact Smith at besmith@uw.edu, Fricker at hafricker@ucsd.edu, Gardner at alex.s.gardner@jpl.nasa.gov and Neumann at thomas.neumann@nasa.gov.��

This article is adapted from a NASA .

NASA grants: NNX15AE15G, NNX15AC80G, NNX16AM01G, NNX17AI03G