The blue whale is the largest animal on the planet. It consumes enormous quantities of tiny, shrimp-like animals known as krill to support a body of up to 100 feet (30 meters) long. Blue whales and other baleen whales, which filter seawater through their mouths to feed on small marine life, once teemed in Earth’s oceans. Then over the past century they were hunted almost to extinction for their energy-dense blubber.

As whales were decimated, some thought the krill would proliferate in predator-free waters. But that’s not what happened. Krill populations dropped, too, and neither population has yet recovered.

A recent theory proposes that whales weren’t just predators in the ocean environment. Nutrients that whales excreted may have provided a key fertilizer to these marine ecosystems.

Research led by 91̽�� oceanographers supports that theory. It finds that whale excrement contains significant amounts of iron, a vital element that is often scarce in ocean ecosystems, and nontoxic forms of copper, another essential nutrient that in some forms can harm life.

The open-access , the first to look at the forms of these trace metals in what’s commonly known as whale poop, was published in January in Communications Earth & Environment.

“We made novel measurements of whale feces to assess how important whales are to recycling important nutrients for phytoplankton,” said first author , a 91̽��doctoral student in oceanography. “Our analysis suggests that the decimation of baleen whale populations from historical whaling could have had larger biogeochemical implications for the Southern Ocean, an area crucially important to global carbon cycling.”

The Southern Ocean encircling Antarctica harbors little human life but is thought to play an important role in the global climate. Strong circumpolar currents bring deep ocean water up to the surface. Huge blooms of plant-like organisms known as phytoplankton support populations of krill, which are still harvested in unprotected waters today for aquaculture and pet food.

To investigate what role whale poop may have played in this ecosystem, the study analyzed five stool samples. Two samples were from humpback whales in the Southern Ocean and three were from blue whales off the central Californian coast. The samples were collected when researchers out studying whale populations saw an opportunity.

“The nice thing, I guess, is that whale excrement floats,” said senior author , an assistant professor of oceanography at the UW. Researchers collect it using a net attached to a jar to collect the substance typically found as a slushy or slurry material.

“The hypothesis is that the whales were actually adding nutrients to the ecosystem that these phytoplankton were able to use, so they would bloom more and then the krill could eat them,” Bundy said.

Previous research had found significant amounts of , like nitrogen and carbon, in whale poop samples. The new paper instead looked for metals that are in short supply far from land and are often a limiting factor for the growth of ocean ecosystems.

“In the Southern Ocean, iron is considered to be one of the most scarce, or limiting, nutrients that phytoplankton need to survive,” Bundy said

Results showed iron was present in all the samples. The researchers also found another metal, copper.

“We were really shocked by how much copper was in the whale poop. We initially thought, ‘oh, no, is the whale poop actually toxic?’” Bundy said.

Further analysis showed that organic molecules known as attached to the copper atoms transformed them into a form that is safe for marine life. Other ligands helped make the iron accessible to living organisms. The researchers don’t yet know the source of the ligands but suspect they may come from bacteria in the whales’ stomachs.

Bundy’s research focuses on trace metals in the ocean environment. This project began as Monreal’s introductory research project as a graduate student but it grew into a larger endeavor as the results came in.

“I think animals play a larger role in chemical cycles than many experts give them credit for, especially when thinking at the ecosystem scale,” Monreal said. “When I say animals, I really mean their gut microbiome. Based on what we see, it seems like bacteria in the whales’ guts could be important.”

Co-authors are postdoctoral researcher , former doctoral student and former undergraduate student from the UW; Matthew Savoca and Jeremy Goldbogen at Stanford University; Lydia Babcock-Adams at Florida State University; Logan Pallin, Ross Nichols and Ari Friedlaender at the University of California, Santa Cruz; John Calambokidis at the Cascadia Research Collective in Olympia, Washington; and at the National Oceanic and Atmospheric Administration and the UW’s Cooperative Institute for Climate, Ocean and Ecosystem Studies. Funders are MAC3 Impact Philanthropies, the MUIR Program at the Stanford Woods Institute for the Environment, the 91̽�� Program on Climate Change and the Ford Foundation.

For more information, contact Monreal at pmonreal@uw.edu and Bundy at rbundy@uw.edu. Note: Monreal is on New Zealand time through mid-February and responses may be delayed.

It turns out the rate of that increase matters for non-living systems, too. A recent 91̽�� study looked at how a major current in the Atlantic Ocean that includes the Gulf Stream will respond to a doubling of carbon dioxide from preindustrial levels. The , published in the Proceedings of the National Academy of Sciences, found that when carbon dioxide levels rise more gradually, they have less impact on the ocean circulation.

91̽��News sat down with author , a 91̽��postdoctoral researcher in the , to learn more about her study.

Why did you choose to study how the rate of rising CO2 affects the climate system?

Camille Hankel: In my PhD, some of my work was on “climate tipping points,” which emerge from the hypothesis that there might be some sort of critical thresholds of warming or CO2 change that can lead to very abrupt and irreversible change in some parts of the climate system. Through that work, I got exposed to some literature on “rate-induced tipping points,” which is the idea that instead of crossing a critical level, that there could be some critical rates of CO2 change that are important for the climate system.

Specifically, I read this study that was looking at this idea in the context of the AMOC, the , which is this large-scale ocean circulation. That study was using what we call a box model — a simplified, mathematical representation of the ocean circulation. And I thought, hey, I can run these global models, which are much more realistic representations of the Earth’s climate, including ocean, atmosphere, land and sea ice, and test whether the rate of CO2 change really is that important.

What is the Atlantic Meridional Overturning Circulation, which includes the Gulf Stream ocean current, and why is it so important for Earth’s climate?

CH: It’s one of the large-scale, key features of the climate system. In particular, it transports a lot of heat from the low latitudes in the South Atlantic to the higher latitudes closer to the North Pole. So it delivers a lot of heat, primarily to Northern Europe. It also distributes nutrients around through this sort of sinking motion that characterizes the circulation — it draws the surface waters down into the deep ocean, and recirculates deep water up to the surface. It’s a big feature of the climate system, particularly in the North Atlantic, but also globally.

We’ve heard about a potential slowdown of the Gulf Stream current that could affect European weather. This was dramatized (perhaps not accurately) in the 2004 disaster movie ‘.’ Are we actually seeing a slowdown in Atlantic Ocean circulation?

CH: We have a pretty short observational record of the AMOC current, and it’s sparse. You have to imagine, this is a 3D circulation in the entire Atlantic basin, and we have a couple little slices of data in particular parts of the Atlantic. We are seeing a modest slowdown so far, but it’s a pretty noisy and uncertain observational record, so it’s hard to tell.

I would say, however, that slowdown seen in current observations would match the model predictions of future slowdowns. And we also see a pattern in temperature changes where, while the rest of the globe is warming right now as we increase CO2, there’s what people call a “warming hole” over the North Atlantic: We’re not seeing as much warming in that North Atlantic region compared to the rest of the globe. And it’s hard to conclusively attribute what’s causing it in the Earth’s climate, but the idea is that the modest slowdown of the AMOC that we’ve seen so far could be one contributing factor to that lack of warming we’re seeing in the North Atlantic.

So the observations suggest some slowdown, though much less dramatic than what was depicted in that movie.

Why is the AMOC expected to slow down under climate change?

CH: One way of thinking about what drives this major ocean current is differences in ocean density. You have this really important zone in the North Atlantic where the waters sink because the surface waters are heavier than the waters below. When you change CO2 levels, you do two things. You start to warm the ocean’s surface, and by melting glaciers as well as changing sea ice, you add freshwater to the surface of the otherwise salty ocean. Both warming and freshening reduce the density of that upper ocean water and potentially inhibit or disrupt that critical sinking motion.

There are other ways of looking at it, but the one I look at in the study is understanding how those density perturbations happen in a higher-CO2 climate and how they modulate the sensitivity to the rate of CO2 change that I find in the AMOC’s response to CO2.

Your study finds that if atmospheric carbon dioxide doubles from pre-industrial levels more slowly, there’s less slowdown in the Atlantic Ocean compared to if CO2 doubles more quickly. Is that because everything is happening more slowly?

CH: Yes, that’s part of it. The different parts of the climate system — the ocean, atmosphere, and ice — all have different response timescales to CO2 changes, meaning they respond to perturbations with different lag times. Then how these components of the climate interact with each other under slower or faster CO2 changes can look very different, and in this case influence the ocean circulation.

Specifically, I found what’s known as a positive feedback — a sort of self-amplifying cycle — that helps explain why the level of AMOC weakening depends on the rate of CO2 change. In this feedback cycle, the initial modest amount of AMOC slowdown leads to a reduction of heat transport into the Arctic, which in turn cools the region and leads to a temporary period of Arctic sea ice expansion. This sea ice expansion causes more ice to be exported to the North Atlantic, where it melts and adds freshwater to the ocean, causing the AMOC to slow down even more: hence the self-amplifying cycle. It turns out that this feedback cycle is more effective at amplifying AMOC weakening under more rapid CO2 changes than under gradual CO2 changes.

What is the importance of this work?

CH: We know about AMOC slowdowns — there’s a ton of work on that, and the mechanisms that drive such an AMOC slowdown. But what’s new is this sensitivity of circulation changes to the rate of CO2 increase, independent of the total change in concentration of CO2.

When we think about policy and basic science, we tend to focus a lot on how the level of global warming can impact the climate system. I’m trying to bring a new perspective by thinking about the rate of increase as a driver itself, that could have a lot of impacts.

You can imagine that if multiple different climates are possible for the same level of warming, then limiting us to 1.5 C or 2 C could have different meanings, right? I do think the most important thing for the climate system is always how much CO2 have you put into the atmosphere, but how quickly you got to that point clearly matters as well.

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For more information, contact Hankel at crhankel@uw.edu.

Murres, a common seabird, look a little like flying penguins. These stout, tuxedo-styled birds dive and swim in the ocean to eat small fish and then fly back to islands or coastal cliffs where they nest in large colonies. But their hardy physiques disguise how vulnerable these birds are to changing ocean conditions.

A 91̽�� citizen science program — which trains coastal residents to search local beaches and document dead birds — has contributed to a new study, led by federal scientists, documenting the devastating effect of warming waters on ��in Alaska.

In 2020, participants of the UW-led Coastal Observation and Seabird Survey Team, or , and other observers first identified the massive mortality event affecting common murres along the West Coast and Alaska. That study documented 62,000 carcasses in a single year, mostly in Alaska. In some places, beachings were more than 1,000 times normal rates. But the 2020 study did not estimate the total size of the die-off after the 2014-16 marine heat wave known as “the blob.”

In this , published Dec. 12 in Science, a team led by the U.S. Fish and Wildlife Service analyzed years of colony-based surveys to estimate total mortality and later impacts. The analysis of 13 colonies surveyed between 2008 and 2022 finds that colony size in the Gulf of Alaska, east of the Alaska Peninsula, dropped by half after the marine heat wave. In colonies along the eastern Bering Sea, west of the peninsula, the decline was even steeper, at 75% loss.

The study led by , a wildlife biologist at the U.S. Fish and Wildlife Service, estimates that 4 million Alaska common murres died in total, about half the total population. No recovery has yet been seen, the authors write.

“This study shows clear and surprisingly long-lasting impacts of a marine heat wave on a top marine predator species,” said , a 91̽��professor of aquatic and fishery sciences and of biology, who was a co-author on both the 2020 paper and the new study. “Importantly, the effect of the heat wave wasn’t via thermal stress on the birds, but rather shifts in the food web leaving murres suddenly and fatally without enough food.”

The “warm blob” was an unusually warm and long-lasting patch of surface water in the northeast Pacific Ocean from late 2014 through 2016, affecting weather and coastal marine ecosystems from California to Alaska. As ocean productivity decreased, it affected food supply for top predators including seabirds, marine mammals and commercially important fish. Based on the condition of the murre carcasses, authors of the 2020 study concluded that the most likely cause of the mass mortality event was starvation.

Before this marine heat wave, about a quarter of the world’s population, or about 8 million common murres, lived in Alaska. Authors estimate the population is now about half that size. While common murre populations have fluctuated before, the authors note the Alaska population has not recovered from this event like it did after previous, smaller die-offs.

While the “warm blob” appears to have been the most intense marine heat wave yet, persistent, warm conditions are becoming more common under climate change. A 2023 study led by the UW, including many of the same authors, showed that a 1 degree Celsius increase in sea surface temperature for more than six months results in multiple seabird mass mortality events.

“Whether the warming comes from a heat wave, El Niño, Arctic sea ice loss or other forces, the message is clear: Warmer water means massive ecosystem change and widespread impacts on seabirds,” Parrish said. “The frequency and intensity of marine bird mortality events is ticking up in lockstep with ocean warming.”

“We may now be at a tipping point of ecosystem rearrangement where recovery back to pre-die-off abundance is not possible.”

Other co-authors are and at the U.S. Fish and Wildlife Service offices in Alaska; , a former federal scientist now with the World Puffin Congress in Port Townsend; and at Tern Again Consulting in Homer.

For more information, contact Parrish at jparrish@uw.edu and Renner at heather_renner@fws.gov. Note: Parrish is currently attending a meeting in Washington, D.C.��

Amid all the changes in Earth’s climate, sea ice in the stormy Southern Ocean surrounding Antarctica was, for a long time, an odd exception. The maximum winter sea ice cover remained steady or even increased slightly from the late 1970s through 2015, despite rising global temperatures.

That began to change in 2016. Several years of decline led to , more than five standard deviations below the average from the satellite record. The area of sea ice was 2.2 million square kilometers below the average from the satellite record, a loss almost 12 times the size of Washington state. The most recent winter’s peak, recorded in September 2024, was to the previous year’s record low.

91̽�� researchers show that the all-time record low can be explained by warm Southern Ocean conditions and patterns in the winds that circled Antarctica months earlier, allowing forecasts for sea ice coverage around the South Pole to be generated six or more months in advance. This could support regional and global weather and climate models.

The open-access was published Nov. 20 in Nature Communications Earth & Environment.

“Since 2015, total Antarctic sea ice area has dramatically declined,” said lead author , a 91̽��doctoral student in atmospheric and climate science. “State-of-the-art forecasting methods for sea ice generally struggle to produce reliable forecasts at such long leads. We show that winter Antarctic sea ice has significant predictability at six- to nine-month lead times.”

The authors used a global climate model to simulate how ocean and air temperatures, including longer-term cycles like El Niño and La Niña, affect sea ice in the Southern Ocean.

Results showed that the 2023 El Niño was less important than previously thought. Instead, an arching pattern of regional winds, and their effects on ocean temperatures up to six months in advance, could explain 70% of the 2023 record-low winter sea ice. These winds cause ocean mixing in the Southern Ocean that can pull deeper warm water up to the surface, thus suppressing sea ice growth. Winds can also push sea ice poleward toward Antarctica to prevent the sea ice edge from expanding north, transport heat from lower latitudes toward the poles, and generate ocean waves that break up sea ice.

Using the same approach for the 2024 observations correctly predicted that this would be another low year for Southern Ocean sea ice cover.

“It’s interesting that, despite how unusual the winter sea ice conditions were in 2023 and again in 2024, our results show they were remarkably predictable over 6 months in advance,” said co-author , a 91̽��research associate professor of atmospheric and climate science.

Antarctic sea ice is important because it affects marine and coastal ecosystems and interactions between ocean and atmosphere in the Southern Ocean. It also affects global climate by reflecting sunlight in the Southern Hemisphere and influencing ice sheets and global currents.

“Antarctic sea ice is a major control on the rate of global warming and the stability of ice on the Antarctic continent,” Espinosa said. “In fact, the sea ice acts to buttress ice shelves, increasing their stability and slowing the rate of global sea level rise. This ice is also important for marine and coastal ecosystems.”

As summer arrives in the Southern Hemisphere, the remains sparse around Antarctica, close to a record low for this time of the year.

“Our success at predicting these major sea ice loss events so far in advance demonstrates our understanding of the mechanism that caused them,” said co-author , a 91̽��professor of atmospheric and climate science. “Our model and methods are geared up to predict future sea ice loss events.”

The research was funded by the National Science Foundation and the U.S. Department of Energy.

For more information, contact Espinosa at zespinosa97@gmail.com, Bitz at bitz@uw.edu and Blanchard-Wrigglesworth at edwardbw@uw.edu.

From its base at the southwest corner of the Seattle campus, the provides expertise, tools and resources on “all things climate” to partners and communities across the state.

was announced in the spring as the . Mauger is a research scientist with the 91̽��Climate Impacts Group, which now houses the state climatologist’s office. Mauger’s research focuses mainly on water and floods in the context of climate change.

, a 91̽��research scientist and the deputy state climatologist, studies such things as nighttime heat in Seattle and new ways to display weather data, as well as other trends involving heat and drought.

Together, they provide data and share news on whatever’s in the skies. From heat domes to hailstorms, from snowpack to summer drought, they provide perspective on the short-term and long-term weather woes and questions facing Washingtonians.

“Our goal is to help people understand the climate and how it affects their daily lives,” Mauger said.

Right now, many people in the region are curious about the upcoming winter season.

“This year we’re expecting to see a weak La Niña develop in the tropical Pacific Ocean,” Bumbaco said. For Washington that means “on average, we tend to have cooler-than-normal temperatures, a little bit more precipitation, and more snowpack by the end of our winter season during La Niña winters.”

Mauger and Bumbaco also conduct research on changes in rainfall patterns and flood risks, and on temperatures and wildfire risks for the coming season and over the longer term. Visit the Office of the Washington State Climatologist’s website to check out the seasonal , a list of or to subscribe to a on the current state of Washington’s climate.

For more information, contact Mauger at mauger@uw.edu or Bumbaco at kbumbaco@uw.edu.

Since its launch in late 2021, NASA’s James Webb Space Telescope has raised the possibility that we could detect signs of life on exoplanets, or planets outside our solar system.

Top candidates in this search are rocky, rather than gaseous, planets orbiting low-mass stars called M-dwarfs — easily the most common stars in the universe. One nearby M-dwarf is , a star about 40 light years away that hosts a system of orbiting planets under intense scrutiny in the search for life on planets orbiting stars other than the sun.

Previous research questioned the habitability of planets orbiting TRAPPIST-1, finding that intense UV rays would burn away their surface water. That would leave the planet’s surface desiccated and — if only the hydrogen part of the water vapor molecules escapes — potentially with huge amounts of reactive oxygen that would inhibit origin-of-life chemistry.

Now, a 91̽��-led recently published in Nature Communications finds that a sequence of events during the evolution of certain rocky planets orbiting M-dwarfs creates an atmosphere that would be stable over time.

“One of the most intriguing questions right now in exoplanet astronomy is: Can rocky planets orbiting M-dwarf stars maintain atmospheres that could support life?” said lead author , a 91̽��assistant professor of Earth and space sciences. “Our findings give reason to expect that some of these planets do have atmospheres, which significantly enhances the chances that these common planetary systems could support life.”

The James Webb Space Telescope is sensitive enough that it can observe a select few of these planetary systems. Data coming back so far suggests that the hottest rocky planets, closest to the TRAPPIST-1 star, do lack significant atmospheres. But the telescope has not yet been able to clearly characterize planets in the “Goldilocks zone,” slightly farther from their star, at a distance most favorable to supporting liquid water and life.

The new study modeled a rocky planet through the course of its molten formation and cooling over hundreds of millions of years into a solid terrestrial planet. Results showed that hydrogen or other light gases did initially escape into outer space. But for planets farther away from the star, where the temperature is more moderate, hydrogen also reacted with oxygen and iron in the planet’s interior. This produced water and other, heavier, gases, forming an atmosphere that results show is stable over time.

Results also showed that for these “Goldilocks zone” planets, water rains out of the atmosphere fairly quickly, making the water less likely to escape.

“It’s easier for the JWST to observe hotter planets closest to the star because they emit more thermal radiation, which isn’t as affected by the interference from the star. For those planets we have a fairly unambiguous answer: They don’t have a thick atmosphere,” Krissansen-Totton said. “For me, this result is interesting because it suggests that the more temperate planets may have atmospheres and ought to be carefully scrutinized with telescopes, especially given their habitability potential.”

The JWST has not yet been able to see whether the planets a little farther from the TRAPPIST-1 star have atmospheres. But if they do, that means they could have surface liquid water and a temperate climate conducive to life.

“With the telescopes that we have now, the James Webb and the extremely large ground-based telescopes coming soon, we’re really only going to be able to look at a very small number of habitable zone rocky planets’ atmospheres — it’s the TRAPPIST-1 planets and a couple of others,” Krissansen-Totton said. “Given the huge interest in the search for life elsewhere, our result suggests that it’s worthwhile investing telescope time to continue studying the habitability of these systems with the technology we have now, rather than waiting for the next generation of more powerful telescopes.”

Co-authors are Nicholas Wogan, who did this work as a 91̽��graduate student and is now at NASA; Maggie Thompson at Carnegie Institution for Science in Washington, D.C.; and Jonathan Fortney at the University of California, Santa Cruz. This research was supported by NASA.

For more information, contact Krissansen-Totton at joshkt@uw.edu.��

Polar bears in some parts of the high Arctic are developing ice buildup and related injuries to their feet, apparently due to changing sea ice conditions in a warming Arctic. While surveying the health of two polar bear populations, researchers found lacerations, hair loss, ice buildup and skin ulcerations primarily affecting the feet of adult bears as well as other parts of the body. Two bears had ice blocks up to 1 foot (30 centimeters) in diameter stuck to their foot pads, which caused deep, bleeding cuts and made it difficult for them to walk.

The led by the 91̽�� was published Oct. 22 in the journal Ecology. It’s the first time that such injuries have been documented in polar bears.

The researchers suggest several mechanisms for how the shift from a climate that used to remain well below freezing to one with freeze–thaw cycles could be causing ice buildup and injuries.

“In addition to the anticipated responses to climate change for polar bears, there are going to be other, unexpected responses,” said lead author , a senior principal scientist at the 91̽��Applied Physics Laboratory and a professor in the 91̽��School of Aquatic and Fishery sciences. “As strange as it sounds, with climate warming there are more frequent freeze-thaw cycles with more wet snow, and this leads to ice buildup on polar bears’ paws.”

Between 2012 and 2022, Laidre and co-author , a wildlife veterinarian, studied two populations of polar bears living above 70 degrees north latitude and saw the injuries.

In the Kane Basin population, located between Canada and Greenland, 31 of 61 polar bears showed evidence of icing-related injuries, such as hairless patches, cuts or scarring.

In the second population in East Greenland, 15 of 124 polar bears had similar injuries. Two Greenland bears at separate locations in 2022 had massive ice balls stuck to their feet.

“I’d never seen that before,” Laidre said. “The two most-affected bears couldn’t run — they couldn’t even walk very easily. When immobilizing them for research, we very carefully removed the ice balls. The chunks of ice weren’t just caught up in the hair. They were sealed to the skin, and when you palpated the feet it was apparent that the bears were in pain.”

Researchers have studied these two polar bear populations since the 1990s but haven’t reported these types of injuries before. Consultations with lifetime Indigenous subsistence hunters and a survey of the scientific literature suggests this is a recent phenomenon.

Polar bears have small bumps on their foot pads that help provide traction on slippery surfaces. These bumps, which are larger than those on the pads of other bear species like brown and black bears, make it easier for wet snow to freeze to the paws and accumulate. This problem also affects sled dogs in the North.

The authors hypothesize three possible reasons for increasing ice buildup on polar bears’ paws — all related to climate warming. One is more rain-on-snow events, which creates moist, slushy snow that clumps onto paws and then freezes to form a solid once temperatures drop.

A second possibility is that more warm spells are causing the surface snow to melt and then refreeze into a hard crust. The heavy polar bears break through this ice crust, cutting their paws on its sharp edges.

The final possible reason is that both these populations live on “” connected to the land, near where freshwater glaciers meet the ocean. Warming in these environments leads to thinner sea ice, allowing seawater to seep up into the snow. This wet snow can clump onto bears’ feet and then refreeze to form ice. Also, unlike other areas, polar bears living at glaciers’ edges rarely swim long distances in spring, which would help thaw and dislodge accumulated ice chunks because the water is warmer than the air.

While the bears are clearly affected by the ice buildup, the researchers are cautious regarding broader conclusions about the health of the two populations.

“We’ve seen these icing-related injuries on individual polar bears,” Laidre said. “But I would hesitate to jump to conclusions about how this might affect them at a population level. We really don’t know.”

, a research scientist at UW’s Applied Physics Laboratory, recently published a separate analyzing snow cover on Arctic sea ice over recent decades.

“The surface of Arctic sea ice is transforming with climate change,” Webster said. “The sea ice has less snow in late spring and summer, and the snow that does exist is experiencing earlier, episodic melt and more frequent rain. All these things can create challenging surface conditions for polar bears to travel on.”

Asked what can be done to help the polar bears, Laidre had a simple response: “We can reduce greenhouse gas emissions and try to limit climate warming.”

The field observations of polar bears were funded by the governments of Canada, Denmark, Nunavut and Greenland. Laidre is also affiliated with the Greenland Institute of Natural Resources.

For more information, contact Laidre at klaidre@uw.edu.

These “” events have happened only a handful of times and do not occur on regular cycles. Each lasts for millions of years or tens of millions of years and is followed by dramatic warming, but the details of these transitions are poorly understood.

New research from the 91̽�� provides a more complete picture for how the last Snowball Earth ended, and suggests why it preceded a dramatic expansion of life on Earth, including the emergence of the first animals.

The recently published in Nature Communications focuses on ancient rocks known as “cap carbonates,” thought to have formed as the glacial ice thawed. These rocks preserve clues to Earth’s atmosphere and oceans about 640 million years ago, far earlier than what ice cores or tree rings can record.

“Cap carbonates contain information about key properties of Earth’s atmosphere and ocean, such as changing levels of carbon dioxide in the air, or the acidity of the ocean,” said lead author , a 91̽��doctoral student in Earth and space sciences. “Our theory now shows how these properties changed during and after Snowball Earth.”

are layered limestone or dolomite rocks that have a distinct chemical makeup and today are found in over 50 global locations, including Death Valley, Namibia, Siberia, Ireland and Australia. These rocks are thought to have formed as the Earth-encircling ice sheets melted, causing dramatic changes in atmospheric and ocean chemistry and depositing this unique type of sediment onto the ocean floor.

They are called “caps” because they are the caps above glacial deposits left after Snowball Earth, and “carbonates” because both limestone and dolomite are carbon-containing rocks. Understanding their formation helps explain the carbon cycle during periods of dramatic climate change. The new study, which models the environmental changes, also provides hints about the evolution of life on Earth and why more complex lifeforms followed the last Snowball Earth.

“Life on Earth was simple — in the form of microbes, algae or other tiny aquatic organisms — for over 2 billion years leading up to Snowball Earth,” said senior author , a 91̽��professor of Earth and space sciences. “In fact, the billion years leading up to Snowball Earth are called the ‘boring billion’ because so little happened. Then two Snowball Earth events occurred. And soon after, animals appear in the fossil record.”

The new paper provides a framework for how the last two facts may be connected.

The study modeled chemistry and geology during three phases of Snowball Earth. First, during Snowball Earth’s peak, thick ice encircling the planet reflected sunlight, but some areas of open water allowed exchange between the ocean and atmosphere. Meanwhile frigid seawater continued to react with the ocean floor.

Eventually, carbon dioxide built up in the atmosphere to the point where it trapped enough solar energy to raise global temperatures and melt the ice. This let rainfall reach the Earth, and let freshwater flow into the ocean to join a layer of glacial meltwater that floated over the denser, salty ocean water. This layered ocean slowed down ocean circulation. Later, ocean churning picked up, and mixing between the atmosphere, upper ocean, and deep ocean resumed.

“We predict important changes in the environment as Earth recovered from the Snowball period, some of which affected the temperature, acidity and circulation of the ocean. Now that we know these changes, we can more confidently figure out how they affected Earth’s life,” Thomas said.

Future research will explore how pockets of life that may have survived the tumult of the Snowball Earth and its aftermath could have evolved into the more complex lifeforms that followed soon after.

The research was funded by the National Science Foundation and NASA, in part by a NASA Astrobiology Program grant to the UW’s Virtual Planetary Laboratory.

For more information, contact Thomas at tbthomas@uw.edu or Catling at dcatling@uw.edu.

UPDATE (Aug. 2, 2024): A previous version of this story misstated Paul Kinahan’s name.

Fifteen faculty members at the 91̽�� have been elected to the Washington State Academy of Sciences. They are among 36 scientists and educators from across the state . Selection recognizes the new members’ “outstanding record of scientific and technical achievement, and their willingness to work on behalf of the academy to bring the best available science to bear on issues within the state of Washington.”

Twelve 91̽��faculty members were selected by current WSAS members. They are:

• , associate professor of epidemiology, of health systems and population health, and of child, family and population health nursing, who “possesses the rare combination of scientific rigor and courageous commitment to local community health. Identifying original ways to examine questions, and seeking out appropriate scientific methods to study those questions, allow her to translate research to collaborative community interventions with a direct impact on the health of communities.”
• , the Shauna C. Larson endowed chair in learning sciences, for “his work in the cultural basis of scientific research and learning, bringing rigor and light to multiculturalism in science and STEM education through STEM Teaching Tools and other programs.”
• , professor of psychiatry and behavioral sciences, “for her sustained commitment to community-engaged, science-driven practice and policy change related to the prevention of suicide and the promotion of mental health, with a focus on providing effective, sustainable and culturally appropriate care to people with serious mental illness.”
• , the David and Nancy Auth endowed professor in bioengineering, who has “charted new paths for 30-plus years. Her quest to deeply understand protein folding/unfolding and the link to amyloid diseases has propelled her to pioneer unique computational and experimental methods leading to the discovery and characterization of a new protein structure linked to toxicity early in amyloidogenesis.”
• , professor of environmental and occupational health sciences, of global health, and of emergency medicine, who is “a global and national leader at the intersection of climate change and health whose work has advanced our understanding of climate change health effects and has informed the design of preparedness and disaster response planning in Washington state, nationally and globally.”
• , professor of bioengineering and of radiology, who is “recognized for his contributions to the science and engineering of medical imaging systems and for leadership in national programs and professional and scientific societies advancing the capabilities of medical imaging.”
• , the Donald W. and Ruth Mary Close professor of electrical and computer engineering and faculty member in the 91̽��Clean Energy Institute, who is “recognized for his distinguished research contributions to the design and operation of economical, reliable and environmentally sustainable power systems, and the development of influential educational materials used to train the next generation of power engineers.”
• , senior vice president and director of the Vaccine and Infectious Disease Division at the Fred Hutchinson Cancer Center, the Joel D. Meyers endowed chair of clinical research and of vaccine and infectious disease at Fred Hutch, and 91̽��professor of medicine, who is “is recognized for her seminal contributions to developing validated laboratory methods for interrogating cellular and humoral immune responses to HIV, TB and COVID-19 vaccines, which has led to the analysis of more than 100 vaccine and monoclonal antibody trials for nearly three decades, including evidence of T-cell immune responses as a correlate of vaccine protection.”
• , professor of political science and the Walker family professor for the arts and sciences, who is a specialist “in environmental politics, international political economy, and the politics of nonprofit organizations. He is widely recognized as a leader in the field of environmental politics, best known for his path-breaking research on the role firms and nongovernmental organizations can play in promoting more stringent regulatory standards.”
• , the Ballmer endowed dean of social work, for investigations of “how inequality, in its many forms, affects health, illness and quality of life. He has developed unique conceptual frameworks to investigate how race, ethnicity and immigration are associated with health and social outcomes.”
• , professor of chemistry, who is elected “for distinguished scientific and community contributions to advancing the field of electron paramagnetic resonance spectroscopy, which have transformed how researchers worldwide analyze data.”
• , professor of bioengineering and of ophthalmology, whose “pioneering work in biomedical optics, including the invention of optical microangiography and development of novel imaging technologies, has transformed clinical practice, significantly improving patient outcomes. Through his numerous publications, patents and clinical translations, his research has helped shape the field of biomedical optics.”

Three new 91̽��members of the academy were selected by virtue of their previous election to one of the National Academies. They are:

• , professor of atmospheric and climate science, who had been elected to the National Academy of Sciences “for contributions to research and expertise in atmospheric radiation and cloud processes, remote sensing, cloud/aerosol/radiation/climate interactions, stratospheric circulation and stratosphere-troposphere exchanges and coupling, and climate change.”
• , the Bartley Dobb professor for the study and prevention of violence in the Department of Epidemiology and a 91̽��professor of pediatrics, who had been elected to the National Academy of Medicine “for being a national public health leader whose innovative and multidisciplinary research to integrate data across the health care system and criminal legal system has deepened our understanding of the risk and consequences of firearm-related harm and informed policies and programs to reduce its burden, especially among underserved communities and populations.”
• , division chief of general pediatrics at Seattle Children’s Hospital and a 91̽��professor of pediatrics, who had been elected to the National Academy of Medicine “for her leadership in advancing child health equity through scholarship in community-partnered design of innovative care models in pediatric primary care. Her work has transformed our understanding of how to deliver child preventive health care during the critical early childhood period to achieve equitable health outcomes and reduce disparities.”

In addition, Dr. , president and director of the Fred Hutchinson Cancer Center and of the Cancer Consortium — a partnership between the UW, Seattle Children’s Hospital and Fred Hutch — was elected to the academy for being “part of a research effort that found mutations in the cell-surface protein epidermal growth factor receptor (EGFR), which plays an important role in helping lung cancer cells survive. Today, drugs that target EGFR can dramatically change outcomes for lung cancer patients by slowing the progression of the cancer.”

the Boeing-Egtvedt endowed professor and chair in aeronautics and astronautics, will join the board effective Sept. 30. Morgansen was elected to WSAS in 2021 “for significant advances in nonlinear methods for integrated sensing and control in engineered, bioinspired and biological flight systems,” and “for leadership in cross-disciplinary aerospace workforce development.” She is currently director of the Washington NASA Space Grant Consortium, co-director of the 91̽��Space Policy and Research Center and chair of the AIAA Aerospace Department Chairs Association. She is also a member of the WSAS education committee.

“I am excited to serve on the WSAS board and work with WSAS members to leverage and grow WSAS’s impact by identifying new opportunities for WSAS to collaborate and partner with the state in addressing the state’s needs,” said Morgansen.

The new members to the Washington State Academy of Sciences will be formally inducted in September.

Corn is one of the planet’s most important crops. It not only provides sweet kernels to flavor many dishes, but it’s also used in oils, as a sweetener syrup, and as a feed crop for livestock. Corn has been bred to maximize its yield on farms around the world.

But what will happen under climate change? Research led by the 91̽�� combined climate projections with plant models to determine what combination of traits might be best adapted to future climates. The study used projections of weather and climate across the U.S. in 2050 and 2100 with a model that simulates corn’s growth to find the mix of traits that will produce the highest, most reliable yield under future conditions across the country.

The open-access was published in April in Environmental Research Food Systems. 91̽��News asked senior author , a 91̽��professor of atmospheric sciences and of biology, about the study and its findings.

Our future climate will be warmer, have drier air and have a higher concentration of atmospheric carbon dioxide. Is there a broad understanding of how all these changes together will affect plant growth?

Abigail Swann: For corn, a by our group found that higher temperatures and drier air have about the same size impact, with both leading to less corn yield, while more CO2 available for photosynthesis increased yield. The increase in yield from CO2 wasn’t enough to counteract the decrease from the other two changes, however, so corn yields went down overall.

Overall, hotter temperatures like those we expect in the future will make crops grow faster but be less productive. Of course, shifts in precipitation also affect their growth in different locations, though that has less impact overall, and particularly for agricultural crops that rely on irrigation.

Typically, many people think of climate change as something that will shift where certain crops can grow. Your study says the crop varieties we plant today aren’t ideal for any location in the future. Why is that?

AS: As climate continues to warm, we can adapt by moving existing crop varieties closer to the poles, where the air is cooler. But shifting existing varieties to new places isn’t enough to make up for the loss in crop yield that we expect in a hotter climate because the impacts of higher temperatures are so detrimental.

Our study looked at 100 possible corn varieties, and we find that those that will be most successful in the future are not varieties that are successful now — we need new crops for the new climate.

Can you describe the corn that will perform best in future climates, according to your study, compared to the varieties that do best today?

AS: Corn plants first grow leaves, and then switch to growing grain. We find that today, corn plants must make a tradeoff between growing a lot of leaves and still having enough time left in the growing season to grow a lot of grain. This means the most successful varieties today don’t grow very many leaves, so they can switch to growing grain early in the season.

Growing more leaves could potentially allow corn to increase how much the plant can photosynthesize, which would also increase how much grain it could grow, but today this comes at a cost of a shorter growing season.

In the future, it will be warmer overall, and corn may be planted earlier and harvested later in the season. This longer growing season relieves corn from this tradeoff and allows it to both grow more leaves and still have plenty of time to grow grain (there is an additional boost from faster growth under hotter temperatures).

So basically, in this sense the corn plants of the future can have their cake and eat it too. The varieties we simulated that took advantage of the ability to grow more leaves yielded more under future climate than the varieties with less leaf growth. This isn’t good news for corn, though. While corn will be able to grow more leaves and still have plenty of time to grow grain, the adverse impacts of hot temperatures and drier air will decrease the overall yields. Growing more leaves and having a longer growing season help buffer these adverse impacts, but overall, all of the corn plants we simulated did worse under future climate conditions.

Is there any way to verify these results on real plants before these climate conditions become reality?

AS: While the plants that we found would do best under future climate conditions don’t exist right now, plants with many of these characteristics can be bred quickly, using genetic techniques like CRISPR. Then they can be grown under controlled climate conditions to see if our findings hold up for real plants. That part of the process is surprisingly fast, so we can create and trial new plant varieties before they are needed.

Why is it helpful to use computer models, rather than just selective breeding as has been done in the past?

AS: Breeding new crop varieties is a very slow process. It can take decades to go from initial breeding to testing and adoption by farmers. The process starts with selecting among the existing crop varieties for desirable characteristics, including high yield. Then these new potential varieties are combined, grown and tested in multiple environments and with different management. Finally, the final varieties are released commercially and then can be adopted by farmers.

With simulations we can test a much wider range of possible combinations of characteristics that could work well for a new variety, and use that knowledge to guide the first stages of breeding. This can speed up the breeding process and accelerate our ability to adapt to a changing climate. It also gives us information about what characteristics we might try to create that are farther from our existing varieties.

How does your study fit into the broader field of climate adaptation?

AS: We will need to adapt agriculture in many ways to support a growing population with a growing demand for food, combined with the loss in crop yield that we expect as climate gets hotter. Our study helps to jumpstart the process of breeding climate-resilient crops by envisioning what those crops should look like. Our study also provides a blueprint for how to do this analysis for other crop types, besides corn.

Although we focus on corn for this study, we see our work as a demonstration of an approach that can be applied to any crop, and so more of a blueprint of how we can incorporate the expected impacts of climate change into the breeding of new crop varieties.

In the U.S. we heard recently about population leveling off due to lower birth rates and about shifts to less resource-intensive, plant-based diets. Can you explain why, worldwide, we still expect an increase in demand for corn?

AS: Worldwide population is still growing, and in addition to growing in total number, the global population is growing more affluent and increasing its consumption of meat. In the U.S. our diet is already very meat-intensive, and so shifts towards less resource-intensive and plant-based diets make a lot of sense from a health and environmental standpoint.

But meat consumption in many parts of the world is currently very low. As these populations increase their wealth, we expect that in some cases meat consumption will grow. This increase in wealth is a good thing for the well-being of those people. By adapting agriculture, we hope to buffer the losses in yield expected from hotter temperatures and help provide enough food for everyone.

What’s next for this research?

AS: We would like to work with breeders to create some of the corn varieties our study proposed, and do similar studies on other major global food crops. We are currently seeking additional funding sources to conduct these next steps.

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Lead author did the work as part of her 91̽��doctoral degree in biology. Co-authors are , 91̽��professor of environmental and forest sciences; at the U.S. Department of Agriculture; and at Colorado State University. The research was funded by the National Science Foundation, the U.S. Department of Agriculture and the UW’s Royalty Research Fund.

For more information, contact Swann at aswann@uw.edu.