Eric Meola

In this year of extreme weather events — from devastating West Coast wildfires to tropical Atlantic storms that have exhausted the alphabet — scientists and members of the public are asking when these extreme events can be scientifically linked to climate change.

Dale Durran, a professor of atmospheric sciences at the University of Washington, argues that climate science need to approach this question in a way similar to how weather forecasters issue warnings for hazardous weather.

In a new paper, published in the October issue of the Bulletin of the American Meteorological Society, he draws on the weather forecasting community’s experience in predicting extreme weather events such as tornadoes, flash floods, high winds and winter storms. If forecasters send out a mistaken alert too often, people will start to ignore them. If they don’t alert for severe events, people will get hurt. How can the atmospheric sciences community find the right balance?

Most current approaches to attributing extreme weather events to global warming, he says, such as the conditions leading to the ongoing Western wildfires, focus on the likelihood of raising a false alarm. Scientists do this by using statistics to estimate the increase in the probability of that event that is attributable to climate change.  Those statistical measures are closely related to the “false alarm ratio,” an important metric used to assess the quality of hazardous weather warnings.

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LE Baskow

The Columbia River is home to one of the West Coast’s most important Chinook salmon runs. Through late spring and early summer, mature fish return from the sea and begin their arduous journey upriver to spawn. In recent years, these fish have faced an additional challenge: hungry California sea lions.

A new University of Washington and NOAA Fisheries study found that sea lions have the largest negative effect on early-arriving endangered Chinook salmon in the lower Columbia River. The results published Oct. 19 in the Journal of Applied Ecology.

Opportunistic sea lions have learned that by swimming as far as 145 miles upriver, they can easily feast on migrating salmon, including those hindered by the Bonneville Dam.

“We investigated whether mortality rates varied depending on the specific threatened Chinook salmon population, determined by when they arrive in the river,” said lead author Mark Sorel, a doctoral student at the UW School of Aquatic and Fishery Sciences. “We found that, based on their individual return timing and the abundance of sea lions in the river when they return, individual populations experience different levels of sea lion-associated mortality.”

Researchers learned that the earliest arriving populations of Chinook salmon experienced an additional 20% mortality over previous years, and the later arriving populations experienced an additional 10%. This increase in mortality was associated with increased sea lion abundance at those times of year in the period of 2013 to 2015 compared to the period of 2010 to 2012.

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Nicolás Young/Columbia University

If human societies don’t sharply curb emissions of greenhouse gases, Greenland’s rate of ice loss this century is likely to greatly outpace that of any century over the past 12,000 years, a new study concludes.

University of Washington scientists are among the authors of the study published Sept. 30 in the journal Nature. The research employed ice sheet modeling to understand the past, present and future of the Greenland Ice Sheet.

Scientists used new, detailed reconstructions of ancient climate to drive the model, and validated the model against real-world measurements of the ice sheet’s contemporary and ancient size.

The findings place the ice sheet’s modern decline in historical context, highlighting just how extreme and unusual projected losses for the 21st century could be.

“This study shows that even with uncertainties accounted for, current ice loss from Greenland is about as high as it has ever been in thousands of years, and the ice loss is increasing,” said co-author Eric Steig, a UW professor of Earth and space sciences. “We will enter a unique time within this century, if we have not already done so, for Greenland ice loss at any time in the past 12,000 years.”

Though the project focused on southwestern Greenland, research shows that changes in the rates of ice loss there tend to correspond tightly with changes across the entire ice sheet.

“We relied on the same ice sheet model to simulate the past, the present and the future,” says co-author Jessica Badgeley, a UW doctoral student in Earth and space sciences. “Thus, our comparisons of the ice sheet mass change through these time periods are internally consistent, which makes for a robust comparison between past and projected ice sheet changes.”

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Summers for UW Environment students are often spent working as interns, taking summer classes or accompanying faculty conducting field research. But the spring and summer of 2020 were anything but typical as COVID-19 forced faculty and students to figure out alternative plans or rethink research. With the belief that many students learn best when doing, known as immersive learning, many researchers have had to pivot to still provide students with the resources and opportunities normally available.

School of Environmental and Forest Sciences’ Georgia Coleman had planned on traveling with Professor John Marzluff to Yellowstone National Park back in March in a class titled Wildlife Conservation in Northwest Ecosystems (ESRM 459). That trip was scrapped as both the park and in-person classes were shut down, but luckily Coleman was eventually able to make the journey east in June.

So how did she manage field work for this class when COVID-19 guidelines were still in place? ESRM 459 is a field course, meaning that class time is spent working on a project in preparation for the trip to the field station after the end of the quarter. This June, instead of the entire class taking the trip, just Coleman and one other student met with Marzluff and his wife in Yellowstone to conduct field work. They drove separately and slept in separate cabins, and signed daily attestations that they had no signs of illness two weeks prior and every day on the trip. Daily temperature checks were routine, and masks and social distancing were used. As visitors started to increase at the park after reopening, the group stayed off-trail while out in the field.

Other aspects of field work remained the same. Marzluff led the group in studying common ravens (Corvus corax) in Yellowstone, finding raven nests to count the young, and observing ravens foraging and settling into their night roosts. 

Part of their research included monitoring about 60 ravens in the park, all wearing solar-powered GPS backpacks with an antenna that submits the birds’ locations every 30 minutes throughout the day. Using this data, Marzluff and his students are able to piece together the movement of ravens from sunrise to sunset. Using these data, Coleman was able to make estimates about where ravens forage, and where they roost at night.

Marzluff spent much of his career investigating raven roosting and foraging, but the technology needed to answer these questions and closely follow ravens didn’t exist. Following one raven on foot from one foraging site to the next, or from a foraging site to a roost posed not only logistical challenges, but was also extremely time consuming and relied on luck to find these sites. Now, with these GPS backpacks, Marzluff and his students are able to get much more accurate data with significantly less effort.

For her project, Coleman specifically investigated whether the ravens return to the same roosts every night and what the birds are roosting on, referred to as a substrate. Yellowstone is an interesting place to conduct this research because the park contains a variety of substrates – everything from trees to roofs to powerlines to exposed mountains higher than 10,000 feet.

“I think roosting in particular is fascinating because of the role it plays in the birds’ lives,” said Coleman. “Ravens are social animals, so roost sites are not only a safe place to rest, they also provide the birds with the chance to form social bonds and allow them to gain information about foraging opportunities. Knowing the benefits of roosting makes me curious to know why they roost where they do.”

Looking at the data points that bookend the day, Coleman determines where roosts are located based on the earliest point (usually around sunrise) and marks that area as a roost site. These data points tell a varying story – sometimes the latest and earliest points are near one another leading Coleman to be fairly confident in roost sites, and other times the points are thousands of meters apart, leading to less confidence.

Besides studying ravens in the field, the group also saw and learned about some of Yellowstone’s rich wildlife history. While at the park they stayed at the historic Lamar Buffalo Ranch, where bison, now plentiful in the park, were raised in the early 1900s after hunting nearly decimated the population. The successful reintroduction of bison to the park is a wildlife conservation success story that many are not even aware of. 

Another historic location visited was the Rose Creek pen, where wolves captured from Canada were acclimated before their reintroduction back into the park as part of a wolf restoration plan. Wolves were virtually eliminated from most of the lower 48 states by the mid-1900s, so the visit to the pen was timely as this year marks the 25th anniversary of the wolf reintroduction. The massive fence of the pen is starting to fall over, but the wooden boxes the wolves were brought in still remain, as do the bones of their meals.

“Visiting the pen, and then getting to watch adult wolves hunt and wolf pups play, was a surreal, beautiful experience,” said Coleman. “Learning about these conservation success stories in my classes at UW is interesting but observing healthy bison and wolf populations in person is an experience I’ll never forget.”

In this time of great uncertainty, even the best laid plans need adjusting in efforts to adhere by COVID-19 guidelines and keep everyone as safe and healthy as possible. A lot of changes  had to be made, with maximum flexibility and quick decision making, but field work is still possible and can be just as impactful as always.

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A small subpopulation of polar bears lives on what used to be thick, multiyear sea ice far above the Arctic Circle. The roughly 300 to 350 bears in Kane Basin, a frigid channel between Canada’s Ellesmere Island and Greenland, make up about 1-2% of the world’s polar bears.

New research shows that Kane Basin polar bears are doing better, on average, in recent years than they were in the 1990s. The study, published Sept. 23 in Global Change Biology, finds the bears are healthier as conditions are warming because thinning and shrinking multiyear sea ice is allowing more sunlight to reach the ocean surface, which makes the system more ecologically productive.

“We find that a small number of the world’s polar bears that live in multiyear ice regions are temporarily benefiting from climate change,” said lead author Kristin Laidre, a polar scientist and associate professor in the School of Aquatic and Fishery Sciences.

If greenhouse gases continue to build up in the atmosphere and the climate keeps warming, within decades these polar bears will likely face the same fate as their southern neighbors already suffering from declining sea ice.

“The duration of these benefits is unknown. Under unmitigated climate change, we expect the Kane Basin bears to run into the same situation as polar bears in the south — it’s just going to happen later,” Laidre said. “They’ll be one of the last subpopulations that will be negatively affected by climate change.”

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The events of this year have brought to the forefront the importance of the natural world to humanity, the intersection of science informing action and the fundamental human compact to elevate the lives of all people and leave a better world to future generations.

Brought to you by the University of Washington’s College of the Environment, this live discussion was moderated by Dean Lisa Graumlich with featured speakers:

• Jonathan Foley, Executive Director of Project Drawdown
• Ayana Elizabeth Johnson, Founder and CEO of the consultancy Ocean Collectiv, and Founder of Urban Ocean Lab

Watch the recording of the 2020 Doug Walker lecture below.

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