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Scientist Measures an Overlooked Greenhouse Gas

This summer, Katey Walter traveled from her base in Fairbanks, Alaska, to Barrow on the Arctic Ocean, to gather methane samples from a lake.
Lindsay Mangum, NPR /
This summer, Katey Walter traveled from her base in Fairbanks, Alaska, to Barrow on the Arctic Ocean, to gather methane samples from a lake.

Alaska scientist Katey Walter studies an aspect of climate change that has been largely overlooked: methane emissions.

Methane is a greenhouse gas that is 23 times more powerful than carbon dioxide, which means it is much more efficient at trapping heat. As a result, methane feeds into a loop of global warming.

Thawing Yields More Methane

As global temperatures rise, permafrost thaws. Ponds and lakes form in the depressions left behind by melting chunks of ice in the ground. In the bottoms of ponds and lakes, bacteria feed on the carbon that previously had been frozen underground and burp it out as methane.

And because methane emissions from lakes haven't been carefully studied, scientists worry that projections for global warming could be far worse than currently estimated.

Walter, who teaches at the University of Alaska in Fairbanks, says that methane is being released from lakes in the far north — Alaska, Siberia, elsewhere — at a far greater rate than anyone has estimated.

Childhood Love of Lakes

One of the first people to calculate just how much methane is bubbling out of lakes, the 31-year-old Walter is passionate about her work.

Walter is what's known as a limnologist — from limne, the Greek word for lake. Her love for lakes goes back to her childhood in Oregon and Nevada and the hikes she took with her family in the Sierra Nevada mountains.

Her father and grandfather would ask her how the huge granite boulders in the area split in half so cleanly.

"It was ice that got in there ... and then when it freezes, it expands, and it has [the] strength to crack open those rocks — which is kind of ironic, because that's the same process I'm studying in the Arctic: the power of water in its frozen and unfrozen forms," Walter says. "I remember being inspired by those questions."

After majoring in biogeochemistry at the all-women's Mount Holyoke College, Walter got her Ph.D. measuring methane emissions in north Siberian lakes.

Balancing Research, Personal Goals

Last month, Walter took a research trip to the northernmost community in the United States: Barrow, Alaska, which is located on the Arctic Ocean, 340 miles north of the Arctic Circle. There, she gathered more methane samples, from a geyser of gas bubbling up from the bottom of a lake.

Walter's enthusiasm for her work is infectious. Recent years have provided many exciting research opportunities. But she knows there are tradeoffs. She thinks a lot about balancing her career and the family she'd like to have.

"I think a lot of women do make decisions for families rather than [for] doing science head on," she says. "And I've often heard women say you could do two of the three well — between being a scientist, being a mother and being a wife — but few that have said that it's easy to do all three."

For now, Walter will keep returning to Siberia to study lakes for months at a time.

"I think what's really exciting about it all is that the lake is going to get cold, and it's going to turn over, and gas is going to come out anyways, whether you're there or not," Walter says. "And so to be able to be there and watch it and understand what's going on, it's a great opportunity."

NPR's Art Silverman produced this story.

Copyright 2023 NPR. To see more, visit https://www.npr.org.

As special correspondent and guest host of NPR's news programs, Melissa Block brings her signature combination of warmth and incisive reporting. Her work over the decades has earned her journalism's highest honors, and has made her one of NPR's most familiar and beloved voices.