NASA Flights Link Methane Plumes to Tundra Fires in Western Alaska

by | Nov 2, 2023 | Climate Change

Tundra wetlands are shown in late spring at the Yukon Delta National Wildlife Refuge in Alaska. Scientists are studying how fire and ice drive methane emissions in the Yukon-Kuskokwim Delta, within which the refuge is located. Credit: U.S. Fish and Wildlife Service

In Brief:

Methane ‘hot spots’ in the Yukon-Kuskokwim Delta are more likely to be found where recent wildfires burned into the tundra, altering carbon emissions from the land.

In Alaska’s largest river delta, tundra that has been scorched by wildfire is emitting more methane than the rest of the landscape long after the flames died, scientists have found. The potent greenhouse gas can originate from decomposing carbon stored in permafrost for thousands of years. Its release could accelerate climate warming and lead to more frequent wildfires in the tundra, where blazes have been historically rare.

The new study was conducted by a team of scientists working as part of NASA’s Arctic-Boreal Vulnerability Experiment (ABoVE), a large-scale study of environmental change in Alaska and Western Canada. Researchers found that methane hot spots were roughly 29% more likely to occur in tundra that had been scorched by wildfire in the past 50 years compared to unburned areas. The correlation nearly tripled in areas where a fire burned to the edge of a lake, stream, or other standing-water body. The highest ratio of hot spots occurred in recently burned wetlands.

The researchers first observed the methane hot spots using NASA’s next-generation Airborne Visible/Infrared Imaging Spectrometer (AVIRIS-NG) in 2017. Mounted on the belly of a research plane, the instrument has an optical sensor that records the interaction of sunlight with molecules near the land surface and in the air, and it has been used to measure and monitor hazards ranging from oil spills to crop disease.

Methane bubbles pop on the surface of an Alaskan lake being studied by scientists with NASA’s Arctic-Boreal Vulnerability Experiment. A potent greenhouse gas, methane is released in bubble seeps when microbes consume carbon released from thawing permafrost. Credit: NASA/Kate Ramsayer

Roughly 2 million hot spots – defined as areas showing an excess o …

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