The flames have died out on Alaska’s largest river delta, but emissions are still seeping out of the tundra’s ground.
A recent NASA study found that methane “hot spots” in the Yukon-Kuskokwim Delta are more likely to be found where wildfires burned into the tundra. The greenhouse gas reportedly originates from decomposing carbon stored in the tundra’s permafrost for thousands of years.
“We find that [methane] hotspots are roughly 29 percent more likely on average in tundra that burned within the last 50 years compared with unburned areas, and that this effect is nearly tripled along burn scar perimeters that are delineated by surface water features,” the researchers said. “Our results indicate that the changes following tundra fire favor the complex environmental conditions needed to generate emission hotspots.”
The correlation also nearly tripled in areas where fires burned to the edge of a lake, stream, or other body of standing water, according to NASA. The highest ratio of methane hot spots occurred in recently burned wetlands. Researchers detected roughly 2 million hot spots across 11,583 square miles. The team believes more hot spots could soon emerge.
“By some projections, the fire risk in the Yukon-Kuskokwim Delta could quadruple by the end of the century due to warming conditions and increased lightning storms – the leading cause of tundra fires,” they said.
Alaska had two of its largest tundra fires ever in 2022. The East Fork Fire ignited on May 31 after a lightning strike, and burned more than 150,000 acres along the Yukon River. The Apoon Pass Fire, the second largest, burned 84,130 acres.
Previous research found that the majority of yearly methane emissions from Alaska’s tundra occur during the cold season between September and May, indicating that total emissions are sensitive to soil climate and snow depth.
