Zombie Emissions: Wildfires Thawing Permafrost Release Ancient Carbon into Atmosphere

Police – Accident – Death – Obituary News : Zombie Emissions Rising as Wildfires Thaw Permafrost in the Arctic

November 19, 2023, 8 AM ET

Chunks of carbon-rich frozen soil, known as permafrost, are prevalent in the Arctic tundra. This layer of perpetually frozen soil acts as a carbon sink, sequestering carbon from the atmosphere and holding it beneath the boggy ground for thousands of years. However, the insulation provided by a cool, wet blanket of plant litter, moss, and peat is at risk of being incinerated by tundra wildfires, leaving the permafrost vulnerable to thawing. The consequence of this thawing is the release of ancient carbon, which is then converted into methane by soil microbes. Methane is a potent greenhouse gas that contributes to climate change and the drastic transformation of northern latitudes worldwide.

Recent research published in Environmental Research Letters, a scientific journal, has revealed that methane hot spots on the tundra are more likely to be found in areas where wildfires have recently occurred. The study focused on the Yukon-Kuskokwim, Alaska’s largest river delta, which was previously identified as emitting significant amounts of methane. Scientists from NASA’s ABoVE project (Arctic-Boreal Vulnerability Experiment) explored the cause of these methane hot spots by overlaying maps of the areas with recent fire activity. They discovered that the hot spots were nearly 30 percent more likely to occur in areas that had experienced wildfires in the past 50 years, rising to almost 90 percent likelihood if the fire had touched water. Wetlands with carbon-rich soil that had been recently burned showed the highest ratio of hot spots. Lead author Elizabeth Yoseph, an intern at the time, emphasized the importance of fires in increasing emissions.

These large-scale findings, covering an area of almost 700 square miles in Alaska, complement field measurements and provide valuable insights into the expansive tundra. Merritt Turetsky, an ecologist at the University of Colorado at Boulder, who was not involved in the research, highlights the significance of satellite images in bridging the gap between ground observations and understanding the vast tundra. The limitations of field research in marshy terrain make aerial surveys crucial in comprehending the effects of thawing permafrost.

The consequences of thawing permafrost extend far beyond the Arctic. Wildfires’ impact on frozen permafrost sets off a climate feedback loop: wildfires release methane, which accelerates climate change, leading to more frequent wildfires. Tundra fires, although still relatively uncommon, are projected to increase due to rising temperatures and increased lightning activity. Projections indicate that wildfires in the Yukon-Kuskokwim Delta could quadruple by the end of the century. Unlike forest fires, tundra fires tend to creep slowly along the ground, smoldering for months, and sometimes even going underground, only to resurface later.

The potential consequences of thawing permafrost are immense, considering the vast amount of carbon stored beneath Arctic soil. Arctic permafrost acts as a massive repository, containing an estimated 1,700 billion metric tons of carbon. This amount is over 50 times greater than the carbon released from global fossil fuel emissions in 2019.

According to Turetsky, addressing these significant episodic releases of greenhouse gases is crucial to achieving a more certain climate future. Evidence suggests that portions of the tundra are transitioning from being a carbon sink to becoming a carbon (and methane) source. Wildfires exacerbate this transition, marking a tipping point in the Arctic’s delicate ecosystem.

This article was originally published by High Country News..