CIRCUMPOLAR WILDLAND FIRE AND PERMAFROST THAW
GLOBAL CLIMATE IMPLICATIONS
BY BRENDAN ROGERS AND SUSAN NATALI
Wildfires have been a natural part of Arctic ecosystems – including tundra and boreal forests – for thousands of years. As in other regions, wildfire helps to shape and maintain these ecosystems, impacting plant traits, ecosystem diversity, and composition. However, climate change is making Arctic fires more frequent, intense, and widespread. The Arctic is warming two to four times faster than the rest of the planet, leading to longer fire seasons, more extreme fire weather, and increased lightning strikes that ignite fires.
In addition to combusting vegetation, wildfires in the Arctic also burn the organic soil layers, which play an important role in insulating and protecting the permanently frozen ground, called permafrost, that underlies the tundra and much of the boreal forest. When vegetation and soils are removed by fire, this can trigger or accelerate permafrost thaw.
Most permafrost has been frozen for hundreds to thousands of years. Over time, organic carbon derived from plants has slowly accumulated in permafrost soils because the frozen conditions slow decomposition, leading to the accumulation of an immense amount of carbon – on the order of 1,600 billion tons, or roughly three times the amount of carbon contained aboveground in all the world’s forests. With climate warming, permafrost is thawing, and microbes are decomposing this ancient carbon and releasing it into the atmosphere as greenhouse gasses, carbon dioxide and methane. The release of greenhouse gasses from permafrost thaw, referred to as the permafrost carbon feedback, could be a major accelerant of global climate change in the coming decades and centuries.
Wildfires amplify the permafrost carbon feedback. At the time of burning, Arctic wildfires release large amounts of carbon in the form of carbon dioxide, methane, and other gases and aerosols due to the combustion of organic soils. In fact, the levels of carbon emitted per unit area from Arctic wildfires are among the highest on Earth, rivaled only by tropical peatland and deforestation fires. For the most part, this carbon can ultimately be removed from the atmosphere by vegetation regrowth and stored by ecosystems over a period of decades to centuries. However, by burning the upper soil layers that otherwise keep permafrost cool, Arctic fires also initiate and exacerbate permafrost thaw. In some cases, this is barely noticeable from the surface but can still generate greenhouse gas emissions. In other cases, permafrost with high ice content can thaw abruptly, leading to dramatic features such as thermokarst lakes and permafrost thaw slumps, generating even higher levels of carbon emissions.
HOW ARE ARCTIC FIRES CHANGING?
Many studies have documented the links between Arctic fires and climate change. The best long-term observational data come from Alaska and Canadian government databases, which detail fires and their area burned since the mid-20th century. From the databases, we know the average yearly burned area across Alaska and Canada during the past two decades is roughly twice that of pre-climate change levels. By far, the most severe fire season was 2023. Canadian wildfires in 2023 burned more than twice the area of any other year on record and emitted between 480 and 760 million tons of carbon. For perspective, that’s three to five times higher than annual emissions from all other sectors in Canada combined, and higher than every country’s annual emissions except China, the United States, and India. It should be noted that regrowing forests from these fires are unlikely to re-sequester much carbon by the mid-21st century – when the world otherwise needs to be approaching net-zero emissions to limit the most damaging impacts from climate change –and that these estimates do not include postfire permafrost emissions.
Novel fire years are not limited to Canada. Russia, for instance, experienced unprecedented wildfire activity in eastern Siberia and north of the Arctic circle in 2019, 2020, 2021 and 2024, which has been linked to warming temperatures, early snow melt, and polar jet dynamics associated with climate change. If current climate warming trends continue, Arctic fires will likely become even more frequent and intense. Studies project a 75 per cent increase in Arctic burned area for every degree Celsius of global warming.
The carbon released by these fires, combined with emissions from permafrost thaw, could rival those of major global economies. Yet these emissions are not currently accounted for in global climate models nor are they fully
accounted for in the “accounting framework” used to assess progress toward the Paris Agreement goal of limiting warming to well below two degrees Celsius above pre-industrial levels.
Carbon and climate are not the only causes for concern over increasing Arctic wildfires. These fires emit smoke that degrades air quality and threatens human health for communities near and far. Wildfires impact habitat and subsistence activities for Indigenous communities, can shut down aviation and overland travel, damage infrastructure, and lead to mass evacuations.
WHAT TO DO?
The situation is urgent, and solutions exist. Governments can prioritize wildfire preparedness and community protection plans, fuels treatments and fire breaks around fire-prone communities, and improve real-time forecasting and information sharing, especially with rural and Indigenous communities. Supporting cultural burning practices, where Indigenous communities conduct controlled burns to manage landscapes, can also reduce the risk of severe wildfires. Finally, the combination of improved satellite detection and emerging technology such as autonomous firefighting aircraft presents opportunities for early action suppression of the most damaging wildfires.
However, the most critical solution lies in reducing global greenhouse gas emissions. Cutting global emissions will slow Arctic warming, reducing the conditions that fuel these fires and making other wildfire prevention efforts more effective. Arctic fires are a growing global concern with widereaching implications for the climate and communities worldwide. By investing in local adaptation, embracing Indigenous knowledge, and tackling the root cause – climate change –we can work toward a more resilient future.
