Arctic Wildfires Increase as Global Temperature Rises

Friday - July 21 2023, 13:55 UTC - 1 year ago

Wildfires have been a natural part of northern forest and tundra ecosystems for thousand of years. However, the severity, frequency and types of wildfires in northern and Arctic regions have changed in recent decades due to rising global temperatures. This has resulted in 'zombie fires' which smoulder through winter, cause hazardous smoke production and are difficult to extinguish. Rising temperatures could potentially exceed the 1.5 Celsius global threshold, putting the Arctic in a precarious position.

The blanket of wildfire smoke that spread across large parts of the U.S. and Canada in 2023 was a wake-up call, showing what climate change could feel like in the near future for millions of people.

Apocalyptic orange skies and air pollution levels that force people indoors only tell part of the story, though.

As global temperatures rise, fires are also spreading farther north and into the Arctic. These fires aren’t just burning in trees and grasses. New research on the exceptional Arctic fire seasons of 2019 and 2020 points to fires moving into the ground as well.

These underground fires are known as "zombie fires," and there are a number of reasons to worry about the trend.

First, as the organic-rich Arctic soils dry up because of changing climate conditions, they can burn slowly and release vast amounts of smoke into the atmosphere.

Second, soil fires that spread underground are harder for firefighters to tame and extinguish, thus demanding more resources for longer periods of time. Firefighters in Alberta, Canada, where carbon-rich peatlands are common, have been dealing with fires smoldering to depths dozens of feet underground in 2023. Because peat fires can make the ground unstable, using heavy equipment to excavate the fire areas also becomes risky.

Finally, these soil fires don’t die easily. Recent research finds that Arctic soil fires can smolder through the winter and reignite during early spring when temperatures rise, hence the nickname "zombie fires." .

The Arctic is increasingly flammable .

Wildfires have been a natural part of northern forest and tundra ecosystems for thousand of years. However, the severity, frequency and types of wildfires in northern and Arctic regions have changed in recent decades.

One major culprit is the rising temperature: The Arctic is warming nearly four times faster than the rest of the world, a phenomenon known as Arctic amplification.

While governing bodies that are working to curtail the pace of climate change worry about exceeding a 1.5-degree Celsius (2.7-degree Fahrenheit) threshold globally, the Arctic has already exceeded a 2 C (3.6 F) increase compared with pre-industrial times. That rise in temperature brings with it a number of changes to the environment that make the forest and tundra more susceptible to burning, for longer, and in more extensive ways than just a few decades ago.

Among the changing conditions that favor wildfires are changes in atmospheric circulation that create periods of extreme heat, dry out vegetation and reduce moisture in soils, and, importantly, lead to more frequent lightning strikes that can spark blazes.

Although lightning remains infrequent at very high latitudes, it is expected to increase and expand over larger territories into the far north as the climate warms and generates more storms that can produce lightning. In 2022, thousands of lightning strikes help sparked one of Alaska’s worst fire seasons on record.

As the Arctic warms and fires move farther northward, peat soils rich in dead plant material burn at an accelerated rate.

The burning peat also removes the layer insulating permafrost, the region’s frozen carbon-ric .