More fires in Alaska now than in past 3,000 Years: Arctic warning signal

©Dana Davis via Unsplash

Fires in the Arctic of Alaska exceed anything recorded in the past 3,000 years. That's according to a new reconstruction that pairs modern satellite data with charcoal remains preserved in soil peat layers. It thus reveals that the tundra is no longer protected by the cold and humidity that made fire rare in the past.

The turnaround marks the beginning of a new era of more frequent and intense fires, fueled by drying soils, thawing permafrost and the expansion of woody shrubs due to global warming.

To reconstruct the development of the fires, researchers analyzed drill cores containing peat along the Dalton Highway in northern Alaska. In these soils, rich in partially decomposed plant material, microscopic charcoal particles remain, telling of the occurrence of ancient fires.

For some 2,000 years, fires were rare in the tundra north of the Brooks Mountains. Even in the slightly drier periods between the year 1000 and 1200, traces of burning indicate long intervals without fire. After a brief phase with more activity, fire levels then remained low for another seven centuries. The sharp increase began only after 1950, in parallel with rising temperatures and profound environmental changes observed in the Arctic.

The research

A team of researchers from the University of Alaska Fairbanks reconstructed the history of fires in the Arctic tundra - an environment traditionally cold, moist and low fire prone - by analyzing peat layers at nine sites along the North Slope, north of the Brooks Range. These samples, reaching back to 1000 B.C., show that fires were rare and sporadic events for much of these millennia, even as soils dried out slightly between 1000 and 1200 A.D. and then again for seven centuries.

A radical turnaround occurs from the 20th century, and especially after the 1950s: fire activity increases sharply, eventually surpassing any other period in the region's millennial history. This complete reversal is mainly related to two phenomena associated with global warming. First, the thawing of permafrost - soil that has been frozen for at least two consecutive years - allows surface water to sink deeper, making the peat and soil topsoil increasingly dry and thus vulnerable to fire. Second, the rise in temperature promotes the spread of more flammable, woody shrubs in areas previously dominated by mosses and plants typical of wet, hard-to-flame environments.

The result is a tundra that burns more frequently and with more intense flames, as the dry soil and more woody vegetation combine to form an ideal fuel package. Peat core analysis combined with satellite data confirms an acceleration and expansion of fires unprecedented in the past three millennia - a sign that the Arctic climate is rapidly entering a new fire regime.

This development is not limited to the local landscape: fires in the Alaskan tundra emit large amounts of carbon that was stored for centuries in frozen soils. Thus, they contribute to the increase of greenhouse gases in the atmosphere and further fuel global warming. Moreover, the smoke can travel long distances, affecting air quality far from the hot spots.

The picture that emerges is downright worrying: an ecosystem that for millennia was relatively stable and had little to do with fire is becoming more vulnerable year by year, with increasingly intense and predictable fire seasons. Scientists warn that this dynamic could spread to other Arctic regions if global warming is not halted or at least slowed.

In other words, Arctic Alaska is not just on fire; more importantly, it's holding up a mirror to us and clearly showing us the face of a changing climate, with consequences that reach far beyond the Arctic Circle.

(©Science Daily via GreenMe.it 2026/Managing Editor: Selma Keshkire - The Press Junction/Picture: ©picture alliance/dpa/dpa-POOL | Peter Kneffel)