Tundra fire surge reshapes Arctic landscape

by Clarence Oxford
Los Angeles CA (SPX) Dec 18, 2025

Wildfires on Alaska's North Slope have been more active in the last century than at any point in the previous 3,000 years, according to a study published in the journal Biogeosciences. The research links this increase to expanding woody shrubs and drying tundra soils under a warming climate.

An international team from Germany, Poland, the United Kingdom, Romania and the University of Alaska Fairbanks' Toolik Field Station investigated long-term fire history in Arctic Alaska. Lead author Angelica Feurdean, a senior researcher at Goethe University, said the group used a multidisciplinary approach to understand how vegetation, moisture and fire have changed together over millennia.

To reconstruct past wildfire activity, the researchers collected half-meter peat cores from tundra soils at nine locations north of the Brooks Range, along the Dalton Highway between Toolik Lake and the Franklin Bluffs. Each core contained layers of charcoal, pollen and remains of plants and microbes that record environmental conditions through time.

The team measured the abundance of charcoal and biological material in each layer and used radiocarbon and lead dating to determine their ages. These measurements allowed the scientists to infer past fire activity, dominant vegetation types and surface moisture conditions over thousands of years.

Material in the peat cores extended back roughly 3,000 years to about 1000 B.C., with charcoal records indicating low fire activity during the first two millennia. Fire occurrence rose modestly between about A.D. 1000 and 1200 as tundra soils began to dry, then declined to lower levels again for the following 700 years.

Fire activity began to increase around 1900, and by 1950 it had reached levels not previously seen in the record as peat soils became drier and woody shrubs expanded. Activity continued to rise through 2015, the year the cores were collected, as drying conditions persisted.

The scientists compared this long-term record with modern satellite observations by pairing charcoal evidence with remote sensing data. Satellite records confirmed a marked increase in fire activity since the latter half of the 20th century, with particularly frequent fires in the late 1960s, 1990 and the 2000s through 2010s.

Randy Fulweber, a co-author and geographic information systems and remote sensing manager at UAF's Toolik Field Station, said combining charcoal records with satellite data provided new insight into how intensely recent fires are burning. Evidence from recent large fires, Fulweber said "may be indicative of these fires burning hotter, consuming more fuel and leaving behind less charcoal."

"It may suggest a shifting fire regime, one in which fires are really burning hot," he said.

Feurdean said the study shows that long-term ecological links are now amplifying fire behavior. "The interlinked changes across millennia mean recent fires are indicators of a system undergoing rapid transformation," Feurdean said.

Fulweber noted that the collaboration at Toolik Field Station made it possible to integrate paleoecology, GIS and remote sensing expertise in a single project. He said this kind of multidisciplinary work helps identify emerging changes in Arctic ecosystems and raises new questions about how tundra landscapes will respond to continued warming.

Research Report:Fire activity in the northern Arctic tundra now exceeds late Holocene levels, driven by increasing dryness and shrub expansion