A 3,000-year high: Alaska’s Arctic is entering a dangerous new fire era

The research took place in Arctic Alaska and involved an international group of scientists from Germany, Poland, the United Kingdom, Romania and the University of Alaska Fairbanks' Toolik Field Station.

Angelica Feurdean, the study's lead author and a senior researcher at Goethe University in Germany, said the team combined multiple scientific methods to rebuild a long-term record of wildfire activity. The results show that recent fire levels are the highest on record, driven by the spread of woody vegetation and increasingly dry soils. Both trends are linked to rising temperatures.

"The interlinked changes across millennia mean recent fires are indicators of a system undergoing rapid transformation," Feurdean said.

Digging Into the Arctic's Fire History

To uncover this history, researchers extracted peat cores reaching about half a meter deep from nine tundra locations north of the Brooks Range. The sites stretched along the Dalton Highway between Toolik Lake and the Franklin Bluffs.

Each peat layer contained traces of past conditions, including charcoal fragments, pollen, and remains of plants and microbes. The team measured how much of each material was present and used radiocarbon and lead dating to determine when the layers formed. This allowed them to reconstruct patterns of wildfire activity, vegetation changes, and soil moisture over time.

The oldest material in the cores dated back roughly 3,000 years to around 1000 B.C. For the first 2,000 years of that record, fires were rare. Activity increased modestly between about A.D. 1000 and 1200, a period when tundra soils began to dry. Fire levels then declined again and remained low for the next 700 years.

A Sharp Rise in Modern Fire Activity

Around 1900, wildfire activity started to increase once more. By 1950, fires surged to levels not seen anywhere else in the record. During this time, peat soils reached extreme dryness and woody shrubs became more widespread. Fire activity continued to rise as soils kept drying through 2015, when the samples were collected.

To connect the ancient record with present-day conditions, scientists compared charcoal evidence from the peat cores with modern satellite observations.

Satellite data supported the long-term findings, confirming that wildfire activity has increased since the latter half of the 20th century. The late 1960s, the 1990s, and the 2000s-2010s all experienced frequent fires across the region.

Signs of Hotter, More Severe Fires

Randy Fulweber, a study co-author and the geographic information systems and remote sensing manager at UAF's Toolik Field Station, said combining satellite imagery with charcoal data revealed more than just how often fires occur.

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.

Fulweber said this insight was possible because of the collaborative environment at Toolik Field Station, where specialists in paleoecology, GIS, and remote sensing work closely together.

"There's something unique that a field station like Toolik provides in terms of the breadth and depth of specialties that helps studies like this happen and, ultimately, opens up more scientific questions to answer," Fulweber said.