Thawing permafrost to trigger sudden shift in Arctic climate, models predict

Oct. 30 (UPI) -- New climate models suggest the Arctic climate could experience abrupt shifts as thawing permafrost fuels a variety of disruptive feedback loops.

Researchers at the University of McGill in Canada realized the Arctic was vulnerable to dramatic shifts in climate while modeling the impacts of climate change on the region's infrastructure -- its roads, ports, buildings, pipelines and mining infrastructure.

"Arctic infrastructure is particularly impacted by permafrost degradation and associated soil moisture changes, among other factors," Laxmi Sushama, a professor of civil engineering at McGill, said in a news release. "As we started analyzing more closely climate model simulations for the Arctic region, we noticed abrupt changes in soil moisture, as well as abrupt increases in intense rainfalls with a probable increase in lightning and wildfires too."

According to Sushama and her colleagues, most climate models project a gradual decline of the region's permafrost, with limited impacts on regional climate trends. Part of the problem is that most Arctic climate models look at changes in large temporal increments, with timelines split into blocks of 20 or 30 years -- too large to spot abrupt changes.

"There's not much high-resolution climate modelling done of the Arctic. Our initial climate model experiments at 50 kilometer resolution allowed us to extract critical information on climate shifts," said Bernardo Teufel, who is currently working on his doctoral research at McGill. "We used climate model data spanning the 1970 to 2100 period to understand probable changes in the Arctic climate and permafrost. What we came away with, was a picture of alarming changes to climate driven by permafrost degradation."

The updated models, detailed this week in the journal Nature Climate Change, suggest the degradation of the region's permafrost will result in increased drainage, which could fuel heavier precipitation and an increased risk of wildfires sparked by lightning.

Over the summer, the Arctic experienced dozens of large wildfires, several of which burned farther north than ever before.

While rising air temperatures are likely to remain the major driver of climate change in the Arctic, the latest research offers a reminder of the many feedback loops that can trigger abrupt climate and ecological shifts in the region.