Global warming has profoundly transformed Arctic in just 15 years, report warns

The dire prediction is reported in a study in eLife that simulates how a changing climate would affect the boundary between the tundra and the forests that border it. When researchers modeled how the forests would respond to climate change, they found what they call an “invasion of forests under global warming.” They predict that a climb in summer temperatures would cause the trees’ habitat to creep northward, overtaking the tundra and threatening both the landscape and its species.

The model simulated the life cycle of thousands of individual trees and how they would probably respond to warmer air temperatures. Researchers studied everything from the density of the trees to their growth, seed production and dispersal, and their aging and death.

Trees are particularly susceptible to warm summer temperatures, so the team looked at how they’d fare if summers became between 1.2°C and 5°C (34 and 41°F) warmer.

Radical warming in Siberia leaves millions on unstable ground

The researchers predict the tree line will advance more than 18 miles every decade. And although the trees’ migration will probably lag behind warming by about a century, the researchers warn that only ambitious measures to tackle climate change can protect the tundra.

Tundras look barren, but their harsh conditions play host to all kinds of plants and animals, even bumblebees and reindeer. Even if they’re not completely lost, the researchers say, the unbroken tundra could split in two, shrinking significantly as more and more trees encroach.

And even with consistent climate protection policies, they say it’s possible that just 30 percent of Siberia’s tundra will survive by mid-millennium.

“At this point, it’s a matter of life and death for the Siberian tundra,” Eva Klebelsberg, a project manager at WWF Germany, said in a news release. “Larger areas can only be saved with very ambitious climate protection targets.”