He Hiked 5 Days, Found Trees Where They Shouldn't Be

White spruces are migrating north to places where trees haven’t grown for a thousand years. That's not a good thing. As Quartz reports, the trees are normally found in the boreal forests that dominate central Alaska. Climate models have predicted such forests migrating northward as the planet warms, but nobody expected it to happen for at least another century. Biologist Roman Dial of Alaska Pacific University was the first to notice the shadows of the trees while browsing satellite imagery of Arctic tundra of northern Alaska. He had to hike five days to see them for himself. "It was shocking to see trees there. No one knew about them, but they were young and growing fast," Dial recounted, per the Guardian.

Dial says the trees "basically hopped over the mountains into the tundra," where they wouldn’t have stood a chance at taking root much less surviving until recent years. Per his study, which was published in Nature, the white spruce are moving north at a rate of about 2.5 miles per year. And while trees are generally considered beneficial for the environment, that's not the case in the tundra, where the icy ground normally reflects heat from the sun. The trees will instead absorb heat and cause more warming. The Arctic already has plenty of that. Scientists have learned that the entire polar region is warming four times faster than the rest of the planet.

NPR reports the excess polar warming is driven by many factors, including looping behavior that scientists are only beginning to understand. For example, as permanent sea ice shrinks near the Arctic Circle, more open water is left exposed to absorb the sun’s heat, thus causing more ice to melt. Farther south in the boreal forests that ring the northern hemisphere, many tree species are struggling to cope with a warming climate. As white spruce and others gradually migrate northward, they leave behind an increasingly barren biome, where dead trees invite wildfire and release additional carbon into the atmosphere. (More global warming stories.)