Boreal Forests Are Heading North

Forests in the far north aren't standing still. A new analysis of 36 years of satellite imagery finds that the planet's boreal forests have expanded by about 12% since 1985 and inched northward by 0.29 degrees mean latitude and 0.43 degrees median latitude, as they respond to a warming climate. These conifer-heavy forests, which ring the Arctic, are among the world's biggest land-based carbon stores—and they're heating up faster than any other major forest type. The study, published in Biogeosciences and led in part by NASA scientists using machine learning, mapped tree cover at a fine resolution to track the shift, per Futurism. NASA Science calls it "the longest and highest-resolution satellite record of calibrated tree cover to date."

The expansion equals 0.844 million square kilometers. Younger, newly established forests could pull an additional 1.1 to 5.9 gigatons of carbon from the atmosphere, the researchers estimate, plus quite a bit more if allowed to mature. But the potential upside comes with major caveats: hotter, drier conditions are feeding large wildfires, insect outbreaks, disease, and drought, all of which threaten tree cover and could erase gains. The team stresses that the overall global trend hides big regional differences and complex on-the-ground dynamics, and calls for combining satellite data with field measurements to better predict how these critical forests will influence the climate in the decades ahead.