Using tricked-out drones, scientists are watching vegetation boom in the far north. Their findings could have big implications for the whole planet.

THE ARCTIC ISgetting greener, and it’s about as pretty as you might expect—vast stretches of coastal land positively glowing against cobalt seas. But all that green is in fact an alarm: Vegetation is growing more abundant as this region warms twice as fast as the rest of the planet. Northern landscapes are undergoing massive change, with potential consequences not just for the Arctic itself, but the world as a whole.

One group of researchers has been on a multiyear quest to understand that change on a fine scale. They’re combining satellite data, quadcopter measurements, and good old boots-on-the-frigid-ground fieldwork. We’re talking about labor like measuring individual leaves on plants to determine how much they’re growing, year after…