It’s not easy to spot an insect from space, but NASA has figured out a way to do it—sort of. Long before the confected debate on whether climate change was real or just a theory was resolved in favor of science, the space agency was turning the eyes of its weather satellites on the problem, looking at global temperature and precipitation patterns and seeing how these jibed with warming models. Now the space agency is taking a more pointillist approach, using its LANDSAT satellite to study the damage being done by the mountain pine beetle—a pest that’s benefited from global warming in a big way.
Mountain pine beetles love the heat, and while they’ve long been a fixture across the western stretches of North America, the hotter summers and milder winters of the past two decades have caused their populations to soar. That’s bad news for the lodgepole and white bark pines, which are the beetles’ favorite nesting spots. From Mexico all the way up to Alaska—but especially in British Columbia, Colorado and other parts of the Rockies—billions of pines have died off, literally chewed to death by beetles.
It’s no secret where the greatest damage has been done, since beetle-infested trees turn red as they die, giving vast stretches of forests an odd, autumnal look. In a just-released video, NASA reveals how it’s using LANDSAT to survey the toll the beetles have taken on a continent-wide scale, and then get down into the woods to examine things up close. It’s important to study the forest from both perspectives, since simply because a stretch of landscape looks dead or red from space doesn’t mean that beetles are the perps. Drought or other diseases or infestations could have caused the damage.
Space agency scientists thus study satellite photos to look for suspect areas, then find those exact spots on the ground and measure out 30-meter by 30-meter squares—the equivalent of a single pixel as seen from space. Then they study the trees looking for the telltale boreholes that indicate the beetles are nesting inside. That sometimes reveals that beetles are nowhere to be found, but most of the time the insects do turn out to be the agents of the trees’ destruction.
One spot of good news from the otherwise depressing—if informative—video: The dead pines, contrary to fears, do not necessarily increase the risk of forest fires. That’s because as the needles die, they lose their oils, and it’s the oil that’s particularly flammable. What’s more, when the dead needles fall off, they reduce the trees to poles with no kindling, making them paradoxically harder to ignite. Cold comfort in a warmer world.