Calbuco volcano, which erupted in southern Chile last week for the first time since 1972, has been injecting climate-changing
gases directly into an upper layer of the atmosphere, NASA satellite data show. The particularly explosive eruption shot sulfur dioxide, an acrid-smelling gas that can cause respiratory problems at ground level, up into the stratosphere, where it reacts with water vapor to create sulfate aerosols that reflect sunlight and can sometimes have a slight cooling effect. So far, Calbuco has released an estimated 0.3 to 0.4 million tons of sulfur dioxide (SO2) as high as 13 miles, where it will last much longer and travel much farther than if released closer to the earth’s surface. The SO2 will gradually convert to sulfate aerosol particles, but it is not clear yet whether there will be a cooling effect associated with Calbuco’s eruption, researchers say.