After two months of eruption—with activity ranging from lava flows, to outburst floods, to ash plumes—Iceland’s Eyjafjallajökull Volcano appeared to be quieting down. As of May 24, 2010, heat signatures at the summit had dropped according to the Iceland Met Office, and explosive eruptions of ash had not occurred for several days.
This image from the Advanced Land Imager on NASA’s Earth Observing-1 (EO-1) satellite on May 18 captured one of the last explosive ash eruptions from the volcano. The thick plume spread east from the summit, casting a black shadow over the clouds below.
Although Eyjafjallajökull had a big impact on human activity—airspace over Europe was closed several times to volcanic ash hazard—its eruption is unlikely to have a big influence on climate, either warming or cooling.
Although volcanoes do release carbon dioxide and other greenhouses gases, the total annual emissions from all volcanoes combined is small compared to what people release burning coal and other fossil fuels.
Volcanic particles can cool the planet by reflecting sunlight, but to have a big effect, the particles have to be pushed all the way to the stratosphere and the volcano usually needs to be located in the tropics, where the particles have a better chance of spreading all around the Earth.