Since 2000, atmospheric particles from volcanic eruptions have cooled the Earth more than scientists had suspected.

Credit: Ulet Ifansasti/Getty

Aerosols from volcanoes cool the planet by reflecting sunlight, and are typically tracked by satellites that monitor altitudes of 15 kilometres and higher. A team led by David Ridley, of the Massachusetts Institute of Technology in Cambridge, used laser and aerosol measurements from the ground, as well as from balloons, to estimate volcanic particles occurring at altitudes of roughly 8–15 kilometres.

They found a high enough level of particles to account for a global cooling of 0.05–0.12 °C since 2000. This could be contributing to the observed pause in global warming since then, the authors say.

Geophys. Res. Lett. (2014)