Physics Buzz

This week's physics central podcast is about hot and cold. Volcanoes—which spew material that reaches thousands of degrees Fahrenheit—can actually cool the planet. Volcanoes eject aerosols that reflect sunlight, and climate scientists have observed the cooling effects of major volcanic events in 1991 and 1982. Those effects can sometimes take years to reverse. New research in the journal  Nature Geophysics has shown that the combination of minor volcanic events between 1998 and 2010 had a measurable cooling effect on the Earth. This is a big deal because it partly explains the so-called global warming slow-down: a decrease in the acceleration of rising global temperatures. For the most part, climate models have not been able to replicate the slow-down. But most of those models do not include recent volcanic activity as a cooling factor. In 2011, Susan Solomon and colleagues at MIT wrote a paper showing that the volcanic contribution from 1998 to 2010 was likely large enough t