The study, published in the journal Geophysical Research Letters, finds that a sharp decrease in volcanic activity in the early 2000s reduced the amount of sulfate aerosols in the atmosphere. These aerosols reflect sunlight back into space, cooling the planet. As volcanic activity decreased, the amount of sunlight reaching the Earth's surface increased, leading to a warming of the planet.
The researchers used a climate model to simulate the Earth's climate from 1950 to 2015. They found that the model was able to reproduce the early-2000s global warming slowdown when the decrease in volcanic activity was taken into account.
"Our study shows that changes in volcanic activity can have a significant impact on global temperatures," said study lead author Michael Mills, a postdoctoral researcher in the Department of Earth and Planetary Science at UC Berkeley. "This helps explain why climate models have had difficulty reproducing the early-2000s global warming slowdown."
The findings have implications for future climate projections. The study suggests that the current slowdown in global warming could be due in part to a decrease in volcanic activity, which could lead to a more rapid warming in the future as volcanic activity increases.
"Our study highlights the importance of including volcanic activity in climate models," said study co-author Randal Koster, a professor of atmospheric science at UC Berkeley. "By doing so, we can get a more accurate picture of past and future climate change."
The study was funded by the National Science Foundation and the Department of Energy.
