Using computer models of the climate, Muschitiello’s team tried to reproduce the effects of those eruptions. They found an eruption in the summer would have cooled northern Europe by as much as 3.5 degrees Celsius (6.3 degrees Fahrenheit). Meanwhile, even small changes in the amount of sunlight could have sped up dramatically the amount of water they shed.
“Even though you have sort of a long-term cooling, you have an immediate response of the ice sheet, which increases melting,” he said.
That process may be relevant today, as researchers attempt to project the effects of climate change and its impact on future sea levels.
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The Arctic is already warming at twice the rate of the rest of the globe, with sea ice shrinking and Greenland’s ice sheet shedding water. Today’s thaw is also opening up the far North to more human activity, like shipping, which results in more soot falling on the remaining ice, fueling more melt. Those effects aren’t well represented in today’s climate projections, Muschitiello said.
“What I hope we’re showing in the study is it’s really important to figure out the physics, the links between atmospheric dynamics and ice-sheet melting, because there seems to be a very important relationship there,” he said.