Big snowstorms will still occur in the Northern Hemisphere following global warming

Jennifer Chu at the MIT News Office:  If ever there were a silver lining to global warming, it might be the prospect of milder winters. After all, it stands to reason that a warmer climate would generate less snow. But a new MIT study suggests that you shouldn’t put your shovels away just yet. While most areas in the Northern Hemisphere will likely experience less snowfall throughout a season, the study concludes that extreme snow events will still occur, even in a future with significant warming. That means that, for example, places like Boston may see less snowy winters overall, punctuated in some years by blizzards that drop a foot or two of snow.

“Many studies have looked at average snowfall over a season in climate models, but there’s less known about these very heavy snowfalls,” says study author Paul O’Gorman, an associate professor in MIT’s Department of Earth, Atmospheric and Planetary Sciences. “In some regions, it is possible for average snowfall to decrease, but the snowfall extremes actually intensify.”

O’Gorman studied daily snowfall across the Northern Hemisphere using 20 different climate models, each of which projected climate change over a 100-year period, given certain levels of greenhouse gas emissions. He looked at both average seasonal snowfall and extreme snowfall events under current climate conditions, and also following projected future warming.

Not surprisingly, O’Gorman found that under relatively high warming scenarios, low-elevation regions with winter temperatures initially just below freezing experienced about a 65 percent reduction in average winter snowfall. However, in these same regions, the heaviest snowstorms became only 8 percent less intense. In some higher-latitude regions, extreme snow events became more intense, depositing 10 percent more snow, even under scenarios of relatively high global warming.

“You might expect with a warmer climate there should be major changes in snowfall in general,” O’Gorman says. “But that seems to be true to a greater extent for average snowfall than for the intensities of the heaviest snowfall events.”

Over this 100-year period, O’Gorman found that average snowfall decreased substantially in many Northern Hemisphere regions in warm-climate scenarios compared with the milder control climates, but that snowfall amounts in the largest snowstorms did not decrease to the same extent....

A snowfall, shot by Landskronadino, Wikimedia Commons, under the Creative Commons 3.0 license