Large storms like the blizzard that battered New England last week may become more severe but less frequent as the Earth’s climate changes, scientists say.
A Canadian-led study noted that warmer air can hold more moisture, meaning more fuel for rain, hail or snow, and it found indirect effects from higher temperatures on how the atmosphere generates storms. “In a future climate, the global atmospheric circulation might comprise highly energetic storms,” they wrote in the journal Science.
But “fewer numbers of such events” may occur, they said. Additional evaporation and precipitation of water are likely to use up more energy in the atmosphere, which may help reduce the intensity of winds around the world.
The report, part of an effort to pin down the probable effects of climate change, looks at how the atmosphere shifts solar heat from the tropics toward the poles.
“This is about the large-scale storms . . . like the storm in the northeast of the United States,” lead author Frederic Laliberte of the University of Toronto said of the study, which also involved experts in Britain and Sweden. “More moisture creates very strong storms.”
The blizzard that struck Boston and the rest of New England caused coastal flooding and deposited as much as three feet of snow.
In 2013, a U.N. report by leading climate scientists found that heavy downpours and days with extreme heat and cold had become more frequent. It linked the shift to man-made emissions of greenhouse gases.
Richard Allan, a professor of climate science at Britain’s University of Reading, said last week’s study gave a new perspective into how the atmosphere acts as a heat engine.
More powerful but less frequent storms would be “more bad than good” overall, said Allan, who was not involved in the study. “The intensity of the rainfall can do damage to crops. And a lack of rainfall over extended periods can also do damage.”
Governments will meet in Paris in late 2015 in an attempt to work out a global deal to limit rising emissions of greenhouse gases.