According to a new report from the National Wildlife Federation, global warming is having a peculiar effect on winter weather in the northern U.S.
Winter weather is broadly changing in some ways that might be expected with global warming: winters are a couple of degrees warmer, winters are ending 1-2 weeks earlier, and there is less ice on lakes and rivers.
How global warming affects snowstorms is more difficult to dissect because the development of big snowstorms depends on moisture availability, temperature, and storm tracks. One unexpected impact is that snowstorms could get heavier in the next couple decades. As air warms, it can hold more moisture, which can make for heavier snowfalls as long as the temperature is still below freezing. In addition, areas near the Great Lakes may get more lake-effect snow as milder winters mean more open water from which storms can gather moisture.
"Odd-ball winter weather is yet another sign of how uncontrolled carbon pollution amounts to an unchecked experiment on people and nature," says NWF Climate Scientist Dr. Amanda Staudt. "While global warming means shorter, milder winters on average, some snowbelt areas could see more heavy snowfall events."
Winter 2009-2010 is already proving to be unusual for the United States, with the Pacific Northwest and the Northeast getting relatively little snow and the Mid-Atlantic on track to have one of the snowiest winters on record. These patterns are related to natural climate variations, including El Niño and the Arctic Oscillation. While it's too early to determine what role global warming is playing, the record-setting snowfall in the Mid-Atlantic this winter is generally consistent with how global warming could contribute to heavier snowfalls.
THE NATIONAL WILDLIFE FEDERATION is America's largest conservation organization, working with more than 4 million members, partners and supporters in communities across the country to protect and restore wildlife habitat, confront global warming and connect with nature.