March 2, 2011

Is Global Warming To Blame For Record Snowfalls?

Believe it or not, the snowstorms that battered much of the US this winter and set records in Chicago and New York are the result of global warming, climate scientists at a non-profit environmental group claimed during a Tuesday press event.

Speaking on behalf of the Union of Concerned Scientists (UCS) from Washington DC, Jeff Masters, director of meteorology for the Weather Underground website told reporters, "Heavy snowstorms are not inconsistent with a warming planet."

"In fact, as the Earth gets warmer and more moisture gets absorbed into the atmosphere, we are steadily loading the dice in favor of more extreme storms in all seasons, capable of causing greater impacts on society," Masters added during the phone-based media briefing.

According to Doyle Rice of USA Today, 49 of the 50 states in the US have been at least partially snow-covered during the year, with only Florida remaining snow free. Likewise, Masters points out that that the past two winters marked just the second and third times that the northeastern part of the country had been hit by three storms of at least Category 3 during the same season.

However, as the Weather Underground meteorologist pointed out, just because locales in New York, Pennsylvania, Minnesota, and North and South Dakota have suffered through record or near-record snowfalls in 2010 and 2011, that doesn't prove that climate change is not a factor.

Quite the opposite, in fact.

"The old adage, 'It's too cold to snow,' has some truth to it," Masters said. "A colder atmosphere holds less moisture, limiting the snowfall that can occur"¦ [and] if the climate continues to warm, we should expect an increase in heavy snow events for a few decades, until the climate grows so warm that we pass the point where it's too warm for it to snow heavily."

He noted that as much as 80% of all US snowstorms topping 6 inches in accumulated snow during the 20th century occurred in winters with above-average temperatures. According to a March 1 UCS press release, temperatures this winter "have not been significantly below average," which is one factor that helps provide "an explanation for the heavy snowfalls."

Another factor is the visible warming occurring in the Arctic region, claims Mark Serreze, director of the National Snow and Ice Data Center in Boulder, Colorado. He reported that temperatures there have been close to record high levels, and that area covered by ice in the region shrunk to record low levels in December, January, and February. That melting ice means that there is more moisture in the atmosphere, which in turn results in heavier snowfalls further south.

"We're also experiencing spring creep, where the warmer than average temperatures are shortening the length of winter," said Masters. "For instance, we're now seeing spring runoff in the mountains in the western U.S. starting one to three weeks earlier than 60 years ago."

"If the climate continues to warm we should expect an increase in heavy snowstorms for a few decades," he added. "But eventually, with winters getting shorter, we may reach the point where it's too warm to snow heavily."


Image Caption: Chicago's Lake Shore Drive, with abandoned, snowed-in cars and empty lanes. Credit: Wikipedia 


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