A look at weather extremes and the big-picture climate connections.

Loading the Dice for Heavier Snowfall

  Data from the National Weather Service's analysis of snow depth in the U.S., showing how much snow was on the ground following a January 10-12 snowstorm. Credit: NOAA

It’s been a snowy winter across much of the U.S., particularly in the Midwest and in states like Oklahoma and Arkansas, where snowfall records were recently broken. Southern states like California, Georgia, and New Mexico (all but Florida, really) also experienced snow this winter. And with more wintry conditions forecast for the coming weeks (meteorological winter ended on Feb. 28, but calendar year winter continues until March 19), yesterday’s press briefing from the Union of Concerned Scientists (UCS) — that heavier and more frequent snowstorms are consistent with climate change — seems perfectly timed.

In reality, it’s probably just lucky timing.

During a telephone press conference, experts at UCS, a non-profit environmental organization, as well as outside the group talked about the heavy snow-climate change connection. The message wasn’t that all this snow could be blamed on global warming. Instead, the experts emphasized that research suggests that snowy winters, like those of 2010-2011 and 2009-2010, could become more common in the future, as the climate warms and more water vapor is put into the atmosphere.

During the call, meteorologist Jeff Masters of Weather Underground, a private weather forecasting company, explained:

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.

Climate Central has previously highlighted the possible connection between long-term climate change and the greater odds of heavy snowfall events. We’ve also written about recent research suggesting that melting snow and ice in the Arctic might bring more severe winters to the U.S., and the UCS press call drew attention to the same findings.

  Scientists are investigating an atmospheric circulation pattern that brings milder-than-average air to parts of the Arctic, while cold air is routed south into North America and Europe during the winter.

According to Mark Serreze, the director of the National Snow and Ice Data Center in Boulder, Co., the continued loss of snow and ice in the Arctic may be contributing to unusually strong atmospheric circulations that are sending a lot of cold air down over the North American and European continents, while leaving the Arctic itself relatively warm:

It’s still cutting edge research and there’s no smoking gun, but there’s evidence that with less sea ice, you put a lot of heat from the ocean into the atmosphere, and the circulation of the atmosphere responds to that.

UCS has launched a website to rebut the frequent claims from climate skeptics that snowstorms demonstrate the absence of global warming.

Also of note: Jason Samenow of Washington Post's Capital Weather Gang blog posted a commentary on this subject today, criticizing a USA Today story on the UCS-organized press call for mischaracterizing the relationship between a warming climate and the frequency and severity of major snowstorms.

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