Houston Weather Blog: Is global warming creating heavy snow storms?

byTravis HerzogABC 13 Meteorologist

A flurry of record-breaking snowstorms over the US the past two winters has many asking, “What happened to global warming?” The answer from some scientists: Global warming is causing the giant snowstorms.

Earlier this week, the Union of Concerned Scientists attempted to link this winter's snowstorms to global warming. this is the same group that released a report in 2006 claiming global warming would lead to less snowy winters in the northeast.

Dr. Jeff Masters, who runs a terrific blog at the Weather Underground, participated in the teleconference and offered up some simple theories as to why a warmer globe might be causing bigger storms. First he noted how sometimes it can be "too cold to snow." The closer temperatures are to the freezing mark, the heavier the snow can get. He suggested that because a warmer atmosphere can also hold more moisture, this can lead to heavier precipitation events.

Remember, these are just theories. No studies have been put forth yet proving a link between northeast snowstorms and global warming. As Texas state climatologist, Dr. John Nielsen-Gammon, told me, “It's speculation: not demonstrably wrong, but not coherent enough to be a hypothesis.”

Same cause and effect as last year?After the record breaking storms during the winter of 2009-2010, NOAA released a report attributing the heavy snow to “natural climate variability.” NOAA blamed a combination of warm water in the tropical Pacific (El Nino) and a “negative” phase of an atmospheric circulation pattern known as the North Atlantic Oscillation (NAO).

The report also concluded the strongly negative NAO was “an extreme event that is not consistent with the overall upward trend in the NAO index since 1950, and is opposite to the current understanding of projected future change in the NAO.”

So what’s causing the upper air pattern over the North Atlantic to change?

Enter Dr. mark Serreze, director of the National Snow and Ice Data Center. He also participated in the teleconference, and while he said there is no “smoking gun,” there is reason to believe that a loss of arctic sea ice might be impacting the atmospheric circulation.

He compared it to a “chicken and egg” problem: is the atmospheric circulation melting the ice or is the loss of ice affecting the upper level winds? Serreze conceded it would be difficult to prove either way because the climate is more complex than our computer models.

Lots of questions, few answersWe don’t know if anything out of the ordinary is causing the giant snowstorms, but there is no shortage of speculation. Could they be caused by man’s emissions of greenhouse gases? Maybe. Could they be caused by changes in the solar cycle? Maybe. Could they be caused by changes in arctic sea ice? Maybe. Could they be caused by a combination of all three? Maybe.

Or, perhaps record snowstorms are simply caused by the weather.

Photo from AP/Jessica Hill