Friday, March 14, 2008

If Globe is Warming, why the Harsh Winter?

According to the US National Climactic Data Center, "the average temperature of the global land surface in January 2008 was below the 20th century mean (-0.02°F/-0.01°C) for the first time since 1982," reports the Telegraph. The record cold has led to record snow falls, the return of arctic sea ice and a heyday for global warming skeptics.

So is the party over for Al Gore and the overwhelming majority of scientists who agree the planet is getting hotter, due in part to human activity?

Not exactly.

In
a NY Times piece on this subject, one scientist shrugged, "The current downturn is not very unusual." The Earth has had other extremely cold winters over the past 20 years, for example in 1988, 1991 and 1998. But a "long-term warming trend" persists.

According to the Times, one cold winter just ain't enough to debunk global warming. "The cool spell in no way undermines the enormous body of evidence pointing to a warming world," according to a consensus among scientists, gathered by the Times.

So what's going on?

In
a recent feature at the Christian Science Monitor, they blame a couple of natural phenomena for the recent, brutal winter. First, a La Niña event in the Pacific which causes warm water to concentrate in the western tropics, while colder-than-usual water settles in the east.

Ottawa recently had more than 20 inches of snow in one day
(Photo courtesy of Pound360 Canadian correspondent, The Grizzly)

But La Niña can't be the only factor since, compared to previous La Niña winters, "this winter failed to follow that script," reports the Monitor. Usually, La Niña leaves the US Southwest and Southeast dry. However, this winter, another weather anomaly, the "Madden-Julian Oscillation" is also in play.

The Madden-Julian, from what I gather at the Monitor and
Wikipedia's entry on the subject, is a moisture-packed event that persistently circles the globe every couple of months. It appears the Madden-Julian remains a mystery in many ways, but explains the unusual La Niña this year.

Combined, the Madden-Julian and La Niña seem to better explain this year's extreme winter better than a sudden end to global warming.

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I started pound360 to channel my obsession with vitamins, running and the five senses. Eventually, I got bored focusing on all that stuff, so I came back from a one month hiatus in May of 2007 (one year after launching Pound360) and broadened my mumblings here to include all science.