January 7, 2010

Does Recent Cold Weather Discredit Global Warming?

With the recent emergence of record-breaking cold snaps all over the world, climate experts say that it doesn't disprove global warming, but is only a blip in the long-term heating trend, The Associated Press reported.

Beijing had its coldest morning in almost 40 years and its biggest snowfall since 1951. Britain is suffering through its longest cold snap since 1981. And freezing weather is gripping the Deep South, including Florida's orange groves and beaches.

Such weather doesn't seem to fit with warnings from scientists that the Earth is warming because of greenhouse gases.

Gerald Meehl, a senior scientist at the National Center for Atmospheric Research in Boulder, Colo., said it is part of natural variability.

"With global warming, we'll still have record cold temperatures. We'll just have fewer of them," he said.

In fact, 2009 will rank among the 10 warmest years for Earth since 1880, according to Deke Arndt of the National Climatic Data Center in Asheville, N.C.

Climate scientists agree that man-made climate change does have the potential to cause more frequent and more severe weather extremes, such as heat waves, storms, floods, droughts and even cold spells.

Arndt said the world has seen just an outbreak of Arctic air over populated areas of the Northern Hemisphere.

"The Arctic air has really turned itself loose on us," he added.

Experts say large rivers of air travel roughly west to east around the globe between the Arctic and the tropics in order to act as a fence to keep Arctic air confined.

However, in recent years this airflow has become bent into a pronounced zigzag pattern, meandering north and south. If you live in a place where it brings air up from the south, you get warm weather.

But Arctic air is swooping down from the north in the eastern United States, like some other unlucky parts of the globe, creating a temperature of 3 degrees in Beijing, a reading of minus-42 in mainland Norway, and 18 inches of snow in parts of Britain.

Michelle L'Heureux, a meteorologist at the Climate Prediction Center of the National Oceanic and Atmospheric Administration, told AP the zigzag pattern arises naturally from time to time, but it is not clear why it's so strong right now. The center says the pattern should begin to weaken in a week or two.


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