John L. Ward: When freezing means warming
Published: Monday, January 31, 2011 at 6:01 a.m.
Last Modified: Tuesday, January 25, 2011 at 9:04 p.m.
Record freezing weather in Europe this year and last? Snow, ice, and sleet blanketing the South following last year's extra-cold February? Do these events prove that fears of global warming are unwarranted?
The truth is just the reverse: Colder winters in Europe and the eastern U.S. are caused by global warming.
Judah Cohen, group manager of the Climate Analysis Group and Seasonal Forecasting at Atmospheric and Environmental Research (AER), explains that the overall warming of the world's atmosphere is responsible for the record cold and snowfall.
The previously-ignored variable incorporated in his model is Siberian snow cover, which has increased over the last quarter century even as glaciers and other snow deposits have been shrinking.
Increased atmospheric moisture caused by global warming (up by 4 percent) has raised average precipitation worldwide, including Siberian snow.
The vast white area of Siberian snow cover cools temperatures by reflecting the sun's energy back into space. The jet stream, a river of fast-flowing air that normally moves around the planet in a primarily eastward direction, encounters a dome of cold air built up over the Siberian snowfields as part of it flows northward around the exceptionally high Asian mountain ranges.
The increased wave energy produced by the encounter exaggerates the normal north-and southward undulations of the jet stream, sending warm air north from subtropical oceans into Alaska and Greenland and pushing cold air south from the Arctic down the east side of the Rockies. Cold Siberian air moves southward into East Asia and Europe.
But that is only one of the mildest changes in worldwide weather produced by global warming.
Flooding in China in 2010 killed 3,222 people and left another 1,003 missing. Yet severe drought affected winter wheat crops in 17 percent of China's northern bread basket.
Australia, after years of drought, experienced incredible flooding in 2010.
The number of individuals affected by the Pakistan flood exceeded the combined total of individuals affected by the 2004 Indian Ocean tsunami, the 2005 Kashmir earthquake and the 2010 Haiti earthquake.
Catastrophic rains last fall put two-thirds of Benin underwater and left 150,000 people homeless.
In early December torrential rains created floods and landslides Colombia and Venezuela that left 1.5 million homeless.
In October 2010, an unprecedented, freak "land hurricane," accompanied by the lowest atmospheric pressure ever observed over the continental U.S., left a path of devastation from Saskatchewan to Texas.
A 100-year flood in Britain, severe drought in the horn of Africa, a drought worse than the 100-year drought of 2005 in the Amazon basin, the deadliest fire in Israel's history, devastating drought and fires in Russia, the worst floods in a century in Bosnia, Albania, Serbia and Montenegro, and extensive flooding in Tennessee, Kentucky, and Mississippi: these were some of last year's severe weather events that typify those we can expect to be repeated with increasing intensity as the planet warms.
Ninety-seven percent of the top 100 climate researchers in the world endorse the IPCC's conclusions that global warming is real and largely man-made. The best science says that all use of carbon-based fuel must be stopped as soon as possible, because any global warming effects we fail to stop will be with us for 1,000 years.
An all-out war on global warming is needed now to avoid leaving our children and grandchildren a future of increasingly acidic oceans with expanding dead zones, extreme drought, deadly temperatures, crop failures, insect infestations, loss of arable land, and, paradoxically, flooding and more violent storms.
Our failure to act will result in a radically transformed world marked by famine, economic collapse, social unrest, vast migrant populations, disease, and growing extinctions of fish and animal species.
Serious global warming mitigation done soon is very affordable; ignoring the problem is unthinkable.
John L. Ward is a Professor Emeritus in the School of Art and Art History at the University of Florida.
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