February 25, 2010

Recent Cold Spells Haven’t Hindered Global Warming

Climate scientists said on Thursday that the pace of global warming continues unabated, despite images of Europe crippled by a deep freeze and parts of the United States blasted by blizzards, Reuters reported.

Some have been led to question if global warming has stalled, due to the bitter cold, with more intense winter weather forecast for March in parts of the United States.

Experts say estimating consumption of energy supplies, such as demand for winter heating oil in the U.S. northeast, and impacts on agricultural production, require a more specific understanding of the overall trend.

Veteran Australian climate scientist Neville Nicholls told an online climate science media briefing that it's not warming the same everywhere but it is really quite challenging to find places that haven't warmed in the past 50 years.

"January, according to satellite data, was the hottest January we've ever seen. Last November was the hottest November we've ever seen, November-January as a whole is the hottest November-January the world has seen," Nicholls said of the satellite data records since 1979.

2000-2009 was the hottest decade since records began in 1850, and 2009 would likely be the fifth warmest year on record, according to the World Meteorological Organization (WMO).

WMO data showed that eight out of the 10 hottest years on record have all been since 2000.

Such severe winter freezes like the one this year, one of the coldest winters in the country for nearly 30 years, could become increasingly rare because of the overall warming trend, said the UK Met Office, Britain's official forecaster.

But many climate scientists say that global warming is not uniform in all areas and that climate models predict there will likely be greater extremes of cold and heat, floods and droughts.

Kevin Walsh, associate professor of meteorology at the University of Melbourne, told Reuters that global warming is a trend superimposed upon natural variability, variability that still exists despite global warming.

"It would be much more surprising if the global average temperature just kept on going up, year after year, without some years of slightly cooler temperatures," he said.

The U.N. climate panel recently came under attack for including an error about the estimated thaw of Himalayan glaciers in a major 2007 report.

Climate skeptics have seized upon the discovery of the error, but the Intergovernmental Panel on Climate Change (IPCC) produces reports based on the work of thousands of scientists that are the main guides for policymakers on tackling global warming.

In the 2007 report, researchers wrongly said Himalayan glaciers could all melt by 2035, an apparent typographical error that stemmed from using "grey literature" outside peer-reviewed scientific journals.

Grey literature could play a key role in the climate debate and not all valuable data or reports were published formally in journals. Nicholls said such examples included reports on extreme weather events by government meteorological agencies.

He said the IPCC does not exclude the use of that sort of grey literature because it would be stupid to talk about extremes, for instance, and not include that sort of grey literature.

More stringent checks are needed for the next IPCC reports but the inclusion of one or two wrong predictions didn't undermine the whole peer-reviewed IPCC process because scientific study was always evolving, experts said.