Threat from warming is closer than thought

February 24, 2009|Associated Press

WASHINGTON - The Earth won't have to warm up as much as had been thought to cause serious consequences of global warming, including more extreme weather and increasing threats to plants and animals, says an international team of climate specialists.

The Intergovernmental Panel on Climate Change estimated that the risk of increased severe weather would rise with a global average temperature increase of between 1.8 degrees and 3.6 degrees above 1990 levels.

The National Climatic Data Center currently reports that global temperatures have risen 0.22 degree since 1990.

Now, researchers report that "increases in drought, heat waves, and floods are projected in many regions and would have adverse impacts, including increased water stress, wildfire frequency, and flood risks starting at less than [1.8 degrees] of additional warming above 1990 levels."

Indeed, "it is now more likely than not that human activity has contributed to observed increases in heat waves, intense precipitation events, and the intensity of tropical cyclones," concluded the researchers led by Joel B. Smith of Stratus Consulting Inc., in Boulder, Colo.

Other researchers, they noted, have suggested that "the likelihood of the 2003 heat wave in Europe, which led to the death of tens of thousands of people, was substantially increased by increased greenhouse gas concentrations."

The new report is in this week's online edition of Proceedings of the National Academy of Science.