Yahoo News 24 Feb 09;
WASHINGTON (AFP) – The risk posed to mankind and the environment by even small changes in average global temperatures is much higher than believed even a few years ago, a study said Monday.
Published by the Proceedings of the National Academy of Sciences, the study updated a 2001 assessment by the Inter-governmental Panel on Climate Change that looked at temperature changes and the risks they pose.
"Today, we have to assume that the risks of negative impacts of climate change on humans and nature are larger than just a few years ago," said Hans-Martin Fussel, one of the authors of the report.
The new study found that even small changes of global mean temperatures could produce the kinds of conditions singled out as "reasons for concern" in the 2001 assessment.
Those included risks to threatened systems such as coral reefs or endangered species; and extreme weather events like cyclones, heat waves or droughts.
Other "reasons for concern" involved the way the impact of climate change is distributed, the aggregate damage caused and the risk of "large scale discontinuities" such as the deglaciation of the Greenland ice sheets.
"Compared with results reported in the (2001 assessment), smaller increases in GMT (global mean temperatures) are now estimated to lead to significant or substantial consequences in the framework of the five 'reasons for concern,'" the study said.
The report said its conclusions were based in part on observations of impacts already occurring because of global warming and better understanding of the risks associated with rising mean temperatures.
They also were based on "growing evidence that even modest increases in GMT (global mean temperature) above levels circa 1990 could commit the climate system to the risk of very large impacts on multiple century time scales," the study said.
Three of the authors of the latest report contributed to the 2001 assessment's chapter on "reasons for concern."
"If the associated risks are larger, the necessity is also larger to reduce the greenhouse gases emissions and to support affected regions to cope with the unavoidable consequences of climate change," Fussel said in a statement.
It was the third report published in recent weeks carrying grim news about climate change.
On February 15, a report by Chris Field, of the Carnegie Institution and a former member of the Inter-governmental Panel on Climate Change, warned that greenhouse gases have accumulated more rapidly in the atmosphere between 2000 and 2007 than anticipated.
Three weeks before that, a study by Susan Solomon, the senior scientist at the National Oceanic and Atmospheric Administration, said changes in surface temperature, rainfall and sea level are "largely irreversible for more than 1,000 years after CO2 emissions are completely stopped."
Global warming danger threat increased
Randolph E. Schmid, Yahoo News 23 Feb 09;
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 experts.
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 Fahrenheit 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, in this week's online edition of Proceedings of the National Academy of Science, comes just a week after Christopher Field of the Carnegie Institution for Science told the annual meeting of the American Association for the Advancement of Science that humans are now adding carbon to the atmosphere even faster than in the 1990s.
Carbon dioxide and other gases added to the air by industrial and other activities have been blamed for rising temperatures, increasing worries about possible major changes in weather and climate. Carbon emissions have been growing at 3.5 percent per year since 2000, up sharply from the 0.9 percent per year in the 1990s, Field said.
The new study found evidence of greater vulnerability to climate change for specific populations, such as the poor and elderly, in not only developing but also developed countries.
"For example, events such as Hurricane Katrina and the 2003 European heat wave have shown that the capacity to adapt to climate-related extreme events is lower than expected and, as a result, their consequences and associated vulnerabilities are higher than previously thought," the scientists report.
Co-authors of the report include Stephen H. Schnieder of Stanford University, Michael Oppenheimer of Princeton University and researchers in India, Germany, Canada, Zimbabwe, Australia, Bangladesh, Cuba and Belgium.
