Researchers Forecast Rapid,
Irreversible Climate Warming
By Environmental News Network

There's a nine out of ten chance that global average temperatures will rise between three and nine degrees Fahrenheit over the coming century, with a four to seven degree increase most likely, according to a new probability analysis by scientists in the United States and England. The most likely projected increase is five times greater than the one degree temperature rise observed over the past century.
As early as the year 2030, the planet is likely to heat up between one and two degrees, say the scientists. The study appears in the July 20 issue of the journal "Science," a publication of the American Association for the Advancement of Science.
In arriving at their estimates, the scientists assumed that no policies would be implemented to curb climate change before 2100.
"We are assigning probabilities to long-term projections to aid policy makers in assessing the risks that might accompany various courses of action or non-action," says first author Tom Wigley of the U.S. National Center for Atmospheric Research (NCAR). "If all scenarios are believed to be equally likely, it's difficult to plan."
National Center for Atmospheric Research, located in Boulder, Colorado, has as its primary sponsor the National Science Foundation. NCAR is managed by the University Corporation for Atmospheric Research, a consortium of 66 universities offering Ph.Ds in atmospheric and related sciences.
An estimated global warming range of 2.5 to 10.4 degree F was announced in January by the Intergovernmental Panel on Climate Change (IPCC), a body of scientists created by the World Meteorological Organization and the United Nations Environment Programme in 1988. Many hundreds of scientists from many countries participated in the preparation and review of three comprehensive climate change reports.
"New analyses of proxy data for the Northern Hemisphere indicate that the increase in temperature in the 20th century is likely to have been the largest of any century during the past 1,000 years," the IPCC reported in January. "It is also likely that, in the Northern Hemisphere, the 1990s was the warmest decade and 1998 the warmest year."
But the likelihood that the earth's temperature would warm only 2.5 degree or as much as 10.4 degree is very low, say Wigley and his coauthor Sarah Raper of the University of East Anglia in England and the Alfred Wegener Institute for Polar and Marine Research in Germany.
Even warming of four to seven degrees F, however, is very large compared with the observed warming over the past century, Raper and Wigley write. "Whether or not such rapid warming will occur ... depends on actions taken to control climate change."
Global climate change is linked to the accumulation in the atmosphere of six gases that trap the Sun's ray's close to the Earth's surface. These gases are emitted by the burning of coal, oil and gas.
International negotiations are currently underway in Bonn, Germany to finalize the rules for implementation of the Kyoto Protocol, a supplement to the United Nations Framework Convention on Climate Change, that would limit the emission of these gases by 38 industrialized nations.
The United States signed the Kyoto Protocol under the Clinton administration, but President George W. Bush announced in March that the United States would not ratify the treaty. This move caused a crisis in the international approach to the agreement since the United States emits 25 percent of the world's heat- trapping greenhouse gases.
The European Union is leading a renewed effort to finalize the protocol. Today, final talks are talking place aimed at making a breakthrough on compliance, the area that appears to be the final stumbling block to an agreement.
If greenhouse gases are not limited and global warming does occur, Raper and Wigley says it would be almost impossible to reverse. If a rapid warming and its expected impacts occur in the near future, even swift societal attempts at control would yield little immediate success, say they write. "The climate's inertia would lead to only a slow response to such efforts and guarantee that future warming would still be large."
New estimates of sulfur dioxide and other emissions, along with updated information on carbon storage, ocean circulation, radiation, and other components of the Earth's system have improved computer models of the earth's climate and led the Intergovernmental Panel on Climate Change to both raise and widen its estimated range of global temperature increase.


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