Evidence of Rapid Global Warming Accepted by 99 Nations
SHANGHAI, China, January 22, 2001 (ENS) - The scientific basis for the reality of rapid global warming is clear, a comprehensive new United Nations report reveals. Snow cover has decreased, the duration of lake and river ice cover is shorter, and the atmospheric concentration of heat trapping carbon dioxide has increased by a third since 1750, climate scientists say.
Over 150 delegates from 99 governments met in Shanghai from January 17 to 20 to consider the new evidence contained in the contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change, "Climate Change 2001: The Scientific Basis."
The full report, which runs to over 1,000 pages, has been more than three years in production. It is the work of 123 lead authors from around the world. They in turn drew on the work of 516 contributing authors. The report has gone through extensive review by experts and governments.
After line-by-line consideration, the government delegates unanimously accepted the full report.
Watson warned rising temperatures will "cause decreases in agricultural productivity in the tropics and sub-tropics ... areas where we already have hunger."
New analyses of data from tree rings, corals, ice cores and historical records for the northern hemisphere show that the increase in temperature in the 20th century is the largest of any century during the past 1000 years.
Globally, the 1990s were the warmest decade and 1998 the warmest year in the instrumental record since 1861, the scientists found.
"The scientific consensus presented in this comprehensive report about human induced climate change should sound alarm bells in every national capital and in every local community, said Klaus Toepfer, executive director of the United Nations Environment Programme and a former German environment minister.
"We must move ahead boldly with clean energy technologies, and we should start preparing ourselves now for the rising sea levels, changing rain patterns, and other impacts of global warming," Toepfer urged.
Michael Zammit Cutajar, executive secretary of the United Nations Climate Change Convention, said, "The scientific findings being reported today should convince governments of the need to take constructive steps towards resuming the climate change talks that stalled last November in The Hague."
Key findings of the report include new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities.
Since the IPCC’s 1995 Report, confidence in the ability of models to project future climate has increased. There is now a longer and more closely scrutinized temperature record.
Reconstructions of climate data for the past 1,000 years, as well as model estimates of natural climate variations, suggest that the observed warming over the past 100 years was unusual and is unlikely to be entirely natural in origin.
In recent decades, there has been about a 40 percent decline in Arctic sea ice thickness during late summer to early autumn, the researchers found.
Global warming is linked to the emissions of six gases formed by the combustion of oil, coal and natural gas; the major one is carbon dioxide. These gases form a blanket in the upper atmosphere which keeps the heat of the Sun from radiating back out into space, trapping it close to the Earth.
Since 1750, the atmospheric concentration of carbon dioxide has increased by 31 percent from 280 parts per million to about 367 ppm today. The present carbon dioxide concentration has not been exceeded during the past 420,000 years and likely not during the past 20 million years, the scientists report.
Five years ago the same panel predicted a rise in global temperature of 1 to 3.5 degrees Celsius (1.8 to 6.3 degrees Fahrenheit).
Scientists say the prediction of even higher global temperatures is largely because future sulphur dioxide emissions, which help to cool the Earth, are now expected to be lower than forecast in 1995.
Sea levels are projected to rise by 0.09 to 0.88 meters (3.51 to 34.32 inches) from 1990 to 2100.
Despite higher temperature projections these sea level projections are slightly lower than the range projected five years ago, primarily due to the use of improved models, which give a smaller contribution from glaciers and ice sheets.
The Intergovernmental Panel on Climate Change Report will include a report on the impacts of climate change, to be finalized in mid-February, and another report on response strategies, expected in early March.