British Cite Evidence of Global Warming Trend
Global surface temperatures in 1989 were the fifth warmest on record, providing further evidence of a worldwide warming trend, the British Meteorological Office reported Friday.
“It makes it more obvious that there is global warming taking place,” said Barry Parker, a spokesman for the office, in a telephone interview from England. “The important thing about it is (that) we have so many of the highest temperatures occurring in the 1980s, in fact the highest temperatures.”
Six of the 10 warmest years since the mid-1800s, when global temperatures were first recorded, occurred in the 1980s. The warmest year on record was 1988.
Some scientists believe that rising amounts of carbon dioxide and other man-made gases in the atmosphere, which trap heat much as the panes of a greenhouse absorb warmth, will eventually produce major climatic shifts. The meteorological office’s report, however, does not directly attribute the unusual warmth to this greenhouse effect. Even many greenhouse theory proponents say that one decade’s temperatures are not conclusive evidence that the trend is under way.
“It’s possible, but obviously we can’t say anything about that because we don’t know,” Parker said.
Skeptics of the greenhouse theory contend that temperature increases over the last century may have nothing to do with greenhouse gases and complain that the warming projections fail to consider possible mitigating factors, such as cooling cloud cover.
But Stephen Schneider, a climatologist at the National Center for Atmospheric Research in Boulder, Colo., said temperatures in 1989 and the rest of the decade were “consistent” with models that predict a greenhouse effect.
“The entire century has seen a warming trend of one (degree) Fahrenheit, which is consistent with the middle to low end of what computer models (for the greenhouse effect) say should have happened,” said Schneider, a greenhouse theory proponent.
He noted, however, that the decade’s temperatures could represent a natural climatic fluctuation, and warned that “proof” of the greenhouse theory could require as many as two more decades of such readings.
F. Sherwood Rowland, an expert in atmospheric chemistry, agreed.
“The likelihood that this is totally accidental, totally by chance, gets less and less as we keep piling up very warm years,” said Rowland, a UC Irvine chemistry professor. “Obviously, we had a very cold winter in parts of the U.S., but last summer was blistering in Western Europe.”
The recent warming pattern does not preclude unusually cool seasons in parts of the world because the trend is “not that strong yet,” said James Hansen, a National Aeronautics and Space Administration scientist and the nation’s leading greenhouse theory proponent.
“Many people in the U.S. suddenly got the impression, based on a very cold winter, that maybe in fact everything is getting cold again,” Hansen said. He explained that the warming trend still is too small to result in uniform temperature increases around the globe.
Although the British Meteorological Office report contained no individual temperature readings for areas of the earth last year, it said the surface of the globe warmed by .45 degrees Fahrenheit over the last 20 years. Although small, such rises can have significant effects on local weather patterns, scientists say. Eventually, they say, such rises could produce dramatic events, such as droughts, hurricanes and coastal flooding.
The British report also proved some climate predictions wrong. Many oceanographers had believed that 1989 would mark a dramatic drop in average global temperatures because of the influence of a weather pattern that brings unusually cold temperatures to the eastern Pacific Ocean. The chairman of the British Meteorological Office is heading an intergovernmental panel on climate change for the United Nations Environment Program and the World Meteorological Organization.
