WASHINGTON Official government measurements show the world's temperature has dropped a bit since reaching its most recent peak in 1998.
That's given global warming skeptics new ammunition to attack the prevailing theory of climate change. Skeptics argue the current stretch of slightly
lower temperatures means that costly measures to limit carbon dioxide emissions are ill-founded and unnecessary.
Many scientists agree, however, that hotter times are ahead. A decade of level or slightly lower temperatures is only a temporary dip to be expected
as a result of natural, short-term variations in the complex climate system, they say.
“The preponderance of evidence is that global warming will resume,” Nicholas Bond, a meteorologist at the National Oceanic and Atmospheric
Administration's Pacific Marine Environmental Laboratory in Seattle, said in an e-mail.
“Natural variability can account for the slowing of the global mean temperature rise we have seen,” said Jeff Knight, a climate expert at the Hadley
Centre for Climate Prediction and Research in Exeter, England.
According to data from the National Space Science and Technology Center in Huntsville, Ala., the global high temperature in 1998 was 1.37 degrees
Fahrenheit above the average for the previous 20 years. So far this year, the high has been 0.76 degrees Fahrenheit above the 20-year average, cooler
than before.
“It's entirely possible to have a period as long as a decade or two of cooling superimposed on the long-term warming trend,” said David Easterling,
chief of scientific services at NOAA's National Climatic Data Center in Asheville, N.C.
“The temperature peak in 1998 to a large extent can be attributed to the very strong El Niño event of 1997-98,” Bond said. “Temperatures for the globe
as a whole tend to be higher during El Nino.”
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