Quarter-Degree Fix Fuels Climate Fight
By ANDREW C. REVKIN, The New York Times Posted: 2007-08-26 13:51:58 Filed Under: _Science News_ (http://news.aol.com/science)
(Aug. 26) - Never underestimate the power of the blogosphere and a quarter of a degree to inflame the fight over _global warming_ (javascript:;) .
A quarter-degree Fahrenheit is roughly the downward adjustment _NASA_ (javascript:;) scientists made earlier this month in their annual estimates of the average temperature in the contiguous 48 states since 2000. They corrected the numbers after an error in meshing two sets of temperature data was discovered by Stephen McIntyre, a blogger and retired business executive in Toronto. Smaller adjustments were made to some readings for some preceding years.
All of this would most likely have passed unremarkably if Mr. McIntyre had not blogged that the adjustments changed the rankings of warmest years for the contiguous states since 1895, when record-keeping began.
Suddenly, 1934 appeared to vault ahead of 1998 as the warmest year on record (by a statistically meaningless 0.036 degrees Fahrenheit). In NASA's most recent data set, 1934 had followed 1998 by a statistically meaningless 0.018 degrees. Conservative bloggers, columnists and radio hosts pounced. "We have proof of man-made global warming," Rush Limbaugh told his radio audience. "The man-made global warming is inside NASA."
Mr. McIntyre, who has spent years seeking flaws in studies pointing to human-driven climate change, traded broadsides on the Web with James E. Hansen, the NASA team's leader. Dr. Hansen said he would not "joust with court jesters" and Mr. McIntyre posited that Dr. Hansen might have a "Jor-El complex" -- a reference to _Superman_ (javascript:;) 's father, who foresaw the destruction of his planet and sent his son packing.
Blogs are still reverberating, but Mr. McIntyre, Dr. Hansen and others familiar with the initial data revisions are clarifying what is, and is not, at issue.
One thing not in question, Mr. McIntyre and Dr. Hansen agree, is the merit of shifting away from energy choices that contribute heat-trapping greenhouse gases to the atmosphere.
Mr. McIntyre said he feels "climate change is a serious issue." His personal preference is to shift increasingly to nuclear power and away from coal and oil, the main source of heat-trapping carbon dioxide.
Mr. McIntyre and Dr. Hansen also agree that the NASA data glitch had no effect on the global temperature trend, nudging it by an insignificant thousandth of a degree.
Everyone appears also to agree that too much attention is paid to records, particularly given that the difference between 1934, 1998, and several other sets of years in the top 10 warmest list for the United States are so small as to be statistically meaningless.
Mr. McIntyre said that when he posted the revised list under the heading "A New Leaderboard at the U.S. Open," "I just was sort of having some fun with it as much as anything."
He added: "The significance of things has been misstated by Limbaugh and people like that."
Dr. Hansen and his team note that they rarely, if ever, discuss individual years, particularly regional findings like those for the United States (the lower 48 are only 2 percent of the planet’s surface). "In general I think that we want to avoid going into more and more detail about ranking of individual years," he said in an e-mail message. "As far as I remember, we have always discouraged that as being somewhat nonsensical."
Jay Lawrimore, a scientist at the National Climatic Data Center of the Commerce Department who works on assembling the climate records that NASA analyzed, said his agency could probably do a better job of emphasizing the uncertainty surrounding its annual temperature announcements.
Indeed, there is enough wiggle room in the numbers that the center has a different list of the 10 warmest years than those produced using NASA’s and Mr. McIntyre’s analyses. By the climate center’s reckoning, 1998 remains the warmest year for the 48 states (with 2006 second and 1934 third).
Dr. Lawrimore, Dr. Hansen and other experts said that trends are far more important than particular years, and the recent widespread warming trend has been clear — and very distinct from the regional hot spell that drove up United States temperatures in the 1930s.
Mr. McIntyre and the government scientists do agree on at least one more thing: the need to improve the quality of climate data gathered around the world, including in the United States, which has by far the planet’s biggest network of meteorological stations.
Mr. McIntyre is not alone in pointing out that the need to adjust and revise such data -- with the attendant risk of mistakes -- would be reduced with more care and consistency taken in collecting climate data.
The National Academy of Sciences has repeatedly called for improvements in climate monitoring. An independent group of meteorologists and weather buffs is compiling its own gallery of American weather stations at www.surfacestations.org, with photographs showing glaring problems, like thermometers placed next to asphalt runways and parking lots.
Dr. Lawrimore said that the government is preparing to build a climate reference network of more sophisticated, and consistent, monitoring stations that should cut uncertainty in gauging future trends.
In any case, he said, the evidence for human-driven warming remains robust. "Saying what they're saying has just provided an opportunity for them to create doubt in people's minds," he said of the bloggers.
Copyright © 2007 _The New York Times Company_ (http://www.nytimes.com/ref/membercenter/help/copyright.html) 2007-08-26
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