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[greenyes] Global Warming - The Hockey Stick & The Risks of Overstatement
WALL STREET JOURNAL

February 14, 2005


Global Warring
In Climate Debate, The 'Hockey Stick' Leads to a Face-Off Nonscientist 
Assails a Graph Environmentalists Use, And He Gets a Hearing Defenders Call 
Attack Political
By ANTONIO REGALADO
Staff Reporter of THE WALL STREET JOURNAL

One of the pillars of the case for man-made global warming is a graph 
nicknamed the hockey stick. It's a reconstruction of temperatures over the 
past 1,000 years based on records captured in tree rings, corals and other 
markers. The stick's shaft shows temperatures oscillating slightly over the 
ages. Then comes the blade: The mercury swings sharply upward in the 20th 
century.

The eye-catching image has had a big impact. Since it was published four 
years ago in a United Nations report, hundreds of environmentalists, 
scientists and policy makers have used the hockey stick in presentations and 
brochures to make the case that human activity in the industrial era is 
causing dangerous global warming.

But is the hockey stick true?

According to a semiretired Toronto minerals consultant, it's not. After 
spending two years and about $5,000 of his own money trying to double-check 
the influential graphic, Stephen McIntyre says he has found significant 
oversights and errors. He claims its lead author, climatologist Michael Mann 
of the University of Virginia, and colleagues used flawed methods that yield 
meaningless results.

Dr. Mann vigorously disagrees. On a Web site launched with the help of an 
environmental group (www.realclimate.org1), he has sought to debunk the 
debunking, and counter what he calls a campaign by fossil-fuel interests to 
discredit his work. "It's a battle of truth versus disinformation," he says.

But some other scientists are now paying attention to Mr. McIntyre. Although 
a scientific outsider, the 57-year-old has forced Dr. Mann to publish a 
minor correction. Now a critique by Mr. McIntyre and an ally is being 
published in a respected scientific journal. Some mainstream scientists who 
harbored doubts about the hockey stick say its comeuppance is overdue.

The clash has grown into an all-out battle involving dueling Web logs 
(www.climateaudit.org2), a powerful senator and a score of other scientists. 
Mr. McIntyre's new paper is circulating inside energy companies and 
government agencies. Canada's environment ministry has ordered a review.

Mr. McIntyre's critique isn't going to settle the broader global-warming 
debate. Indeed, he takes no strong position on whether fossil-fuel use is 
heating the planet or, if so, how to cope. He just says he has found a flaw 
in a main leg supporting the global-warming consensus, the consensus that 
led to an international initiative taking effect this week: Kyoto.

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The problem, says Mr. McIntyre, is that Dr. Mann's mathematical technique in 
drawing the graph is prone to generating hockey-stick shapes even when 
applied to random data. Therefore, he argues, it proves nothing.

Statistician Francis Zwiers of Environment Canada, a government agency, says 
he now agrees that Dr. Mann's statistical method "preferentially produces 
hockey sticks when there are none in the data." Dr. Zwiers, chief of the 
Canadian agency's Center for Climate Modeling and Analysis, says he hasn't 
had time to study Dr. Mann's rebuttals in detail and can't say who is right.
Dr. Mann, while agreeing that his mathematical method tends to find 
hockey-stick shapes, says this doesn't mean its results in this case are 
wrong. Indeed, Dr. Mann says he can create the same shape from the climate 
data using completely different math techniques.

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Some scientists believe the debate has little bearing on the broad case for 
man-made warming. That's because, they say, other studies of past 
temperatures also indicate that the late 20th century was unusually warm. 
Recent temperature increases also square with the known effects of 
greenhouse gases. "The main punch line still appears in many other studies," 
says Jonathan Overpeck, a climate specialist at the University of Arizona. 
He shares some other scientists' concern that critics have unfairly singled 
out Dr. Mann's work. A variety of critics appear to be "on some kind of 
witch hunt," Dr. Overpeck says.
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Now the IPCC is preparing a new global warming report, due in 2007, and 
charges of exaggeration are again flying. A U.S. hurricane researcher, Chris 
Landsea, quit the U.N. body last month after an IPCC senior author, Kevin 
Trenberth, said storms could get worse because of global warming. Dr. 
Landsea called that idea unsupported by data and said the IPCC was 
"motivated by pre-conceived agendas." Dr. Trenberth, defending his analysis, 
said his critic is the one "politicizing" the science.
As the IPCC revisits the warming issue -- and the hockey stick -- it is 
taking account of all views, including Mr. McIntyre's, say the group's 
leaders.
Mr. McIntyre says he intends to continue his audit of climate science and 
has demanded that other researchers send him details of their work. He isn't 
satisfied with the responses so far. "When I ask them for additional data, 
you can imagine how cooperative they are," he says.
_________________________
Peter Anderson, President
RECYCLEWORLDS CONSULTING
4513 Vernon Blvd. Suite 15
Madison, WI 53705-4964
Ph: (608) 231-1100
Fax: (608) 233-0011
Cell: (608) 698-1314
eMail: anderson@no.address
web: www.recycleworlds.net

 



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