Global warming debate all but over

Global warming debate all but over
 
 
Andrew Thomson, CanWest News Service; Ottawa Citizen
Published: Saturday, February 03, 2007

OTTAWA -- For the majority of scientists, the debate about climate change -- if it ever really existed -- has long been over.

Friday's release of the much anticipated political summary by the Intergovernmental Panel on Climate Change, the world's paramount scientific authority on global warming, appeared to bring further closure. The group is now more than 90 per cent certain that fossil fuels are contributing heavily to global warming. This figure goes beyond the last IPCC report, published in 2001, which referred to "new and stronger evidence" of human liability.

"There's been a cautious weighing of the evidence going back 20 years now," said Richard Peltier, a University of Toronto physicist and lead author of a chapter on paleoclimate trends.

Some skeptics in politics and the media - many of whom continue to place figurative quotation marks around the term global warming - poured cold water on the latest summary even before its release. They criticized the 12-page summary as a political document written by governments, not scientists.

It's all white noise to nearly all experts who specialize in climate change. They consider the debate finished. The overwhelming evidence points to rising temperatures, they say, and the major role of human activities such as fossil fuel burning and deforestation.

Peltier believes proof of human-induced climate change is now "indisputable," with agreement among 90 to 95 per cent of scientists working in the field.

"There's a small number who are still agnostic on the issue," he said. "The media has done an enormous disservice by presenting the evidence (on both sides of the climate-change debate) as equal."

A Fraser Institute report being released Monday is expected to argue that the IPCC summary is a political document that fails to reflect debates among scientists.

"There is no compelling evidence that dangerous or unprecedented changed (in climate) are underway ... the available data allow the hypothesis to be credibly disputed," said a January draft assessment from the Vancouver think tank, leaked on Wednesday to a Canadian climate change website.

IPCC contributors have lauded the full report - to be released this spring - as one of the largest pieces of peer-reviewed scientific research in history. Peltier said several rounds of review took place, involving thousands of scholars worldwide. The data gathered by the group's 140 lead authors was doggedly scrutinized, with every argument levelled by skeptical reviewers catalogued and archived for the public record.

"The whole process attempts to deal head-on with criticisms," Peltier said. "There's no attempt to sideline them."

Some skeptics seem to have softened their stance in light of the IPCC release. A congressional committee heard this week from several American scientists accusing the Bush administration of political interference and censorship in climate change research.

But President George W. Bush called global warming a "serious challenge" during his recent state of the union speech. And Friday, after the release of the climate change report, his energy secretary called the debate over climate change finished, given the evidence supporting humankind's role in warming the planet.

In Ottawa, the revelation of a 2002 letter by then-opposition leader Stephen Harper to Canadian Alliance members questioning the science behind global warming drew fire from opposition parties this week. Harper has promised more vigilant government action in recent days, dispatching Environment Minister John Baird to meet scientists in Paris.

Andrew Weaver, an IPCC report author, and professor at the University of Victoria's School of Earth and Ocean Sciences, argues there was never any debate among major researchers.

"The community has been saying the same thing all along," he said. "The so-called denialist crowd - I'm not going to call them skeptics, because all scientists are skeptics - they would say things like: Oh, the satellite measurements show there's actual cooling."

As recently as 15 years ago, however, a large portion of mainstream science organizations wasn't convinced. The U.S.-based National Academy of Sciences claimed in 1991 that "there was no evidence yet" that climate change was a pressing danger. Surveys of climatologists that same year showed lukewarm support for the concept.

Remaining doubts among most skeptics waned during the 1990s. The same academy told the Bush administration in June 2001 that the IPCC accurately reflected the scientific consensus on greenhouse gas emissions and rising temperatures. In 2005, the heads of 11 national science academies, including the Royal Society of Canada, signed a joint statement affirming human responsibility for global climate change. Ninety Canadian climate experts signed an open letter to now Prime Minister Harper in April 2006, pleading for a national climate change strategy. One month later, the American government's main climate change science program reported "clear evidence of human influences" on greenhouse gas levels, compared to natural causes.

Ottawa Citizen
© CanWest News Service 2007