The science of climate change is inexact. It is about uncertainty and probabilities. Based on the evidence, a criminal lawyer would not be able to prove that humans are responsible for potentially catastrophic climate change. But the evidence would certainly nail down a civil conviction.
If the vast bulk of evidence says climate change is real and that humans are almost certainly to blame, why is the science being dismissed as exaggerated, unreliable or even fraudulent by the climate change doubters?
Opinion polls show that public skepticism about man-made climate change has climbed in recent months as the stories questioning the legitimacy of the science migrate from the Internet's fringes to the mainstream media.
The University of East Anglia affair certainly did a lot of damage. The university's Climatic Research Unit failed to keep proper records about Chinese weather stations and probably deleted potentially embarrassing correspondence to get around the Freedom of Information Act, among other sins. As far as scandals go, it's genuine.
The UN Intergovernmental Panel on Climate Change "scandal" is less convincing, though the skeptics' blogs would have you believe it's a con job that makes Bernie Madoff look like a saint. Marc Morano's Climate Depot calls the IPCC a "train wreck." The site hosts blogs with provocative headlines such as "Is Anything in the IPCC Report Accurate?"
The IPCC's 2007 report on climate change concluded that "warming of the climate system is unequivocal" and that most of the recent warming was "very likely due" to human activity. Left unchecked, the greenhouse gas emissions have the potential to raise average global temperatures by between 1.1 to 6.4 degrees by the end of the century, the report said.
Produced by 800 contributing authors and reviewed by some 2,500 scientists, the report tipped the balance in favour of the argument that humans are the main contributors to climate change.
It built momentum for December's Copenhagen climate change summit, which tried (and failed) to launch a global successor to the relatively narrow Kyoto Protocol. (The IPCC shared the 2007 Nobel Peace Prize with Al Gore.)
What got the skeptics all hot was the IPCC claim that the Himalayan glaciers would be gone by 2035, even though the figure did not appear in any of the "Technical Summaries" or "Summaries for Policy Makers," only on one page of the 3,000-page report. In truth, there is almost no evidence to suggest the glaciers will melt that quickly.
Another claim said global warming could reduce rain-fed North African crop production by 50 per cent by 2020. This scenario, too, is dubious. The Dutch government has asked the IPCC to correct the claim that more than half of the Netherlands is below sea level; the official Dutch figure is 26 per cent.
Mistakes in a 3,000-page report were inevitable, especially given that the IPCC does not conduct its own research; it collects and reviews research done by climate scientists everywhere. More mistakes will surface, if only because the climate change skeptics, backed by well-financed armies of lobbyists employed by companies that cringe at the thought of tight emission reduction targets, are straining every word through their truth filters.
They have been doing so for three years and the biggest mistake they could find is the Himalayan claim. None of the IPCC's central conclusions have been demolished. We know that greenhouse gases trap heat in the atmosphere, that global average temperatures are increasing, and that natural phenomena can explain only part of the warming. Glaciers are indeed melting, including those in the Himalayas.
In regions where little climate data have been collected, the climate change evidence may not be compelling. Change can only be measured against a base. If the base isn't known, any climate change claims are open to challenge. But in areas where a lot of data have been collected, there is no argument that climate change is real. The thoroughly studied ice packs in the Arctic and Greenland are disappearing faster than most scientists had expected.
The IPCC has struggled to defend itself. That's in good part because it has no resources. It is not an institution or a company or a movement. It is a small secretariat with an annual budget of about $5-million (U.S.), insignificant compared with the financial firepower of the climate change skeptics. IPCC chairman Rajenda Pachauri's delayed apology for the Himalayan mistake made a bad situation worse.
Sadly, the British government is one of the few to have come out in defence of the IPCC's report, even though scientists from many dozens of countries contributed to the study.
"It's right that there's rigour applied to all the reports about climate change," British Secretary of State for Energy and Climate Change Ed Miliband told the Observer newspaper last month. "But I think it would be wrong that, when a mistake is made, it's somehow used to undermine the overwhelming picture that's there."
Hear, hear Mr. Miliband. Governments ignore the IPCC at their peril. The preponderance of evidence, to use a civil lawyer's term, suggests climate change is real and dangerous.
Eric Reguly