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SCIENCE & TECHNOLOGY
Climate change and politics

Feb 3rd 2005
From The Economist print edition

The debate over global warming is getting rancorous

“THE intermixing of science and politics is a bad combination, with a bad history.” So warns Michael Crichton at the end of his current, popular novel, “State of Fear”. He argues that wilful obfuscation by politicians and wild-eyed greens is leading to a herd mentality over global warming, akin to the uncritical embrace of eugenics a century ago. “Once again,” he intones ominously, “critics are few and harshly dealt with.”

At first blush, it appears that Dr Crichton might have a point. Of course, there was once an intense global debate over global warming's most sacred cow—the Kyoto protocol on climate change. The treaty calls for immediate reductions in emissions of greenhouse gases by industrialised countries. George Bush upset many greens by abruptly confirming in 2001 that America would never ratify the Kyoto treaty. But other countries did ratify it, and it is due to come into full force for them on February 16th, so the Kyoto debate is over.

The concern about crusading politicians also seems relevant. Tony Blair, Britain's prime minister, says climate change is his top priority, along with Africa, this year. He asked Sir David King, his chief science adviser, to organise a scientific conference in Britain this week to work out what adds up to “dangerous interference” with the climate system. The conference had not ended as The Economist went to press, but there was talk of pressure from politicians for agreement on a specific numerical definition of what is “dangerous”—a notion some participants said was not justified by the science.

They said, they said

Despite Kyoto's coming into force, vigorous debate between and among climate sceptics and climate hawks continues. First, consider the ongoing haggling over the science. The Intergovernmental Panel on Climate Change (IPCC), a body of leading scientists which advises the UN on climate issues, has established that the Earth is indeed warming, thanks in part to man's burning of fossil fuels. However, questions still remain as to the particulars.

For example, when Kevin Trenberth, head of the IPCC's panel on hurricanes, recently suggested that there exists a link between climate change and the wave of powerful hurricanes last year, he was immediately challenged. Christopher Landsea, a hurricane expert at America's National Oceanic and Atmospheric Administration, resigned from the IPCC panel, arguing that Dr Trenberth's comments went beyond what the peer-reviewed science could justify. He wrote a public letter complaining that: “because of Dr Trenberth's pronouncements, the IPCC process has been subverted and compromised, its neutrality lost.”

Dr Trenberth retorts that “politics is very strong in what is going on, but it is all coming from Landsea and colleagues. He is linked to the sceptics.” He explains the remarks in question by saying that he did not suggest climate change was affecting the number of hurricanes, but was affecting their intensity, because of hotter ocean temperatures, a conclusion he says the data readily bears out.

Another example is the controversy over the most important totem of global warming: the “hockey stick”. That is the nickname given to the plot of global temperatures published by Michael Mann, then of the University of Massachusetts in Amherst, and his colleagues in 1998, which shows a sharp upturn beginning at the time of the industrial revolution. This chart has often been trotted out as the clinching proof of anthropogenic warming. Sceptics have never liked this chart, which necessarily relies on statistics to infer historical temperatures from tree rings.

Two critics, Stephen McIntyre of the Northwest Exploration Company, in Toronto, and Ross McKitrick of the University of Guelph, also in Ontario, are about to publish a paper in Geophysical Research Letters (GRL), which alleges that Dr Mann's statistics are inaccurate, and that the hockey stick is a mere statistical artefact. Dr Mann and many other climate scientists dismiss Mr McIntrye's and Dr McKitrick's arguments.

The statistical issues involved are complicated—even Stephen Mackwell, the editor-in-chief of GRL, which also published some of Dr Mann's earlier papers (along with Nature), admits that he does not understand the details of the new paper.

The debate over the economics of warming is, if such a thing were possible, even more robust than the one over the science. The IPCC has come under attack for its scenarios of future growth. One chief sin is the reliance by IPCC modellers on market-based exchange rates instead of purchasing-power parity, which adjust wealth according to domestic purchasing power—which many economists believe is more accurate. That, says David Henderson, an economist at London's Westminster Business School, leads to unrealistic projections for economic growth and therefore emissions growth. He and Ian Castles provided the IPCC with detailed critiques.

Did the IPCC welcome the chance to improve its projections? Initially, it most certainly did not. Dr Henderson was frustrated by that reaction. However, he was encouraged to learn this week that serious economists were cloistered away at a recent meeting studying ways of incorporating his critiques into the IPCC modelling process. Whether any substantive changes will emerge remains unclear, but a proper re-think may be in the works.

Disagreements are also breaking out among those economists relatively sceptical about the effects of climate change. The Copenhagen Consensus, a project led by Bjorn Lomborg, a professor at the University of Aarhus, in Denmark, and publicised by this newspaper, made something of a splash a few months ago by ranking climate change at the bottom of a list of pressing global problems. A panel of eminent economists, among them three Nobel prize-winners, placed initiatives to tackle HIV/AIDS, malaria, sanitation and other problems confronting the world's poor ahead of proposals to tackle global warming, which were described as “bad” investments compared with those aimed at tackling these other problems. But several participants now say that there was confusion about how they were ranking ways to spend development aid, or ranking which general global problems should be tackled.

Of course, greens howled in protest at the dismissal of climate change, and pointed to some sort of stitch up: after all, some argued, Dr Lomborg is well known for his opposition to the Kyoto treaty. He rejects such claims, insisting that the effort was in good faith. He points out that the man selected to write the “expert paper” on climate, William Cline of the Centre for Global Development, a think-tank based in Washington, DC, has impeccable credentials; indeed, he is known as an advocate of forceful, early action to slow global warming. Dr Lomborg explains that the proposals on climate change fared poorly because they offered the lowest benefits for the costs incurred.

Now, some members of the Consensus are dissenting. Thomas Schelling of the University of Maryland, who voted on the final choices, thinks that presenting climate change at the bottom of the list as “bad” is misleading. He says he and the other gurus did not like Kyoto or the aggressive proposals made by Dr Cline, whom he sees as the “most alarmist of the serious climate policy experts”, but Dr Schelling says he would have ranked modest climate proposals higher on the list, because he sees climate as a real problem. Robert Mendelsohn, a conservative Yale economist who was an official “critic” of the climate paper in this process, goes further: because Dr Cline's positions are “well out of the mainstream”, he had no choice but to reject them. He worries that “climate change was set up to fail.”

Dr Lomborg insists that that was not at all the case. Picking an enthusiast like Dr Cline also could suggest that climate was being taken seriously by the Copenhagen process. However, he accepts that more modest proposals (such as a small carbon tax or investments in research) would have ranked higher on the list. Dr Cline, for his part, acknowledges that his views (for example, on the right discount rates to use when pondering long-term policies) “have not yet been accepted by the mainstream.” He is unhappy with how climate has been portrayed by the Copenhagen process, but he still feels that the attempt to assess global problems was well intentioned and worthwhile.

The death of environmentalism?

Perhaps the clearest sign that the imminent arrival into force of Kyoto has not led to a bout of green triumphalism comes from the debate among America's greens today. Michael Shellenberger and Ted Nordhaus, political strategists and green organisers, argue in a recent policy paper that, judging from polling data, America's big environmental groups have failed to persuade most Americans. They argue that greens need to develop more convincing arguments to get Americans to take global warming more seriously.

Predictably, Messrs Shellenberger and Nordhaus have unleashed a stream of counter-attacks that have led to a lively debate among American environmentalists. They conclude: “We in the environmental community today find ourselves head-down and knee-deep in the global warming river. It's time we got back to shore and envisioned a new path for the crossing.” Despite the arrival of Kyoto, the debate and dissent of recent weeks suggests that the treaty has not produced the world of self-confident greens and smothered critics feared by Dr Crichton. In fact, the contrary seems to be true.

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