Chill in this warm new year

Conservative politicians and a few scientists, many with ties to energy companies, have variously countered that human-driven warming is inconsequential, unproved or a manufactured crisis. A third stance is now emerging, espoused by many experts who challenge both poles of the debate.

They agree that accumulating carbon dioxide and other heat-trapping smokestack and tailpipe gases probably pose a momentous environmental challenge, but say the appropriate response is more akin to buying fire insurance and installing sprinklers and new wiring in an old, irreplaceable house (the home planet) than to fighting a fire already raging.

“Climate change presents a very real risk,” said Carl Wunsch, a climate and oceans expert at the Massachusetts Institute of Technology. “It seems worth a very large premium to insure ourselves against the most catastrophic scenarios. Denying the risk seems utterly stupid. Claiming we can calculate the probabilities with any degree of skill seems equally stupid.”

Many in this camp seek a policy of reducing vulnerability to all climate extremes while building public support for a sustained shift to nonpolluting energy sources. They have made their voices heard in Web logs, news media interviews and at least one statement from a large scientific group, the World Meteorological Organisation.

In early December, that group posted a statement written by a committee consisting of most climatologists assessing whether warming seas have affected hurricanes. While each degree of warming of tropical oceans is likely to intensify such storms a percentage point or two in the future, they said, there is no firm evidence of a heat-triggered strengthening in storms in recent years. The experts added that the recent increase in the impact of storms was because of more people getting in harm’s way, not stronger storms.

There are enough experts holding such views that Roger A. Pielke Jr., a political scientist and blogger at the University of Colorado, Boulder, came up with a name for them (and himself): “nonskeptical heretics”. “A lot of people have independently come to the same sort of conclusion,” Pielke said.

This approach was most publicly laid out in an opinion article on the BBC website in November by Mike Hulme, the director of the Tyndall Center for Climate Change Research in Britain. Hulme said that shrill voices crying doom could paralyse instead of inspire. “I have found myself increasingly chastised by climate change campaigners when my public statements and lectures on climate change have not satisfied their thirst for environmental drama,” he wrote. “I believe climate change is real, must be faced and action taken. But the discourse of catastrophe is in danger of tipping society onto a negative, depressive and reactionary trajectory.”

Other experts say there is no time for nuance, given the general lack of public response to the threat posed particularly by carbon dioxide, a byproduct of burning fossil fuels and forests that persists for a century or more in the air and is accumulating rapidly in the atmosphere and changing the pH of the oceans.

James E. Hansen, the veteran climate scientist with the National Aeronautics and Space Administration who has spoken out about climate dangers since 1988, has recently said that scientists have been too quiet too long. “If we want to avoid producing a different planet, we need to start acting now,” and not with paltry steps, he said in a recent e-mail exchange with a reporter and other scientists.

In three previous reports, the last published in 2001, this global network of scientists operating under the auspices of the United Nations has presented an ever-firmer picture of a growing human role in warming. Studies used to generate the next report have shown a likely warming in the 21st century—unless emissions of greenhouse gases abate—at least several times that of the last century’s one-degree rise.

But substantial uncertainty still clouds projections of important impacts, like how high and quickly seas would rise as ice sheets thawed.

Recent drafts of the climate report used a conservative analysis that does not project a rise most people would equate with catastrophe, scientists involved in writing it say. Other experts say this may send too comforting a message.

–ANDREW C. REVKIN