3rd stance in climate debate

Amid the shouting lately about whether global warming is a human-caused catastrophe or a hoax, some usually staid climate scientists in the usually invisible middle are speaking up.

The discourse over the issue has been feverish since Hurricane Katrina. Seizing the moment, many environmental campaigners, former Vice President Al Gore and some scientists have portrayed the growing human influence on the climate as an unfolding disaster that is already measurably strengthening hurricanes, spreading diseases and amplifying recent droughts and deluges.

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 Organization. In early December, that group posted a statement written by a committee consisting of most of the 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."