Whatever happened to global warming?

NOTE: This column is available through the New York Times Syndicate. For permission to reprint it, please contact pearsmh@nytimes.com or call 800-535-4425.

SUPPOSE the climate landscape in recent weeks looked something like this:

Half the country was experiencing its mildest winter in years, with no sign of snow in many Northern states. Most of the Great Lakes were entirely ice-free. Last December 25^th, not a single Canadian province had woken to a white Christmas. There was a new scientific study discussing a mysterious surge in global temperatures -- a warming trend more intense than computer models had predicted. Other scientists were admitting that, because of a bug in satellite sensors, they had been vastly overestimating the extent of Arctic sea ice.

If all that were happening on the climate-change front right about now, do you think you'd be hearing about it on the nightly news? Seeing it on Page 1 of your daily paper? Would politicians be exclaiming that global warming was even more of a crisis than they'd thought? Would environmentalists be skewering global-warming "deniers" for clinging to their skepticism despite the growing case against it?

Without a doubt.

But it isn't such hints of a planetary warming trend that have been piling up in profusion lately. Quite the opposite.

Snow falls on New Orleans's St. Charles Avenue streetcar in December

The United States has shivered through an unusually severe winter, with snow falling in such unlikely destinations as New Orleans, Las Vegas, Alabama, and Georgia. On December 25^th, every Canadian province woke up to a white Christmas, something that hadn't happened in 37 years. Earlier this year, Europe was gripped by such a killing cold wave that trains were shut down in the French Riviera and chimpanzees in the Rome Zoo had to be plied with hot tea to keep them warm. Last week, satellite data showed three of the Great Lakes -- Erie, Superior, and Huron -- almost completely frozen over. In Washington, DC, what was supposed to be a massive rally against global warming was upstaged by the heaviest snowfall of the season, which all but shut down the capital.

Meanwhile, the National Snow and Ice Data Center has acknowledged that due to a satellite sensor malfunction, it had been underestimating the extent of Arctic sea ice to the tune of 193,000 square miles -- an area the size of Spain. In a new study, University of Wisconsin researchers Kyle Swanson and Anastasios Tsonis conclude that global warming could be going into a decades-long remission. The current global cooling "is nothing like anything we've seen since 1950," Swanson told Discovery News. Yes, global cooling: 2008 was the coolest year of the past decade -- average global temperatures have not exceeded the record high measured in 1998, notwithstanding the carbon-dioxide human beings continue to pump into the atmosphere.

None of this proves conclusively that a period of planetary cooling is irrevocably underway, or that anthropogenic CO₂ emissions are not the main driver of global temperatures, or that concerns about a hotter world are overblown. Individual weather episodes, it always bears repeating, are not the same as broad climate trends.

But considering how much attention would have been lavished on a comparable run of hot weather or on a warming trend that was plainly accelerating, shouldn't the recent cold phenomena and the absence of any global warming during the past 10 years be getting a little more notice? Isn't it possible that the most apocalyptic voices of global-warming alarmism might not be the only ones worth listening to?

There is no shame in conceding that science still has a long way to go before it fully understands the immense complexity of the Earth's ever-changing climate(s). It would be shameful not to concede it. The climate models on which so much global-warming doomsaying rests "do not begin to describe the real world that we live in," says Freeman Dyson, the eminent physicist and futurist. "The real world is muddy and messy and full of things that we do not yet understand."

But for many people, the science of climate change is not nearly as compelling as the religion of climate change. When Al Gore insisted yet again at a conference last Thursday that there can be no debate about global warming, he was speaking not with the authority of a man of science, but with the closed-minded dogmatism of a religious zealot. Dogma and zealotry have their virtues, no doubt. But if we want to understand where global warming has gone, those aren't the tools we're going to need.

(Jeff Jacoby is a columnist for The Boston Globe.)

Related Topics: Global Warming receive the latest by email: subscribe to jeff jacoby's free mailing list