"An Inconvenient Truth" About Al Gore's Movie

John Tierney is fast becoming one of my favorite journalists. He's the op-ed columnist for the NY Times who represents the non-ideological pragmatist point of view. He also periodically writes a sort of "myth-buster" column called "Findings" in the "Science Times" supplement each Tuesday.

Today he takes on "An Inconvenient Truth," Al Gore's movie and book about global warming. The hook for the piece was the fact that Al Gore was sitting beside Virgin Airlines founder Richard Branson when Branson announced that he is offering a $25 million dollar prize to anyone who can figure out how to remove a couple billion tons of CO2 from the atmosphere each year. Tierney uses the prize idea as bookends between which he contrasts the hysteria of Gore's "An Inconvenient Truth" with the reality of the recently released findings of the Intergovernmental Panel On Climate Change. Here is one example:

Whatever happens, you can stop fretting about the Gulf Stream scenario in Mr. Gore’s movie and that full-fledged Hollywood disaster film "The Day After Tomorrow." Mr. Gore’s companion book has a fold-out diagram of the Gulf Stream and warns that "some scientists are now seriously worried" about it shutting down and sending Europe into an ice age, but he must have been talking to the wrong scientists.

There wouldn’t be glaciers in the English shires even if the Gulf Stream did shut down. To understand why, you need to disregard not only the horror movies but also what you learned in grade school: that the Gulf Stream is responsible for keeping London so much warmer than New York even though England is farther north than Newfoundland.

This theory, originated by a 19th-century oceanographer, is “the earth-science equivalent of an urban legend,” in the words of Richard Seager, a climate modeler at the Lamont-Doherty Earth Observatory of Columbia University. He and other researchers have calculated that the Gulf Stream’s influence typically raises land temperatures in the north by only five degrees Fahrenheit, hardly enough to explain England’s mild winters, much less its lack of glaciers.

Moreover, as the Gulf Stream meanders northward, it delivers just about as much heat to the eastern United States and Canada as to Europe, so it can’t account for the difference between New York and London. Dr. Seager gives the credit to the prevailing westerly winds — and the Rocky Mountains.

When these winds out of the west hit the Rockies, they’re diverted south, bringing air from the Arctic down on New York (as in last week’s cold spell). After their southern detour, the westerlies swing back north, carrying subtropical heat toward London. This Rocky Mountain detour accounts for about half the difference between New York and London weather, according to Dr. Seager.

The other half is caused by to the simple fact that London sits on the east side of an ocean — just like Seattle, which has a much milder climate than Siberia, the parallel land across the Pacific. Since ocean water doesn’t cool as quickly as land in winter, or heat up as much in summer, the westerly winds blowing over the ocean moderate the winter and summer temperatures in both Seattle and London.

So unless the westerlies reverse direction or the Rockies crumble, London and the rest of Western Europe will remain relatively mild.

Tierney is not a global warming denier. He accepts, or at least appears to accept, the findings of the IPCC. But what I find refreshing is that he recognizes the realities as well:

The I.P.C.C. considers options for reducing greenhouse emissions, but projects that even the most radical (and politically painful) policies wouldn’t make much difference the first two or three decades. To politicians worried about the next election, especially in poor countries, 2030 sounds like eternity.

It’s always possible that something will galvanize people around the world into taking short-term pain for long-term gain. But I suspect there’s a better chance of someone claiming that $25 million prize. Whether it’s carbon-dioxide-gobbling nanobots or something else, it’d be good to have a backup plan when 2030 rolls around.