May 2004

The forthcoming Hollywood movie, The Day After Tomorrow stars Dennis Quaid as an earnest climatologist trying to save the world from catastrophic global coolingbrought on by burning fossil fuels. The special effects are said to be spectacular, but the film is no more realistic than Planet of the Apes.

One of the movies big dramatic elements is that the meltwater from globally warmed polar ice caps has overwhelmed the Gulf Stream, so London and New York are turning into ice cubes.

The last time such a thing happened was 12,800 years ago, when the last Ice Age ended and we had an extra trillion tons of ice to melt. The Laurentide Ice Sheet then covered all of Canada, and the U.S. into Ohio. Similar ice sheets covered much of northern Europe and Asia. There was so much water tied up in ice that the ocean levels dropped 300 feet. Stone Age hunters walked to America across the Bering Sea with dry feet.

Has anybody noticed an ice sheet a mile thick over Chicago recently?  Where did Hollywood get the extra trillion tons of ice to shoot this movie?

The other problem for Mr. Quaids credibility is that the Gulf Stream isnt what keeps Britain warm. Its the Rocky Mountains.

The textbooks say the Gulf Stream is what keeps Britain from being sub-Arctic, but theyre wrong. Theyre based on nothing more substantial than a statement by a U.S. Navy lieutenant, Matthew Maury in1856.

One of the benign offices of the Gulf Stream is to convey heat from the Gulf of Mexico, where otherwise it would become excessive, and to disperse it in regions beyond the Atlantic for the amelioration of the climates of the British Isles and of all Western Europe, wrote Maury.

He wasnt wrong. He just wasnt very right.

The Gulf Stream does carry heat from the tropics to the shores of Britainin fact, 27,000 times as much heat as UKs powerplants generate. The warm current helps keep London 25 to 35 degrees F warmer than Newfoundland, which is at the same latitude.

However, new climate research shows that only about 10 percent of Britains winter warming comes from the Gulf Stream. Half of the rest comes from the Atlantic Ocean itself, which holds heat longer than the land.

The rest of the warming for Britain is delivered by west-to-east winds from the Americas Rocky Mountains.

Dr. Richard Seager, of Columbia Universitys Lamont-Doherty Earth Observatory, says, Belief in the benign role of the Gulf Stream is so widespread that it has become folklore.  But Seager and his research team used weather data from the past 50 yearsand a powerful computer model to describe how heat is shifted around the globe. They found the key to Britains climate was the warm wind from southern North America. The American wind is forced into a giant meander as it flows southeast around the Rocky Mountains.

This vast kink in the atmosphere circulation helps to explain the winter temperature contrast across the North Atlantic, says Seager. Winds, going to eastern North America, flow north around the Rockies and carry cold air to New York. The southern air flow moves over the American southwest and on to Europe. When the scientists flattened the U.S. topography by removing the Rockies from their computer models, British winter temperatures fell radicallyand the summer temperatures became suffocatingly hot.

The other big problem for the Quaid movie is that even major, abrupt climate change isnt very dramatic by Hollywood standards.

Icelanders colonized their island about 850 AD, and lived through the Medieval Warming (9001300 AD), which had the highest temperatures the earth has seen in 5,000 years. Then they suffered through the chillingly colder winters of the Little Ice Age (13001850 AD) with their winds and storms coming straight from the Polar Ice Cap.

As of 1917, after 1500 years of constant major climate changes, the Icelanders argued they hadnt seen any! They thought theyd just had periodic bad weather. But theres so much bad weather in the good (warmer) phases of the climate cycle that it takes a century of weather data to reliably spot a bad trend. The Icelanders didnt have thermometersor movies.

DENNIS T. AVERY is a senior fellow for Hudson Institute in Indianapolis and the Director for Global Food Issues (www.cgfi.org).  He was formerly a senior analyst for the U.S. Department of State. 

Readers may write him at Post Office Box 202, Churchville, VA 24421