20 January 2004

Shivering Gore

Some pundits (using the term loosely) have drawn a certain joy from Al Gore speaking about global warming on one of the coldest New York days on record. If you assume that global warming means a uniform temperature across across the whole planet then Gore looks a fool. But if that assumption is wrong then the pundits are merely showing their own ignorance.

The assumption is wrong, according to the Ocean & Climate Change Institute - Abrupt Climate Change

Here is a simplified description of some basic ocean-atmosphere dynamics that regulate Earth's climate:

The equatorial sun warms the ocean surface and enhances evaporation in the tropics. This leaves the tropical ocean saltier. The Gulf Stream, a limb of the Ocean Conveyor, carries an enormous volume of heat-laden, salty water up the East Coast of the United States, and then northeast toward Europe.

This oceanic heat pump is an important mechanism for reducing equator-to-pole temperature differences. It moderates Earth's climate, particularly in the North Atlantic region. Conveyor circulation increases the northward transport of warmer waters in the Gulf Stream by about 50 percent. At colder northern latitudes, the ocean releases this heat to the atmosphere - especially in winter when the atmosphere is colder than the ocean and ocean-atmosphere temperature gradients increase. The Conveyor warms North Atlantic regions by as much as 5 degrees Celsius and significantly tempers average winter temperatures.

But records of past climates - from a variety of sources such as deep-sea sediments and ice-sheet cores - show that the Conveyor has slowed and shut down several times in the past. This shutdown curtailed heat delivery to the North Atlantic and caused substantial cooling throughout the region. One earth scientist has called the Conveyor 'the Achilles' heel of our climate system.'

It's often best to do a little research before you laugh too loud.

Link via City Comforts

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