Gulf Stream Instability

When I sailed my 30' sailboat to Bermuda in 2002 I contracted with Jennifer Clarke, The Gulfstream Lady, to plot my course across this massive north flowing current. She tracks the warm and cold eddies that spin off the stream and can bring a boat to a standstill. It was well worth the price as we made the trip in under 7 days, pretty good for such a slow small boat as mine. I have heard that even she, one of the worlds foremost authorities on the gulfstream, is finding it increasingly difficult to accurately predict the flow.

3 years ago, before we left Bermuda the first time, I was lucky enough to meet Neal Peterson. Author of Journey of a Hope Merchant, an excellent read by the way, he told me that he had been crossing the gulf stream for years from his home in South Carolina. He used to be able to reliably find the well defined edge of the stream in the roughly the same place but no more. Now he never knows where he will find it.

Now that I am back in Bermuda I'm told by locals that they are noticing a definite cooling trend. This is consistent with the 30% reduction in flow of the warm gulfstream waters that influence the climate which I posted on back on April 20th 2008 here on this blog.

Read more about this over on Celsias. Here's an excerpt from the post by Jeanne Roberts,

"The mechanism of abrupt climate change is, according to climate scientists, a failure of an ocean current called "The Great Conveyor Belt" (also known as thermohaline circulation). This ocean current is in trouble as freshwater glaciers and ice sheets melt. Excess freshwater entering the saltwater ocean interrupts how the current operate, threatening to stop its circulation.

If the current stops bringing warm, equatorial air northward via the Gulf Stream, it would lead to increasing cold in Northern Europe and the Atlantic Coast of the United States.

For example, Europe and Alaska are at the same latitude, but Europe is warmer because of this thermohaline circulation, which is the result of differences in water temperatures and salinity between the North Atlantic and the Pacific. When the Great Conveyor Belt circulates in the ocean, warmer equatorial waters raise the temperature of the Atlantic Ocean, most notably between Europe and the Atlantic coastline off New York. Winds circulating around and over this warmer sea area bring warmer temperatures to adjacent landmasses in Europe and America.

If thermohaline circulation were to fail as some anticipate, currently temperate areas of the globe would become close to uninhabitable, and food production in those areas would fail almost entirely. According to one source, the Gulf Stream has already slowed by six million tonnes of water per second over the past three decades, and computer modeling projections suggest that another global temperature rise of as little as 3 degrees Celsius creates a 50-percent risk of the current collapsing altogether."

Thanks to the BBC via the celsias post for the image.