A Study In 's'

Pulse

oi-Staff

By Staff

Tuesday, July 21, 2009, 13:44

A new research, based on the longest experiment of its type, has determined that the ocean current shut down may take place more slowly and gradually than previously suggested.

The research,which run on a 'general circulation model' that simulated the Earth's climate for 21,000 years back to the height of the last Ice Age, shows that major changes in these important s can occur, but they may take place more slowly and gradually.

The newest findings, however, are consistent with other recent studies that are moving away from the theory of an abrupt 'tipping point' that might cause dramatic atmospheric temperature and ocean circulation changes in as little as 50 years. "Research is now indicating that this phenomenon may happen, but probably not as a sudden threshold we're crossing," said Peter Clark, a professor of geosciences at Oregon State University. He adds: "For those who have been concerned about extremely abrupt changes in these ocean current patterns, that's good news," he added.

Over the last few years, there has been an immense effort to understand the same, but looking back at it, Clard says, "In the past, it appears the ocean did change abruptly, but only because of a sudden change in the forcing". "But," he explains, " When the ocean is forced gradually, such as we anticipate for the future, its response is gradual. That would give ecosystems more time to adjust to new conditions."

A particular concern for some time has been the operation of an ocean current pattern called the Atlantic meridional overturning circulation, or A.M.O.C. This current system is part of what keeps Europe much warmer than it would otherwise be, given its far northern latitudes, and there is evidence that it has 'shut down' with some regularity in Earth's past - apparently in response to large influxes of fresh water, and sometimes quite rapidly.

Clark, however, opines that the climate change is inevitable and prominent, and the same has been witnessed by millions, but to say that the world will come down in decades is, he says, a wrong assumption. He corroborates: "Our data still show that current is slowing, and may decline by 30 percent by the end of this century," Clark said. He concludes by saying, "That's very significant, and it could cause substantial climate change. But it's not as abrupt as some concerns that it could shut down within a few decades."

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