Atlantic yields climate secrets

Scientists have painted the first detailed picture of Atlantic ocean currents crucial to Europe's climate.

Using instruments strung out across the Atlantic, a UK-led team shows that its circulation varies significantly over the course of a year.

Writing in the journal Science, they say it may now be possible to detect changes related to global warming.

The Atlantic circulation brings warm water to Europe, keeping the continent 4-6C warmer than it would be otherwise.

As the water reaches the cold Arctic, it sinks, returning southwards deeper in the ocean.

Some computer models of climate change predict this Atlantic Meridional Overturning Circulation, of which the Gulf Stream is the best-known component, could weaken severely or even stop completely as global temperatures rise, a scenario taken to extremes in the Hollywood movie The Day After Tomorrow.

Last year the same UK-led team published evidence that the circulation may have weakened by about 30% over half a century.

But that was based on historical records from just five sampling expeditions, raising concerns that the data was not robust enough to provide a clear-cut conclusion.
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