Ocean Forces Threaten Our Climate

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From the dawn of time, people have suspected powerful forces lurking deep in the oceans ‚ from the Greeks' fearsome sea-god Neptune to John Wyndham's submarine aliens in his 1950s novel The Kraken Wakes. But science is once again going one better than science fiction. Researchers are discovering that hidden 'rivers' run through the oceans, and these powerful currents hold the destiny of our planet's climate.

The beneficial aspects of ocean currents have long been known. For countries on the east side of the Atlantic, winters are a balmy holiday compared with the same latitudes on the west: the frigid coasts of Newfoundland and Labrador. It's a reminder that "weather" is not just a matter of the Sun's heat affecting the Earth's atmosphere. The world's interconnected oceans can store up solar heat in one part of the globe in one season, and invisible rivers in the ocean can transport the warmth thousands of kilometres to another part of the globe and deliver it in another season.

In the case of the North Atlantic, heat is carried northward and eastward by the Gulf Stream. This current warms the coast evenly through the year, in winter as well as summer. Averaged over a year, the Gulf Stream provides Western Europe with a third as much warmth as the Sun does.

This ocean warmth is so important to Europe that climatologists are seriously concerned about the stability of the Gulf Stream. If it switched off, Europe would be plunged into a mini-Ice Age. And current studies suggest that the unseen river in the North Atlantic is dangerously fickle.

The focus of today's worries is the problem of global warming - the way that human activities are changing the climate, as the world gets warmer through the build-up of so-called greenhouse gases, such as carbon dioxide. Climatologists think that global warming may put the brakes on the Gulf Stream. While the rest of the world comes to swelter in greenhouse conditions, Europe would freeze!

This concern is based on a new understanding of how the great ocean currents are all interconnected. The Gulf Stream is part of a giant pattern of moving water that stretches right around the globe.

The Ocean Conveyor Belt