Environment: Is Europe Due For a Big Chill?

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THE GULF STREAM As the currents move warm surface water from the equator to the north, the water releases its heat into the atmosphere and cools. That heat loss makes the water saltier and very dense. By the time it reaches north of Iceland and east of Labrador, it becomes dense enough to sink

SINKING WATER In wintertime the cold, salty, dense water that originates in the Gulf Stream plunges down into the deep ocean, beginning the return of the conveyor belt. The deep current slowly flows back across the equator and into the Pacific, Indian and Southern oceans

MID-ATLANTIC CIRCULATION The addition of fresh, less salty water in the northern hemisphere essentially locks the flow of new warm water from the Tropics. That water heads east and south instead of pursuing the northward part of its normal route

>> Warm surface current >> 50% larger southward-moving mid-ocean recirculation of warm surface water

<< Deep cold current << 50% decrease in the southward transport of Lower North Atlantic Deep Water

ARRAY OF 22 MOORINGS HOW THE MEASUREMENTS WERE TAKEN In spring 2004, scientists deployed 22 moorings across a strip of the Atlantic about 25 north. Each mooring was equipped with numerous instruments that gathered all types of information, from temperature and salinity to current speed and direction

• Large buoyancy sphere • Current meter • Every two days a sensor crawls up and down 14,436 ft. of wire as it measures conductivity, temperature and depth • Current meter • Buoyancy spheres • Acoustic release • Anchor made of railway wheels

POOR CIRCULATION Recent findings suggest that the Atlantic Ocean currents that warm Northern Europe are weakening as a result of global warming and may ultimately mean frigid weather for Europe

The slowing of the Gulf Stream conveyor belt could mean that less warm water would reach the northeastern Atlantic

Sources: Nature; Professor Harry Bryden, University of Southampton; NASA; USGS