Atlantic current slowing
The Gulf Stream, the Atlantic Ocean current that transports warm, salty water from the tropics to Western Europe and America’s East Coast like a giant conveyor belt, is circulating at its slowest rate in 1,600 years. The likely culprit: climate change. A team of scientists analyzed sediment samples and fossil records from the ocean floor to determine how deep currents and ocean temperatures have changed over time. A separate group of researchers directly measured ocean temperatures dating back to the late 19th century. Both teams found that the Gulf Stream, or Atlantic Meridional Overturning Circulation (AMOC), has weakened by 15 to 20 percent over the last 150 years. Normally, AMOC releases heat into the atmosphere and warms Western Europe as it moves north. Once in the North Atlantic, the water cools, sinks, and circulates back south. This powerful current is gradually ebbing as melting glaciers reduce the salinity and density of the water, reports TheGuardian.com. If global warming continues to escalate, the disruption of the current could reach “a tipping point,” says study co-author Stefan Rahmstorf, a climate scientist. “This is uncharted territory,” he warns. A collapse of the Gulf Stream could result in rapid sea-level rise on the U.S. East Coast and extreme winters in Europe, and may have a major impact on fisheries and ocean ecosystems.