2006: Freshwater flowing into the North Atlantic could shut down the ocean conveyor belt that shuttles warm water toward Western Europe. EVERY WHICH WAY Tracking the motion of floating markers dropped into the northwest Atlantic (white-rimmed circles), researchers found that the idea of an ocean conveyor belt is overly simplistic. Investigations into Earth’s ancient climates show that the overturning circulation weakened around 12,800 years ago, probably causing cooling in Europe and sea level rise along North America’s East Coast, as piled-up water in the north sloshed southward.