| Caption: |
Idealized diagram of the oceanic conveyor belt current. The actual system is more complex, but, in general, warm surface water (red) is transported westward and northward (increasing in salinity from evaporation) to near Greenland where it cools from contact with cold Arctic air. As the water increases in density, it sinks toward the bottom and flows south, then east to the Pacific, where upwelling occurs. The mass of sinking and upwelling waters balances, and the total flow rate is about 20 million m3 (26 million yd.3) per second. The heat released to the atmosphere from the warm water helps keep northern Europe 5° to 10°C (9° to 18°F) warmer than if the conveyor belt were not present. (Modified after Broecker, W. 1997. Will our ride into the greenhouse future be a smooth one? Geology Today 7[5]:1-7) |
