Results from a Geophysical Fluid Dynamics Laboratory (GFDL) Coupled Climate ModelThese maps show variations in surface air temperature around the North Atlantic resulting from changes in the strength of the thermohaline circulation. From year 0 to year 99, an external source of freshwater is added to the North Atlantic between 50°N and 70°N at a rate of 0.1 Sverdrup (1 Sv = 106 m3/s). The addition of freshwater weakens the thermohaline circulation and cools the region south of Greenland.
After year 100, freshwater is no longer added to the North Atlantic. Ocean convection resumes within decades and temperatures warms rapidly southeast of Greenland and in Western Europe (color changes from green to yellow). Compare year 99 to year 199, for example, to see the contrast between periods of weakened and normal thermohaline circulation. In this view of average temperature (rather than temperature change) the differences between years appear small compared to the large temperature gradient than exists between low and high latitudes. Help on using this page