North Atlantic Cooling

While most of the North is warming up, the Labrador Sea and the adjoining land masses of western Greenland and eastern Baffin Island are an exception - this area is cooling down. Measurements taken in the early 1990s show that the Labrador Sea is the coldest and freshest (least saline) in the 35 years since measurements began. [26]

Although this change may be a natural variation, there is evidence that this cooling is paradoxically, influenced by greenhouse gases. The most recent coupled atmosphere-ocean climate models project that increased levels of greenhouse gases will cause North Atlantic cooling. [27] This is likely driven in part by increased snow and in part by cold meltwater from the shrinking Greenland ice sheet and Arctic sea ice pack.

The Greenland Sea (and the adjacent Ice-landic and Norwegian Seas) is one of the only two places in the world where large amounts of cold salty surface water sinks into the deep ocean ( the other place is the Weddell Sea off Antarctica). [28] Computer models suggest that increased precipitation in the North Atlantic may reduce the salinity of North Atlantic water, making it more buoyant and less likely to sink into the deep ocean.

Since deep water formation in the North Atlantic is one of the major drivers of global ocean circulation, these expected changes are likely to profoundly disrupt ocean currents and ecosystems worldwide. One likely out-come, in particular, is a weakening of the Gulf Stream, and a local cooling of Ireland, the U.K., and Scandinavia. [29]

The combination of North Atlantic cooling and global warming may create erratic and unpredictable weather worldwide. In fact, there is some evidence of wildly fluctuating past climate in the North Atlantic from ice cores recently extracted from the Greenland ice sheet. [30]