Atlantic Ocean off of the U.S. East Coast Rising 3–4 Times Higher than the Global Average

A study from the National Oceanic and Atmospheric Administration warns that waters off of the U.S. East Coast may be particularly susceptible to dramatic level increases, due to the effects of global warming. This study used computer models that tracked sea level increases under a variety of carbon emission scenarios, with the goal of discovering the potential differences in the rise in sea level in the Atlantic, versus the Pacific. The outcome was dramatic, showing levels rising “~ 3–4 times higher than the global average” along a large stretch of the U.S. East Coast.

This "hotspot" is due to the faster turnover of water through the Atlantic’s currents as compared to the Pacific, where water can take 200-300 years to make a full circuit from one end of the Atlantic to the other, as compared to the 600-900 years it might take for water to get around the Pacific.

In this case, warm waters from the Caribbean Sea that would normally be circulated northeast across the Atlantic Ocean are instead pooling off of the U.S. East Coast, due to the interruption of the North Atlantic Current. As water warms it expands, causing the ocean level to be higher wherever this expansion is experienced. NASA currently uses this effect to track ocean temperatures via satellite, using radar to record regional sea level changes to determine their temperatures.

Another recent study has shown that this has already happened, when a 4-inch sea level rise was recorded in a region of ocean between New York and Newfoundland that occurred in 2009 and 2010, due to a sudden change in the North Atlantic current.

There is also a concern that the reduction of ice in Antarctica may have a compounded effect on global sea levels, but not due just to the release of water from it’s glaciers, but rather from it’s gravitational pull. With a volume of 26.5 million cubic kilometers (6,400,000 cubic miles), Antarctica’s ice sheet exerts it’s own gravitational pull, albeit a meager one compared to the rest of the Earth’s influence. This pull, however, does subtly pull the ocean in it’s direction, causing a drop in sea levels in regions further north. If the Antarctic ice sheet were to recede substantially, this pull would lessen, allowing the world’s oceans to slosh back northward, increasing their volumes in northern latitudes.