Sea Level Rise — and its Acceleration — is Worse than we Thought

A new study published in the journal Nature has illustrated that the global rise in sea levels is worse than originally anticipated, and the rate of increase is accelerating. Between 1993 and 2014, the rate of increase jumped by 50 percent, with the average rise in 1993 being 2.2 millimeters (0.87 inches), and 2014 showing a rise of 3.3 millimeters (0.13 inches). This study follows an earlier paper that found that sea level increases are now nearly triple that of their pre-1990 levels.

This acceleration is due to the increase in melting observed from the Greenland ice sheet: in 1993, Greenland’s contribution only accounted for five percent of sea level increases, but by 2014 this amounted to one-quarter. Global ice sheet contributions have also risen from 50 percent to 70 percent in the same time frame.

The ocean off of the U.S. East Coast is also expected to be hit much harder than the global average, especially off of the North Carolina and Virginian coasts, as increases there are already three times more than the global average. A significant portion of sea level rise is simply due to the water expanding as it stores more heat; as fresh meltwater from Greenland slows the North Atlantic Current, warm Caribbean water that would ordinarily flow northeast to northern Europe pools up off of the east coast, causing the waters in the region to expand from the trapped heat.