Global sea level and the Earth's climate are closely linked. The Earth's climate has warmed about 1.8°F during the last 100 years. The two major causes of global sea level rise are thermal expansion of the oceans (water expands as it warms) and the loss of land-based ice due to increased melting. Along the Mid-Atlantic Coast, coastal lands are subsiding further exacerbating sea level rise. In addition, oceanographic effects due to shifting of the Gulf Stream will potentially affect sea level in this region.
Global sea level is projected to rise during the 21st century at a greater rate than during 1961 to 2003. Thermal expansion is currently contributing about half of the average rise, but land ice will lose mass increasingly rapidly as the century progresses. It is uncertain how much of the current land ice located in the Antarctic and Greenland ice sheets may melt. Other factors include changes in ocean dynamics, glacial isostatic adjustment and sediment compaction.