Global mean sea level has been generally rising since the end of the last ice age. In the 18th and 19th centuries the rise was small, but during the 20th century the seas rose faster, primarily because ocean waters have warmed and expanded, and larger volumes of meltwater from mountain glaciers are now reaching the sea.
Conservative projections expect the seas will rise by 7 to 23 inches by 2100, but do not account for rapid melt of land-based ice. The latest studies take into account rapid ice melt, which we are already observing, to project a rise in global mean sea level of three feet or more.
Rising sea levels pose serious threats to coastal communities and natural resources, both worldwide and in New York. To ensure the future usability and security of facilities, transportation and critical resources (such as drinking water), government officials and private sector planners need the best available sea level rise projections.
How Sea Level Rise Will Impact New York
Well over half of New Yorkers live in marine coastal counties. Already, many communities and natural resources along the ocean coast and tidal portions of the Hudson River are at risk to damaging storms. This risk affects not only built resources, but also critical ecosystem services such as flood buffers, drinking water protection and species habitat.
According to the 2007 Northeast Climate Impacts Assessment by the Union of Concerned Scientists, as seas rise
- The risk of severe flooding and storm damage will increase
- Beaches and bluffs will suffer increased erosion
- Low-lying areas will be inundated, with potential for saltwater to infiltrate into surface waters and aquifers
- Sewage and septic systems, transportation and water treatment infrastructure will be at risk from flooding and erosion.