Abstract

Sea levels are rising at an accelerating rate, and the scientific community is confident that global warming is the most important cause. Higher sea levels translate to more and higher coastal floods. Using local sea level projections based on National Climate Assessment scenarios, this analysis finds a 3-in-4 chance of historically unprecedented coastal flooding in the northern New Jersey/New York Harbor area by 2100, assuming sea level rises on the fast end of the spectrum; or a 1-in-10 chance under a slow rise scenario as might be expected under reduced carbon emissions. We find that sea level rise from warming has already increased the likelihood of extreme flooding in the area – flooding high enough to seriously threaten the PATH transit system – by 50%.

285 square miles of land lie less than 5 feet above the high tide line in New Jersey. This land is home for 295,000 residents, 23% of whom live in just 3 zip codes. $114 billion in property value sits on the same land, as do some 2,100 miles of road, 1,600 EPA-listed sites, and 45 public schools. These numbers nearly double when assessed at 9 feet above the high tide line – Sandy’s peak flood elevation as measured at the Battery in New York City, and most likely close to the peak flood height at Sandy Hook, NJ, as well.

In the coastal and low-lying counties of New Jersey, the most socially vulnerable populations are twice as likely than the population as a whole to be flooded at either level.