HOW HIGH WILL SEA LEVEL RISE?
Projecting the magnitude and rate of sea level rise in the coming decades is a challenging task. Much depends on future greenhouse gas emissions and subsequent global warming. Scientists are also intensively studying Greenland and Antarctica to better understand the dynamics of melting ice sheets and the possibility that they are approaching the point of irreversible, catastrophic meltdown.

To account for this uncertainty, scientists project future sea level rise as a range of probabilities (see figure 1, above). For example, according to a 2019 report from Rutgers University, it is likely – meaning at least a 66% chance – that New Jersey will experience sea level rise of 0.5 to 1.1 feet between 2000 and 2030, and 0.9 to 2.1 feet between 2000 and 2050.

Looking farther into the future, the rate of sea level rise will depend upon how successful the world is at curtailing greenhouse gas emissions. If we meet the goals of the Paris Agreement, which aims to hold global warming to no more than 2°C above early industrial temperatures, New Jersey is likely to experience sea level rise of 1.3 to 2.7 feet by 2070, and up to 4 feet by 2100. In a scenario where there are few to limited actions to reduce fossil fuel emissions, New Jersey is likely to see sea level rise of 1.5 to 3.5 feet by 2070, and 2.3 to 6.3 feet by 2100.

HOW IS SEA LEVEL RISE AFFECTING NEW JERSEY?
While it’s impossible to pin down the exact level of future sea level rise, there’s no doubt it’s already having serious consequences along the coast. Of these, flooding is perhaps the most obvious and impactful.

In some cases, coastal flooding is the result of storm tide, which is the total observed seawater level during a storm, resulting from the combination of storm surge and the astronomical tide. Because of sea level rise, storm tides start at a higher baseline and push seawater farther inland. Hurricanes Sandy and Irene are all-too-vivid illustrations of just how destructive and potentially deadly storm tides can be.

High-tide flooding – sometimes called sunny-day or nuisance flooding – has become a bigger problem, too. The number of high-tide flooding days in Atlantic City, for instance, has increased since the mid-20th century, from an average of less than one per year in the 1950s to an average of 8 per year in the 2000s. While generally less dangerous than storm tides, high-tide flooding is still damaging and costly.

In addition to flooding, sea level rise degrades coastal ecosystems. The inland advance of seawater has transformed once thriving woodlands into “ghost forests” of leafless branches and fallen trees and can threaten water supplies just inland of this transition zone. Marshes – a vital marine nursery and natural buffer against flooding – are being drowned by rising waters and are often unable to “retreat” inland because of existing development. Coastal farmland exposed to salt water is less productive. And shoreline erosion scours beaches, one of the Garden State’s most lucrative tourist attractions.