Hurricane Sandy and Sea Level Rise
In New Jersey, Hurricane Sandy caused 34 deaths, destroyed over 30,000 homes and businesses, and caused a total of $36.9 billion in damages. But a storm the same strength as Sandy would likely have caused much less damage one hundred years ago. Why? Because sea levels have risen nearly a foot since then. As noted in the 2015 New York City Panel on Climate Change Report:
…the ∼12 inches of sea level rise in New York City since 1900 may have expanded Hurricane Sandy’s flood area by approximately 25 square miles, flooding the homes of more than 80,000 additional people in New York and New Jersey alone.
According to the Rutgers Institute of Marine and Coastal Science:
Sea level is rising faster at the New Jersey shore than the global average because of land subsidence (sinking)… In the 20th century, sea level rose by 12 inches at bedrock locations (Bayonne, Trenton, and Camden). Along the Jersey shore from Sandy Hook to Cape May, it rose an additional four inches due to compaction of sediments caused by natural effects and groundwater withdrawal. There is a 95% probability that the 20th century rate of sea-level rise along the New Jersey shore was faster than it was in any century in the last 4,000 years.
This chart shows the combined impact that sea level rise and sinking land have had on the New Jersey coastline:
FRONTLINE: Business of Disaster: FRONTLINE investigates who profits when disaster strikes in this post-Sandy documentary.
Sea Bright and South River
The borough of Sea Bright, which is featured in the “Rebuild or Retreat?” video series, was devastated by Hurricane Sandy. While the borough is still recovering five years later, the future remains uncertain as sea levels continue to rise and chronic inundation (that is, when at least 10 percent of usable land area is flooded 26 times or more per year) becomes an ever present issue.
Understanding Chronic Inundation Outlooks
Low Scenario : A scenario that assumes carbon emissions decline steeply and warming is limited to less than 2 degrees Celsius—in line with the primary goal of the Paris Climate Agreement. Sea level rise is driven primarily by ocean warming with very little ice loss.
Intermediate Scenario : This scenario projects carbon emissions peaking around mid-century and about 4 feet of sea level rise globally, with ice melting at a moderate rate that increases over time.
High Scenario : A scenario in which emissions rise through the end of the century and ice sheets melt faster to yield about 6.5 feet of sea level rise.
Predictions for Chronic Inundation in Sea Bright
In the Low Scenario, 27% of Sea Bright’s useable land will experience chronic inundation by 2060. That number goes up to 49% by 2100. In the Intermediate Scenario, 21% of Sea Bright will experience chronic inundation by 2035. That percentage goes up to 43% by 2060. In the High Scenario, 25% of Sea Bright will experience chronic flooding by 2030, 42% by 2060, and a staggering 91% by 2100.
Even in the Low Scenario, nearly half of Sea Bright will experience flooding on average twice a month by 2100. The outlook is even worse when looking at the Intermediate Scenario which forecasts 43% by as soon as 2060, less than 50 years from now.
What About the Seawall?
Sea Bright has a sea wall which acts as a line of defense against storm surge. The sea wall, which dates back to the 1870’s and stretches to the neighboring town of Monmouth Beach is 18 feet high, with the top 6 to 8 feet above ground. While sea walls, like Sea Bright’s, can be effective against the impact of storm surge, they are not effective at defending against chronic inundation. Most of this frequent flooding is caused by the bays and rivers in New Jersey. This is true for Sea Bright, which experiences most of it’s flooding from the Navesink River side.
Future Sea Level Rise in NJ
Sea Level Rise Projections
As sea levels rise, damage from storms will increase. Sandy had a storm tide (sum of surge and tide) of 13.9 ft in NYC and 8.9 ft in Atlantic City. Sandy was added onto the 12-16 inch 20th century sea level rise, causing it to flood an area 27 square miles greater than it would have in 1880, increasing the number of people living on land lower than the storm tide by about 38,000 in New Jersey. A sea-level rise of 1.5 ft would cause the 1-in-10 year flood in Atlantic City (the flood level that has a 1-in-10 chance of happening in any given year) to exceed the highest flood level experienced over the last century. (Source)
Resources for Residents
NJ Flood Mapper: This interactive mapping tool allows users to zoom into their communities to view projected potential flooding given various levels of future sea level rise.
Getting to Resilience: A Community Planning Evaluation Tool: “This online self-assessment process is a tool to assist communities to reduce vulnerability and increase preparedness by linking planning, mitigation, and adaptation. Through this assessment you will find out how your preparedness can be worth valuable points through FEMA’s Community Rating System and Sustainable Jersey.”
New Jersey Climate Adaptation Alliance: This group focuses on “climate change preparedness in key impacted sectors (public health; watersheds, rivers and coastal communities; built infrastructure; agriculture; and natural resources)”
Go Deeper: “Climate Change and the Jersey Shore: Impacts on Coastal Communities, Ecosystems and Economies” is a 25 minute documentary developed by Rutgers University and produced by the New Jersey Climate Adaptation Alliance.