Four years after Sandy, rising sea levels predicted
10/27/2016 Volume XLIX, No. 42
Four years ago, Superstorm Sandy flooded and destroyed structures on much of New Jersey’s coastline. Sandy was a wake-up call to a state that had gone decades without destructive storms.
As New Jersey continues to recover from Sandy, many residents wonder what the future will bring, in light of the Earth’s changing climate and rising sea levels.
Two new reports from Rutgers University offer a sobering look at sea-level rise and an update on how coastal communities are planning for a future that includes higher water in even the calmest weather conditions.
The first report, Assessing New Jersey’s Exposure to Sea-Level Rise and Coastal Storms: Report of the New Jersey Climate Adaptation Alliance Science and Technical Advisory Panel, summarizes the predictions of leading scientists.
According to the scientists, it’s likely that New Jersey’s coastal areas will experience a sea-level rise between 1.0 and 1.8 feet by 2050. Under a worst-case scenario, however, these communities could see the sea-level rise to as much as 2.8 feet by 2050.
The extent of sea-level rise after 2050 depends on whether global greenhouse gas emissions are reduced or continue to rise:
- Under a “high-emissions” scenario, in which little is done to limit carbon in the atmosphere, it’s likely that New Jersey’s coast will experience between 2.4 and 4.5 feet of sea-level rise by 2100.
- Under a “low-emissions” scenario, in which greenhouse gas levels are greatly reduced to bring global mean temperatures to pre-industrial levels, it still is likely that coastal areas of New Jersey will experience between 1.7 and 3.1 feet of sea-level rise by 2100.
Because the new “normal” ocean level will be higher in the future, the report warned, impacts of coastal storms and storm surges will be more severe than they are today.
As the report notes, global sea-level rise is caused by thermal expansion of ocean water, melting glaciers, ice caps and ice sheets, and changes in how much water the land is able to absorb.
The second Rutgers report describes how coastal communities are reacting and preparing for sea-level rise. Based on interviews with municipal officials and professionals, researchers found:
- Heightened awareness of the impacts of sea-level rise as a result of Superstorm Sandy;
- Greater support for regulatory measures such as requiring that new construction be elevated above the minimum state standard;
- A need for disaster preparation, response and recovery training; and
- A need for greater knowledge about planning for sea-level rise among local officials with decision making authority.
Sea-level has only risen about a foot in the last 100 years, yet towns like South Cape May have long been lost to the ocean. Old trolley tracks lie out beyond the breakers. If the high estimates are accurate, and sea-level rises by over four feet in the next 80 years, enormous areas will become uninhabitable to people.
Although this is bad news for New Jersey’s coastal communities, a report from the University of California at Santa Cruz offers some hope.
The report, Coastal Wetlands and Flood Damage Reduction, found that more than $625 million in property damages were prevented during Superstorm Sandy by coastal wetlands along the Northeast coast. In addition, it found that in Ocean County alone, protecting salt marshes can significantly reduce average annual flood losses by more than 20 percent.
“Our coastal habitats are natural defenses,” said Siddharth Narayan, lead author. “In this study, we show that their risk reduction services add up to hundreds of millions of dollars along the U.S. East Coast.”
Coastal wetlands and marshes help mitigate the impacts of storms and flooding, and New Jersey should be doing everything possible to protect them from development. Unfortunately, most tidal marshes will disappear with modest sea-level rise, because in most cases they are penned in by developed land and cannot retreat into low-lying forests on slightly higher lands. Eventually, people will have to retreat from the most flood prone areas, and restore those areas to natural lowland forests and salt marsh. “Marsh plain elevation” is an ecological restoration technique that may help existing salt marshes keep pace with sea-level rise, and pilot projects should be funded and expanded.
Rising sea-level poses a major threat to New Jersey’s coastline, and accurate climate data is essential to help communities plan and make informed decisions for the near term, and also plan a managed retreat from areas that will be under sea-level in the long-term.
It’s also time that New Jersey responsibly transitions to clean and renewable energy - and do its part to slow and hopefully reverse the increase in global temperatures. We need stronger leadership at all levels of government to rapidly and significantly reduce greenhouse gas emissions in order to avoid or minimize the potentially catastrophic impacts predicted to occur along New Jersey's coasts and beyond.
To read the Rutgers sea-level reports, go to http://njadapt.rutgers.edu/resources/nj-sea-level-rise-reports. To read the University of California at Santa Cruz study, go to http://news.ucsc.edu/2016/10/coastal-wetlands.html.
Also check out the Rutgers Flood Mapper, an interactive mapping tool to visualize sea-level rise and coastal flood hazards, at http://njfloodmapper.org/.
And to learn more about preserving New Jersey’s land and natural resources, visit the New Jersey Conservation Foundation website at www.njconservation.org or contact me at email@example.com.