Climate changes and the local environment:
For coastal communities such as New York City, global warming is a particularly pressing threat and its effects have already been experienced. Over the past century, the concentration of greenhouse gases in the atmosphere has increased, thus raising the global average temperature. With temperatures rising, sea levels rise as well. Global sea level rise can be attributed to two main factors: Arctic ice caps are melting, and oceans are warming thus expanding in volume.
Rising sea levels have left New York City vulnerable to floods and storm surges. Historically, one important line of defense for these coastal areas have been salt marshes, which are estuaries where fresh and saltwater mix. Jamaica Bay is an estuary that can be found in the highly urbanized intersection between the Brooklyn and Queens boroughs, and is particularly valuable for both the humans and the natural environment.
During the last one hundred years alone, local sea levels have risen by nearly 30cm in New York City, with the rate of sea level rise in Jamaica Bay being almost twice the mean global rate. These two graphs, taken from NOAA’s Tides and Currents website, depict historic sea level is rise in Kings Point and The Battery in New York City. This data can be used to extrapolate the changes in sea level for Jamaica Bay, due to their proximity and similar conditions to the salt marsh.
Salt marshes like Jamaica Bay provide some protection from the effects of sea level rise by slowing wave velocity, absorbing excess rainwater, and mitigating storm surges. They also protect shorelines from erosion by buffering wave action and trapping sediments. Additionally, they provide numerous other ecological benefits such as high biodiversity, improved water quality, flood reduction, and carbon sequestration.
In addition to contributing to sea level rise, warming temperatures lead to an increase in evaporation, and thus, an increased frequency in storm events. Higher sea levels and storm events work synergistically – the greater the sea level rise, the more flooding each storm will bring, as well as more wave intensity and greater erosion. With New York City seeing a 350% increase in heavy downpours since 1950, marshes like those in Jamaica Bay have become increasingly vulnerable to erosion and floods from these worsening storms.
How we know:
This information relies on data from easily two accessible online tools, including the National Oceanic and Atmospheric Administration (NOAA) Tides and Currents tool and Climate Central’s Surging Seas: Risk Finder projections. It also uses data from a Climate Central research report.
The NOAA Tides and Currents resource reports local mean sea level changes from 1850 to today. It uses data collected from U.S. and global water level stations to reconstruct local sea level trends.
Climate Central’s Surging Seas tool generates projections for sea level rise and flood risks, which are based on the different emissions scenarios presented in the NOAA Technical Reports. The tool additionally shows the floods that coastal locations have experienced, distinguishing between which floods are driven by climate-linked sea level rise and which would have occurred naturally.
Climate Central’s Heaviest Downpours research report displays the increase in heavy downpours in the United States. At each station, a heavy downpour was defined as the top 1 percent daily precipitation amounts over the period from 1950 to 2014. The analysis is based on precipitation observations from 2,962 climate stations across the US.
While salt marshes can be quite resilient to sea level rise, Jamaica Bay experiences a variety of other stressors that make it particularly vulnerable to this threat. Factors that exacerbate the already damaging effects of sea level rise include the general sediment deficit, a deepening of the Bay through dredging, waves generated by boat traffic, and excessive waterfowl grazing. While in less metropolitan areas, salt marsh loss can be compensated for by expanding the marsh onto adjacent upland or freshwater zones, Jamaica Bay shows the catastrophic repercussions of deteriorating salt marshes that have no hopes for expansion.
Salt marshes in New York are one of the primary defenses against rising sea levels for coastal areas, but have been steadily deteriorating throughout the last several centuries. In New York State, salt marshes have reduced by 60% from 1780 to 1980. Field studies conducted in Jamaica Bay show that from 1989 to 2003, the Bay’s marshes were in rapid decline losing 13.4 ha/year. From 2003 to 2013, this has declined to 2.1 ha due to restoration efforts.
While the expected rising sea levels and future storms provide significant cause for concern, particularly in the Jamaica Bay region, this estuary is also a fascinating example of resilience in the face of climate change. In 2012, Hurricane Sandy tore through the northeast, causing significant flooding and massive devastation to infrastructure and coastal lagoons in the New York City area.
During Hurricane Sandy, Jamaica Bay experienced a storm surge of 8 to 10 feet during the worst of the storm. The damage felt after the storm was significant as well, with debris from destroyed homes and buildings coming from Queens and Brooklyn ultimately ending up in the Bay. Additionally, thousands of gallons of oil coming from home fuel tanks leaked into the area, creating yet another expense in the clean up after the storm.
The massive damages that Jamaica Bay, and the New York region as a whole, experienced from Hurricane Sandy displayed how instrumental proper governance and human action are in dealing with natural emergencies. Disaster relief funds provided swift critical aid to the region; however, many of these efforts were contained to the short-term and were more of a response tactic, rather than a preventative measure.
Despite the destruction New York City faced in 2012, human efforts have caused impressive improvement in the conditions of Jamaica Bay within the last two decades. Compared to 2003 when restorations first began, there has been a marked decrease in deterioration for the Bay. This ultimately was responsible for how swiftly the area recovered after Hurricane Sandy; however, constant monitoring is necessary, as even post-restoration, salt marsh loss continues to occur in the Bay.
Considering how important Jamaica Bay has historically been for the economic, social, and ecological health of New York, it is imperative that a concerted effort be made to help inoculate this area from the threats of future climate change, as rising sea levels and stronger storms will likely increase the risks facing the region.
Five Years After Hurricane Sandy, NYC’s Coastal Communities Remain Vulnerable. Curbed New York
Jamaica Bay Walloped by Hurricane Sandy. Queens Chronicle
New York Today: A ‘Maritime Forest’ Where Sandy’s Waters Rose. New York Times
Article Author: Nicole Sheynin, Georgetown University
Article Editor: Maddie Bowen, Georgetown University