Metro East Coast

-- An overview prepared by Janine Bloomfield, Ph.D. (Environmental Defense) --
 

Climate and changes in it – regardless of their cause – matter to people, communities and businesses. Global warming is likely to bring many changes to the nation. The United States as a whole is in a strong economic position to adapt to many of these changes, but adaptation is often expensive, not always possible or successful, and during transitions ecosystems, communities, and individuals could suffer. Moreover, national impact summaries disguise local dislocations and disruptions to the ways we live, work and recreate. Climate change adds a serious stress to our already threatened resources and treasured places. Overall impact statements also mask significant opportunities. To minimize the negative changes and make the most of the positive changes we need to take a close look at how climate change will affect each region. How will the Metro East Coast region experience the effects of global warming? And how can we respond?

Summary
The Metro East Coast Region is highly vulnerable to global warming and resulting increases in sea level. New York City has close to 600 miles of coastline. Four out of the five New York City boroughs are situated on islands, linked together and to the mainland by about 80 of the approximately 2200 bridges and tunnels in the City.  Entry points to many of the tunnels and much of New York City’s subway system lie less than or near to ten feet above sea level as do the three major airports serving the New York City metropolitan area. Potential impacts of climate change and sea-level rise include widespread coastal and inland flooding, dangerously hot summers, increased threats from mosquito-borne diseases, stressed water supplies and loss of beaches.  Potential benefits from global warming could include lower risk of disease and mortality due to extreme cold during the winter. 

Climate Projections for Metro East 

The National Assessment synthesis as well as the more detailed Metro East Coast regional assessment uses a series of climate change and sea-level rise scenarios derived from global climate models and historical records to project the potential impacts of climate change.  The material summarized here is based on initial findings from the regional assessment as well as the National Assessment synthesis.  While considerable uncertainties remain, especially when applying these computer simulations to a small region, the trends are indicative of the risks the Metro East Coast Region may face as climate change continues.  Models examined in the study project that temperatures in the Metro East Coast Region will rise by about 1-4 °F compared to today by the year 2030 and 5-10 ° F by the year 2100.  Sea level regionally is expected to rise 3/4 to 3 1/2 feet by the year 2100.  Warming may already be occurring in this region.  Both maximum and minimum temperatures have increased about 4°F since 1880 according to historical weather data at Central Park in New York City.  While some of this may be due to the "urban heat-island" effect in which temperatures tend to increase with urbanization, surrounding rural communities show similar amounts of warming.

Key Findings
 

Global warming adds a significant stress to the Metro East Coast region which is already experiencing intense development and population pressures. Among the issues highlighted in the National Assessment and dealt with in more detail in the forthcoming Regional Assessment, three key issues are discussed in this overview: weather-related stresses on human health; sea-level rise and related threats to coastal areas and; water supply and quality stresses.

Human Health: Heat and Ozone
The health of Metro East Coast residents is vulnerable to extremes of climate. Higher temperatures could lead to increases in heat-related mortality and health risks due to air pollution. The elderly, children and those already plagued with respiratory problems are most at risk.

In the Metro East Coast region, heat-related mortality increases significantly on days when the temperature tops 90 °F. Some climate models project that the number of days per year that surpass that temperature threshold could increase from an historical average of 13 days to between 38 and 80 days by the year 2100. That is, in the future, New York may have as many 90-degree-plus days as Miami has today in the best case (double New York’s current levels) or almost as much as Houston in the worst-case scenario (more than six times New York’s current levels). Even if temperatures increase no faster than they already have over the last hundred years, the average number of days over 90 degrees would be 27 by the year 2100.  Meanwhile, the Metro East Coasts’ elderly population, one of the groups most threatened by increased temperatures, is expected to grow substantially between now and the year 2010. On the other hand, warmer winters could decrease mortality due to extreme cold as the number of days below freezing drops by more than half in the warmest projections. 

Much of the New York Metropolitan Region is listed in the “severe” category for non-attainment of EPA’s National Ambient Air Quality Standards for ozone, the primary constituent of urban smog.  Warming may exacerbate air pollution because higher temperatures increase ozone production. Ground-level ozone in high concentrations causes eye and nose irritation, coughing, and impaired lung function. 

Sea-level Rise, Storm Surges and Coastal Hazards
As more heat is retained in the Earth’s atmospheric, oceanic, and terrestrial systems, ocean waters expand and many mountain glaciers melt. This process leads to higher sea levels, which cause beach erosion, inundation and erosion of coastal wetlands and, intrusion of saltwater in coastal aquifers and other urban water supplies. With higher sea levels, small storms could produce large amounts of flooding, similar to that which strong, relatively infrequent storms produce today. The projected amount of sea-level rise may not seem particularly large—estimated sea-level rise in the Metro East Coast Region could be ¾ to 3 ½ feet by 2100—but, when a storm hits, that small increase may be enough to flood coastal areas. 

For example, in 1992, a powerful nor’easter shut down New York City’s subways, trains, highways and airports, battered coastal residences and caused substantial beach erosion. By the 2050s, flooding of the same magnitude as the ’92 nor’easter are projected to occur every 8 to 18 years, depending on the climate scenario. By the year 2100, the range drops to once every 1 to 13 years.

A large part of lower Manhattan would be at risk from frequent flooding by the end of the next century according to these scenarios, even if storms did not become more intense or frequent. Without expensive protection measures, the foundations of Battery Park City and the World Trade Center would be flooded regularly. The East River would flood Bellevue Medical Center, the FDR Drive and East Harlem between 96^th and 114^th Streets.  Storms would flood much of Coney Island, submerging or creating islands of residential communities there and in Staten Island nearly annually. In New Jersey, storm surges would temporarily transform the Meadowlands into a salty lake. During storm surges, the barrier islands of Long Island—including Jones Beach, Fire Island, and Westhampton Beach—could narrow and fragment into small islets, while highly productive saltmarshes could shrink permanently due to higher sea levels. Although marshes adapt to moderate rates of sea-level rise, they may be unable to keep up with the accelerated rates that are expected to occur as a result of human-induced climate change.

Water Supply System
Global warming may increase the frequency of extreme weather events, including both prolonged periods with little precipitation and periods of heavy downpour and snowfall, leading both to more droughts and more inland floods.  Higher temperatures alone can lower water supply through increased evaporation and reduced runoff from watersheds.  In one scenario, a drought of the severity that currently occurs about once every hundred years could occur every 3-11 years by the year 2100.  In another scenario, droughts are less likely but wetter conditions could lead to an increase in the number of floods. Drought and sea-level rise could push saltwater on the Hudson River further upstream, possibly requiring costly adaptations to an important emergency pumping station located at Poughkeepsie used to supply water to New York City during drought emergencies.  The impact to New York City water users will depend on the degree of variability and severity of the weather events, the amount of sea-level rise, the demand for water in the future, and the effectiveness of institutional and infrastructure adaptations and planning efforts. Institutional changes and possibly substantial and costly infrastructure investments may be required to cope with these stresses.

Adapting to the Potential Impacts of Global Warming
 

Climate scientists agree that further climate change may be inevitable and will therefore require adaptation, although most scientists also think that the pace of climate change can be slowed by substantially reducing greenhouse gas emissions. This would give governments, businesses, and ecosystems around the world more time to respond and adapt to climate change as well as reducing the overall severity of climate change-related impacts, thereby buying "insurance" for an uncertain future.  Another way to buy insurance now is to incorporate climate change into all long-term decisions about natural resources, thereby providing greater resilience.

The single most important thing that the region can do to prepare for a changing climate is to develop and maintain a dialogue between scientists and decision-makers.  An increased awareness of how climate affects the region will increase resilience to climate variations and change. In addition, we can reduce local pressures on our resources and ecosystems.

The Metro East Coast regional report, which will present a more in-depth analysis of the issues presented in this summary as well as a discussion of possible adaptation strategies, is scheduled for release for public comment beginning June 19.  For more information on the report and a conference discussing the findings on June 19, see the web site for the Metro East Coast regional assessment below.  Final release of the report is scheduled for this summer. 

For Further Information
For more detailed information on the impacts of global warming on the Metro East coast region, contact these authors of the Metro East Coast regional assessment:

Dr. William Soleki, Montclair State University, 
 Tel: (973) 655-5129  Email: soleckiw@saturn.montclair.edu
Dr. Cynthia Rosenzweig, NASA-GISS
 Tel.: (212) 678-5562  Email: crosenzweig@giss.nasa.gov

For more information on potential impacts of climate change to the New York Metropolitan Region, see the Metro East Coast regional assessment web page:
http://metroeast_climate.ciesin.columbia.edu

The Environmental Defense report, "Hot Nights in the City: Global Warming, Sea-Level Rise and the New York Metropolitan Region", based on early findings from the Metro East Coast assessment is available on the web at http://www.edf.org/hotny

The author of that report, Dr. Janine Bloomfield, can be reached at 
 Tel: (212) 505-2100  Email: jbloomfield@environmentaldefense.org