Global Warming Effects Around the World

New York City, NY, USA

Top Impact

Oceans (Sea level)

Other Impacts

People (Costs)

Ecosystems (Salt water)

Aerial view looking down Manhattan at sunset shows New York's vulnerability to sea level rise

New York City's location on the Atlantic Ocean—at the mouth of the Harlem River, and in a tidal strait connecting upper New York Harbor to Long Island Sound—has served its growth as a global center of commerce and culture. Now, sea-level rise caused by global warming threatens the Big Apple's future. 1

Key Facts

New York City, a global hub of business, arts and culture, transportation, and education, is threatened by sea-level rise stemming from climate change.3

  • Global sea-level rise is accelerating: from 1993 to 2003 the rate was 70 percent higher than the average rate for the twentieth century.
  • Recent analyses suggest that New York City and other parts of the U.S. Northeast are likely to be affected by regional changes in ocean currents on top of rising global sea level—and related increases in coastal flooding, storm surge, erosion, property damage, and loss of wetlands.3,12,13,18
  • If our heat-trapping emissions continue unabated,15 scientists project that what is now considered a once-in-a-century coastal flood is likely to occur twice as often by mid-century, and once per decade by late this century.3,13,19

Details

With more than eight million inhabitants, New York City is by far the largest U.S. city.2 Sea-level rise linked to global warming is dramatically increasing the likelihood of flooding in New York City,3 a global hub of business, arts and culture, transportation, and education.

Sea level has been rising globally since the end of the last ice age, but the rate of that rise has accelerated over the past two decades.4 From 1993 to 2003, for example, that rate rose to an average of 0.12 inches (3.1 millimeters) per year—70 percent more than the average rate for the twentieth century.5,6 Scientists attribute this recent acceleration in global sea-level rise to climate change.7,8 Oceans are expanding as they warm, and melting glaciers and shrinking Greenland and Antarctic ice sheets are adding water to the oceans.3,5

Besides global sea-level rise, several other factors influence regional sea-level rise, including sinking (subsidence) or rising (uplift) of the land, circulation of the atmosphere and the ocean, and the origin of the meltwater.3,9 Local sea level rose more than 8 inches (20.3 centimeters) in some areas along the Atlantic over the past 50 years.3

What the Future Holds

Scientists expect a warming world to drive further sea-level rise over this century and beyond.3,10,11 New York City faces increases in coastal flooding, the extent and frequency of storm surge, erosion, property damage, and loss of wetlands.3,12,13

If we do nothing to reduce our carbon emissions, scientists project that global sea level could rise as much as nearly two feet (59 centimeters) over recent average levels by the end of this century.14,15 If, on the other hand, we make significant efforts to reduce heat-trapping emissions, sea-level rise between now and the end of the century could be limited to at most 1.25 feet (38 centimeters).14,15

Recent evidence of faster rates of global sea-level rise suggests that these projections may be too low.3,4,5 Given recent accelerated shrinking of glaciers and ice sheets, scientists now think that a rise of 2.6 feet (80 centimeters) is plausible—and that as much as 6.6 feet (2 meters) is possible though less likely.16

Scientists expect regional variations in land motion to continue, and to affect local sea-level rise.3 So, for example, a two-foot (61.0cm) rise in global sea level would produce a relative sea-level rise of 2.3 feet (70.1cm) at New York City.3,17

A recent analysis found that the effects of future changes in ocean circulation on the U.S. Northeast will amplify the local sea level rise.18 For New York City, sea-level rise owing to changes in ocean circulation is projected to be around 8.3 inches (21 centimeters) if emissions continue unabated, or 5.9 inches (15 centimeters) if we make significant efforts to curb emissions.15,18

If our heat-trapping emissions continue to rise at current rates, what is now considered a once-in-a-century coastal flood in New York City is projected to occur twice as often by mid-century, and once per decade by late this century.3,13,19 If we make significant cuts in our emissions,15 we can expect such catastrophic floods every two decades by the end of the century.3,13,19

Rising sea levels are expected to worsen storm flooding in low-lying coastal areas, and permanently inundate some parts. Retreating shorelines and accelerating erosion will threaten coastal homes and businesses.3 With $2.3 trillion in insured coastal property,3,20 New York State is particularly vulnerable. Some insurers have already withdrawn coverage from thousands of New York City homeowners.3

Scientists also expect sea-level rise to alter coastal ecosystems such as the salt marshes and estuaries of Long Island, threatening feeding grounds for migrating waterfowl and nursery habitat for commercial fish.19

Credits

Endnotes

  1. Photograph courtesy of Thinkstock. Accessed 30 Nov 2010 at http://www.thinkstockphotos.com/ search/ #97692040
  2. U.S. Census Bureau. 2008. Population estimates. Online at http://www.census.gov/ popest/ cities/ SUB-EST2008.html. Accessed April 6, 2010.
  3. U.S. Global Change Research Program. 2009. Global climate change impacts in the United States. Edited by T.R. Karl, J.M. Melillo, and T.C. Peterson. Cambridge University Press.
  4. Rahmstorf, S., A. Cazenave, J.A. Church, J.E. Hansen, R.F. Keeling, D.E. Parker, and R.C.J. Somerville, 2007: Recent climate observations compared to projections. Science 316(5825):709.
  5. Bindoff, N.L., J. Willebrand, V. Artale, A, Cazenave, J. Gregory, S. Gulev, K. Hanawa, C. Le Quéré, S. Levitus, Y. Nojiri, C.K. Shum, L.D. Talley, and A. Unnikrishnan. 2007. Observations: Oceanic climate change and sea level. In: Climate change 2007: The physical science basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Edited by S. Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor, and H.L. Miller. Cambridge University Press, pp. 386-432.
  6. Douglas, B.C. 1997. Global sea rise: A redetermination. Surveys in Geophysics, 18: 279-292. doi:10.1023/A:1006544227856.
  7. Hegerl, G.C., F. W. Zwiers, P. Braconnot, N.P. Gillett, Y. Luo, J.A. Marengo Orsini, N. Nicholls, J.E. Penner and P.A. Stott. 2007. Understanding and attributing climate change. In: Climate change 2007: The physical science basis. Contribution of Working Group I to the Intergovernmental Panel on Climate Change. Edited by S. Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor, and H.L. Miller. Cambridge University Press, pp. 386-432, 664-745.
  8. Douglas, B.C. 1997. Global sea rise: A redetermination. Surveys in Geophysics 18, doi:10.1023/A:1006544227856: 279-292.
  9. Mitrovica, J.X., N. Gomez, and P.U. Clark, 2009: The sea-level fingerprint of West Antarctic collapse. Science 323(5915):753.
  10. Meehl, G.A., T.F. Stocker, W.D. Collins, P. Friedlingstein, A.T. Gaye, J.M. Gregory, A. Kitoh, R. Knutti, J.M. Murphy, A. Noda, S.C.B. Raper, I.G. Watterson, A.J. Weaver, and Z.-C. Zhao. 2007. Global climate projections. In: Climate change 2007: The physical science basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Edited by S. Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor, and H.L. Miller. Cambridge University Press, pp. 747-845.
  11. Clark, P.U., A.J. Weaver, E. Brook, E.R. Cook, T.L. Delworth, and K. Steffen. 2008. Introduction: Abrupt changes in the Earth's climate system. In: Abrupt climate change. Synthesis and assessment product 3.4. Reston, VA: U.S. Geological Survey, pp. 19-59.
  12. Gornitz, V., S. Couch, and E.K. Hartig. 2001: Impacts of sea level rise in the New York City metropolitan area. Global and Planetary Change 32(1):61-88.
  13. Kirshen, P., C. Watson, E. Douglas, A. Gontz, J. Lee, and Y. Tian. 2008. Coastal flooding in the northeastern United States due to climate change. Mitigation and Adaptation Strategies for Global Change 13(5-6):437-451.
  14. Solomon, S., D. Qin, M. Manning, R.B. Alley, T. Berntsen, N.L. Bindoff, Z. Chen, A. Chidthaisong, J.M. Gregory, G.C. Hegerl, M. Heimann, B. Hewitson, B.J. Hoskins, F. Joos, J. Jouzel, V. Kattsov, U. Lohmann, T. Matsuno, M. Molina, N. Nicholls, J. Overpeck, G. Raga, V. Ramaswamy, J. Ren, M. Rusticucci, R. Somerville, T.F. Stocker, P. Whetton, R.A. Wood, and D. Wratt. 2007. Technical summary. In: Climate change 2007: The physical science basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Edited by S. Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor, and H. L. Miller. Cambridge University Press, pp. 20-91.
  15. The emissions scenarios referred to here—from the Intergovernmental Panel on Climate Change—are the high-emissions path known as A1FI, and the low-emissions path known as B1. Emissions over the past several years have followed the high-emissions path.
  16. Pfeffer, W.T., J.T. Harper, and S. O'Neel. 2008. Kinematic constraints on glacier contributions to 21st-century sea-level rise. Science 321:1340-1343.
  17. U.S. Global Change Research Program. 2009. Global climate change impacts in the United States. Edited by T.R. Karl, J.M. Melillo, and T.C. Peterson. Cambridge University Press. The program based its projections of sea-level rise on data from NOAA tide gauge stations with records exceeding 50 years, as reported in Zervas, C. 2001. Sea level variations of the United States, 1985-1999. NOAA technical report NOS CO-OPS 36. Silver Spring, MD: National Oceanic and Atmospheric Administration. Online at http://tidesandcurrents.noaa.gov/ publications/ techrpt36doc.pdf.
  18. Yin, J., Schlesinger, M.E., and Stouffer, R.J. 2009. Model projections of rapid sea-level rise on the northeast coast of the United States. Nature Geoscience DOI:10.1038/NGEO462.
  19. Frumhoff, P.C., J.J. McCarthy, J.M. Melillo, S.C. Moser, and D.J. Wuebbles. 2007. Confronting climate change in the U.S. Northeast: Science, impacts, and solutions. Synthesis report of the Northeast Climate Impacts Assessment. Cambridge, MA: Union of Concerned Scientists.
  20. AIR Worldwide Corp. 2008. The coastline at risk: 2008 update to the estimated insured value of U.S. coastal properties. Boston, MA. Online at www.airworldwide.com/ download.aspx?id=15836. Accessed April 7, 2010.
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