Sea Level Rise along the East Coast of the United States

Sea Level Rise along the East Coast of the United States

Introduction

It is estimated that 1.2 billion people, or approximately 23 % of the world's population, live within 100 m of sea level and 100 km from a coast (Nicholls and Small, 2002; Nicholls, 2003). The population densities in coastal regions occur at approximately three times the global average with maximum densities occurring below 20 m in elevation (Nicholls, 2003). At the same time, people continue to migrate to coastal cities and towns where economic opportunities dependent on coastal resources are concentrated. These coastal regions are home to some of the world's most productive and complex systems and support a diversity of plant, fish, and wildlife species.

The Third Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) has concluded that increasing greenhouse gas concentrations are having a detectable effect on earth's climate system, including an increase in globalmean sea level (IPCC, 2001). These effects are likely to intensify over the course of this century (IPCC, 2001; Church et al., 2001). An increase of global surface temperatures would raise sea level by expanding ocean water, melting glaciers, and increasing melting and calving of the Greenland and potentially West Antarctic ice sheets. Sea level rise would increase the susceptibility of coastal populations and ecosystems through the permanent inundation of low-lying regions, amplification of episodic flooding events, and increased beach erosion and saline intrusion (Mclean et al., 2001). Ultimately, this may lead to the displacement of millions of people, significant damage to property and infrastructure, and a considerable loss of coastal ecosystems by the end of the 21st Century (Nicholls and Lowe, 2004).

Sea level rise is a significant and growing threat to New Jersey. The coastal area spans 204 km along the United States mid-Atlantic coast with an additional 134 km of shoreline along the Raritan and Delaware Bays (Figure 1). Structural development along the coast varies from heavily urbanized centers, such as Atlantic City, to sparsely populated agricultural communities on the Cape May peninsula. New Jersey is the most densely populated state with over 8.6 million people inhabiting 19,210 km². The coastal region has experienced significant population growth and development over the past 50 years with the population of New Jersey's coastal counties growing from 3,345,010 in 1950 to 5,281,247 in 2000 (Ocean County Department of Planning, 2002; NJ Department of Labor and Workforce Development, 2004). Today, the population of the state's coastal counties accounts for approximately 60 % of the total.

Sea Level Rise Projections

Changes in sea level are closely related to fluctuations in global temperature. Global sea level has risen over 120 m at some locations from the low stand of the last glacial maximum 20,000 years ago when temperatures were between 5º and 10º C cooler than today (Jouzel et al., 1989; Fleming et. al., 1998; Church et al., 2001). Geologic evidence suggests a global-mean sea level rise rate of 0.1 to ...