Revised to Reflect the Discussions at the U.S. Climate Forum

Regional Workshops:

Southeast, July 1997

Hawaii and the Pacific Islands, March 1998

Caribbean and the Southern Atlantic, Spring 1998

Gulf Coast, Spring 1998

What is the scope of this consolidated region? What are the primary characteristics of the geography and regional economy? The scope of this breakout group includes the coastal regions and islands of the United States, including Puerto Rico, the U.S. Virgin Islands, and the Pacific islands. On the mainland United States, the focus is primarily but not exclusively on the Gulf and South Atlantic Coasts; the eastern coast is largely covered in the Eastern U.S. breakout group, California in the Dry West breakout group, and Oregon and Washington in the Northwest breakout group.

Agriculture, recreational and commercial fishing, and tourism are all important components of the coastal region's economy. The Florida Gulf and Atlantic coastlines have long been an important tourist destination and the natural beauty, tropical ecosystems and unique (often endangered) species found in the Pacific and Caribbean islands provide a prime attraction to travelers. Many parts of the coastal region reflect a significant investment in infrastructure and services designed to support this important component of the regional economy. Climate-related changes in coastal hazards such as sea-level rise, tropical storms (including storm surge and wind damage, for example), and coastal erosion all have potentially-significant consequences for the natural and human systems in this region.

Coastal areas are also important because they provide habitat for diverse and abundant flora and fauna, including many endangered or threatened species. The U.S. coastal region is also home to many indigenous peoples and communities, with unique social and cultural lifestyles.

What are current stresses on this region? Coastal regions are currently burdened by extensive development and high rates of population influx. At present, more than 50% of the U.S. population resides within 80 miles of the coastline; population density in coastal areas is five times the national average. Industrial operations in nearshore waters, coastal bays, estuaries and coastal wetlands, combined with the high coastal population density are resulting in high rates of pollution affecting coastal water quality, at times contaminating fisheries, and harming other ecosystems including wetlands and coral reefs. Some symptoms of this include outbreaks of harmful algal blooms, such as Pfisteria, and the closure of oyster-growing areas to commercial harvests.

Sea-level rise and coastal storms (especially hurricanes) are also current threats to coastal regions. Climate-induced sea-level rise and fall has affected coastal ecosystems throughout time. The earth entered a warming trend approximately 18,000 years ago, but during the last 3,000 years of the Holocene transgression rates appear to have been generally constant and driven by processes related to eustacy (i.e., thermal expansion of the oceans and melting of glaciers and ice sheets). Global sea level has risen between 10 and 25 cm over the past 100 years, and the IPCC now projects that sea level will rise by 15-95 cm over the next century as a result of thermal expansion and melting of glaciers and ice sheets. Sea-level rise increases flooding associated with storm surge, even if the intensity or frequency of extreme weather events does not increase as some models suggest. Sea-level rise and coastal erosion are already impacting many U.S. coastal areas, particularly along the low-lying and highly-developed South Atlantic and Gulf shoreline. Some U.S. islands are also experiencing high rates of coastal retreat; over the past 50 years about 25% of the beaches in Oahu, Hawaii have been severely degraded or lost.

Due in part to intensive development, some coastal regions are also already highly vulnerable to the year-to-year changes in temperature, rainfall and tropical storms associated with the El Niño Southern Oscillation (ENSO) cycle, highlighting the potential vulnerability to long-term changes associated with greenhouse warming. ENSO-related changes in ocean temperature, circulation and productivity may have significant impacts on fisheries stock yield and availability. For example, El Niño phase appears to influence the migratory patterns of Pacific tuna stocks, posing challenges and opportunities for both vessel owners and cannery operators such as those in American Samoa. Anticipating the impacts of both year-to-year variability and long-term climate change can provide valuable information to support decision making in the coastal region.

Additionally, some smaller island communities face a number of special challenges, e.g., because they depend on rainfall catchment systems as their primary source of water.

How might climate change and variability exacerbate or ameliorate these stresses? Increasing demands for limited water resources associated with a rapidly growing population represent a current stress which could be exacerbated by changes in rainfall patterns and rising sea level that are predicted to accompany climate change. This is particularly true for those island communities which depend primarily on rainfall catchment systems (rather than groundwater aquifers) for their water supplies.

The following factors associated with future climate could have pronounced effects on coastal ecosystems and communities: Sea-level rise could increasingly affect beaches, coastal communities, infrastructure and ecosystems. The mid-Atlantic, southern Atlantic, and Gulf coasts are likely to lose large areas of wetlands if sea-level rise accelerates. Associated salinity changes could dramatically alter coastal habitat zonation and quality.

• Higher mean sea level would mean that coastal storms will likely be more destructive to people and infrastructure, because storm surges will reach further inland and protective barrier islands may be destroyed. Weather extremes, such as floods and droughts, may increase in frequency, but predictions of long-term changes in weather patterns are still debated and somewhat speculative.
• Changes in the patterns of precipitation could threaten already scarce fresh water supplies in some areas.
• Heat stress could affect some vulnerable populations in the U.S. coastal regions, particularly those that are already quite humid.
• Increased siltation could impact fisheries, water supplies, and drainage patterns.

Further, any decreased runoff flow to coastal estuaries could cause declines in most shellfish species, a mainstay of the commercial fishing industry along the Gulf Coast. Also, coastal wetlands are extremely vulnerable to changes in sea-level rise, especially along the Louisiana coast, where subsidence, levee building and channelization contribute to wetland loss.

Another area of concern involves the additive effect of climate change on sensitive coastal ecosystems such as coral reefs and oyster beds are already under significant pressure from excess nutrients, pesticides and sedimentation associated with urban runoff and non-point source pollution.

What are the most important information needs that have been identified? Southeast regional workshop participants identified several information needs related to sea-level rise and its impacts on coastal ecosystems, changes in precipitation regimes and extreme events, and impacts of increasing temperature, UVB, and CO₂. The Southeast participants also identified a need for a baseline monitoring program for studying change including climatic relationships. The regional workshop identified the need to link existing "baseline-controlled use sites" (e.g., National Wildlife Refuges, National Estuarine Research sites, LTERs, LMERs, etc.) as a baseline system. These systems need to recognize the importance of socioeconomic variables along with climate and biological/physical ones. Also, more emphasis needs to be placed on distinguishing between climate-related sea level rise and natural processes so that the potential future impacts can be more accurately estimated.

What are possible coping strategies that have been identified? There are three major categories of coping strategies that are relevant to the coastal areas of the US. The first is the engineering design strategies that have been and are being practiced across the country. They include erecting bulkheads, seawalls, dikes and pumping stations in response to potential sea level rise in the future. In addition, the elevation of land surfaces and buildings may be required in some low-lying coastal areas. Beach replenishment is probably one of the most environmentally-sound shoreline engineering fixes, although it may be costly. However, some of these engineering "fixes" may be like fighting a losing battle, and may come with great environmental costs. Further, many of these engineering endeavors are designed based on historical records and historical risks. Climate change may make these historically-based decisions insufficient to cope successfully with the problems.

A second category of strategies involves institutional solutions. For example, land use policies should be encouraged that limit new development and reduce land subsidence in sensitive, coastal areas, and encourage setbacks and easements in the most critical areas. The National Flood Insurance Program also needs to be re-evaluated so that enforcement of development restrictions in hazardous and sensitive areas is encouraged. Another institutional strategy is to improve the resource and coastal management practices through a strengthening of the state coastal management programs as administered through the Coastal Management Act. In this regard, only Georgia and Texas are coastal states with no federally approved and funded coastal zone management program. Education and outreach represent a third general category of coping strategies. We need to do a much better job of communicating and educating the broad citizenry about the importance of coastal ecosystems, the nature and range of probable changes related to climate, and how such changes will impact our lives and our economy.