From July 21-23, 1998, the International Hurricane Center at Florida International University hosted the Atlantic Coastal/Caribbean Regional Scoping Workshop ("Climate Change and Extreme Events") to set the foundation for the region's assessment.

Complex interactions of natural cycles and oscillations, ranging from hours to centuries, contribute to natural variations of the climate. On top of this, manyfindings suggest that human activities are already contributing to climate change and altering the natural climate. A major objective of the workshop is to understand what specific effects climate change may have on the U.S. South Atlantic Coastal and Caribbean region, which comprises 1,000 miles of Atlantic coastal regions from North Carolina through South Florida, and a veritable archipelago of more than 250 islands including Puerto Rico, the U.S. Virgin Islands, the Florida Keys and more than 26% of the total acreage of barrier islands of the East and Gulf coasts.

At the end of 1997 the population of this region hit 15.5 million permanent residents. To them we add some 5.0 million seasonal residents, and more than 30.0 million tourists visiting these areas in a given year. This results in a regional population at any moment ranging from 20.0 to 24.0 million and continuing to grow. The region also harbors unique and irreplaceable ecosystems such as the Everglades, coral reefs, forests, wetlands and Lake Okeechobee, the second largest reservoir of freshwater entirely within the borders of the contiguous 48 states.

The region is home to our spaceport in Cape Canaveral, the largest single-dish radio telescope in the world in Arecibo, Puerto Rico, and the Southern and Central Florida Flood Control Project, perhaps the largest public works projects of its kind. In addition, important commercial ports, airports, numerous academic institutions and a myriad business and public institutions linking the U.S.A. to huge developing markets in Latin America, are also in the region.

In addition to human and technological hazards, this region is vulnerable to hurricanes, drought, sea-level rise, coastal and riverine flooding, flash floods, severe lightning, wild fires, beach erosion , saltwater intrusion, sink holes, coral reef bleaching, and other natural hazards. This vulnerability creates stresses on regional systems that may be aggravated by climate change. The workshop will focus on these vulnerabilities, with special emphasis on the impacts of climate change on hurricanes and on water resources.

Climate Change and Hurricanes:

This entire region is within hurricane alley. The historical record shows a large number of intense hurricanes have made landfall in the coastal areas of this region. Puerto Rico and the U.S. Virgin Islands have also experienced hurricane impacts.

Empirical data indicate continued global warming will provide more favorable physical parameters for cyclogenesis. Sea-surface [SST] temperatures exceeding 26 C, a deep thermocline, (meaning a thick layer of warm surface waters), high relative humidity, and atmospheric conditional instability are all anticipated results of global warming that promote tropical cyclones. Global circulation and hurricane models have been used to simulate changes in hurricane intensities in a global climate warmed by increases in atmospheric CO2 . Results indicate increases of 5% to 12% (3-7 m/s) in wind speeds, and drops in central pressures in the order of 7 to 20 mb; and both of these indicators point to higher intensity hurricanes. Others have also used these models to investigate potential changes in Atlantic hurricane activity due to climate change resulting from higher CO2, but with mixed results. It is clear that uncertainties remain and model refinement is needed to improve the reliability of results.

Against this background of empirical data and of tentative, but still inconclusive, results of scientific modeling of tropical cyclone variability, the population and development of our coastal and island areas continue to grow, increasing the region's vulnerability to extreme events. This issue of increasing vulnerability must be paramount in analysis of responses to the potential consequences of climate change on this region.

Water Resources:

Another interesting case-study of potential regional consequences of climate change provides the effects on regional water resources. Florida coastal counties depend on a combination of surface/ground water sources for municipal uses, agriculture, industry, recreation, and natural ecosystems. These competing demands for water and the continuous urbanization/development trend are already placed significant stress on the regional water resources.

Regional water sources include the following: a) natural drainage from the Appalachian mountains, b) 1,700 rivers/streams and 7,800 fresh water lakes including Lake Okeechobee, c) the Florida Aquifer estimated to contain 1x1014 gallons of freshwater, d) local rainfall, and e) the Everglades. Stresses result from demands of a coastal population of 8.6 million (1997), and from flood control measures draining an average of 1.8 million gallons of freshwater per day into the sea. This has reduced the Everglades by 2.0 million acres, reducing its ability to resupply the aquifer. Recent studies also suggest a decline in rainfall has occurred since 1960. This could be the consequence of urbanization, related wetland draining and flood control measures, which together result in a reduced rate of evapotranspiration and thus precipitation.

Should climate change result in an increase of hurricanes and rainfall, current stresses could be aggravated due to the need to increase drainage related to flood control, the combination of sea-level rise, storm surge and beach erosion leading to salt water infiltration of the aquifer, and the consequential loss of some ground water sources. If the regional consequence should be less rainfall, the aggravation of stresses would result from freshwater supply management cutbacks. This would adversely impact the Everglades Agricultural Area, as well as the supply for drinking, industry, recreation and ecosystems. Other consequences of changes to regional freshwater water resources include alteration of salinity in estuaries, decreased biodiversity, and interruption of food chain systems leading to loss of fishing habitats.

The July 1998, workshop will be one step in the process of understanding these potential consequences. There is a need for continued research on direct causal links of human activity and climate change, and on using technological tools for more accurate and timely data acquisition to model our coastal and island regions. We need to look at ways to improve our built environment to reduce the damage from extreme events. Above all, we must increase our efforts to educate all sectors of society, from children to adults, practitioners to academics, business leaders to our political leadership, in the need for considering adaptive actions now.

For more information, contact:

Ricardo Alvarez, Associate Director, International Hurricane Center, Florida International University, (305) 348-1607, alvarez@fiu.edu