Box 1-D - Climate Change, South Florida, and the Everglades

Lying close to sea level and in the preferred path of a sizable percentage of Atlantic hurricanes, South Florida is potentially one of the most vulnerable areas of the United States to climate change. It is also one of the most distinctive. South Florida's famed Everglades, a vast subtropical wetland of which about one-seventh is preserved in Everglades National Park, is seen by many as one of the crown jewels of the U.S. National Park System. Miami, Palm Beach, and other coastal communities in South Florida make up one of the most popular seaside vacation destinations in the world. Despite hurricane and flood hazards, these cities have experienced phenomenal growth in recent years. In addition, varieties of crops can be grown in the warm, subtropicai climate that grow nowhere else in the United States. And Miami has become a gateway between North and South America, transforming South Florida into an important international crossroads.

Despite, or perhaps because of, its distinctiveness and popularity, South Florida is under stress and, like a few other heavily developed parts of the United States, beginning to bump up against limits to growth. The critical factor is water. Although the region receives an annual average of 60 inches (152 centimeters) of rain, annual evaporation can sometimes exceed this amount, and rainfall variability from year to year is quite high, resulting in periodic droughts and floods. In the past century, moreover, South Florida has been transformed from a virtual wilderness into a complex, interconnected system of developed and undeveloped land. The main elements of this system--the growing urban sector, agricultural areas, and the Everglades and other remaining natural areas must all compete for the limited supply of water, and the competition is increasing with every new resident.

Much of the growth of South Florida has occurred since 1870. Then, fewer than 100 people lived in what are now Dade, Broward, and Palm Beach Counties. Now, about 5.2 million people occupy the same area. The vast unaltered Everglades, which originally extended from Lake Okeechobee to Florida Bay, were seen by early settlers as hostile to human welfare and completely without value. Encouraged by a grant from the U.S. Congress, the State of Florida began draining these "useless" wetlands for agriculture, and by the early 20th century, the natural character of the Everglades had begun to change. Farmers planted sugar cane and a variety of vegetables in the drained area south of Lake Okeechobee now known as the Everglades Agricultural Area (EAA).

The initial drainage system worked well enough during normal years but was stressed during occasional abnormal events and failed completely during a major hurricane in 1928. At that time, 2,000 people died in the EAA when the protective dike around Lake Okeechobee burst. This incident prompted the initiation of a massive public works project, as attention shifted from drainage of wetlands to flood control. Eventually, an 85 mile (137-kilometer)[1] earthen dike was built around Lake Okeechobee, and the meandering 98-mile Kissimmee river, which fed the lake from the north, was transformed into a canal 48 miles long and 33 feet (10 meters) deep. Flooding problems diminished, but the former broad, riverlike system north of Everglades National Park has been greatly altered into a series of canals and pools. The former sheet-like flow of water to the park, necessary to its health, has been blocked. Today, the area has more than 1,395 miles of canals and levees and 143 water-control structures.

Projects to expand the supply of water to growing urban centers proceeded in tandem with flood-control projects. To accommodate demands for agricultural and urban expansion, diking and draining of wetlands continued, and as the expansion progressed, more water was diverted for these purposes. Today, additional water is diverted for sewage dilution, pest control, and frost protection. Some water is used to recharge aquifers that supply cities east of the Everglades and the populated areas of the Florida Keys. Large quantities of water that could be recycled or used to recharge urban aquifers are dumped into the Atlantic Ocean (see vol. 1, ch. 5, and vol. 2, ch. 4, for complete discussions of water and wetland issues).

A major effect of this decades-long restructuring of the natural hydrological system has been to drastically reduce the supply of water from the Kissimmee River watershed that reaches the much-diminished-in-size Everglades. The natural system has suffered in several ways as a result: 1) the abundance of species characteristic of Everglades habitats (e.g., wood storks. white ibis, tri-colored herons, and snowy egrets) has declined dramatically in the past 50 years, 2) more than a dozen native species have been listed as endangered or threatened (e.g., the Florida panther, snail kite, Cape Sable seaside sparrow, American alligator, and American crocodile), 3) nonnative and nuisance species have invaded the area (e.g., Melaleuca quinquinervia and the Brazillan pepper tree), 4) sizable land subsidence and water-level' declines have occurred throughout the region, 5) water quality has been degraded by agricultural runoff containing excessive nutrients, such as phosphorus, 6) saltwater intrusion of coastal aquifers has occurred, 7) vulnerability to fire has increased, and 8) massive algal blooms have appeared in Florida Bay, accompanied by die-offs of shrimp, lobster, sponge beds, and many fish.

The impacts of development have not been limited to natural areas. As water use in the region has grown, susceptibility to periodic droughts has increased. A 1981 drought for example, led to mandatory water restrictions for half the counties of South Florida and water rationing in the EAA. Pollution from cities, as well as from agricultural areas, has added to water-quality problems. Saltwater intrusion threatens aquifers used for urban water supplies.

Everglades National Park was created in 1947, the culmination of efforts that began in the 1920's. The transition of the Everglades from being perceived as "worthless land" to an important preserve worthy of designation as an International Biosphere Reserve and World Heritage Site took decades, but preservation of this area and restoration of other degraded wetlands are now considered high priority by a broad spectrum of people and organizations. Although there is broad agreement that the hydrology of the everglades should be restored to a pattern similar to that found in the original system, it will not be easy to balance the needs of the Everglades for water with the similar needs of other users.

South Florida's Everglades and coastal areas, clearly already under stress, face an unusually difficult problem in the light of global climate change. Both are already vulnerable to sea level rise and intense tropical storms (see vol. 1, ch. 4). (Damage from Hurricane Andrew, for example, was not confined to urban areas--coastal mangrove forests were heavily damaged, as were trees in many densely forested hammocks.) Climate change could increase the current vulnerability to these events. Climate change may also result in a hotter and drier climate for South Florida, although predictions from general circulation models (GCMs) are not consistent on this point. Whatever occurs, the future is likely to be increasingly stressful for South Florida. Cities are likely to continue to grow and will almost certainly be protected from sea level rise, but the expense of protecting them could be immense. the Everglades, once deemed worthless, is now considered a valuable natural resource. As valuable as it is, however, the Everglades will probably not receive the same attention as cities threatened by rising seas will. Farmers are likely to resist attempts to hinder or reduce long-established patterns of agriculture in favor of other uses for water. In short, South Florida is a system increasingly "close to the edge." The flexibility to satisfy competing interests for water and land has been reduced by actions taken since the turn of the century, and climate change may further reduce flexibility.

In recent years, some efforts have been made to offset some of the damage to the Everglades and restore some of the lost flexibility to the natural system. In 1970, for example, Congress directed that not less than 315,000 acre-feet (389 million cubic meters) of water be delivered annually to Everglades National Park. In 1989, Congress enacted the Everglades National Park Protection and Expansion Act (P.L 101-229), one purpose of which was to enable more natural flow of water through a portion of the park. More recently, the Federal Government sued the Florida Department of Environmental Regulation for not upholding its own water-quality laws, thereby allowing degradation of the Everglades to continue. As a result, the State has agreed to design and construct treatment areas in the EAA where drainage could be filtered before it is discharged to the park. The State has also directed the South Florida Water Management District to implement an Everglades Surface Water Improvement and Management Plan. Finally, as authorized in the 1992 Water Resources Development Act (P.L 101-640), the U.S. Army Corps of Engineers will soon begin a long-term project to restore the Kissimmee River to an approximation of its original meandering route, thereby increasing wetlands north of Lake Okeechobee, helping to improve water quality in the lake, and increasing the water-storage capacity of the entire Everglades system.

Although important steps are being taken to restore the Everglades, some major obstacles are stymieing the more comprehensive ecosystem planning that will be required to address the full range of South Florida's current and climate-change-related problems. One of the most vexing, and one encountered many times in OTA's study, is the lack of coordination among the responsible State and Federal agencies. Part of the problem is a result of a lack of shared values among agencies and among the constituencies they represent. Furthermore, each agency has a different mandate, and agencies' jurisdictional boundaries seldom coincide with boundaries of natural systems. One might expect that the preservation mandate of the U.S. Fish and Wildlife Service and the Florida Department of Environmental Regulation would often clash with the flood-control mandate of the Corps of Engineers and with the interests of EAA farmers, and such has been the case in South Florida. However, lack of coordination has extended even to agencies with similar mandates; a prominent example has been the difficulty of reconciling the National Park Service's ecosystem-wide approach to restoring the Everglades with the Fish and Wildlife Service's mandate under the Endangered Species Act (P.L. 100-707) to focus on protection of individual species.

Recently, Interior Secretary Bruce Babbit expressed a strong interest in Everglades National Park and has made clear his intention to get the National Park Service and the Fish and Wildlife Service to work more closely together to develop a common policy. Babbit has also announced plans to form a Federal task force in an attempt to overcome some of the coordination problems.

The broader challenge for the region is to manage this complex system in an integrated fashion to maximize the health of all its diverse elements. This is no small challenge because it may be very difficult to sustain agriculture without environmental costs, for example, or for urban areas to continue to grow indefinitely without some restraints. the effort to sort through these problems must take place with some understanding of what climate change may mean.

Sources: S. Light, L. Gunderson, and C. Holling, "The Everglades: Evolution on Management in a Turblent Ecosystem," University of Florida, Arthur C. Marshall Labratory, unpublished manuscript, 1993; National Audubon Society, Report of the Advisory Panel on the Everglades and Endangered Species (New York: National Audubon Society, 1992); J. de Golla, Everglades: The Story Behind the Scenery (Las Vegas, NV:KC Publications, Inc, 1978); K. Kemezis, "Babbit To test Ecosystem Policy in the Everglades," Environment Week, Feb. 25, 1993.

1 To convert miles to kilometers, multiply by 1.609.