Florida and other Southeastern states are "exceptionally vulnerable" to sea level rise, extreme heat events, hurricanes and a decreasing freshwater supply, according to the National Climate Assessment released Tuesday.
Coastal areas in Miami, Tampa and Apalachicola are singled out as major concerns in the 11-state region that is home to seven major ports and fast-growing metropolitan areas that hug the coastline. Rising sea levels, higher temperatures, flooding and the threat of hurricanes make the state among the most exposed to climate dangers.
The Southeast is both a major producer and consumer of energy, and it's already suffered more billion-dollar disasters than any other part of the country. Disruptions to infrastructure could spell an economic disaster for areas dependent on tourism. More than 115 million people visited Louisiana and Florida alone in 2012.
According to the study, Florida and the Southeast faces three key threats:
Sea Level Rise: Miami and Tampa as well as Charleston, New Orleans and Virginia Beach are among the most vulnerable to the impacts of sea level rise with roads, railways, ports, airports, oil and gas facilities and water supplies at low elevations.
Low-lying coastal areas are increasingly prone to flooding during tropical storms and hurricanes, and the report's authors worry that a migration of coastal residents fleeing unaffordable insurance costs may stress the social fabric in other areas.
Rising waters also put more pressure on utilities, contaminating freshwater supplies with saltwater or burdening aging storm water drainage systems designed to empty into the ocean. Barrier islands protecting oil and gas production infrastructure along the Gulf Coast are expected to become increasingly vulnerable to storm surge and deterioration from rising seas, the report says.
Rising Temperatures: Tampa and Miami, and New Orleans and Atlanta already have had increases in the number of days with temperatures above 95 degrees, and Florida has set five different monthly records since 2010: two for heat, one for cold, one for wetness and one for dryness.
Higher temperatures also are expected to contribute to an increase in harmful air pollutants in the region's 19 largest urban areas, which the report says will lead to an increase in deaths. Crops are expected to wither in hotter summers, especially when there's a drought.
In Georgia, that could mean corn harvests decline by 15 percent and wheat yields by 20 percent through 2020. Many fruit crops may need to be replaced.
Less Water: The net freshwater supply availability is expected to decline over the next several decades, particularly in the western part of the region, as demands for water go up due to increases in population, development and agriculture.
Higher sea levels will accelerate saltwater intrusion into freshwater supplies near the coast. That’s a major concern to areas such as Apalachicola’s already-depleted oyster industry. Global sea level has risen 8 inches since 1880 and is projected to rise between 1 foot and 4 feet by 2100.
And porous aquifers like Florida's are particularly vulnerable — the city of Hallandale Beach has already abandoned six of eight drinking water wells due to saltwater intrusion.
Scientists and the White House called it the most detailed and U.S.-focused scientific report on global warming. The report looks at regional and state-level effects of global warming, compared with recent reports from the United Nations that lumped all of North America together.
"All Americans will find things that matter to them in this report," said scientist Jerry Melillo of the Marine Biological Laboratory, who chaired the science committee that wrote it. "For decades we've been collecting the dots about climate change; now we're connecting those dots."
In a White House conference call with reporters, National Climatic Data Center Director Tom Karl said his two biggest concerns were flooding from sea level rise on the U.S. coastlines — especially for the low-lying cities of Miami; Norfolk, Virginia; and Portsmouth, New Hampshire.
The report also says the intensity, frequency and duration of the strongest Atlantic hurricanes have increased since the early 1980s, but it is still uncertain how much of that is from man-made warming.
Later this summer, the White House plans to propose new regulations restricting gases that come from existing coal-fired power plants.
Not everyone is convinced.
Republican Sen. David Vitter of Louisiana said the report was supposed to be scientific but "it's more of a political one used to justify government overreach." And leaders in the fossil fuel industry, which is responsible for a large amount of the heat-trapping carbon dioxide, said their energy is needed and America can't afford to cut back.
"Whether you agree or disagree with the report, the question is: What are you going to do about it? To us that is a major question," said Charlie Drevna, president of the American Fuel and Petrochemical Manufacturers. He called the report "overblown."
Reporter Mary Shedden contributed to this story.