Residents of the southeastern United States should begin to prepare for more drastically changing weather conditions due to climate change, researchers say. The warning is set out in a report released as part of the National Climate Assessment, a comprehensive national analysis mandated by Congress of the effects of climate change. "The Southeast already experiences extreme weather events, including floods, droughts, heat waves, cold outbreaks, winter storms, severe thunderstorms, tornadoes and tropical cyclones," lead report editor Keith Ingram of the University of Florida said. "In the future, these events are likely to become more frequent or more severe, causing damage to most of our region's agriculture, stressing our region's water resources and threatening human health." Climate change effects predicted by the report include annual temperatures increases through the 21st century, sea levels rising 1 to 5 feet by the end of the century and a deterioration of air quality. "Climate variability is already affecting the southeastern U.S. and a changing climate is projected to increasingly affect the region in the next 20 years and beyond," Ingram said in a university release Tuesday. The report was based on analysis of data from Florida, Georgia, South Carolina, North Carolina, Virginia, Tennessee, Kentucky, Arkansas, Louisiana, Mississippi, Alabama, the Virgin Islands and Puerto Rico.