Land that roughly 50 percent of Americans call home is under threat from the coastal effects of climate change, a study published Tuesday (PDF) by the National Oceanic and Atmospheric Administration (NOAA) warns.

“An increase in the intensity of extreme weather events such as storms like Sandy and Katrina, coupled with sea-level rise and the effects of increased human development along the coasts, could affect the sustainability of many existing coastal communities and natural resources,” report co-author Virginia Burkett, of the U.S. Geological Survey, said in an advisory.

The study warns that approximately 50 percent of Americans live in coastal watershed communities -- a number that is projected to grow -- that face increasing flood risks due to storm surges, extreme weather and rising sea levels as the climate grows more unpredictable. These risks are compounded by changes to coastal ecosystems brought about by human activity, causing "toxic algal blooms" and depleted fish stocks, loss of wetlands and dying coral reefs.

As these ecosystems degrade, the study notes that coastal areas which help buffer human settlements and infrastructure from the worst storm damage go with them, leading to wetlands disappearing, beaches eroding and more property damage costs every year. A similar effect was witnessed after Hurricane Sandy hit the eastern seaboard in 2012: the U.S. Geological Survey said the superstorm eroded away nearly 30 years worth of sand buildup on New York beaches.

The risks aren't just in the most logical areas like New York or New Orleans, either: the NOAA's report warns that climate change "could basically transform much of Alaska from frozen to unfrozen," with "extensive" impacts for the whole region. It also suggests that the northeastern U.S. is in for more extreme rains and flooding, while heat-related deaths and an increase in diseases can be expected in warmer areas.

“Sandy showed us that coastal states and communities need effective strategies, tools and resources to conserve, protect, and restore coastal habitats and economies at risk from current environmental stresses and a changing climate,” study co-author Margaret A. Davidson, of NOAA’s Office of Ocean and Coastal Resource Management, said in an advisory. “Easing the existing pressures on coastal environments to improve their resiliency is an essential method of coping with the adverse effects of climate change."


Photo: Photo: Leonard Zhukovsky /