Politics & Government

New report predicts big increases in coastal flooding due to climate change

A new report says that scores of coastal communities in the United States could see a significant increase in tidal flooding in coming decades as global warming drives sea levels higher.

The report from the advocacy group Union of Concerned Scientists said that flooding linked to high tides is having a greater impact on coastal communities than in decades past. That’s partly because shorelines are more heavily developed than they once were and because tides occur on top of elevated sea levels.

From 1880 to 2009, the report said, global sea level rose roughly eight inches, as rising temperatures melted land-based ice. In coming decades, that sea-level rise is expected to continue. And based on a mid-range scenario for such increases, communities up and down the coast will see big increases in yearly flooding, the report said.

In the process, what are often nuisances – coastal roads covered for a few hours, for example – will turn into major headaches.

“As sea level rises, many tidal flooding events will shift from being minor to more extensive, with accompanying increases in disruptions and damage,” the group said. It added: “Places such as Annapolis, Maryland, and Washington, D.C., can expect more than 150 tidal floods a year, and several locations in New Jersey could see 80 tidal floods or more.”

For its report, the group analyzed 52 tide gauges from Portland, Maine, to Freeport, Texas.

While the country is engaged in a major debate over how and whether to attack climate change by reducing carbon pollution, the new report said any resulting efforts won’t stop the waters, given the flooding scenarios analyzed. Because of the long lag between releasing carbon into the atmosphere and the impact on the oceans, “more sea level rise and more tidal flooding are virtually guaranteed,” the report said.

The report suggests infrastructure and development changes that can take place now to help deal with the coming high waters.