NU Online News Service, March 14, 3:41 p.m.EDT

Sea levels are rising at such a rate that, by 2050, coastalflooding will far exceed four feet above the local high-tide line,according to a research report released today.

Climate Central, a non-profit research group headquarteredinPrinceton,N.J., says sea-level rise due to global warming “hasdoubled the annual risk of coastal flooding of historic proportionsacross widespread areas of theUnited States.”

The report says by 2030 many coastal areas of theUnitedStateswill likely see storm surge combining with sea-level rise toclose to four feet above the local high-tide line.

It says close to 5 million people live in 2.6 million homes thatsit on land below the four foot level.

The report, titled Surging Seas, “is the first to analyze howsea-level risk caused by global warming is compounding the riskfrom storm surges throughout the coastal contiguousU.S.”

The report also generates local and national estimates on theland, housing and population in vulnerable low-lying areas. Theinformation is coupled with flood-risk timelines.

The report includes online, searchable maps that zoom down into neighborhoods to showrisk zones and statistics for 3,000 coastal towns, cities, countiesand states affected by seas up to 10 feet above the high-tideline.

Across every coastal state exceptMaineandPennsylvaniain thelower 48 states, there are 676 towns and cities that sit below thefour-foot tidal mark, or more than 10 percent of thepopulation.

“Sea-level rise is not some distant problem that we can just letour children deal with,” says Ben Strauss, lead author of thereport in a statement. “The risks are imminent and serious.”

He says a small sea-level rise that will probably occur withinthe next 20 years “can turn yesterday's manageable flood intotomorrow's potential disaster. Global warming is already makingcoastal floods more common and damaging.”

The report says that global warming has raised sea levels by 8inches since 1880 and levels are expected to rise 20 to 80 inchesthis century, depending on the amount of pollution emitted byman.

When asked to comment on the Climate Central research PeterDailey, director of Atmospheric Science at AIR Worldwide, respondedin an e-mail, saying “AIR, in collaboration with its sister companyAER, have published peer reviewed research showing that recenttrends in rising sea levels may lead to significantly elevated riskof coastal storm surge in conjunction with land falling hurricanes.Portions of the U.S. coastline are particularly sensitive to smallchanges in sea level—such as the Louisiana coastline and the NewOrleans metropolitan area—where hurricanes can bring strong coastalsurges of 25 feet or more. Such surges are only exacerbated byhigher mean sea level. The impact on storm surge will be mostapparent where land lies close to or even below sea level and wherehurricane frequency is relatively high, such as the U.S. Gulf Coastand the Mid-Atlantic Coast.

This story was updated at 9:43 p.m. EDT with comments fromAIR Worldwide