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Thursday, June 26, 2008

Rhode Island planning for rising sea levels

Prepare now for future coastal climate change impacts

Sea level rises of at least three to five feet by 2100 and the likely increase in the frequency and strength of major storms due to carbon dioxide emissions from burning oil and coal, require Rhode Island to plan for major coastal disruptions, said Rhode Island Coastal Resources Management Council Executive Director Grover Fugate at a climate change conference last week in Narragansett.

"We're vulnerable. We're low and we're flat," agreed University of Rhode Island Coastal Institute director Peter August.

In January, the CRMC, Rhode Island's coastal regulatory agency, decided its policies on zoning and design must recognize the expected sea level rise. Rising sea levels and strong coastal storms will push barrier dunes, like those on Quonochontaug, Ninigret and Green Hill Ponds, inland, they predicted. They will also contaminate clean water supplies, salinate septic systems and reduce salt marsh area, Fugate warned. Finally, rising seas will submerge low-lying bridges and roads like Block Island's Corn Neck Road. The CRMC must consider innovative steps, Fugate urged, including the increase of set backs for coastal buildings, the elevation of bridges and the acquisition of land that will be transformed to environmentally important salt marsh as sea levels rise.

The CRMC is also preparing a plan to regulate which ocean areas are best for wind power, Fugate said, by balancing the potential for electricity generation with fishing and recreational boating. Rhode Island Governor Donald Carcieri has proposed several off-shore sites near Block Island for building wind power turbines.

Just how much sea levels will rise during the next one hundred years is unclear, said URI Oceanography professor Kate Moran. Scientists are particularly puzzled, she said, by the behavior of melting ice sheets on Greenland and Antarctica. Most of the recent sea rise can be attributed to the melting of glaciers and expansion of oceans due to warming, she said, but scientists are puzzled by the effects of melting ice sheets on Greenland and Antarctica.

Their rapid melting would raise levels considerably more than the CRMC's projection of 3-5 ft. by 2100, according to CRMC Coastal Geologist Janet Freedman. The pace of global sea rise is increasing, she said. According to a tide gauge in Newport, Rhode Island, sea levels rose an average of 1.27 mm per year between 1970 and 1988, Freedman related, but an average of 4.06 mm per year between 1989 and 2008. Overall, Newport sea levels have risen about 8 inches since 1929.

But for coastal communities, the biggest threat is not sea level rise, insisted state Geologist John Boothroyd, but more frequent and more powerful storms. Southern New England has not had a series of major storms since Hurricane Bob in the early 1990s, he said, adding that he cannot predict when another set of erosion causing storms may hit. Fugate said that careful planning for big storms requires good maps with up-to-date elevations of coastal areas. The current U.S. Federal Emergency Management Agency maps are old and inaccurate, he said, and called on conference attendees to contact their Congressmen to get the federal government to produce better maps.

To battle shoreline erosion, Boothroyd advocated beach replenishment, but said it can be prohibitively expensive to local communities who must assume 30 to 50 percent of the cost under federal programs. Moving buildings inland to higher ground is more practical, he added. Fugate agreed, saying, "Our primary policy is retreat."

Because sea walls, or revetments, encourage beach erosion and potentially block shoreline access, Freedman said that the CRMC does not allow construction of new sea walls. Property owners may maintain existing walls, but if a storm destroys more than 50 percent of a wall, it cannot be rebuilt, she said.

While Fugate and Freedman discussed local precautions, Moran called for action on the causes of climate, "heavy consumerism in the West, plus [world] population growth." She endorsed a cap and trade system on carbon dioxide emissions like the plans advocated by Presidential candidates John McCain and Barack Obama, but rejected by the United States Senate earlier this month.

"The rest of the world gets it," Moran said, "It's time for the United States to stop believing editorials in the Wall Street Journal."

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