When it grows grey and ugly, its sea foam whipped by and carried on the winds, the Atlantic Ocean chews into the Eastern Seaboard, at times tearing islands in half, at others rearranging beaches by pushing sand around.

Cape Hatteras National Seashore witnessed that in August 2011, when Hurricane Irene dredged through the Pea Island National Wildlife Refuge just north of the national seashore and ripped out sections of Highway 12. Tropical Storm Ida in 2009 inflicted much damage to Assateague Island National Seashore, leaving in its wake beach erosion, overwash, and damage to infrastructure.

Similar scenarios, and worse, are likely to happen in the years ahead if nothing is done to blunt climate change, according to a report from the Natural Resources Defense Council and the Rocky Mountain Climate Organization.

Sea Level Rise

Lying at sea level as they do, the seashores -- Cape Cod, Fire Island, Assateague Island, Cape Hatteras, Cape Lookout, Cumberland Island, and Cape Canaveral -- are helpless when the Atlantic is churned up by storms, and to sea levels that rise as the polar caps melt.

Much of the land in those seashores is barely 1 meter above the current sea level, Stephen Saunders, president of the Rocky Mountain Climate Organization, said Wednesday during a conference call with reporters. That low-lying landscape makes them highly susceptible to overwash and higher sea levels, he said.

"In five of these seashores, five out of the seven, over half of the lands, in all cases I think well over half of the lands, are low-lying enough to be below that 1-meter threshhold, meaning they are vulnerable to being submerged by the ocean during this century," said Mr. Saunders.

According to the report, Atlantic National Seashores In Peril, the Cape Cod, Fire Island, Assateague, and Cape Hatteras seashores already are "experiencing above-average rates" of sea-level rise.

And while Cape Cod is somewhat invulnerable to barrier-island-busting storms, when compared to the other seashores, because geologically it is "a relatively stable peninsula," the report stated that the other seashores are much more vulnerable to more powerful hurricanes, which climate change is predicted to spawn.

Such potential was demonstrated last August, when Hurricane Irene tore into Cape Hatteras. The hurricane sliced through North Carolina Highway 12 in several places just north of Rodanthe, outside of the national seashore. The largest breach went through the national wildlife refuge.

At Cape Lookout National Seashore to the south of Hatteras, the wake of Hurricane Irene left the seashore's dock at Harker's Island needing to be rebuilt, damaged all cabins on Great Island to varying degrees, inflicted "heavy damage" to Cape Lookout Village, and washed away the dump station at Cape Point. Overwash from the hurricane also covered most of the national seashore with 2 feet of sand.

Assateague Island National Seashore hasn't been cut in half, but storms in years past have done substantial damage, so much so that seashore officials are keeping climate change in mind as they work on updating their General Management Plan for managing the seashore. Though the GMP is still in draft stage, one scenario seashore officials are keeping in mind is the possibility that a storm could knock out the Verrazano Bridge that ties Maryland's mainland to the seashore.

"The bridge on the Maryland end is a state bridge, it's not owned by the National Park Service. So the decision on whether or not the bridge would be put back would be up to the state of Maryland," Superintendent Trish Kicklighter said Wednesday. "However, there's no guarantee that there would be an island for the bridge to connect to. So what we would propose in a couple of the alternatives is to develop a ferry shuttle, a pedestrian ferry shuttle to the island."

With the prospect of more potent storms breaching barrier islands and knocking out roads and bridges, the sheer cost of repairing or replacing this infrastructure will become considerable, Mr. Saunders said.

"One of the first major impacts that we'll experience, before we have actual inundation by the ocean, is that we will have loss of visitor access through the bridges and roads that provide that access now. We have already had much more expensive repair work that has to be done on bridges and roads that go out to these seashores," he said.

Hotter Summers and Fleeting Political Will

Beyond sea-level rise and island-dredging storms, the report said climate change threatens to boost the average summertime temperatures at these seashores anywhere from 3 degrees Fahrenheit at Cape Hatteras and 3.6 degrees Fahrenheit at Fire Island by mid-century under "medium-high" greenhouse gas emission levels, to as much as 6.5 degrees Fahrenheit at Fire Island by century's end. Already, the report notes, high seashore temperatures recorded from 2000-2011 were as much as 1.8 degrees Fahrenheit warmer than 1961-1990 readings.

"How much these seashores are affected by climate change depends on how much climate change we humans produce. It is not set how much the climate will change. A whole lot depends on our level of emissions, of heat-trapping gases. Must of the worst impacts can at least be reduced, if not avoided entirely, if we get serious now about reducing the carbon pollution," said Mr. Saunders.

But the federal government has demonstrated little will to address climate change head on. While it once was a major item for the Obama administration, the administration seemingly has decided not to spend any of its scant political capital on the issue, and Congress has largely avoided it as well.

Whether it is mentioned in the presidential campaign remains to be seen. The GOP platform adopted at this week's Republican Convention mentions climate change only in deriding the Obama administration, noting that in the president's National Security Strategy the "word 'climate,' in fact, appears in the current President’s strategy more often than Al Qaeda, nuclear proliferation, radical Islam, or weapons of mass destruction."

Theo Spencer, senior advocate, Climate and Clean Air Program, for the Natural Resources Defense Council, noted the Obama administration's move this week to hike the minimum miles-per-gallon requirements for automobiles between 2012-2025 as a step in the right direction to cut emissions.

"That is the biggest step the federal government has ever taken to cut our oil dependency and our carbon pollution," he said. "Cars, SUVs and light trucks account for 20 percent of America's heat-trapping carbon pollution. Second only to our power plants."

But the NRDC staffer agreed the country has a long way to go to confront climate change.

"For half a century, the federal government has been playing favorites," said Mr. Spencer. "Helping the fossil fuel industry through subsidies and other measures. Now, some in Congress want to stop similar help for clean energy by eliminating the production tax credit that helps provide a level playing field for clean, renewable energy like wind and solar.