If King Canute had a roads policy... North Carolina's Highway 12 is at the centre of a ferocious and politically charged dispute

Out of America: One of the US's most scenic roads is under threat, but the chorus of climate-change deniers prevents action

Road to nowhere: North Carolina’s Highway 12 after Hurricane Irene struck in 2011 (Chuck Liddy)

Is there a more amazing road in the US than North Carolina's Highway 12? I'm not talking about the high season, when it's jammed with holidaymakers heading for their beachfront homes on the Outer Banks.

But in autumn and winter, when the tourists and summer residents are gone, when the ocean lowers and a cold, hard wind cuts through the dunes, the road reverts to its original purpose – a precarious nature-defying lifeline, 120 miles long and linking some of America's most exposed and isolated communities to the mainland and civilisation beyond. And today there's even more to it. Highway 12 is front and centre in one of the country's most ferocious and politically charged disputes over climate change.

The Outer Banks are one of Earth's wonders: a necklace of barrier islands made of sand, ever at the mercy of hurricanes and nor'easters, their shape constantly shifting, their width varying from a couple of miles to barely 100 yards in some places. Today, however, climate scientists will tell you, they are under unprecedented threat.

Sea levels off North Carolina are rising faster than virtually anywhere along the US shoreline; if present trends continue (or accelerate, as most predictions warn) the Outer Banks may not even be there by century's end, and Highway 12 would be washed away with them. This may not be a matter of riveting concern right now if you're from Kansas City or Chicago. But it most certainly is if you happen to live or own property there, or are a North Carolina official trying to deal with this slow-motion crisis.

Matters came to a head in 2011, when the state authorities embraced a forecast that over this century sea levels would rise 39 inches, a figure in the middle range of the estimates, but which, if true, would leave sections of the Outer Banks under water and others clinging to survival.

Left to nature, the islands are in constant motion, edged steadily westward by the Atlantic waters, with new inlets appearing and disappearing at a fierce storm's whim. Highway 12, however, is an artificial anchor for the Outer Banks – often flooded, constantly under repair, but vital for the communities and settlements it served.

For them, the 39-inch rise was, as one resident told The Washington Post last week, "a death sentence". The tacit message was unmistakable: there was no resisting this kind of advance by the sea: the road wasn't worth keeping, and the Outer Banks a generation or two from now would be in practice uninhabitable. If you owned property there, or had a stake in the flourishing tourist industry, you were on a financial hiding to nothing.

But that was when the Democrats ran the state. In 2012, the Republicans, instinctively hostile to climate doom and gloom, took over. Outer Banks residents joined forces with global warming sceptics, and the 39-inch forecast soon became history. Now North Carolina is about to adopt a new forecast, looking only 30 years ahead, and predicting a far more manageable increase of just eight inches. Climate change, what climate change? Or maybe on this part of America's mid-Atlantic, no one ever heard of King Canute.

But the argument there is but part of a wider national quarrel. A characteristic of America, sometimes endearing, sometimes infuriating, is that however cast-iron a scientific or political case may seem, someone will always come up with facts to prove exactly the reverse.

For this administration in particular, the issue is "settled science". That the Earth is warming is incontestable; the only question is what we should do about it. Sceptics, though, will have none of it: the figures, they say, have been shamelessly manipulated by scientists. Forget Arctic ice melt, rising sea levels and changing plant and animal zones: in truth, one widely followed climate contrarian insisted last week, America has been cooling since the 1930s.

Politics reflects the to-and-fro. President Obama came to office in 2009 vowing to make climate change a priority. But that year, although the Democrats controlled Congress, a cap-and-trade bill that would have curbed greenhouse gas emissions foundered on Capitol Hill. With Republicans now in charge of the House, and well placed to recapture the Senate as well at November's mid-terms, the measure is a non-starter.

So, Obama has taken matters into his own hands. Earlier this month, he issued a proposal for new rules to be enforced by the federal government's Environmental Protection Agency that would reduce such emissions by 30 per cent in 2030, from the levels of 2005. Such an improvement, as is usually the case when governments claim good deeds, is less than meets the eye.

And it's good politics. The President was in cracking form addressing environmentalists here the other day, mocking his Republican foes. In Congress, "folks will tell you climate change is a hoax or a fad or a liberal plot". Or, he went on, they duck the question, saying "Hey, I'm not a scientist". That, though, Obama said amid gales of laughter from his sympathetic audience, "really translates into, I accept that man-made climate change is real, but if I say so out loud, I will be run out of town by a bunch of fringe elements... so I'm going to just pretend like, I don't know, I can't read".

All of this plays into the wider Democratic contention, as elections approach, that Republicans are a bunch of Neanderthals, denying everything from evolution to climate change, from gay rights to sensible gun control.

Alas, there are just two problems here. First, while climate change plays well in polls (70 per cent of Americans say they worry about it), for most it is an abstract concern compared with jobs, healthcare and the rest. Yes, it resonates more among the young. But in America, the young vote less. And then there's the siren song of the sceptics that the problem doesn't exist, so nothing need be done. Thus it is with North Carolina, the Outer Banks and Highway 12. King Canute? Forget him.