Coastal property values won’t wait to (permanently) fall until sea levels have actually risen four or five feet, as they almost certainly will by the end this century on our current CO2 emissions path).

Coastal property values will crash when a large fraction of the financial community and of opinion-makers — along with a smaller but substantial fraction of the public — realize that it is too late for us to stop four to five feet of SLR. And remember, if we don’t get on the sustainable sub-450-ppm path soon, then people will quickly come to understand that SLR won’t stop in 2100. Seas will continue rising post-2100 perhaps 10 to 20 inches a decade (or more) for centuries until we are ice free and seas are 250 feet higher. And that makes protecting most coastal cities very, very difficult and expensive.

One of the points of my post “Ponzi, Part 1,” of course, is that we haven’t hit that critical mass of knowledge yet. If we had, the world would be engaged in a massive, desperate effort to avert catastrophe.

And so I pose the question in my talks: What year will coastal property values crash?

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I pose the question mostly to stimulate thinking. And certainly the collapse is unlikely to happen in just one year — so perhaps the better question is, What year will U.S. coastal property values peak?

I tend to think the peak comes some time in the 2020s.

The peak will probably be linked to one or more major climate disasters of a kind that I enumerated in “What are the near-term climate Pearl Harbors?” Note that the growing fear of a hurricane damage has already been made getting new insurance for coastal homes in places like Long Island difficult (see here).

But awareness on SLR is growing. And it is poised to grow even more quickly in the coming years, as yesterday’s article in U.K.’s Guardian newspaper, “Scientists to issue stark warning over dramatic new sea level figures” makes clear:

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This week’s climate change conference in Copenhagen will sound an alarm over new floodings — enough to swamp Bangladesh, Florida, the Norfolk Broads and the Thames estuary.

Scientists will warn this week that rising sea levels, triggered by global warming, pose a far greater danger to the planet than previously estimated. There is now a major risk that many coastal areas around the world will be inundated by the end of the century because Antarctic and Greenland ice sheets are melting faster than previously estimated.

Low-lying areas including Bangladesh, Florida, the Maldives and the Netherlands face catastrophic flooding, while, in Britain, large areas of the Norfolk Broads and the Thames estuary are likely to disappear by 2100. In addition, cities including London, Hull and Portsmouth will need new flood defences.

“It is now clear that there are going to be massive flooding disasters around the globe,” said Dr David Vaughan, of the British Antarctic Survey. “Populations are shifting to the coast, which means that more and more people are going to be threatened by sea-level rises.”

It certainly bears repeating that it is not too late to prevent the worst, were humanity to engage in an all out effort to stay below 450 ppm, but time is running out for that option very quickly.

This post was created for, a project of the Center for American Progress Action Fund.

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