You write, “Only a particular stormtype causes a major threat, these are the storm depressions that move from north to south on the eastern border of the North Sea, blowing up the water into the southern north sea funnel so that the total southern coast of the North Sea is threatened. The big disaster of 1953 did cause problems in Denmark, Germany, Netherlands and England. A portable system would have to be installed along several hundred km of coastline.”

Well, I’m too lazy to do much looking for sea depths around the various coasts, but it looks like:

1) From the Belgium border to the southwest tip of Zeeland is about 20 km,

2) From that point to The Hague is about 80 km.

That’s about 100 km.

My thought is that a system that could “protect” that 100 km by taking 3-5 meters off the storm surge could be developed and implemented for under 3 billion Euros. That includes the materials that are deployed, plus the equipment to deploy them.

I don’t know what the damage to the system would be for each storm, but it would probably be a good idea to expect that the materials deployed would only last for a couple of storms.

Needless to say, it’s not cheap. But flood damage isn’t cheap, either. And with property values increasing, the costs of flood damage will go up, whereas the costs of the portable protection system will go down (as expertise is gained, and materials are improved).

Someday, a portable system is going to happen.

PS on topic: Al Gore will be visting Holland on October 14th.

You asked,

“After Katrina, New Orleans needs to bring the sea defenses up to level, but to which level must be adapted? Hurricane 3 or 5, and which additional sea level rise until 2100 does yNew Orleans have take into account: one foot (current linear trend extrapolation), two feet (median IPCC), three feet (worst case IPCC) or even five feet (worst case Rahmstorf)?

Five feet just in case, at any cost?”

But there’s another way. The other way is not to protect New Orleans any more than it is already protected (essentially a weak Category 3, with a path that isn’t right over New Orleans, as Katrina was).

The logic for not protecting New Orleans (any more than it is already protected) is that all the dollars spent on improving defenses for New Orleans are dollars that can NOT be spent on improving the defenses for Galveston, TX. Or New York City.

The solution is to instead put the money that would be spent on protecting individual cities into a system that can be moved around to protect *any* city. In fact, such a system could eventually protect any city in any country (e.g. the Netherlands, England, Myanmar, Bangladesh, etc.)

The portable storm surge protection system has the following advantages over fixed defenses. (Note that this is not a comprehensive list.)

1) The same system can be used to protect any city, so the cost is a small fraction of the cost required to protect all of the cities individually,

2) A significant component of the protection system is dependent on how effectively the system is placed, so the system will get more and more effective as computer modelling of storm tracks and storm surges improves,

3) The materials used for the system can be upgraded as materials technology improves (e.g., if carbon nanotubes become economical for reinforcement, this could be incorporated into the new materials),

4) The portable system can be tested on lower-category storms and protecting small areas, then improved. For example, if the system is first deployed to protect only 10 km of coastline from a Category 3 storm, and it is seen that the system would fail from a Category 5 storm, the design can be improved before being deployed to protect 100 km of coastline from a Category 5 storm. In contrast, a fixed defense system might have to be designed only for a Category 3 system (even if it is seen that it would fail during a Category 5 storm), simply because designing for the extremely rare Category 5 storm (*at this one particular location*) is not cost-effective. In other words, it might not be cost-effective to design ANY fixed defense system for a Category 5 storm, because of the rarity of a Category 5 hurricane hitting any particular city. (It might hit a particular city only once in 300 years.) But a portable system CAN be designed for a Category 5 storm, because it’s virtually certain that one or more Category 5 storms will hit somewhere in the U.S. in the next few decades, and

5) A portable system could be used anywhere in the world.

No, all places on the Gulf and East Coasts are vulnerable. Miami is vulnerable. Tampa is vulnerable. New York City and Long Island are vulnerable.

The solution is to come up with something that can protect ALL cities on both coasts.

In other words, the solution is to come up with a portable system:

http://markbahner.typepad.com/random_thoughts/2008/01/the-us-should-b.html

With a portable system, all cities can be protected at a small fraction of the cost of protecting all the cities individually.

But of course, that would require the U.S. government and the U.S. research establishment to behave logically. So it will be a long shot.

Here is how I see such questions . . .

The level of sea defense, in Holland or New Orleans is not a question with a correct answer. It is a political question, to which estimates of future sea level rise and storm behavior are only part of the information considered in making such decisions.

In the US there is good reason not to build New Orleans defenses as strong as they could be, because that would only encourage much more development in a vulnerable place. But at the same time there are really important cultural reasons why many people want to protect New Orleans. The outcome balances these considerations, with many others like costs.

Five feet just in case, at any cost?

On the other hand, the analogy that adaptation is like putting out a fire on the Titanic is profoundly untrue. There is absolutely no similarity between the Titanic cruising smoothly, suddenly hitting an iceberg and disappearing beneath the waves…and climate change. Climate change, regardless of the cause, is not ’sudden’ and does not result in the ‘end of climate’, but in a slightly different climate whose value is more a matter of opinion than of objective, scientific fact. The above analogy is provocative propaganda, but has no resemblance to the reality of climate change. It has no resemblance to reality!

Rejoicing that Al Gore (and the Greens) has finally recognized a little bit of reality is like rejoicing that a man in a coma for 8 years briefly woke up and recognized he was in the hospital. Yes…its great, but we still have the delusions of a comatose man wielding huge influence over global energy policy! To me, that reality is a lot more scary than a hypothetical few degrees centigrade in 100 years!

Thanks for fighting the good fight, Roger. I guess one does not turn the Titanic (of ill-conceived climate change policy) by screaming about an iceberg, but by slowly turning the rudder.