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Comment by themagician | Hacker News Reader

I'm really not convinced Miami will be around in 20 years. The floods are worse every year. Miami Beach doesn't just flood, it shuts down. There will come a time when sea level rise and hurricane season will collide in such a way that it won't be practical to rebuild.

Miami Beach is 4' above sea level on limestone. The slightest acceleration in seal level rise will doom the city. Maybe when the mega mansions on Palm Island become unserviceable people will take things seriously.

People say it could take another 100 years for the sea level to actually consume the land, but that's really not necessary. Just look at New York post Hurricane Sandy. Crippled parts of the city for months. When you get a storm like that, combined with higher tides and more regular flooding it seems like game over because they're just won't be enough time to rebuild before the next flood.

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That's a good point. What high sea levels look like in practice is more frequent flooding. This happens long before total immersion.

For Hurricane Sandy, if the 14th St power substation had been protected, and subway and train tunnels equipped with flood gates (that was supposed to happen after 9/11 as an anti-terrorism measure) the damage would have been much more localized. The appropriate role for government here is to toughen up the infrastructure. New York has a plan.[1]

We just have to write off Miami Beach and parts of New Orleans. New Orleans has higher ground nearby, but Miami doesn't.

There are some tricks used in urban areas subject to river floods. Here's the Tamshui River as it flows through Tapei.[2] The river is bordered by broad parks, and the park is bordered by a freeway raised on a berm. That's all for flood control. During floods, the parks are underwater. Massive floodgates block roads under the freeway. (There are emergency stairs for people caught on the wrong side.) The river bridges are all high enough to bridge any flood. After each flood, the parks need some maintenance, but they have few structures and the ones they have are very solid. San Jose has a similar, but smaller, arrangement for the Guadalupe River. (Yes, that's why there are such nice trails and bike paths in downtown San Jose.)

[1] http://www.nyc.gov/html/sirr/downloads/pdf/final_report/Ch3_... [2] https://en.wikipedia.org/wiki/Tamsui_River#/media/File:Dansh...

ACK. If we are good at anything, then of the optimism bias.

We constantly overestimate our abilities while we underestimate the problems that can emerge.

Combined with our rather low ability to think in systems theory enough, to actually understand the system we are living in...

Bad combo...

As someone who lives in Miami your comments come across as hilariously exaggerated

recent Elizabeth Kolbert new yorker piece on miami and flooding http://www.newyorker.com/magazine/2015/12/21/the-siege-of-mi...

The basic problem is the limestone. Because of the limestone, seawalls are essentially useless as the water goes underneath through the porous ground. I think very likely the comments only seem exaggerated to you because it's difficult to imagine with all the people around you driving fancy cars and buying expensive condos, like pre-cupernican difficult.

No one knows how long miami has, but I would bet it's closer to 20 years than 100 years. To be quite honest, I hope it happens sooner rather than later as maybe something like that will start to wake people the fuck up. Doubtful though. There's always another rationalization.

You're second paragraph is a cruel wish on the lives of millions. You wish this cruelty for the petty purpose of being on the right side of an argument

He's not wrong though.

There is this strange idea, particularly in the US, that we can buy our way out of the problems caused by sea level rise. That's (somewhat) true in some cases, but Miami is not one of them. The ground is simply too porous. You'd have to pull some Dubai-level shit and build a second Miami Beach next to the original and move everyone over.

South Florida will almost undoubtably be the first area in the United States where wealthy people are materially impacted by sea level rise. And because the foundation is so porous it won't take 100 years before areas become untenable. Flooding that last a few days starts to last weeks.

It really doesn't take much.

> He's not wrong though

I have yet to a shred of evidence for this 20 year theory

Why would the place you live in have any baring on your knowledge of the effects of sea levels rising? You aren't handed a geotechtonics degree when you move there.

The idea that Miami will be gone in 20 years and not 200 is a ridiculous one. I live here on an island by the sea, I guess that doesn't make me a geotechtonista but it gives me some perspective other people in their basements in middle America might not have.

I wouldn't even give NYC 20 years. A direct hit from a category-3 hurricane would decimate that city. The building codes were only updated in 2008 to withstand hurricane winds. It's really only a matter of time

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