Flooded Cities

by on September 1, 2017 at 12:35 am in Data Source, History, Science, Uncategorized | Permalink

That is the title of a recent research paper (pdf) by Adriana Kocornik-Mina, Thomas K.J. McDermott, Guy Michaels, and Ferdinand Rauch.  Here is the abstract:

Does economic activity relocate away from areas that are at high risk of recurring shocks? We examine this question in the context of floods, which are among the costliest and most common natural disasters. Over the past thirty years, floods worldwide killed more than 500,000 people and displaced over 650,000,000 people. This paper analyzes the effect of large scale floods, which displaced at least 100,000 people each, in over 1,800 cities in 40 countries, from 2003-2008. We conduct our analysis using spatially detailed inundation maps and night lights data spanning the globe’s urban areas. We find that low elevation areas are about 3-4 times more likely to be hit by large floods than other areas, and yet they concentrate more economic activity per square kilometer. When cities are hit by large floods, the low elevation areas also sustain more damage, but like the rest of the flooded cities they recover rapidly, and economic activity does not move to safer areas. Only in more recently populated urban areas, flooded areas show a larger and more persistent decline in economic activity. Our findings have important policy implications for aid, development and urban planning in a world with rapid urbanization and rising sea levels.

One possible implication of these strong results is that, better pricing of flood insurance, which I favor, still probably won’t get most population centers out of those low-lying, relatively vulnerable areas.

1 Thiago Ribeiro September 1, 2017 at 12:46 am

“still probably won’t get most population centers out of those low-lying, relatively vulnerable areas.”
It is their fault for not possessing gills. Money can not be spent on those loser, the F-35 needs all the money. The military–industrial Moloch is hungry and he wants Americans’ children.

2 Jay September 1, 2017 at 12:49 am

“One possible implication of these strong results is that, better pricing of flood insurance, which I favor”

Enlightened Liberal: Tyler, why do you hate poor people so much? We need “Progressive” national taxes on the rich to pay for flood insurance!

3 mulp September 1, 2017 at 5:17 am

You want to pay for free flood insurance for the poor in India and Bangladesh which is currently subject to higher than normal monsoon flooding that affects an order of magnitude more people than Harvey?

Note the cutoff for flooding excludes all US flood event during the life of any living American in the cited study.

4 Jay September 1, 2017 at 1:21 pm

Those “Enlightened Liberals” are Nationalists and Racists. They only care about redistribution to the American poor because they are American and mostly white. Redistribution to other countries – particularly the ones that have a lot poorer people and are mostly brown or black – is not an issue for Proggers.

5 Steve Sailer September 1, 2017 at 12:54 am

I live near the Los Angeles River. The smart thing to have done after the big flood of 1938 would have been to convert the floodplain to parks and golf courses (as was more or less done in Palm Springs and Scottsdale in more recent times). But economic activity was concentrated near the LA River, so the Army Corp of Engineers just converted the LA River to a big ugly concrete ditch. That’s worked (so far, knock on wood).

6 mkt42 September 1, 2017 at 12:57 am

“won’t get most population centers out of those low-lying, relatively vulnerable areas.”

True but it’s not clear to me that would be desirable. Sure, flood damage would be reduced. But costs at all other times would be higher because the economic activities would no longer be conveniently located near the water and near each other rather than on more remote and difficult-to-build-on uphill land.

The low-lying vulnerable areas include places such as New York City and a good chunk of the Netherlands. We could reduce exposure to flood damage by telling the New Yorkers to relocate up the Hudson River or to New Jersey, and telling the Dutch to move to France or Luxembourg, but I doubt those are the economically efficient choices.

7 Anonymous September 1, 2017 at 1:13 am

Well, we’ll never know whether moving uphill would be more efficient or not, because we subsidize people to live near the water by bailing them out, right? Or is that not the case for this dataset?

8 Dan Lavatan-Jeltz September 1, 2017 at 1:25 am

We do know, because the companies that moved upstate of NYC hundreds of years ago did quite well.

Basically annoying people will continue to cause trouble, but at least all their stuff will get wet as a divine punishment.

9 mulp September 1, 2017 at 5:18 am

Where is uphill in Bangladesh?

10 Viking September 1, 2017 at 10:48 am

The Himalayas!

11 J September 1, 2017 at 5:51 am

Urban drainage is designed to 1 in 50 years events, that is, once in fifty years – statistically – part of the city will be flooded. Drainage infrastructure is very costly, it cannot be upgraded easily, so floods are going to take place, maybe once or twice a lifetime. Insurance makes sense.

12 rayward September 1, 2017 at 6:46 am

As I commented to another blog post, imports and exports necessarily rely on coastal cities to move goods out and in, so the people residing and working there are in a sense heroes, assuming a large risk while being on the front lines of global economic activity. “Only in more recently populated urban areas, flooded areas show a larger and more persistent decline in economic activity.” Could that be a reference to the large migration of retirees to coastal areas, not to work on the front lines but to enjoy the view? Of course, retirees migrate to states like Florida for more than the view, the low taxes as or more appealing than the view. Is there an irony: low taxes draw them to coastal areas of Florida while low taxes leave the state with few funds to deal with the crisis from a hurricane when it hits, leaving only the national government to provide funds for relief. Wouldn’t it make more sense for states to cut the tax rates on seniors/retirees so they will stay in New York, New Jersey, Michigan, Illinois, etc. than to encourage them to migrate to low tax states at a high risk of hurricanes?

13 bellisaurius September 1, 2017 at 7:22 am

While I’d prefer more of an economic carrot and stick, it feels weird to think that the one thing cities could do to change this- altering zoning policy, doesn’t really seem to be talked about.

14 Butler T. Reynolds September 1, 2017 at 12:15 pm

“still probably won’t get most population centers out of those low-lying, relatively vulnerable areas.”

But it might nudge them towards building on stilts.

Comments on this entry are closed.

Previous post:

Next post: