When the leeve isn’t dry


Even in the best case scenario, even if warming can be limited to just the 1.5 degrees agreed at Paris, its inevitable that we’re going to see an increased level of flooding. Higher temperatures means sea level rise. And it means more moisture being absorbed by weather systems, which means heavier rainfall and larger storm surges. So that means bigger and better flood defences being needed. Case in point, just last week we had flood warnings here in the UK. And I just came back from a trip overseas where there was, surprise, surprise flooding due to heavy rain.

And that’s the best case scenario. The worse case scenario, sees rapid melting of the Greenland or Antarctic icepack, leading to sea level rises, sufficiently large to drown many major cities and literally redraw the maps of the world.

However, even if a significant level of sea level rise is avoided, just coping with increased flooding isn’t going to be easy and its already stretching flood defences to their limits. As this vlog post from Vice News discusses, across large parts of rural America (hardly a poor country) leeves and flood defences are crumbling. Recent flooding has left dozens of breaches and there’s no money to fix them.


Flood defences across America are crumbling following heavy rain

Furthermore, just fixing them isn’t enough, the defences, built decades ago without considering the impact of climate change, are no longer fit for purpose. This means that not only do they need to be build higher, but set back further to allow more room for the river to discharge excess water. Congress could assign funds, but inevitably this is going to cost more than a lot of money (there’s something like 100,000 km’s of leeves across the US alone, assume a few million $ per km….you do the math’s!) and that would mean acknowledging climate change is real (which Republicans don’t want to do).


A recent congressional backed NCA report suggested that climate change could be costing the US $500 billion/yr by 2090, equivalent to the current military budget!

Instead politicians in DC are too busy lining their own pockets, with corruption under Trump now approaching African dictator levels of absurdity (he’s not so much drained the swamp, but filled it and released alligators). In the mean time many small US communities are left to deal with the aftermath of recent flooding and have to fend for themselves (so they live without reliable drinking water, roads destroyed, crops submerged, oh and Trump’s tariffs hardly help!).

A rising tide might lift all ships, but floods don’t effect everyone equally. Leeves prevent flooding in one location, but by redirecting the water flow they can cause flooding downstream. And that’s what’s been happening in parts of the US. There’s also been a trend of “Bourgeois leeves” getting built. Wealthier (and often white) communities have been building leeves privately, leading to flooding of poorer neighbourhoods down stream.

Thus floods are not equal opportunity catastrophes. The obvious example being how in hurricane Katrina, it was poorer (and often black) neighbourhoods which flooded and richer whiter neighbourhoods which were less severely impacted (plus blacks gathering supplies afterwards is called “looting” while whites doing the same is called “foraging”). And this can lead to a downward spiral. Naturally, those communities without flood protection can’t get flood insurance anymore, their house prices decline and they have to pay the costs of being flooded out regularly, creating a vicious economic circle.

And inevitably as climate impacts bite, without some sort of government intervention, this is only going to get worse. In effect were going to see a certain level of social darwinism play out, with wealthier parts of America being protected and less wealthy parts having to deal with the full fury of climate change. And recall, that in the US those wealthier parts are mostly democrat voting cities and its the smaller rural communities (who vote Trump) who are going to get shafted (so its literally Turkey’s voting for Christmas sort of stuff).


NY is considering a series of large flood defences to protect Manhattan from future storm surges….

Case in point, NY is contemplating a massive series of flood defences, including leeves to protect Manhattan Island (the so called “big U”), as well as another on Staten Island. There’s even talk about a vast array of locks and sea walls being built across the entrance to New York harbour. Not only would these come with a hefty price tag, but they would require regular maintenance (so there’s be a fixed cost NY will pay every year….forever!). And recall, the issues in the Mid west with leeve’s is the cost of that upkeep. And such infrastructure will fundamentally change NY’s relationship with the sea. Some water front property will have to be demolished. No more gentle strolls along the beach, the sea views for some residents blocked by a massive concrete edifice and the constant drone of pumps.


….Which may eventually include a flood barrier across the harbour entrance

There are other alternatives to sea walls. For example, Shanghai a city much larger than NY (which is practically a village next to Shanghai!) is also at risk from climate change induced flooding. They’ve been taking a slightly different approach. Walls alone aren’t seen as enough, so instead they are focusing more on using wetlands to soak up excess water and drainage canals to then flush it out to sea. This is of course a practice the Dutch have been engaging in for centuries. But, like sea walls, such measures have their limits.

While America (or China and the EU) can ultimately afford to defend its more valuable cities from flooding (for awhile anyway), other parts of the world aren’t so lucky. A quick look at this sea level rise predictor will show you how many parts of the world, where they simply can’t afford such infrastructure are at risk of getting flooded. And again, its the poor in these countries who’ll get flooded out. Be they poor farmers in the Bengal delta, lower caste urban dwellers in Mumbai, or the Shanty towns of Lagos. And at the other extreme, others will be displaced by drought.


Of course the problem, even for the wealthy, is that flood defences only work if climate change remains nice and predictable, which it probably won’t be. Sea level rise might occur in sudden spurts (as has happened in the past) meaning flood defences can’t be built quickly enough. And beyond a certain tipping point, if sea levels get high enough, such flood defences just won’t work. The trouble with leeves and sea walls is that once they are breached, the effects are often devastating (as Katrina showed). Plus they only stop floods, if ground water gets contaminated by salt water, then it can make it virtually impossible to maintain large coastal cities.

So this brings up the option of what’s called “managed retreat”. However, this terms has, up until now, only been used with regard to maybe a couple of houses at risk from coastal erosion. We’re now talking about whole suburbs or even cities being abandoned. To say this is going to a big deal is to put it mildly. I mean imagine you live in a small working class town in Pennsylvania. How are you going to feel if a few million pushy New Yorkers suddenly show up and start acting like they own the place (which in time they probably will!), then turn your local bar into a hipster cafe. How do you think the locals inland of Lagos (who are mostly Muslim) will react when millions of those displaced by climate change (often Christian) start moving onto their land? And if the bigot brigade think we’ve got a refugee crisis now in America or the EU, wait till a few hundred million show up and want in.

All in all, what these issues show is that no matter how expensive you’ve been led to believe fighting climate change will be, its still going to be cheaper than dealing with the consequences. And for the record, those costs are often wildly exaggerated by the right wing media. If we can’t afford to transition away from fossil fuels, then fundamentally we can’t afford to keep using them.

About daryan12

Engineer, expertise: Energy, Sustainablity, Computer Aided Engineering, Renewables technology
This entry was posted in climate change, environment, politics, renewables, sustainability, sustainable and tagged , , . Bookmark the permalink.

2 Responses to When the leeve isn’t dry

  1. Pingback: The Coronavirus and the failings of populism | daryanblog

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.