Climate Change megacity flooding climate change

Published on December 19th, 2012 | by James Ayre


World’s Megacities Face Extreme Flooding As Sea Levels Continue To Rise & Storms Increase In Intensity (Large Percentage Of World GDP At Risk)

December 19th, 2012 by  

The megacities of the world are facing the reality of very likely having to deal with increasingly powerful super storms and rapidly rising sea levels as the effects of climate change worsen. Many of these already vulnerable urban areas are rapidly growing and expected to continue to do so into the foreseeable future. These coastal urban areas are also often economic hubs where trillions of dollars of businesses, industry, infrastructure, and banking is based.

megacity flooding climate change

By 2050, the severity of all of these problems may combine to make Hurricane Sandy seem like a minor occurrence. Major adaptations are an absolute necessity to limit the likelihood of extreme destruction to the large coastal urban cities of the world. Even with large investment, it will be impossible to stop all of the effects of climate change. To those that say that large-scale investment to solve these problems isn’t possible, it was large-scale investment in fossil fuel powered infrastructure, deforestation, and the gas-powered automobile that got us here — it can be done again.

By 2070, the most vulnerable of the world’s megacities will be New York City, Miami, and Guangzhou (China), according to the Organization for Economic Cooperation and Development (OECD). “In all these cities, sea level rise will meet a tide of urbanization in the coming decades and set the scene for storms with ever-more catastrophic consequences.”

“Some of those cities with the most at-risk assets now — Tokyo, New Orleans, Amsterdam, Rotterdam, and Nagoya — will, over the next 50 years, be surpassed by Calcutta, Shanghai, Mumbai, Tianjin, Bangkok, Ningbo, and Ho Chi Minh City, booming Asian coastal metropolitan areas where trillions of dollars in economic assets will be vulnerable. So will many millions of these cities’ residents, most of them poor and living in low-lying areas.”

In the same way that many modern banks have grown “too big to fail,” many of these megacities are expected to become “too big to flood.” But they will flood, unless massive infrastructure projects designed to stop the rising seas and increasingly powerful storms are undertaken, many researchers have said. Think about something like the dikes in the Netherlands, but much larger, and also addressing the effects of intensely powerful storms.

“Based on the conservative assumption that sea levels will rise by only 18 inches by 2070, the OECD finds that total assets vulnerable to flooding and storm surges of just 10 of these cities could account for some 9 percent of the world’s GDP. But many climate scientists and coastal experts note that sea level rise forecasts by groups such as the Intergovernmental Panel on Climate Change did not factor in the melting of the Greenland and Antarctic ice sheets. When they are taken into account, these experts say that global sea levels could well rise 3 to 6 feet this century, leaving scores of cities and massive amounts of economic infrastructure dangerously exposed.”

“Even assuming that protection levels will be high in the future,” the study states, “the large exposure in terms of population and assets is likely to translate into regular city-scale disasters at a global scale.”

The majority of the very rapidly growing coastal cities of today’s world have no protection, or close to none. And importantly, and something that is almost always forgotten, many of these coastal regions are sinking. Though this process is to a degree ‘natural’, it has been occurring much more quickly in recent times as a result of large-scale groundwater extraction in these regions.

“If you’re going to live in these places you’re going to spend significant resources protecting your people and your assets,” says Nicholls, co-leader of the Cities and Coasts Research Program at the UK’s Tyndall Centre for Climate Change Research. “How long can you depend upon having the capacity to bounce back?”

As the researchers note, “a major paradox of this century is that we are concentrating more of the world’s wealth and population in vulnerable coastal areas, just as sea level rise and more powerful storms put them at greater risk.”

By the projections of the OECD, more than $35 trillion of the world’s assets will be dependent on these coastal cities by 2070. If these regions suffered large-scale disaster it could seriously damage the world’s economy. And as everyone should know by now, these sorts of disasters are “becoming increasingly endemic.” But there is still “a surprising resistance to looking at what can be done, even among those most familiar with the problems.”

“Society reacts to events,” he says. “Studies don’t trigger action. Floods trigger action.”

Source: The Guardian
Image Credits: Katrina New Orleans via Wikimedia Commons

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About the Author

's background is predominantly in geopolitics and history, but he has an obsessive interest in pretty much everything. After an early life spent in the Imperial Free City of Dortmund, James followed the river Ruhr to Cofbuokheim, where he attended the University of Astnide. And where he also briefly considered entering the coal mining business. He currently writes for a living, on a broad variety of subjects, ranging from science, to politics, to military history, to renewable energy. You can follow his work on Google+.

  • Pingback: Sea Levels Could Rise Substantially More Than Previous IPCC Reports Have Predicted | PlanetSave()

  • Nathan,

    Great post. You point out one of mankind’s major foibles. We are seldom proactive (responding to studies/predictions) but rather we are reactive (responding only after the S*it hit the fan/floods). The IPCC is notoriously behind the curve on the CC issue. Do to the fact that the methane bomb has already exploded ( we are faced with a situation where opining about what might be the outcome in 2070 {in terms of flooded lowlands} is ridiculous [no personal offense meant here]. What we are now faced with is the very high probability of a Permian-Triassic level extinction event on this planet long before then. The sea ,which like the atmosphere respects ONLY the laws of physics, will have risen long before 2070. The science on this is solid and the threat very real ( ) If anyone has ever wanted to be an activist, I’d say that now would be a good time to start.

    Best regards,
    Edward Kerr

    • Nathan

      I agree with you. Any predictions more than a few years into the future aren’t going to address all of the known, and unknown, feed back loops kicking in. And all of the possible effects that will come along with these changes, that simply aren’t known right now.

      On the subject of the Permian extinction event, this research on it (
      says that the whole of the tropics was essentially unlivable for most plants and animals for 5 million or so years because of the extreme heat…

      • Good reference Nathan. I just pray that we can solve this in short order. Too bad that most people think that global warming is a joke or worse some sick hoax. Those of us who understand the problem are sh*tting bricks right now and having most of the people sound asleep is disconcerting, to say the least.

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