Related Articles
0
Disruptive innovation and resilience...
Cities

TARU Leading Edge is a leading Indian Think Tank exploring issues of climate change resilienc...

+ Read More
0
Lessons from the Chennai floods: Local b...
Cities

A year ago this month, heavy rains off the southeast coast of India set off a chain of events...

+ Read More
0
City supply networks: The climate risk b...
Cities

To its inhabitants a city can feel like an island. If you are one of the many billions of peo...

+ Read More
0
The Ethical City: an Idea Whose Time Has...
Cities

Globally, there is intense discussion about the future of urban life through the World Urban ...

+ Read More
Tuesday 23rd October 2012
Can Cities Be 'Sustainable' and 'Resilient'?
Cities Contributor: David Biello

If you've successfully flushed a toilet recently, then you appreciate (at least subconsciously) the workings of a good sewer system. Waste disappears, no matter what time of day or night, or what the weather's like.

But weather is actually a challenge for a sewer system, especially precipitation. That New York City’s sewers can handle the waste of more than 8 million residents on a daily basis—plus the occasional downpour or major storm like Hurricane Irene—is a testament to its resilience.

How does New York do it? Simple: combined sewer outflows. When there's simply too much water in the sewers for the city's wastewater treatment plants to cope, the proverbial flood gates are opened and rainfall mixed with sewage flows into area waterways, such as Newtown Creek or the Gowanus Canal.

That's great for keeping sewage from finding other places to go—like back up into your toilet. But it's less good for places that consistently see such overflows, like the Gowanus Canal. The canal, affectionately called "Lavender Lake" by locals for the multi-hued sheen of its near constant water pollution, carries a raging case of gonorrhea thanks to all that outflow as well as some of the most toxic sludge in the country. In fact, an industrial legacy paired with these "combined sewer outflows" has been enough to turn the canal into a Superfund site—or one of the nation's most polluted localities.

That isn't exactly sustainable. Especially once you consider that downpours and the like are predicted to be on the increase as a result of climate change, as are little threats like sea level rise that could turn outflows into inflows.

In fact, though resilience and sustainability—two of the hottest buzzwords in urban planning—are used practically interchangeably, they are in fact in some tension with each other. A resilient system bounces back from challenges, unharmed, and a big part of building in resilience includes building in ways to fail safely, such as the combined sewer outflows. So, for example, the blackout of 2003 showed how the U.S. power grid remains less than resilient to challenges like untrimmed trees and power lines sagging in the heat. An example of a more resilient technological system is the Internet here in America, where if one route for data fails, another is found.

Sustainability, on the other hand, means efficiency, at least in part, as designers strive to strike a balance between human needs and environmental impacts. This century, the world's megacities will swell to become gigalopolises—vast tracts of urbanized land, like the metropolitan corridor between Boston and Washington, D.C., or the predicted one between Hangzhou and Shenyang. Efficiency in the construction of infrastructure will be vital as the world attempts to build in the next few decades the same amount of urban infrastructure we've cobbled together over the last several millennia. Does that mean foregoing a built-in margin of safety? The Internet may be resilient in the United States, but a reliance on single lines of connection to the rest of the world has disconnected countries across Africa, from Egypt to Uganda. Imagine the same thing happening to an “efficient” sewer system.

Some of the most obvious ways to become more resilient are not sustainable. For example, if you are concerned about reliable electricity, you can increase the resilience of your local grid by buying a diesel generator, or two, or more. In effect, that's what the Googles, Facebooks, and Twitters of the world do. But extra diesel generators are certainly not an efficient, or particularly sustainable, way to create electricity. It's not ideal for the environment to be burning all that extra diesel, with attendant air pollution and the like.

Fortunately, there are ways to think more creatively about how to achieve the same resilience. So, instead of buying a couple big extra generators, a thousand small generators on rooftops might be better, as in the case of solar power on homes. Or programs that reduce the overall demand for power—reducing the stress on the existing electrical grid—can help avoid issues like the 2003 blackout.

Some 5 billion people are projected to live in urban areas by 2030. These cities of the future—most of them cities of today, like New York—will have to cope with climate change, sea level rise, increasing demand for electricity and the logistics of 5 billion peoples' sewage, among other things. New York, at least, has been working on a plan to cope with climate change since 2007, thanks to subtle reminders like an August thunderstorm that year that shut down the city's subway system during morning rush hour. Climate change is predicted to increase the severity of such downpours. That's just as true for heartland cities like Louisville, Ky., which has seen four weather-related disasters in as many years, spurring the development of a climate change adaptation plan, and even up-and-coming cities around the world, such as Surat in India, which is using money from the Rockefeller Foundation to better plan for a history and future of flooding.

As for those combined sewer outflows, well, a little greenery goes a long way. Roofs planted with vegetation, streets that end in rain gardens, even permeable pavement can all go a long way toward making the New York City sewer system both more resilient and more sustainable. In the end, any enduring city must be resilient to a whole host of challenges—from floods and fire to economic collapse—in order to last for the long-term. And what could be more sustainable than that?

 

David Biello is an associate editor for environment and energy at Scientific American

This article also appeared on the website of Scientific American.

Alexandre | Profession | 18.01.2013 | 16:18
1. A quote from the NYTimes article by Muller that I potesd above suggests that he did take instrument sites into account (when he talks about looking at only Rural stations, to avoid the Urban Heat Island Effect:"Our Berkeley Earth approach used sophisticated statistical methods developed largely by our lead scientist, Robert Rohde, which allowed us to determine earth land temperature much further back in time. We carefully studied issues raised by skeptics: biases from urban heating (we duplicated our results using rural data alone), from data selection (prior groups selected fewer than 20 percent of the available temperature stations; we used virtually 100 percent), from poor station quality (we separately analyzed good stations and poor ones) and from human intervention and data adjustment (our work is completely automated and hands-off). In our papers we demonstrate that none of these potentially troublesome effects unduly biased our conclusions."*2. What would convince me that AGW is not a problem? Good question. I admit, if the majority of climate scientists were so convinced, I would feel better about the whole thing. I've come to trust them. When I take the time to look into disputed claims the "alarmists" seem to be right. Perhaps this is because the "skeptic" that I have most often looked at is Christopher Monckton. Perhaps if I had started paying attention to Lindzen things would appear different.Based on what I've seen, we shouldn't be arguing over whether or not AGW is a problem. We should be arguing over the solutions. The "skeptic" camp seems more worried about scary authoritarian "solutions" to the problem. And it seems as if that is driving their skepticism.