中国与世界,环境危机大家谈

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Stretching city limits (1)

Jared Green

Readinch

American academic Kristina Hill is an expert on the impact of climate change on both built and natural environments. Here she tells Jared Green how design professionals must prepare – both practically and psychologically – to help cities adapt.

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Kristina Hill chairs the landscape architecture department at the University of Virginia.

Jared Green: At a recent conference on wildlife habitats, you said that cities are always warmer than surrounding areas because of the urban heat island effect and are “at the edge of climate change”. What can the experience of cities with elevated heat levels teach us about best and worst ways to mitigate and adapt to climate change?

Kristina Hill: The fact is I have yet to see any “worst” – except perhaps no preparation at all. Here, in the United States, we live in what I call the American Media Bubble. The media aren’t using climate change to sell papers, unlike their Canadian and European counterparts. Since they don’t see the headlines the rest of the world is reading, the average American doesn’t know what’s at stake. And as a result, their elected officials are discouraged from taking action. But the rest of the world is starting to prepare. Our economic future, and the health, safety and welfare of many of our citizens, depends on learning from the best practices that are out there.

The best approach I know of can be simply described using three categories of actions: to protect, renew and re-tool. That means, to protect the most vulnerable people and places, especially the ones that offer the greatest future diversity and flexibility; to renew our basic resources, like soil fertility, water quality and quantity, air quality and human health; and to re-tool, altering urban systems – buildings, transit, landscapes — to use less energy (since energy use is still a proxy for CO2 generation, unless you use only clean sources) and generate fewer wastes that can’t be used by someone else, locally. Most American cities are just at the point of taking stock of the magnitude of their exposure to climate change, but European cities have acted and offer practical lessons.

Cities are at the edge of climate change in several ways. First, in the sense that enough people’s lives and property are at stake to force them to take actions to adapt. Rotterdam is investing to try to make itself “climate proof” because its Europe’s biggest cargo port city, it houses an increasingly large portion of the Dutch population and the Dutch believe in their ability to live with the changing dynamics of water. Not only do they believe in it at home, they also see it as a major export – knowledge and ability they can share with cities all over the world, for a profit.

London has built one of the world’s most famous storm barriers on the Thames because the land in the centre of the city is so valuable, and the population so large, that they can’t afford not to protect it. Hamburg has used a different strategy – also driven by the location of its cargo port inside the city limits. It will allow flooding, but designed a major new part of the city to be resilient to high water, with waterproof parking garages, a network of emergency pedestrian walkways 20 feet above the street and no residential units at ground level. Even the parks in this new Harbor City district are designed to withstand battering by waves and storm surge, either by floating as the waters rise, or by incorporating lots of hard surfaces that only need to be washed off when the waters recede.

These examples fall into the “protect” category of adaptive actions. But from an ethical point of view, the most important way to protect cities is to protect the most vulnerable people who live in them: low-income children and their caregivers (often single mothers), people with illnesses and seniors.

All over the world, people with even modest wealth will be able to protect themselves. They’ll buy better air conditioning, pay more for electricity as fuel prices rise, stay in a hotel when floods come, get health care when they need it, maybe even relocate by buying a home in a less vulnerable location. Children born into poor families where their mothers have to both work and care for them without paid help are in a very different situation. Many people in New Orleans who lived paycheck to paycheck did not evacuate when [Hurricane] Katrina came, not because they were stubborn or unaware but because it was the end of the month and they couldn’t afford to stay in a motel or they didn’t own a car to evacuate with in the first place. Most people in the world are that poor. If we want to adapt, we need to help them adapt.

JG: New York City, London and other major cities have been creating detailed climate change adaptation action plans. What should cities focus on as they develop these plans? What about smaller communities with very limited resources?

KH: In the United States, Chicago has the most detailed and strategic climate adaptation plan. Even so, what they mostly have is a good sense of what the problems are – but not a lot of solutions. This is principally because the problems will emerge over time, and it’s difficult in our political climate to spend lots of public money before a problem is part of everyday life.

This past year was a case in point. In winter, there were unusually large snowstorms in cities like Washington, DC, and people claimed that “global warming” was a hoax. By summer, we found ourselves on track to experience the hottest year ever across the planet as a whole. The second hottest year was 2005. People have a hard time understanding that the real problem is not a gradual warming trend; the real problem is that we’re facing an increase in climate extremes – from snowfall to heat and from floods to drought. Flooding this year in Brazil and now Pakistan has affected the health and security of millions of people, most of whom are children.

Cities need to recognise that it’s not about planning for an average of two to 10 degree warmer summers; it’s the new extremes in rainfall, flooding, drought and the duration of heat waves that will really challenge our infrastructure and affect our lives. Cities need to focus on these extremes, and make investments to be more resilient to them in terms of both the duration and the magnitude of these extreme circumstances.

That’s what I mean by “re-tooling”. Urban systems represent enormous investments of public money, and once built, the debt accrued by building them creates a long lag time before these expensive systems can be changed significantly.

Taking out highways makes some sense, financially as well as in terms of new land use options, because maintaining an under-utilised, polluting roadway ad infinitum is expensive. The effort in the South Bronx [in New York] to remove the Sheridan Expressway is a good example; it could be replaced with a mix of public and market-rate housing, and parks that increase the resilience of that district to flooding while providing clean places to swim when it’s hot. That kind of capital investment is expensive in the short term, but may save public money in the relatively near future while increasing resilience. Our ways of thinking about public infrastructure have to change pretty radically from the old “more is better” attitude if we want cities to avoid spending themselves into a dead-end, with lower quality of life and reduced economic competitiveness.

Cities need to focus on resilience as they make their debt commitments. If they are investing in projects that replace old highways with new ones, but don’t add significant alternatives to driving, like public transit, they’re making a mistake. Those cities will be paying for that non-adaptive project for so long they won’t have any money to spend on adaptation. On the other hand, projects like public transit inside growing cities should be able to extend their debt over a longer period, making them more affordable, because they will expand the options of people who live in the future. They are an investment in future flexibility, and increase our adaptability to trends like rising fuel prices. That makes them an investment in resilience.

I think big cities will have to incorporate both centralised and decentralised infrastructure into their investments. Small communities, on the other hand, will likely have to choose between encouraging density or enabling more people to live off the grid in an affordable, healthy way. With greater density, we can use centralised systems to make these small cities more liveable (with less driving, more walkable neighbourhoods, more affordable infrastructure services). With greater energy, water and waste independence on a house by house basis, and access to cleaner transportation technologies (electric cars), small cities can provide fewer services and make themselves more resilient by keeping their costs from growing.

The latter strategy is pretty optimistic that cleaner, house-based technologies will be ready and affordable, and that people will be willing to live within the limits they generate. I’m not such a technological optimist, so I’d advocate for the density strategy.
 

Jared Green is web content and strategy manager at the American Society of Landscape Architects.

This interview was first published by the American Society of Landscape Architects. It is reproduced here with permission.

NEXT: The changing relationship between cities and wildlife

Homepage image from K38 Rescue shows flooding in New Orleans after Hurricane Katrina. 

  

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中外对话和中外差别

对话嘛,不仅仅是为了对话而对话、说胡话。我们的城市按照某位年轻有为的博主的说法,是“让生活更糟糕”,这个生活的主语当然是人了。野生动物有的话也是在一些饭馆里,特别是高档的。野生动物跑到大街上,啊呀,我怎么说呢,那不是“肉包子打狗,有去无回嘛”?这也不更证明了中外对话的必要性嘛?人家的城市是城市,我们呢,就是个“市”,也就是个做买卖的地方。在中外对话的时候,需要特别注明或者说明,否则容易误解。城市是个例子,教授是另一个,房子呢,更是如此,其它的还有宽带、互联网、网速、保险、节能、减排、书、学校、食品以及人。

Sino-foreign dialogue and the Sino-foreign differences

Dialogue is not dialogue for its own sake. According to a famous young blogger's theory, cities "make life much worse", the subject of life being men of course. If wild animals can be found in restaurants, they're normally in the very top ones. Wild animals run in the streets, and oh my, what can I say, is that not "crossing the Rubicon?" Doesn't this prove the necessity of more Sino-foreign dialogue? Other people's cities are cities, ours are just markets, places where men trade. When there's dialogue between China and the West, we need to be particularly clear, otherwise it's easy to misunderstand. City is an instance, professor is another one, house all the more so, and others include broadband, internet, internet speed, insurance, energy saving, carbon emission reduction, book, food and man.


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