????去年十月,颶風“桑迪”猛烈襲擊紐約市時，城市規劃者知道，他們不僅僅在目睹一個極端的自然現象，而且也在注視著未來。由于桑迪來襲時不幸正趕上接近最高潮位的潮汐，颶風上岸時，海平面略高于平均水平，這種情況不僅加劇了洪水泛濫及災害損失的程度，而且也讓我們初步認識到，如果全球氣候變化可以預見的兩個影響——惡劣天氣發生頻率的增加以及海平面的持續上升——協同作用的話，情況會如何。答案是，結果不妙。

????土木工程與建造公司Skansa USA Civil Inc.總裁理查德?卡瓦拉羅說：“對我來說，恢復力（resiliency）最多是幾天的功夫。”他引用的“恢復力”是工程師常用的一個術語，通常用來描述一座城市從一場災難中恢復過來的能力。“基礎供應中斷七八天——居民沒有電、沒有汽油——城市完全不能沒有這些東西，我會說我們城市的恢復力并不好。”

????本月早些時候，紐約市市長邁克爾?布隆伯格大步走上布魯克林海軍造船廠（Brooklyn Navy Yard）的講臺，宣布了一項旨在加強紐約市沿海防災能力、耗資總額達200億美元的宏偉計劃。它不僅是為了防御像桑迪那樣的強烈風暴，而且是為了對抗氣候變化本身——主要是海平面上升問題。他執掌的紐約市政府認為，到本世紀20年代，紐約市周圍的海平面會上升四到八英寸，致使數十萬居民所處的區域遭遇“百年一遇的洪水”。通過一系列工程解決方案——沿一線海灘加強沙丘體系，恢復天然濕地以保留水資源，一系列擋浪堤和擋潮堤、防洪堤，防水壁以及防洪墻，甚至類似于曼哈頓下東區（Lower East Side）炮臺公園城（Battery Park City）的一個抬升地平面的新建街區，紐約市政府認為，它可以通過加強工程建設來繞開氣候變化問題，阻擋漸漸侵入的大西洋。他們準備對上述構想投資數十億美元。

????從全球范圍來講，有這種想法的人并不是只有布隆伯格一個。世界各國及各大城市都在迅速認識到如下事實：不管對關氣候變化的來源看法如何，相關數據表明海平面正在以越來越快的速度上升。與此同時，全球保險業組織——日內瓦協會（ the Geneva Association）本周警告說，海洋變暖正在使得包括英國和美國的部分沿海地區在內的一些沿海地區變成按照行業標準衡量的“不可保”地區，而且隨著海平面上升以及海洋持續變暖，符合這個“不可保”標準的城市數量很可能會繼續增加。對于21世紀的城市而言，“恢復力”正迅速成為一項要求，但全球許多主要樞紐城市由于到處都是20世紀、19世紀甚至18世紀建設的正在日趨老化的基礎設施，極其缺乏恢復力。

????所有這一切都使得布隆伯格的計劃顯得相當大膽，而與此同時，什么都不做的代價也可能會輕松超過他估計這項計劃需要耗費的200億美元（有些人估計說，“桑迪”過后的停電期間，紐約市每天在經濟活動方面的損失就高達10多億美元）。卡瓦拉羅說，世界各地有幾個城市正在采取明智的應對措施，這些城市考慮到了恢復力問題，但沒有一個城市擁有能夠控制海平面上升、極端天氣以及洪水等諸多風險的綜合體系。現在，任期即將結束的布隆伯格市政府似乎急于為紐約市打造這樣一個體系，而桑迪已經讓這個問題得到了足夠的重視（而且得到了足夠的聯邦基金），從而使之成為一個政治現實。

????When Hurricane Sandy slammed into New York City last October, city planners knew they weren't just looking at a freak natural occurrence -- they were looking at the future. Thanks to an unfortunate coincidence of very high tides that were nearly peaking when Sandy struck, sea levels were slightly higher than average when the storm came ashore, a circumstance that not only exacerbated flooding and damage but also provided a glimpse of what it looks like when two of the predicted effects of global climate change -- increased incidence of severe weather and rising sea levels -- work in tandem. The result was not pretty.

????"To me resiliency is a couple of days, tops," says Richard Cavallaro, president of civil engineering and construction outfit Skansa USA Civil Inc., invoking the term engineers commonly use to describe a city's ability to bounce back from a disaster. "Being down seven or eight days -- people didn't have power, no gasoline -- these are things that just can't be. I would say our resiliency was not good."

????Earlier this month, New York City Mayor Michael Bloomberg strode to the podium at the Brooklyn Navy Yard and announced an ambitious $20 billion plan to shore up NYC's coastal defenses, not only against severe storms like Sandy but against climate change itself -- chiefly from rising sea levels, which his office believes could rise four to eight inches by the 2020s, putting hundreds of thousands more residents in the 100-year flood plain. Through a series of engineering solutions -- enhanced dune systems along front-line beaches, restoration of natural wetlands for water retention, a series of surge and tidal barriers, levees, bulkheads, and floodwalls, and even a new, built-from-scratch elevated neighborhood similar to Battery Park City in the Lower East Side -- the administration is ready to wager billions on the idea that it can engineer its way around climate change and keep the encroaching Atlantic at bay.

????Globally speaking, Bloomberg is not alone. Cities and nations around the world are rapidly coming to grips with the fact that regardless of how one feels about the source of climate change, data show that sea levels are on the rise at an accelerating rate. Meanwhile, global insurance industry group the Geneva Association warned this week that warming oceans are making some coastal regions -- including parts of the U.K. and the U.S. -- "uninsurable" by industry standards, and that the number of cities meeting that criteria will likely grow as sea levels rise and oceans continue to warm. Resiliency is quickly becoming a requirement for 21st centuries cities, and one that many major global hubs -- packed with aging infrastructure laid down in the 20th, 19th, and even 18th centuries -- sorely lack.

????All of this makes Bloomberg's plan quite audacious even as the cost of doing nothing could easily eclipse his $20 billion price tag (some estimates say NYC lost more than $1?billion per day in economic activity during the post-Sandy blackouts). There are several cities around the world doing many smart things where resiliency is concerned, Cavallaro says, but there's no single city that has an ideal, integrated system for managing the risks of sea level rise, extreme weather, and flooding. Now on the downslope of its tenure, the Bloomberg administration appears eager to create such a system for New York, and Sandy has brought enough attention (and federal funds) to the problem to make it a political reality.