建設(shè)固若金湯的大都市
????去年十月,颶風(fēng)“桑迪”猛烈襲擊紐約市時(shí),城市規(guī)劃者知道,他們不僅僅在目睹一個(gè)極端的自然現(xiàn)象,而且也在注視著未來(lái)。由于桑迪來(lái)襲時(shí)不幸正趕上接近最高潮位的潮汐,颶風(fēng)上岸時(shí),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(zāi)害損失的程度,而且也讓我們初步認(rèn)識(shí)到,如果全球氣候變化可以預(yù)見(jiàn)的兩個(gè)影響——惡劣天氣發(fā)生頻率的增加以及海平面的持續(xù)上升——協(xié)同作用的話(huà),情況會(huì)如何。答案是,結(jié)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(shuō):“對(duì)我來(lái)說(shuō),恢復(fù)力(resiliency)最多是幾天的功夫。”他引用的“恢復(fù)力”是工程師常用的一個(gè)術(shù)語(yǔ),通常用來(lái)描述一座城市從一場(chǎng)災(zāi)難中恢復(fù)過(guò)來(lái)的能力?!盎A(chǔ)供應(yīng)中斷七八天——居民沒(méi)有電、沒(méi)有汽油——城市完全不能沒(méi)有這些東西,我會(huì)說(shuō)我們城市的恢復(fù)力并不好?!?/p> ????本月早些時(shí)候,紐約市市長(zhǎng)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(tái),宣布了一項(xiàng)旨在加強(qiáng)紐約市沿海防災(zāi)能力、耗資總額達(dá)200億美元的宏偉計(jì)劃。它不僅是為了防御像桑迪那樣的強(qiáng)烈風(fēng)暴,而且是為了對(duì)抗氣候變化本身——主要是海平面上升問(wèn)題。他執(zhí)掌的紐約市政府認(rèn)為,到本世紀(jì)20年代,紐約市周?chē)暮F矫鏁?huì)上升四到八英寸,致使數(shù)十萬(wàn)居民所處的區(qū)域遭遇“百年一遇的洪水”。通過(guò)一系列工程解決方案——沿一線海灘加強(qiáng)沙丘體系,恢復(fù)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(lèi)似于曼哈頓下東區(qū)(Lower East Side)炮臺(tái)公園城(Battery Park City)的一個(gè)抬升地平面的新建街區(qū),紐約市政府認(rèn)為,它可以通過(guò)加強(qiáng)工程建設(shè)來(lái)繞開(kāi)氣候變化問(wèn)題,阻擋漸漸侵入的大西洋。他們準(zhǔn)備對(duì)上述構(gòu)想投資數(shù)十億美元。 ????從全球范圍來(lái)講,有這種想法的人并不是只有布隆伯格一個(gè)。世界各國(guó)及各大城市都在迅速認(rèn)識(shí)到如下事實(shí):不管對(duì)關(guān)氣候變化的來(lái)源看法如何,相關(guān)數(shù)據(jù)表明海平面正在以越來(lái)越快的速度上升。與此同時(shí),全球保險(xiǎn)業(yè)組織——日內(nèi)瓦協(xié)會(huì)( the Geneva Association)本周警告說(shuō),海洋變暖正在使得包括英國(guó)和美國(guó)的部分沿海地區(qū)在內(nèi)的一些沿海地區(qū)變成按照行業(yè)標(biāo)準(zhǔn)衡量的“不可保”地區(qū),而且隨著海平面上升以及海洋持續(xù)變暖,符合這個(gè)“不可?!睒?biāo)準(zhǔn)的城市數(shù)量很可能會(huì)繼續(xù)增加。對(duì)于21世紀(jì)的城市而言,“恢復(fù)力”正迅速成為一項(xiàng)要求,但全球許多主要樞紐城市由于到處都是20世紀(jì)、19世紀(jì)甚至18世紀(jì)建設(shè)的正在日趨老化的基礎(chǔ)設(shè)施,極其缺乏恢復(fù)力。 ????所有這一切都使得布隆伯格的計(jì)劃顯得相當(dāng)大膽,而與此同時(shí),什么都不做的代價(jià)也可能會(huì)輕松超過(guò)他估計(jì)這項(xiàng)計(jì)劃需要耗費(fèi)的200億美元(有些人估計(jì)說(shuō),“桑迪”過(guò)后的停電期間,紐約市每天在經(jīng)濟(jì)活動(dòng)方面的損失就高達(dá)10多億美元)??ㄍ呃_說(shuō),世界各地有幾個(gè)城市正在采取明智的應(yīng)對(duì)措施,這些城市考慮到了恢復(fù)力問(wèn)題,但沒(méi)有一個(gè)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(fēng)險(xiǎn)的綜合體系。現(xiàn)在,任期即將結(jié)束的布隆伯格市政府似乎急于為紐約市打造這樣一個(gè)體系,而桑迪已經(jīng)讓這個(gè)問(wèn)題得到了足夠的重視(而且得到了足夠的聯(lián)邦基金),從而使之成為一個(gè)政治現(xiàn)實(shí)。 |
????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. |