????新加坡濱海堤壩(Marina Barrage)由一系列盤踞在攔海大壩之上的巨型鋼閘組成。每道閘門有100多英尺寬，15英尺深。暴雨來襲時，巨大的液壓升降機開啟閘門，排出過量雨水。此外還有7臺水泵（每一臺都能在1分鐘內(nèi)排干一個奧運會游泳池）協(xié)助排水。這不是一道典型的通海閘門，它的目的并不是保護港口和城市免受大海風暴的侵襲。閘門里面的水才是主要關注的對象：它是淡水，不是海水。它是可飲用的。

????濱海堤壩是新加坡最大的水庫之一，據(jù)稱約占這個城邦島國總面積的六分之一——新加坡約250平方英里，相當于紐約5個行政區(qū)的五分之三那么大，或者說只比芝加哥大一點點。它距離市中心的許多旅游景點僅一箭之遙。新加坡的總?cè)丝诩s540萬，是世界上人口密度第二高的國家。濱海堤壩堪稱水利工程史上的一大壯舉，而且是非常醒目的壯舉。在通海閘門旁邊，一棟安放泵艙的建筑物內(nèi)是一個講述新加坡水故事的博物館，它同時也擔任著宣傳新加坡水處理技術(shù)的作用。新加坡公用事業(yè)局(PUB)在一份題為“作為全球水務中樞的新加坡”的報告中指出，2006年至2012年，這種捕獲、凈化、監(jiān)控和轉(zhuǎn)移水的知識為該國帶來了價值逾70億美元的國際合約。隨著氣候的持續(xù)變化，“水務中樞”的生意只會越做越大。

????“在最干燥的亞熱帶地區(qū)，氣候變化預計將顯著降低可再生地表水和地下水資源，”政府間氣候變化專門委員會(Intergovernmental Panel on Climate Change)在上周早些時候發(fā)布的一份報道指出。“這種情況將加劇農(nóng)業(yè)、生態(tài)系統(tǒng)、居民點、工業(yè)和能源生產(chǎn)對水資源的爭奪。”

????于科學家而言，氣候變化是一個活生生的現(xiàn)實，對于投資者來說也日益如此。許多國家對氣候變化的反應極其遲緩，但站在這一領域前沿的國家并不是只有新加坡一個。荷蘭與水相伴相生，并由此成為阻擋不斷上升的海平面的全球?qū)＜摇：商m阿卡迪斯公司(Arcadis)已經(jīng)在世界各地修建了多個海堤，甚至提議建造一個橫跨紐約港、長6,000英尺（約合1828米）的模塊化結(jié)構(gòu)，工程的造價預計高達65億美元。毫不奇怪的是，新加坡和荷蘭建立了一家合資企業(yè)——新加坡代爾夫特水聯(lián)盟（Singapore Delft Water Alliance)，以協(xié)助解決水資源問題，主要是水基礎設施的研發(fā)工作。以色列早就學會了缺水的生活，而且已經(jīng)把海水淡化技術(shù)出口到了幾乎每一個能夠負擔得起的貧水國家，其中就包括新加坡。（歐洲國家甚至使用這種技術(shù)來造雪，以減緩阿爾卑斯山冰川的融化速度。）請注意這樣一個趨勢：淡水或許正變得稀缺，而且會越來越稀少，但只有那些財大氣粗的國家才有能力應用捕獲和轉(zhuǎn)移淡水的技術(shù)。

????“水向高處流，流向有錢的地方，”馬克?賴斯納在自己講述美國西南部發(fā)展歷程的史詩級著作《卡迪拉克沙漠》(Cadillac Desert)一書中這樣寫道。一些旨在把水轉(zhuǎn)移到有錢地區(qū)的計劃乍一看似乎很荒唐。比如，特里?斯普拉格發(fā)明了一種巨大的聚酯袋，先給它裝滿淡水，然后通過海洋拖走。（他稱之為“斯普拉格袋”，難道還有什么其他的好名字嗎？）但斯普拉格的邏輯是合理的。“我只是想解決問題，”他在接受《意外之財：蓬勃發(fā)展的全球變暖生意》(Windfall: The Booming Business of Global Warming)一書作者，記者麥肯齊?芬克采訪時這樣說道。“世界上有足夠多的水，只是所處的地方不對。”

????供職于新加坡公用事業(yè)局的喬治?馬達范對這個問題的理解非常透徹。在濱海堤壩旁，他給我講述了一番新加坡岌岌可危的用水現(xiàn)狀。這座城市的相當一部分用水都是從馬來西亞進口，經(jīng)管道運送而來的。盡管相關的購水協(xié)議在2011年到期后，又被再次延長到了2061年，但我遇到的每一位新加坡人都感受到了水資源的稀缺，同時也敏銳地意識到一個令人不安的事實：他們的用水來自一個時常不太友好的鄰國。有一位商人對我說：“要是新加坡哪一天爆發(fā)戰(zhàn)爭，原因幾乎只有一種：用水問題。”其他用水基本上都來自集水區(qū)，也就是像濱海堤壩這樣的水庫。新加坡?lián)碛?7座水庫；值得注意的是，這些水庫占據(jù)這片陸地三分之二的表面。更引人注目的是，近三分之一的集水區(qū)是在過去幾年建造的。馬達范說，新加坡打算把每一條溪流，每一條小河都轉(zhuǎn)化為集水區(qū)。到2060年，90%的新加坡土地表層都將具備捕獲淡水的能力。

????Singapore's Marina Barrage is a series of gargantuan steel gates atop a dam that holds back the sea. Each gate is more than 100 feet wide and 15 feet deep. During torrential rains, huge hydraulic lifts open the gates and excess water pours out. Seven pumps, each able to drain an Olympic swimming pool in a minute, assist in draining the marina waters. This is not a typical sea gate, meant to protect a harbor and city from seaborne storm surge. The water inside the gate is the primary concern: It's fresh -- as in, not saltwater. It's drinkable.

????The Marina reservoir is among Singapore's largest, boasting a surface area one-sixth the size of the entire island which, at about 250 square miles, is three-fifths the size of New York's five boroughs or just a touch larger than Chicago. It is only a stone's throw from many of the downtown tourist attractions of the city-state, which is the second-most densely populated nation in the world (its population: about 5.4 million). The Barrage is a feat of hydraulic engineering, and a highly visible one. Next to the sea gates, inside the building that houses the pumps tanks, is a museum that tells the story of Singapore's water, which also acts as an advertisement for Singaporean know-how, water-wise. Such knowledge -- of capturing, purifying, monitoring, and moving water -- brought in more than $7 billion in international contracts to Singapore between 2006 and 2012, according to the national water agency PUB (in a report called "Singapore as global hydrohub"). As the climate changes, the "hydrohub" business will only increase.

????"Climate change is projected to reduce renewable surface water and groundwater resources significantly in most dry subtropical regions," the Intergovernmental Panel on Climate Change reported earlier this week. "This will exacerbate competition for water among agriculture, ecosystems, settlements, industry, and energy production."

????Climate change is a reality for both scientists and, increasingly, investors. Entire nations are the slowest to adapt, but Singapore isn't alone at the front of the pack. The Netherlands lives with water, and as a result has become the global expert in holding back the rising sea. The Dutch firm Arcadis has built seawalls the world over, even proposed a 6,000-foot modular structure across New York Harbor, for a cost of $6.5 billion. It should come as no surprise that Singapore and the Netherlands have a partnership -- the Singapore Delft Water Alliance -- to aid research and development in water issues, mainly infrastructure. Israel has learned to live without water, and its desalination technology is exported to nearly every water-poor nation that can afford it, Singapore included. (It is even applied to make snow, to help slow the retreating glaciers in Europe's Alps.) Notice a trend: Freshwater may be becoming scarce and growing scarcer, but the technology to capture and move it is readily available to the deep-pocketed.

????"Water flows uphill to money," Marc Reisner wrote in his epic book about the development of the southwestern U.S., Cadillac Desert. Some of the schemes to move water to money seem, at first, absurd. Take Terry Spragg, who invented an enormous polyester bag to be filled with freshwater and then towed through oceans. (He calls it -- what else? -- The Spragg Bag.) Yet Spragg's logic is sound. "I'm just trying to solve a problem," he told journalist McKenzie Funk in the book Windfall: The Booming Business of Global Warming. "There's enough water in the world, just not in the right places."

????George Madhavan understands this issue acutely. Madhavan works for the PUB, and described the precarious nature of Singaporean water while we stood next to the Barrage. Much of the city-state's water is imported and arrives through pipes from Malaysia. It's an agreement that expired in 2011 and was renewed again until 2061, but every Singaporean I met felt the water scarcity and were acutely aware of the troubling fact that their water came from an often unfriendly neighbor. One businessmen I spoke with told me that "war in Singapore would almost only come about because of water." Nearly all the rest comes from the catchment area, which means reservoirs like the Marina. Singapore has 17 reservoirs; remarkably, they make up two-thirds of all the land surface on this engineered land. Even more remarkably, nearly a third of this catchment area was constructed in just the last few years. Every major river that flows into every major estuary is dammed and turned into catchment. The goal, said Madhavan, is to turn every stream, every rivulet into catchment, too. By 2060, he said, 90% of Singapore's surface area will capture freshwater.