抵御海平面上升的经济账

    只有遭遇飓风桑迪这样级别的灾害之后,部分知名的政客才会开始讨论气候变化的影响。在经历了这次造成严重人员伤亡以及大约500亿美元财产损失的风暴潮后，纽约州州长安德鲁•科莫表示，纽约州必须考虑围绕纽约市建造一系列海堤——成本至少达到100亿美元。在最近的一篇社论中，纽约市市长迈克尔•布隆伯格重提很多气候科学家和专家一直以来强调的观点：现在要扭转全球变暖的负面后果已经来不及了；正如一位领先的对冲基金经理告诉我的，我们最多能做的就是“适应它”。

    这意味着改变自己：重新设计我们的港口，管理我们的海岸线，以及建设我们的建筑和交通系统从而限制更加频繁和更具威力的飓风所造成的损害。罗森兹威格是美国国家航空航天局戈达德空间研究中心（NASA Goddard Institute for Space Studies）资深研究科学家，同时也是一个名为“纽约市应对气候变化专门委员会”（New York City Panel on Climate Change）的咨询委员会的联席主席。他说像雨水沟这么简单的东西经设计后就可以用来将地铁、铁路和污水处理厂的淹水最小化。9.11之后，高盛集团（Goldman Sachs）在设计其位于曼哈顿下城的新总部时，安装了一套强大的发电机，尽管它所处的楼层非常高，足以避开最近发生的洪水灾害。众所周知，荷兰人正面临海平面上升的威胁，他们现在设计的公寓大厦可以抵御大量的水流进出建筑的情况。

    除了重新考虑建设方式之外，我们还应该重新考虑在哪里建设。联邦洪水保险（Federal flood insurance）补贴那些在飓风袭击后重建家园的屋主和企业主，这已经耗费了美国纳税人数十亿美元。如果取消联邦洪水保险，私营市场在制定保险价格时将更加现实（因此也会更高），容易遭受袭击的海岸线地区可能会因此遭遇发展方面的制约。

    最极端的补救办法是建设水闸来防御风暴潮。全球很多城市，包括伦敦、新加坡和鹿特丹，都建立了类似的水闸。纽约市可能非常需要建造自己的水闸，但是除了费用高昂外，这些水闸还会带来很多问题。例如，工程师设计建筑的标准通常是能够应对百年一遇的灾害。根据美国宇航局的罗森兹威格，在纽约市巴特里公园（Battery Park）地区，8.6英尺高的洪水就被认定为百年一遇。超级飓风桑迪达到10.6英尺高，属于500年一遇的级别。此外，建设海堤以保护曼哈顿仅仅可能将洪水引到这个城市其他未受保护的区域，加剧这些地区的灾害程度。而且，目前并不清楚这类水利工程会对本地区的渔业和河口产生什么环境影响。

    调整自己以适应新的常态将耗费全球企业和政府数千亿美元的资金，但是与桑迪和卡特里娜等飓风所造成的损害相比，这或许更为划算。然而，这个问题有光明的一面：准备重新审视、重新建设我们脆弱的基础设施的企业业务将会非常繁忙。

    翻译：秋闲

    It took a disaster on the scale of Hurricane Sandy to finally get some high-profile politicians talking about the impact of climate change. In the wake of a heavy death toll and an estimated $50 billion in damage from the storm surge, New York Governor Andrew Cuomo argued that the state must consider building a series of seawalls around New York City -- at a cost of at least $10 billion. In a recent editorial, Mayor Michael Bloomberg echoed what many climate scientists and experts have been saying for some time now: It's too late to reverse the negative consequences of global warming; the best we can do, as one leading hedge fund manager told me, is "get used to it."

    This means adaptation: redesign our ports, manage our coastlines, and construct our buildings and transportation systems to limit the damage caused by more frequent and more powerful storms. Cynthia Rosenzweig, a senior research scientist at NASA Goddard Institute for Space Studies who co-chairs an advisory board called the New York City Panel on Climate Change, says that something as simple as a storm drain could be engineered to minimize subway, rail, and sewage-treatment-plant flooding. After 9/11, Goldman Sachs (GS) designed its new headquarters in lower Manhattan with a set of powerful electrical generators on a floor high enough to be safe from the recent floodwaters. The Dutch, who know about living close to rising seas, are designing apartment towers that allow for massive water flow into, and out of, the structures.

    Besides rethinking how we build, we have to rethink where we build. Federal flood insurancesubsidizes home and business owners who rebuild after a storm, and that has cost U.S. taxpayers billions. By eliminating federal flood insurance, the private market will price policies more realistically (and thus higher), which would limit development along vulnerable coasts.

    The most extreme remedy would be to construct sea gates to ward off storm surges. Many cities around the world, including London, Singapore, and Rotterdam, have such gates. New York City may well need to build its own, but they present many problems besides their high cost. For example, engineers usually design a structure to handle a one-in-100-year event. According to NASA's Rosenzweig, in New York City's Battery Park neighborhood an 8.6-foot flood height is designated as a one-in-100-year event. Superstorm Sandy reached 10.6 feet -- a one-in-500-year event. Also, erecting seawalls to protect Manhattan could simply divert the surge to other unprotected areas of the city, exacerbating flooding in those boroughs. And it's unclear what the environmental impact of such maritime structures would be on the region's fisheries and estuaries.

    Adapting to the new normal will cost businesses and governments around the globe hundreds of billions, but that may be a bargain compared with the damage future Sandys and Katrinas cause. There is, however, a bright side: Business should be very good for those companies ready to rethink and rebuild our vulnerable infrastructure.