气候变化冲击保险业，瑞士再保险如何应对挑战

阳光灿烂的夏日里，站在全球保险巨头瑞士再保险（Swiss Re，以下简称“瑞再”）的总部远望，苏黎世湖岸上的一切都那么和谐。这处熙熙攘攘的港湾犹如明信片封面般美丽，有着古铜色皮肤的日光浴者、深色船体的游艇和啜饮着葡萄酒的野餐人群。在沿湖的街道上，骑自行车的人不断地打响铃铛提醒行人，蓝白相间的有轨电车准时地运行着。瑞再的总部包括一座于1913年建成的新巴洛克式大厦，以及一座包裹着波浪形玻璃幕墙的2017年新增建筑。总部内白色的墙壁上悬挂着价值数百万美元的艺术品，以皮革和钢材为主要内饰的咖啡吧供应三种碳酸浓度的矿泉水，员工自助餐厅提供薄荷冰冻凉瓜汤、芒果酸辣酱有机豆腐、水果馅饼和冰淇淋。

但瑞再的情况绝对谈不上平静。这家有着155年历史的公司在2018年实现保费收入364亿美元，是全球最大的“再保险”公司。高管们正在焦急地衡量一些最主要客户在瑞再业绩中的占比。拥有博士学位的科学家则在钻研算法，旨在找出应对成本不断膨胀的方法。面对持续增大的压力，瑞再的高管对很多自己已知的风险评估知识提出了疑问，他们的决定则有可能改变数十亿美元资金的流向。

再保险商几乎不为人所知，但对商业很关键，是全球经济的保障。它们为规模巨大的跨国工业设施提供保险，同时为原保险公司觉得需要对冲的大量风险提供保障。这让它们成为资本主义健康状况的先行指标，四处扩张的企业向它们付费，以便找出并管理潜质的重大风险。如今，气候变化成为了让瑞再特别担心的一种威胁，因为像世界上的所有其他公司一样，瑞再还不知道如何准确地对其进行量化，更不用说予以应对了。

对保险行业来说，全球变暖已经从一个未来的生态挑战演变成了就在眼前的经济冲击。2018年，重大自然灾害和“人为灾难”一共造成了1650亿美元的损失；2017年这个数字是3500亿美元，是前者的两倍以上。因此，瑞再的下属机构瑞再研究院指出，2017和2018年是有记录以来保险商此类巨灾成本最高的两年，它们的全球赔付额超过2190亿美元。2018年保险商的赔付多发生在北美，触发因素包括野火、雷暴和飓风。今年3月，瑞再的首席执行官缪汶乐在2018年年报中对股东表示，2018年巨灾造成的经济影响“令人震惊”。他明确指出，瑞再相信这样的趋势和全球气温上升有关：“我们必须把过去一年的经历视为警告，它要我们团结起来并为应对气候变化做出更多努力。”

保险行业对局势的起起伏伏已经习以为常。过去20年中，瑞再的自然巨灾业务所获保费是其赔付额的两倍以上。2017年，瑞再根据精算平均值预计的大宗“自然巨灾”损失为11.8亿美元，而赔付额达到了36.5亿美元。2018年瑞再预测的损失为11.5亿美元，赔付额则为19亿美元。当年最大的损失来自于飓风，即源于北大西洋和东北太平洋的剧烈风暴。问题在于这是瑞再以往赔付水平的短暂波动，还是气候变化引发的损失开始进入长期上升阶段。

目前瑞再正在进行调整，已免利润受到上述不利因素的影响。瑞再相信煤炭的盈利能力正在下降，因此已经开始压缩对煤矿以及燃煤企业的保险和投资。此举让瑞再的一些蓝筹客户感到不满。由于担心需要慎重地重新考量用于预测自然灾害风险进而为相应保险“定价”的复杂数学模型，瑞再正在努力改进该模型。这些潜在重大调整都有可能对整个瑞再产生影响。但这些措施都处于起步阶段，而且实际情况证明其难度都令人抓狂。

今年夏天的一个上午，我坐在瑞再苏黎世总部大厦的一间会议室中，桌子对面的瘦高个则是瑞再的可持续性风险管理部门负责人、气候科学家蒂埃里·科尔蒂。他告诉我：“我们日思夜想的就是我们这个世界会出现什么样的大麻烦。”但他认为，气候变化“或许是人类智慧不足以真正应付的问题”。我的这次采访就像一个征兆——接下来持续一周的热浪让瑞士乃至欧洲的气温都打破了历史记录。

On a radiant summer day, all looks precisely right on the shore of Switzerland’s Lake Zurich, at the headquarters of global insurance behemoth Swiss Re. The postcard-perfect harbor bustles with bronzed sunbathers, dark-hulled yachts, and picnickers sipping wine. On the street alongside it, cyclists dutifully ring their handlebar bells for pedestrians, and blue-and-white city trams run on time. Inside the headquarters itself—a complex comprising a 1913 neobaroque edifice and a 2017 addition sheathed in undulating glass—art worth millions adorns white walls, coffee bars accented in leather and steel dispense mineral water in three levels of carbonation, and the employee cafeteria serves up chilled melon soup with mint, organic tofu with mango chutney, and fruit tarts and ice cream.

Yet things are anything but placid for Swiss Re, the 155-year-old corporation that, as measured by the $36.4 billion in revenue it collected from premiums in 2018, is the world’s largest “reinsurance” company. Executives anxiously are weighing the insurer’s financial exposure to some of its biggest clients. Ph.D. scientists are poring over algorithms to figure out how to cope with ballooning costs. Under intensifying pressure, they’re questioning much of what they know about assessing risk—and making decisions that could redirect billions of dollars.

Little known but crucial to commerce, reinsurers act as backstops of the global economy. They insure major multinationals, huge industrial facilities, and vast portfolios of risk that first-line insurance companies decide they need to hedge. That makes them leading indicators of the condition of capitalism—sprawling enterprises paid to ferret out and manage emerging mega-threats. Today, the threat that particularly worries Swiss Re is one that, like essentially every other company on the planet, it hasn’t figured out how to accurately quantify, let alone to combat: climate change.

For the insurance industry, global warming has advanced from a future ecological challenge to a present financial shock. Together, total losses to the economy from natural catastrophes and “man-made disasters” reached $165 billion in 2018; that followed a 2017 that, at $350 billion, cost more than twice as much. As a result, according to the Swiss Re Institute, the company’s research arm, 2017 and 2018 were for insurers the most-expensive two-year period of such catastrophes on record, requiring them to fork over $219 billion globally in checks. The majority of the insurers’ 2018 payouts were in North America, triggered by wildfires, thunderstorms, and hurricanes. The economic impact from catastrophes in 2018 alone was “shocking,” Christian Mumenthaler, Swiss Re’s chief executive, told shareholders this past March, in the company’s 2018 annual report. And Swiss Re is convinced, Mumenthaler made clear, that the trend is linked to rising temperatures: “What we’ve experienced over the past year must serve as a wake-up call to stand together in unity and step up our efforts against climate change.”

Ups and downs are old hat to the insurance industry. Over the past two decades, Swiss Re’s natural-catastrophe business has collected more than twice as much in premiums as it has had to spend in payouts. The company’s stock price is robust, and rating agencies generally give Swiss Re high marks. But a potentially worrying trend is developing: For the past two years, Swiss Re has had to pay out vastly more for large natural catastrophes, those over $20 million apiece, than its models anticipated for an average year’s loss. In 2017, Swiss Re expected to incur $1.18 billion in large “nat-cat” losses, based on actuarial averages, but racked up a bill of $3.65 billion. In 2018 it anticipated a $1.15 billion hit but had to absorb $1.9 billion. The biggest single blow that year came from hurricanes—the intense storms that originate in the North Atlantic and Northeastern Pacific. The question is whether this is a rough patch of the sort Swiss Re has absorbed before, or the start of a long-term rise in losses triggered by climate change.

Now the insurer is undertaking a corporate repair job designed to insulate its profits from the heat. Believing that the profitability of coal is on the wane, it’s pulling back from insuring and investing in companies that mine or burn the black rock—a retrenchment that has some of its blue-chip clients fuming. Worried that the complex mathematical models it uses to predict and then “price” coverage for natural-disaster risks need serious rethinking to account for a warming world, Swiss Re is scrambling to improve them. These are potentially pivotal fixes that could have sweeping consequences for business. But each is in its nascent stages, and each is proving maddeningly hard.

One morning this summer, I find myself in a conference room in Swiss Re’s complex in Zurich, sitting across a table from Thierry Corti, a lanky Ph.D. climate scientist who works as the company’s head of sustainability-risk management. “We think day and night about what can go terribly wrong in this world,” he tells me. But climate change, he says, “might be the problem that humanity is not clever enough to really tackle.” As if as an omen, my visit marks the start of a weeklong heat wave that will shatter temperature records across Switzerland and Europe.

在整个金融行业，从银行到养老基金再到保险公司，龙头企业的结论都是气候变化可能让它们蒙受巨大损失。整体而言，它们认为在全球变暖环境下，资本面临两大威胁。

一是“过渡风险”，也就是在监管部门和投资者认真对待碳减排后大量沉淀投资的价值可能缩水的局面。对化石燃料发电厂、煤矿、油田、燃油车制造企业以及这些资产背后的公司来说，随着社会脱碳，它们的盈利能力可能直线下降。如果这种变化真的上了规模，数万亿美元的基础设施就可能失去价值，成为投资者所说的“搁浅资产”。

有迹象表明这种情况已经出现。煤炭股价格下跌，很大一部分原因是低碳燃料的成本竞争力不断增强——道琼斯美国煤炭行业指数已经从2011年的高点下滑95%。今年1月，设在荷兰的大型保险公司首席风险官组织CRO论坛发出警告称，保险商可能遇到和气候有关的新型索赔，其中包括它们提供保险的公司因为打官司而产生的巨额赔付。目前，对造成气候变化或未能就气候变化采取足够应对措施的主要碳排放企业提起诉讼的情况才刚刚出现。但瑞再已经发现了这种不详的趋势，那就是把气候问题归咎于污染企业的科学“发展的很快”。

另一个威胁就是“实体风险”，即不断上升的气温带来的海平面上升、风暴的强化以及干旱引起的野火可能足以大量消耗公司资产负债。瑞再研究院绘制的近期灾害损失图看起来就像一山更比一山高的阿尔卑斯群峰——2012年吹袭纽约的飓风桑迪、2017年横扫得克萨斯与路易斯安那的飓风哈维以及2018年加州宛如末日降临的火灾。观察人士称，到本世纪中叶，同类灾害会让目前已经出现的那些恍如隔世。CRO论坛指出，在美国，一些沿海和紧挨森林的地区“已经处于无法提供保险的边缘”。

这样的担忧已经促使全球经济中一些体量最大的成员采取行动。单是今年的例子就包括，世界上首屈一指的挪威主权财富基金表示它正在抛售纯粹的石油天然气勘探开采公司的股票，以及英国央行要求英国保险公司评估气候变化对其回报可能产生怎样的影响。在过去几年中，多家全球规模最大的保险和再保险公司都宣布开始压缩煤炭相关业务，比如投资或者保险，或二者兼而有之，这包括德国的安联保险和慕尼黑再保险、法国的安盛和法国再保险以及美国市场份额最大的丘博保险。但像瑞再这样深入采取行动几乎还没有。这项措施最终能否像瑞再期望的那样保护它免受巨灾的冲击，还是像部分高管心中所顾忌的那样将大量市场份额拱手让给不那么担心气候问题的对手取决于瑞再度过这个转型期的技巧性如何。

死亡和损失是瑞再的收入源泉。但瑞再的美洲业务负责人J·埃里克·史密斯表示，瑞再发现气候变化关乎自身存亡的一个问题是，随着全球变暖，瑞再在评估今后一系列灾难时“预测频率的能力变得有些儿不可靠了”。史密斯这样描述他和其他高管的对话：“我们私下里会说：‘老天，这两年已经很糟糕了，还会有第三个糟糕的年头吗？’”强大飓风扎堆出现“绝对有问题。年复一年地出现这样的情况绝对不是正常现象”。

Throughout the financial sector, leading players, from banks to pension funds to insurers, are deciding they could lose big from climate change. Broadly, they cite two threats to capital in a warming world.

One, “transition risk,” is the specter that the value of massive sunk investments could shrivel, as regulators and investors get serious about slashing carbon emissions. The profitability of fossil-fueled power plants, of coal mines and oilfields, of factories that make internal--combustion-powered cars—and of the companies behind these assets—could plummet as society decarbonizes. If the shift reached meaningful scale, trillions of dollars worth of infrastructure could lose value, devolving into what investors call “stranded assets.”

There are signs this already is happening. Coal stocks have tanked, in large part because of the increasing cost-competitiveness of lower-carbon fuels: The Dow Jones U.S. Coal Index is down 95% from its 2011 peak. In January, the CRO Forum, a Netherlands-based organization of chief risk officers of big insurers, warned of new sorts of climate-related claims that may confront insurers. Among them: hefty bills from corporations they insure against lawsuits. At this point, legal action charging that big carbon emitters contributed to climate change or failed to react sufficiently to it is just beginning to emerge. But, as the insurance group noted ominously, the science of pinning climate blame on corporate polluters “is developing fast.”

The other threat is “physical risk”: that warming temperatures could trigger enough sea-level rise, storm intensification, and drought-fueled wildfires to wipe vast sums off corporate balance sheets. A Swiss Re Institute chart tracing damage from recent threats looks like ascending peaks in the Alps: Hurricane Sandy in New York in 2012, Hurricane Harvey in Texas and Louisiana in 2017, and the apocalyptic California fires of 2018. By mid-century, observers say, the damage could make what has emerged so far look quaint. In the U.S., the CRO Forum declared, some coastal and forest-fringe areas “are already on the edge of uninsurability.”

Such worries are spurring some of the global economy’s biggest players to act. This year alone, Norway’s sovereign-wealth fund, the world’s largest, said it’s divesting its holdings in pure-play oil-and-gas exploration and production companies, and the Bank of England asked U.K. insurers to assess how climate change might affect their returns. In the past couple of years, many of the world’s biggest insurers and reinsurers—among them Germany’s Allianz and Munich Re, France’s AXA and SCOR, and Chubb, whose biggest market is the U.S.—have announced they are pulling back their coal exposure, either in their investments, their insurance books, or both. Few, though, are taking steps as deep as Swiss Re. Whether those steps end up protecting Swiss Re from cataclysmic exposure, as the company hopes, or handing chunks of its market share to less-climate-concerned rivals, as some executives admit they fear, will depend on how skillfully Swiss Re negotiates this transition.

Death and destruction are Swiss Re’s bread and butter. But what the company finds existentially worrisome about climate change, says J. Eric Smith, Swiss Re’s Americas chief, is that, as the world warms, the company’s “ability to predict frequency” in assessing the future flow of mayhem “is becoming a little shaky.” Smith describes discussions he has had with his fellow executives: “What we say in private is, ‘My gosh, we’ve had two bad years, and now we’re going to have a third bad year?’ ” The crush of intense hurricanes is “ just not right. It’s just not normal that this is happening year after year.”

2015年巴黎气候大会过后，瑞再下决心应对气候变化加剧问题。在这次大会上，大多数国家都主动承诺将进行足够减排，以防止全球平均温度比工业化之前的水平上升逾两摄氏度。大多数的科学家都认为，超过这个水平，气候变化就会带来尤其危险的影响。

和许多大公司一样，瑞再也主动做出了类似承诺。公司内部进而开始分析自己的投资和保险决策方式是怎样帮助碳密集型基础设施筹集资金的。科尔蒂回忆说，很快对煤炭的支持就成了“热点，或者说最显眼的目标”。

瑞再的初步措施比较简单明了，那就是收回对采煤和动力煤使用企业的投资。和所有保险公司一样，瑞再是一位大投资人，它把保费收入用于各种各样的资产，目的是为今后的支出获取资金。2016年，瑞再开始收回采矿领域的投资，标准是收入的三成以上来自于煤炭以及燃煤发电机组装机容量占比超过30%的电力公司。经过筛选，此类投资的规模只有13亿美元，占瑞再1320亿美元总投资的1%左右。但瑞再将此视为向低碳行业转移资产的第一步——此举不光有益于环境，更重要的是，它也具有金融审慎性，因为可再生能源的成本正在不断下降，从而使煤炭的竞争力不断减弱。

瑞再的第二步在其内部引起了较大争议，原因是这涉及到了它的核心业务，也就是首先要决定是否承保。经过内部讨论，瑞再从2018年7月开始不再为煤炭“敞口”超过30%的风险池提供保险服务。在这个概括性词汇之下是一条重要的细节，那就是瑞再不会把这条限制用于要买保险的整个公司，而只会针对后者希望瑞再提供保险或再保险服务的具体资产。

瑞再的高级可持续性风险经理莱斯·沃尔奎斯特解释说，缩小排除范围可以“减少间接伤害”。瑞再甚至可以向偏重煤炭的公司卖保险，前提是这公司希望瑞再承保的对象本身不偏重煤炭。沃尔奎斯特指出：“我们甚至可以为最大的煤炭公司提供保险。”如果后者想让瑞再承保的是“太阳能电站”。他还说，这项决定让瑞再牺牲的保费收入“很少”。

然而，也许涉及的金额不大，但此举让粉丝和对手都觉得瑞再干了件大事。气候变化活动人士非常想让出资人切断资金供应，从而“干掉”已经陷入困境的煤炭行业，而全球最大的再保险商决定采取这样的措施是一次重大胜利。波兰的煤炭发电量占比仍然在80%左右，该国的反煤炭活动人士库巴·戈戈莱夫斯基说：“说到可以解决气候变化问题的领域，那实际上就是再保险，而最发达国家的再保险给我们的杠杆最大。”

瑞再并未透露上述煤炭相关保单让它从哪些公司或保险商那里撤了资，也拒绝就本文对任何公司发表评论。但基于戈戈莱夫斯基的研究，瑞再看来至少终止了一部分为PZU提供的再保险，后者是波兰一家大型保险商，而且有很多煤炭业务。PZU会在年报中列出3至5家为其提供再保险服务的顶尖“合作伙伴”，2015和2016年瑞再曾经被列入PZU的年报，但没有出现在2017年的年报里。PZU称目前瑞再仍然是该公司10大再保险商之一，但拒绝透露瑞再是否撤回了任何保险。

瑞再的行动对于依赖煤炭而且被瑞再切断保险服务的公司来说显然是个问题，这其中就包括美国电力，后者是美国最大的燃煤和发电企业之一。美国电力的投保资产约为7.5亿美元，其中的很大一部分是发电厂，瑞再则是承保团成员之一。美国电力称，瑞再覆盖了该公司约3%的风险。但美国电力总部设在俄亥俄州哥伦布市，该公司负责资金和风险的高级副总裁朱莉·斯洛特说，今年5月，瑞再通知美国电力从7月1日起它将不再续保，原因是相关资产的煤炭发电量超过30%。美国电力称，其他保险公司填补了瑞再留下的缺口，而且没有造成保费增长。但斯洛特也指出，“我们确实得密切关注”保险行业越发抗拒煤炭的问题。

和许多发电企业一样，美国电力也承诺降低碳排放。1999年该公司的燃煤机组装机容量占比为66%，目前已经降至45%。斯洛特说2030年这个比例将下滑到27%，而且现在“除了维护以外，你不会看到我们向任何燃煤型设施投资了”。

斯洛特指出，瑞再在评估美国电力的燃煤业务占比时不应该以现有发电厂为准，而是应该考察美国电力正在建立的新基础设施。决定退出就等同于瑞再放弃了本可以敦促美国电力做出更大改变的杠杆。斯洛特说：“我们把保险商视为合作伙伴，从这个角度来说，天哪，他们的话语权可大了。”她还将瑞再的方法称为“错误路线”。

瑞再却不断加大力度。今年9月，该公司宣布将提高煤炭投资筛选标准，对其投资的公司设定相关占比的绝对上限。瑞再表示，将从煤炭年产量达到和超过2000万吨的采矿企业以及燃煤机组装机容量超过10吉瓦的发电公司撤资。它还提出了更高的目标，那就是到2050年使总投资和保险业务实现碳中性，也就是说届时瑞再所持资产的碳排放量和碳减排量将并驾齐驱。

Swiss Re’s resolve to confront climate change intensified after the 2015 Paris climate conference, the international gathering at which most countries made voluntary pledges to stanch their emissions enough to prevent average global temperatures from jumping more than two degrees Celsius above preindustrial levels. That’s the threshold beyond which, most scientists say, climate change would have particularly dangerous effects.

Like many big companies, Swiss Re signed a similar voluntary pledge. That in turn triggered a decision inside the company to analyze the way its investments and its insurance decisions were facilitating the financing of carbon-intensive infrastructure. It wasn’t long, Corti recalls, before support for coal emerged as “the hotspot—the elephant in the room.”

Swiss Re’s initial move was a relative no-brainer: dialing back the money it invested in companies that mine and burn power-related coal. Swiss Re, like insurance companies generally, is a large investor; it parks premium revenue in various assets to earn money to finance future payouts. In 2016, Swiss Re began pulling its investments in mining companies that derive more than 30% of their revenue from coal and from power companies for which coal represented more than 30% of their generation capacity. The investments snagged by that screen have amounted to only $1.3 billion, or about 1% of Swiss Re’s $132 billion investment portfolio. But Swiss Re saw it as a first step in shifting its assets to lower-carbon sectors—a matter not just of environmental benefit but, more important, of financial prudence, with renewable energy getting cheaper and making coal less competitive.

Swiss Re’s next move was more controversial within the firm because it involved the core of its business—deciding whom it would and wouldn’t cover in the first place. After internal debate, Swiss Re began in July 2018 to decline to insure pools of risk with “exposure” to coal that exceeded 30%. Underneath that catchall word was some important fine print: Swiss Re would apply the restriction not to the whole company that was applying for coverage but only to the specific property that that company wanted Swiss Re to insure or reinsure.

That narrower exclusion would cause “less collateral damage,” explains Lasse Wallquist, senior sustainability-risk manager at Swiss Re. The company could sell insurance even to coal-heavy firms—as long as what those firms wanted Swiss Re to insure wasn’t itself coal-heavy. “We would insure the biggest coal company ever,” Wallquist notes, if that company wanted Swiss Re to cover “a solar plant.” The percentage of premium income that it sacrificed to this decision was, Wallquist says, “low.”

However small the sums involved may be, Swiss Re’s moves have struck both fans and foes as a big deal. To climate campaigners keen to asphyxiate the already-ailing coal industry by pushing financiers to cut off its supply of money, the decision by the world’s biggest reinsurer to begin pulling the plug is a pivotal win. Says Kuba Gogolewski, an anti-coal activist in Poland, which still generates about 80% of its electricity from coal: “When you look at where climate change can be tackled, it’s actually reinsurance—and reinsurance in the most-developed countries —where we have the most leverage.”

Swiss Re doesn’t disclose companies or insurers from which it pulled back coverage as a result of its coal policy, and it declined to comment for this story on any names. But, based on Gogolewski’s research, it appears that Swiss Re stopped reinsuring at least a portion of the book of PZU, a big Polish insurer with lots of coal exposure. PZU’s annual reports list the top three to five “partners” providing PZU with reinsurance; those reports included Swiss Re on that list in 2015 and 2016 but not in 2017. PZU says that Swiss Re today remains among PZU’s top 10 reinsurers, and declined to comment as to whether Swiss Re pulled back any of its coverage.

Swiss Re’s move clearly is problematic to coal-reliant companies whose policies the insurer has cut off. Among those companies is American Electric Power, one of the biggest coal burners and electricity producers in the U.S. Swiss Re was part of a consortium covering AEP’s roughly $750 million in insured property, much of which comprises power plants; Swiss Re had covered about 3% of that risk, AEP says. But in May, the insurer notified the utility, based in Columbus, Ohio, that it would decline to renew the policy, effective this past July 1, because more than 30% of the power generated by the assets came from coal, says Julie Sloat, AEP’s senior vice president for treasury and risk. AEP says other insurers filled the breach and didn’t increase AEP’s premiums. But Sloat says the insurance industry’s rising resistance to coal is “something we really keep a watchful eye on.”

AEP, like many power generators, has pledged to dial down its carbon emissions. The portion of AEP’s power-generating capacity that comes from coal was 66% in 1999, has fallen to 45% today, and will drop to 27% in 2030, Sloat says, and these days “you don’t see us invest in—other than maybe maintenance—any coal-based anything.”

Sloat says Swiss Re should judge AEP’s exposure to coal not on existing plants but by the new infrastructure AEP is building. By pulling out, she says, Swiss Re is relinquishing the leverage it had to prod the company toward bigger change. “To the extent that we have insurers that are our partners, my goodness, they have a big voice,” Sloat says, calling Swiss Re’s approach “the wrong path.”

Yet Swiss Re is turning up the pressure. In September it announced it’s tightening its screen on coal investment, adopting an absolute cap on the exposure it will tolerate from companies in which it invests. It said it will divest from mining companies that produce at least 20 million tons of coal per year and from power generators with more than 10 gigawatts of coal-fired capacity. Swiss Re also announced an even more ambitious goal: By 2050, it says, both its investment portfolio and its insurance book will be carbon-neutral, meaning those holdings will remove as much carbon from the air as they put into it.

瑞再退出煤炭领域的措施演变成了旨在避免为其提供资金的行动，它对自身飓风模型的强化则代表着别的东西，那就是保护瑞再“王冠上明珠”的全方位措施。它的对手就是越来越不稳定的自然母亲。

高额自然巨灾赔付数量猛增对瑞再来说无异于响亮的警钟，因为拥有也许是最完善的灾害模型业务一直让瑞再感到骄傲。马丁·伯托格衣着时髦而且直言快语，他已经在瑞再工作了20年，负责巨灾风险事务，其任务是设法对一系列重大灾害进行预测，除了飓风，这些灾害还包括地震、龙卷风、冰雹和洪水。伯托格对我说，“如果有合理的方法，”或者说让你在理解气候变迁方面“超过竞争对手的方法，你就有钱可赚”。

瑞再的研究部门推出了几十个模型，每一个都针对世界上某个地区的某种灾害。其中经济意义最大的是飓风模型，而且比其他模型要大得多。对墨西哥湾的炼油综合设施、迈阿密的海滨公寓以及曼哈顿下城区的全球金融“神经枢纽”来说，这些越发猛烈的风暴会经过价值数万亿美元的基础设施，这促使瑞再不断重新评估它能够通过哪些资产的再保险获得利润，以及以什么样的价格盈利。

Swiss Re’s coal pullback amounts to a parry intended to preserve the finances of the realm. Its push to shore up its hurricane models represents something else: a full-body-armor campaign to defend its crown jewels. The nemesis: Mother Nature, who’s growing increasingly unstable.

Swiss Re’s spike in bills for large nat-cat payouts sounds loud alarms at a company that prides itself on having perhaps the most sophisticated disaster-modeling operation in the business. Martin Bertogg, a natty dresser and straight talker who has worked at Swiss Re for two decades, oversees what the company calls catastrophe perils. The effort seeks to anticipate trends in a biblical list of disasters that, in addition to hurricanes, includes earthquakes, tornadoes, hail, and floods. “If you have a rational approach,” one that allows you to understand the climate’s vicissitudes “better than your competitors, you can be profitable,” Bertogg tells me.

Dozens of models spin out of Swiss Re’s shop, each for a different kind of disaster in a different part of the world. By far the most financially important one is for hurricanes. From refinery complexes along the Gulf of Mexico, to beach condos in Miami, to the global financial nerve center of lower Manhattan, trillions of dollars in infrastructure lie in the path of increasingly violent storms, pressuring Swiss Re to continually reassess which properties it can profitably reinsure, and at what price.

到目前为止，瑞再利润损失中绝对能和气候变化联系在一起的依然很少。这在一定程度上是因为该公司的财产保险期限通常只有一年，从而使其有机会在通过模型察觉到更大的危险时提高费率。但瑞再认为，到本世纪中叶，气候变化将成为风险和损失上升的主要动力。正因为如此，该公司才会如此急迫地想让自己的模型可以抵御气候的影响。

目前，瑞再的分析师已经十分确信气温上升直接带来的问题，比如海平面上升，再比如风暴数量激增和塌方，将因为气候变化而增多。但瑞再模型团队中的大气物理专家迈克尔·葛鲁尔解释说，飓风等巨灾和气候变化并无直接关系，其行为取决于更高的气温和海洋、大气中的复杂系统交互作用的方式，这些巨灾的恶化“真的属于确信度很低的领域”。换句话说，给瑞再带来最大损失的灾害往往正是行动轨迹最难以掌握的那些。

给飓风建模并非脑部手术。但对外行人来说，二者可能相当接近。为了理解此事，我和葛鲁尔在一间阳关通透的会议室里坐了下来，从那里可以远眺苏黎世湖。和科尔蒂与伯托格一样，葛鲁尔也在著名的理工类大学——苏黎世联邦理工学院做研究。

在大多数保险模型中，过去都是一个起点。他们通过以往风暴的行为来预测今后风暴的路径和强度，进而估算其成本。这是一种精算世界观，它假设未来的平均值在本质上和今天一样。为启动此项工作，建模者要把以前飓风轨迹的公开可用数据输入他们的计算机。然后他们会编写代码，从而使模型改变飓风的行为，这一方面基于以往飓风对世界上相关地区的影响，另一方面则基于对飓风普遍行为的理解来随机改变实际飓风的路径。对他们分析的每一场实际飓风，这个模型都会提供大概100或200个理论上的变体。

So far, the hit to Swiss Re’s bottom line that can definitively be chalked up to climate change remains small. In part that’s because its property policies typically last only a year, giving the company a chance to raise rates as its models detect rising dangers. But by mid-century, Swiss Re has come to believe, climate change will be a major driver of increased risks and losses—which is why the company feels so under the gun to climate-proof its models.

Right now, Swiss Re’s analysts have high confidence that events that result directly from higher temperatures—sea-level rise, for instance, and also storm surges and landslides—will increase as a result of climate change. But a worsening of catastrophes whose relationship to climate change is indirect—including hurricanes, whose behavior depends on the way that higher temperatures interact with complex systems in the oceans and the atmosphere—is “really in a low-confidence area,” explains Michael Gloor, an expert in atmospheric physics who’s on the modeling team. The disasters that tend to cost Swiss Re the most, in other words, are precisely the sorts whose trajectory it is least able to divine.

Modeling hurricanes isn’t brain surgery. But to the uninitiated, it can seem pretty close. To try to understand it, I join Gloor in a sun-drenched conference room overlooking Lake Zurich. Like Corti and Bertogg, he studied at ETH Zurich, a renowned science university in town.

In most insurance models, past is prologue. They extrapolate from the behavior of previous storms to predict the path, fury, and, thus, cost of future ones. That’s the actuarial worldview: an assumption that, on average, tomorrow will be essentially like today. To start the process, modelers input into their computers publicly available data on the trajectory of previous hurricanes. Then they write code that causes the model to alter the behavior of that hurricane both based on how other prior storms in that part of the world have played out and by moving around the actual storm’s trajectory randomly, based on knowledge of how hurricanes typically behave. For each actual hurricane they analyze, the model spits out perhaps 100 or 200 theoretical variants of the storm in question.

在屏幕上出现的图中，实际飓风显示为一条红线，瑞再称之为“妈妈”。所有理论变体都以黑线显示，被称为“女儿”或者“意大利面”，原因是它们有些像细细的面条。2017年的飓风玛利亚给多米尼加、波多黎各和美属维尔京群岛造成了极大危害。葛鲁尔翻着这场飓风的图片，然后停在了一张写有代码的图上，一位建模者在那上面写了一句话，内容是“在不设强度指标的情况下创造一些意大利面”。

对每根“意大利面”，模型都会跟踪一连串可能被飓风吹袭的地区，这个带状区域叫做“风场”。模型还会基于海面温度调整对飓风频率的预期。然后，它将这些数据和另一组信息结合起来，后者是对潜在客户投保财产的量化值。从这里开始出现了瑞再真正关心的东西，即一条显示某个飓风可能带来多少保险损失的曲线，其中的每一个点都代表一个带状地区。瑞再用这些“损失频率曲线”来计算保险价格，而按照该模型，这个价格既包括预期的赔付，也会带来可以接受的利润。

瑞银目前的风暴建模基本目标和几十年前一样，葛鲁尔告诉我：“那就是绘制出这些意大利面，让它们反映现在的气候。”

不过，现在建模者考虑的是气候变化可能会让未来的局势显著有别于以往的情况

Graphed on a screen, the actual hurricane appears as a red line, which Swiss Re calls “the mother.” Each of the theoretical variants appears as a black line—called “the daughters,” and also “spaghettis,” because they vaguely resemble thin strings of pasta. As Gloor flips through the model of Hurricane Maria, which in 2017 wreaked havoc on Dominica, Puerto Rico, and the U.S. Virgin Islands, he stops on one screen of code. “Create some spaghettis with empty intensity measures,” says a note from one of the modelers.

For each spaghetti, the model creates a track of the area likely to be impacted by the hurricane’s winds¬—a track known as a “wind field.” It also adjusts the frequency with which it expects hurricanes to strike based on sea-surface temperatures. Then it combines that data with another trove of information, this one quantifying the value of insured property in a potential client’s portfolio. From that comes what Swiss Re really cares about: a curve showing the likelihood that, in each of a number of geographic swathes, a hurricane strike will produce a given amount of insured loss. The company uses these “loss frequency curves” to calculate a premium price that—according to the model—will both cover the expected payout and deliver an acceptable profit.

Swiss Re’s storm modeling today has the same basic goal today that it did a generation ago: “to build the spaghettis,” Gloor tells me, “in a way that they reflect the current climate.”

What modelers now are reckoning with, however, is the likelihood that climate change will produce a future very different from the past.

这些年来瑞再一直在努力，想把自己的模型用于这个不断变暖的世界。最初它在模型中假设气候变化会让每年的飓风数量增加1%，也就是每年欧洲风暴的频率提高1%。随后瑞再放弃了这种做法，因为它觉得验证前者合理性的科学依据还不够清晰。相反，它添加了一个调节因素，体现的是海面温度对飓风频率的影响方式，这个因素一直用到了今天。但近期灾害成本大幅上升，特别是飓风灾害增多已经清楚表明瑞再需要找到更好的办法。

眼下瑞再正在帮助寻找资金，以便频繁出现风暴的大西洋对岸的人们构建出新的模型，从而像瑞再期望的那样真正实现气候智能。在纽约市的Morningside Heights社区，或者说哥伦比亚大学工程学院应用数学和应用物理系，由前小号手、如今的大气科学家亚当·索贝尔领导的团队正在完善这个模型。他们没有借鉴以前气温较低时出现的风暴，而是利用大规模计算能力来创造“人工”风暴。建模者希望以此更好地反映气温较高时期的实际情况。

索贝尔团队采用的人造风暴方法由麻省理工学院的飓风专家凯利·伊曼纽尔开创。哥伦比亚大学团队的秘笈则是它建立的模型，后者囊括了一些特定的物理学预期，旨在体现气候变化影响飓风的方式。他们用的不是瑞再目前的标准做法，或者说一种自上而下的方法，它以此前飓风的路径为起点，并且就像索贝尔所讲的那样，用历史数据“轻轻地让它摇摆一下”。哥伦比亚大学的建模者采取了自下而上的方式，把天气相关因素的数据作为起点，而且是他们认为既和飓风有关，又有可能受全球变暖影响的数据。这些因素包括“风切变”，即在不同高度出现的速度和方向不同的风，以及海面温度和空气湿度。利用这些数据，他们的算法可以计算出飓风何时形成，如何移动以及有多大强度。理论上，这种更具前瞻性的方法有可能更为准确。

理论上是这样。

到目前为止，由于不能确定哪些假设是对的，该模型产生了很多自相矛盾的结论。一个关键问题就是气温上升和湿度的相互影响。较高的气温会让较多的海洋水汽进入大气中，科学家因此普遍认为气候变化会让飓风变得更猛烈。还有许多科学家相信，较湿润的空气会让飓风出现的更频繁。

但气温上升不光会增加空气湿度，它还会提高空气的吸湿能力。哥伦比亚大学的科学家发现，该算法使用的两个湿度指标会产生不同的结果。其中一个是“相对湿度”，即空气含水量和吸湿能力的比例，此时模型显示气候变化会让飓风出现的更频繁。另一个指标则是“饱和差”，即空气吸湿能力和含水量的绝对值之差，这个时候模型则表明气候变化会降低飓风出现的频率。海水温度上升对这两个指标都有影响，从而把哪个指标更重要的问题留给了科学家们。

Swiss Re has struggled for years to adapt its modeling to a warming world. Initially it built into its models an assumption that climate change would produce a 1% yearly increase in storms. 1% yearly increase in the frequency of European wind storms. Later it stopped that practice, concluding the science wasn’t clear enough to justify it. Instead, it added a dial that factors in the way sea-surface temperature impacts hurricane frequency, a factor it still uses today. But the recent surge in the cost of disasters, particularly hurricanes, has underscored the need to find a better way.

Now Swiss Re is helping to fund, on the other side of the storm-prone Atlantic, work on a new model it hopes really will be climate-smart. In New York City’s Morningside Heights neighborhood, at the applied-mathematics and applied-physics department of the engineering school of Columbia University, a team led by a former trumpeter and current atmospheric scientist named Adam Sobel is working to refine it. Rather than extrapolating from storms that occurred when times were cooler, they’re deploying vast computing power to create “synthetic” storms that—so the modelers hope—will better reflect the realities of an era that’s getting hot.

The synthetic-storm methodology that Sobel’s team uses was pioneered by Kerry Emanuel, a hurricane expert at MIT. The Columbia crew’s secret sauce is the model it has written, which incorporates particular assumptions about the physics of how climate change will affect hurricanes. Rather than employing Swiss Re’s current standard, a top-down approach that starts with the paths of past hurricanes and, as Sobel puts it, uses historical data to “just jiggle it a little bit,” the Columbia modelers use a bottom-up method, starting with data on weather-related factors they think are both relevant to hurricanes and likely to be influenced by global warming. Among those factors: “wind shear,” which is the variation in wind speed and direction at different altitudes; sea-surface temperature; and the amount of moisture in the air. Using that data, their algorithm calculates when a hurricane will form, how it will move, and how intense it will be. Theoretically, this more-forward-looking approach could be more accurate.

Theoretically.

So far, uncertainty about which assumptions are the right ones is causing the model to disgorge contradictory conclusions. One key question concerns the interplay between rising temperatures and moisture. Because higher temperatures stuff more ocean moisture into the air, scientists generally agree that climate change will make hurricanes more intense. Many have come to believe the wetter air will make hurricanes more frequent too.

But warmer temperatures don’t just increase the amount of water in the air; they also increase the amount of water the air can hold. And the Columbia scientists have found that their models spit out differing results depending on which of two moisture metrics they feed the algorithms. Using one, “relative humidity,” which is the ratio of the amount of water the air is holding to the amount it is capable of holding, the models say climate change makes hurricanes more frequent. But using another metric, the “saturation deficit,” which is the absolute difference between the amount of water the air is capable of holding and the amount it’s holding, the models say climate change makes hurricanes less frequent. Warmer oceans affect both those metrics—and leave scientists to debate which matters more.

一天傍晚，索贝尔在他没有窗户的办公室里告诉我，“我们差不多已经让自己相信湿度差是更好”的风暴指标。这个办公室的煤渣砖墙涂成了白色，其中的一面墙上挂着一幅颜色鲜亮的抽象画，描绘的是飓风的移动路径，这是索贝尔的母亲为他画的。他也坦率地说：“但我们还不能确定。”在一篇正在审核的科学论文中，索贝尔和他的同事们承认，按照他们的模型，气候变化对飓风频率的影响取决于建模者选择强调哪个湿度指标。索贝尔说：“拿出这样的结果基本上会让我们觉得尴尬。让我们不那么安心的是这就是行业所掌握知识的现状。”

这让要拿出真金白银的一方陷入了成本颇高的两难境地。和索贝尔同在哥伦比亚大学教学并且领导该团队建模工作的李嘉婷说：“问题在于一个说‘增多’，另一个则说‘减少’，该相信谁呢？”

在苏黎世，瑞再的巨灾模型负责人伯托格也很想知道答案。他以带着瑞士外交克制风格的口吻说：“我希望能够更清楚一些。”对于哥伦比亚大学团队的研究结果，他表示瑞再计划调整前者的模型，从而为飓风频率“注入更多的不确定性”。同时，瑞再还将继续寻求进一步的认知。

对努力推敲全球变暖对其利润有何影响的瑞再来说，生活就是这样，而且它要推敲的足够具体，以便帮助自身业务重新定向。说到底，所有公司都面临着同样的策略性难题，它们的投资者和监管者也是如此。但作为全球经济风向标，保险行业首当其冲，它们需要设法计算出气温的上升以及风的变化会怎样影响自己的利润。

我采访瑞再的美洲业务主管史密斯的那个上午风和日丽。他的办公室设在纽约州阿蒙克市，里面摆满了艺术品，向窗外看去，整齐的草坪、树木和水库构成了壮丽的景观。但有关飓风多里安的思绪让空气变得凝重，这场飓风刚刚横扫在阿蒙克市以南1130英里（约1818.56千米）的巴哈马群岛。多里安消退后，据风险分析公司AIR Worldwide估算，它造成的灾害给保险商带来了15亿美元至30亿美元的损失。

如果没有像那样消散，飓风多里安或许会给瑞再的业绩带来更大的冲击。吹着空调的史密斯放松地呼了口气，他告诉我：“到目前为止，今年的情况还不坏。”当然，今年还有几个月才会结束。（财富中文网）

本文另一版本登载于《财富》杂志2019年11月刊，标题为《和涨潮赛跑》。

译者：Charlie

审校：夏林

“We sort of convinced ourselves that saturation deficit was better” as a storm indicator, Sobel tells me late one afternoon in his windowless office, one of its white-painted cinder-block walls hung with a bright abstract representation of a hurricane’s movement that his mother painted for him. “But we don’t know that,” he confesses. In a scientific paper now under review, he and his colleagues admit that, according to their model, whether climate change makes hurricanes more or less frequent depends on which moisture metric a modeler chooses to emphasize. “We would almost be embarrassed about putting this result out there,” Sobel says. “The thing that makes us less uncomfortable is that this is the state of knowledge in the industry.”

Which raises a costly dilemma for players with real money on the line. “The question,” notes Chia-Ying Lee, a Columbia faculty colleague of Sobel’s who has led the team’s modeling work, “is, with one saying ‘more’ and one saying ‘less,’ which to believe?”

Back in Zurich, Bertogg, the Swiss Re catastrophe chief, would love to know. “I was hoping,” he says, exuding Swiss diplomatic restraint, “for a bit more clarity.” In light of the Columbia team’s results, he says, the insurer plans to tweak its models to “add more uncertainty” about hurricane frequency. Meanwhile, the company will keep searching for more understanding.

Such is life for Swiss Re as it scrambles to understand how global warming will affect its profits—and to understand it specifically enough to help it redirect its business. Ultimately, the same strategic conundrum faces all corporations, as it does their investors and regulators. But, as the weather vane of the global economy, the insurance industry finds itself spinning first, trying to calculate how the warming, shifting winds will buffet its bottom line.

On the morning I visit Smith, Swiss Re’s Americas chief, the weather is gorgeous. The view out the windows of his art-filled office in Armonk, N.Y.—a view framing grass, trees, and a reservoir—is sublime. But the air is thick with thoughts of Hurricane Dorian, which has just finished walloping the Bahamas, 1,130 miles to the south. By the time the storm petered out, it generated damage that, according to an estimate from risk-analysis firm AIR Worldwide, cost insurers between $1.5 billion and $3 billion.

Dorian might have walloped Swiss Re’s coffers harder, had the storm not dissipated as it did. “So far, this isn’t a bad year,” Smith tells me, sitting in the air conditioning and breathing a sigh of relief. There are, of course, a few months yet to go.

A version of this article appears in the November 2019 issue of Fortune with the headline “Racing a Rising Tide.”