氣候變化沖擊保險業，瑞士再保險如何應對挑戰

陽光燦爛的夏日里，站在全球保險巨頭瑞士再保險（Swiss Re，以下簡稱“瑞再”）的總部遠望，蘇黎世湖岸上的一切都那么和諧。這處熙熙攘攘的港灣猶如明信片封面般美麗，有著古銅色皮膚的日光浴者、深色船體的游艇和啜飲著葡萄酒的野餐人群。在沿湖的街道上，騎自行車的人不斷地打響鈴鐺提醒行人，藍白相間的有軌電車準時地運行著。瑞再的總部包括一座于1913年建成的新巴洛克式大廈，以及一座包裹著波浪形玻璃幕墻的2017年新增建筑?？偛績劝咨膲Ρ谏蠎覓熘鴥r值數百萬美元的藝術品，以皮革和鋼材為主要內飾的咖啡吧供應三種碳酸濃度的礦泉水，員工自助餐廳提供薄荷冰凍涼瓜湯、芒果酸辣醬有機豆腐、水果餡餅和冰淇淋。

但瑞再的情況絕對談不上平靜。這家有著155年歷史的公司在2018年實現保費收入364億美元，是全球最大的“再保險”公司。高管們正在焦急地衡量一些最主要客戶在瑞再業績中的占比。擁有博士學位的科學家則在鉆研算法，旨在找出應對成本不斷膨脹的方法。面對持續增大的壓力，瑞再的高管對很多自己已知的風險評估知識提出了疑問，他們的決定則有可能改變數十億美元資金的流向。

再保險商幾乎不為人所知，但對商業很關鍵，是全球經濟的保障。它們為規模巨大的跨國工業設施提供保險，同時為原保險公司覺得需要對沖的大量風險提供保障。這讓它們成為資本主義健康狀況的先行指標，四處擴張的企業向它們付費，以便找出并管理潛質的重大風險。如今，氣候變化成為了讓瑞再特別擔心的一種威脅，因為像世界上的所有其他公司一樣，瑞再還不知道如何準確地對其進行量化，更不用說予以應對了。

對保險行業來說，全球變暖已經從一個未來的生態挑戰演變成了就在眼前的經濟沖擊。2018年，重大自然災害和“人為災難”一共造成了1650億美元的損失；2017年這個數字是3500億美元，是前者的兩倍以上。因此，瑞再的下屬機構瑞再研究院指出，2017和2018年是有記錄以來保險商此類巨災成本最高的兩年，它們的全球賠付額超過2190億美元。2018年保險商的賠付多發生在北美，觸發因素包括野火、雷暴和颶風。今年3月，瑞再的首席執行官繆汶樂在2018年年報中對股東表示，2018年巨災造成的經濟影響“令人震驚”。他明確指出，瑞再相信這樣的趨勢和全球氣溫上升有關：“我們必須把過去一年的經歷視為警告，它要我們團結起來并為應對氣候變化做出更多努力?！?/p>

保險行業對局勢的起起伏伏已經習以為常。過去20年中，瑞再的自然巨災業務所獲保費是其賠付額的兩倍以上。2017年，瑞再根據精算平均值預計的大宗“自然巨災”損失為11.8億美元，而賠付額達到了36.5億美元。2018年瑞再預測的損失為11.5億美元，賠付額則為19億美元。當年最大的損失來自于颶風，即源于北大西洋和東北太平洋的劇烈風暴。問題在于這是瑞再以往賠付水平的短暫波動，還是氣候變化引發的損失開始進入長期上升階段。

目前瑞再正在進行調整，已免利潤受到上述不利因素的影響。瑞再相信煤炭的盈利能力正在下降，因此已經開始壓縮對煤礦以及燃煤企業的保險和投資。此舉讓瑞再的一些藍籌客戶感到不滿。由于擔心需要慎重地重新考量用于預測自然災害風險進而為相應保險“定價”的復雜數學模型，瑞再正在努力改進該模型。這些潛在重大調整都有可能對整個瑞再產生影響。但這些措施都處于起步階段，而且實際情況證明其難度都令人抓狂。

今年夏天的一個上午，我坐在瑞再蘇黎世總部大廈的一間會議室中，桌子對面的瘦高個則是瑞再的可持續性風險管理部門負責人、氣候科學家蒂埃里·科爾蒂。他告訴我：“我們日思夜想的就是我們這個世界會出現什么樣的大麻煩?！钡J為，氣候變化“或許是人類智慧不足以真正應付的問題”。我的這次采訪就像一個征兆——接下來持續一周的熱浪讓瑞士乃至歐洲的氣溫都打破了歷史記錄。

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.

在整個金融行業，從銀行到養老基金再到保險公司，龍頭企業的結論都是氣候變化可能讓它們蒙受巨大損失。整體而言，它們認為在全球變暖環境下，資本面臨兩大威脅。

一是“過渡風險”，也就是在監管部門和投資者認真對待碳減排后大量沉淀投資的價值可能縮水的局面。對化石燃料發電廠、煤礦、油田、燃油車制造企業以及這些資產背后的公司來說，隨著社會脫碳，它們的盈利能力可能直線下降。如果這種變化真的上了規模，數萬億美元的基礎設施就可能失去價值，成為投資者所說的“擱淺資產”。

有跡象表明這種情況已經出現。煤炭股價格下跌，很大一部分原因是低碳燃料的成本競爭力不斷增強——道瓊斯美國煤炭行業指數已經從2011年的高點下滑95%。今年1月，設在荷蘭的大型保險公司首席風險官組織CRO論壇發出警告稱，保險商可能遇到和氣候有關的新型索賠，其中包括它們提供保險的公司因為打官司而產生的巨額賠付。目前，對造成氣候變化或未能就氣候變化采取足夠應對措施的主要碳排放企業提起訴訟的情況才剛剛出現。但瑞再已經發現了這種不詳的趨勢，那就是把氣候問題歸咎于污染企業的科學“發展的很快”。

另一個威脅就是“實體風險”，即不斷上升的氣溫帶來的海平面上升、風暴的強化以及干旱引起的野火可能足以大量消耗公司資產負債。瑞再研究院繪制的近期災害損失圖看起來就像一山更比一山高的阿爾卑斯群峰——2012年吹襲紐約的颶風桑迪、2017年橫掃得克薩斯與路易斯安那的颶風哈維以及2018年加州宛如末日降臨的火災。觀察人士稱，到本世紀中葉，同類災害會讓目前已經出現的那些恍如隔世。CRO論壇指出，在美國，一些沿海和緊挨森林的地區“已經處于無法提供保險的邊緣”。

這樣的擔憂已經促使全球經濟中一些體量最大的成員采取行動。單是今年的例子就包括，世界上首屈一指的挪威主權財富基金表示它正在拋售純粹的石油天然氣勘探開采公司的股票，以及英國央行要求英國保險公司評估氣候變化對其回報可能產生怎樣的影響。在過去幾年中，多家全球規模最大的保險和再保險公司都宣布開始壓縮煤炭相關業務，比如投資或者保險，或二者兼而有之，這包括德國的安聯保險和慕尼黑再保險、法國的安盛和法國再保險以及美國市場份額最大的丘博保險。但像瑞再這樣深入采取行動幾乎還沒有。這項措施最終能否像瑞再期望的那樣保護它免受巨災的沖擊，還是像部分高管心中所顧忌的那樣將大量市場份額拱手讓給不那么擔心氣候問題的對手取決于瑞再度過這個轉型期的技巧性如何。

死亡和損失是瑞再的收入源泉。但瑞再的美洲業務負責人J·埃里克·史密斯表示，瑞再發現氣候變化關乎自身存亡的一個問題是，隨著全球變暖，瑞再在評估今后一系列災難時“預測頻率的能力變得有些兒不可靠了”。史密斯這樣描述他和其他高管的對話：“我們私下里會說：‘老天，這兩年已經很糟糕了，還會有第三個糟糕的年頭嗎？’”強大颶風扎堆出現“絕對有問題。年復一年地出現這樣的情況絕對不是正?，F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年巴黎氣候大會過后，瑞再下決心應對氣候變化加劇問題。在這次大會上，大多數國家都主動承諾將進行足夠減排，以防止全球平均溫度比工業化之前的水平上升逾兩攝氏度。大多數的科學家都認為，超過這個水平，氣候變化就會帶來尤其危險的影響。

和許多大公司一樣，瑞再也主動做出了類似承諾。公司內部進而開始分析自己的投資和保險決策方式是怎樣幫助碳密集型基礎設施籌集資金的?？茽柕倩貞浾f，很快對煤炭的支持就成了“熱點，或者說最顯眼的目標”。

瑞再的初步措施比較簡單明了，那就是收回對采煤和動力煤使用企業的投資。和所有保險公司一樣，瑞再是一位大投資人，它把保費收入用于各種各樣的資產，目的是為今后的支出獲取資金。2016年，瑞再開始收回采礦領域的投資，標準是收入的三成以上來自于煤炭以及燃煤發電機組裝機容量占比超過30%的電力公司。經過篩選，此類投資的規模只有13億美元，占瑞再1320億美元總投資的1%左右。但瑞再將此視為向低碳行業轉移資產的第一步——此舉不光有益于環境，更重要的是，它也具有金融審慎性，因為可再生能源的成本正在不斷下降，從而使煤炭的競爭力不斷減弱。

瑞再的第二步在其內部引起了較大爭議，原因是這涉及到了它的核心業務，也就是首先要決定是否承保。經過內部討論，瑞再從2018年7月開始不再為煤炭“敞口”超過30%的風險池提供保險服務。在這個概括性詞匯之下是一條重要的細節，那就是瑞再不會把這條限制用于要買保險的整個公司，而只會針對后者希望瑞再提供保險或再保險服務的具體資產。

瑞再的高級可持續性風險經理萊斯·沃爾奎斯特解釋說，縮小排除范圍可以“減少間接傷害”。瑞再甚至可以向偏重煤炭的公司賣保險，前提是這公司希望瑞再承保的對象本身不偏重煤炭。沃爾奎斯特指出：“我們甚至可以為最大的煤炭公司提供保險?！比绻笳呦胱屓鹪俪斜５氖恰疤柲茈娬尽?。他還說，這項決定讓瑞再犧牲的保費收入“很少”。

然而，也許涉及的金額不大，但此舉讓粉絲和對手都覺得瑞再干了件大事。氣候變化活動人士非常想讓出資人切斷資金供應，從而“干掉”已經陷入困境的煤炭行業，而全球最大的再保險商決定采取這樣的措施是一次重大勝利。波蘭的煤炭發電量占比仍然在80%左右，該國的反煤炭活動人士庫巴·戈戈萊夫斯基說：“說到可以解決氣候變化問題的領域，那實際上就是再保險，而最發達國家的再保險給我們的杠桿最大?！?/p>

瑞再并未透露上述煤炭相關保單讓它從哪些公司或保險商那里撤了資，也拒絕就本文對任何公司發表評論。但基于戈戈萊夫斯基的研究，瑞再看來至少終止了一部分為PZU提供的再保險，后者是波蘭一家大型保險商，而且有很多煤炭業務。PZU會在年報中列出3至5家為其提供再保險服務的頂尖“合作伙伴”，2015和2016年瑞再曾經被列入PZU的年報，但沒有出現在2017年的年報里。PZU稱目前瑞再仍然是該公司10大再保險商之一，但拒絕透露瑞再是否撤回了任何保險。

瑞再的行動對于依賴煤炭而且被瑞再切斷保險服務的公司來說顯然是個問題，這其中就包括美國電力，后者是美國最大的燃煤和發電企業之一。美國電力的投保資產約為7.5億美元，其中的很大一部分是發電廠，瑞再則是承保團成員之一。美國電力稱，瑞再覆蓋了該公司約3%的風險。但美國電力總部設在俄亥俄州哥倫布市，該公司負責資金和風險的高級副總裁朱莉·斯洛特說，今年5月，瑞再通知美國電力從7月1日起它將不再續保，原因是相關資產的煤炭發電量超過30%。美國電力稱，其他保險公司填補了瑞再留下的缺口，而且沒有造成保費增長。但斯洛特也指出，“我們確實得密切關注”保險行業越發抗拒煤炭的問題。

和許多發電企業一樣，美國電力也承諾降低碳排放。1999年該公司的燃煤機組裝機容量占比為66%，目前已經降至45%。斯洛特說2030年這個比例將下滑到27%，而且現在“除了維護以外，你不會看到我們向任何燃煤型設施投資了”。

斯洛特指出，瑞再在評估美國電力的燃煤業務占比時不應該以現有發電廠為準，而是應該考察美國電力正在建立的新基礎設施。決定退出就等同于瑞再放棄了本可以敦促美國電力做出更大改變的杠桿。斯洛特說：“我們把保險商視為合作伙伴，從這個角度來說，天哪，他們的話語權可大了?！彼€將瑞再的方法稱為“錯誤路線”。

瑞再卻不斷加大力度。今年9月，該公司宣布將提高煤炭投資篩選標準，對其投資的公司設定相關占比的絕對上限。瑞再表示，將從煤炭年產量達到和超過2000萬噸的采礦企業以及燃煤機組裝機容量超過10吉瓦的發電公司撤資。它還提出了更高的目標，那就是到2050年使總投資和保險業務實現碳中性，也就是說屆時瑞再所持資產的碳排放量和碳減排量將并駕齊驅。

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.

瑞再退出煤炭領域的措施演變成了旨在避免為其提供資金的行動，它對自身颶風模型的強化則代表著別的東西，那就是保護瑞再“王冠上明珠”的全方位措施。它的對手就是越來越不穩定的自然母親。

高額自然巨災賠付數量猛增對瑞再來說無異于響亮的警鐘，因為擁有也許是最完善的災害模型業務一直讓瑞再感到驕傲。馬丁·伯托格衣著時髦而且直言快語，他已經在瑞再工作了20年，負責巨災風險事務，其任務是設法對一系列重大災害進行預測，除了颶風，這些災害還包括地震、龍卷風、冰雹和洪水。伯托格對我說，“如果有合理的方法，”或者說讓你在理解氣候變遷方面“超過競爭對手的方法，你就有錢可賺”。

瑞再的研究部門推出了幾十個模型，每一個都針對世界上某個地區的某種災害。其中經濟意義最大的是颶風模型，而且比其他模型要大得多。對墨西哥灣的煉油綜合設施、邁阿密的海濱公寓以及曼哈頓下城區的全球金融“神經樞紐”來說，這些越發猛烈的風暴會經過價值數萬億美元的基礎設施，這促使瑞再不斷重新評估它能夠通過哪些資產的再保險獲得利潤，以及以什么樣的價格盈利。

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.

到目前為止，瑞再利潤損失中絕對能和氣候變化聯系在一起的依然很少。這在一定程度上是因為該公司的財產保險期限通常只有一年，從而使其有機會在通過模型察覺到更大的危險時提高費率。但瑞再認為，到本世紀中葉，氣候變化將成為風險和損失上升的主要動力。正因為如此，該公司才會如此急迫地想讓自己的模型可以抵御氣候的影響。

目前，瑞再的分析師已經十分確信氣溫上升直接帶來的問題，比如海平面上升，再比如風暴數量激增和塌方，將因為氣候變化而增多。但瑞再模型團隊中的大氣物理專家邁克爾·葛魯爾解釋說，颶風等巨災和氣候變化并無直接關系，其行為取決于更高的氣溫和海洋、大氣中的復雜系統交互作用的方式，這些巨災的惡化“真的屬于確信度很低的領域”。換句話說，給瑞再帶來最大損失的災害往往正是行動軌跡最難以掌握的那些。

給颶風建模并非腦部手術。但對外行人來說，二者可能相當接近。為了理解此事，我和葛魯爾在一間陽關通透的會議室里坐了下來，從那里可以遠眺蘇黎世湖。和科爾蒂與伯托格一樣，葛魯爾也在著名的理工類大學——蘇黎世聯邦理工學院做研究。

在大多數保險模型中，過去都是一個起點。他們通過以往風暴的行為來預測今后風暴的路徑和強度，進而估算其成本。這是一種精算世界觀，它假設未來的平均值在本質上和今天一樣。為啟動此項工作，建模者要把以前颶風軌跡的公開可用數據輸入他們的計算機。然后他們會編寫代碼，從而使模型改變颶風的行為，這一方面基于以往颶風對世界上相關地區的影響，另一方面則基于對颶風普遍行為的理解來隨機改變實際颶風的路徑。對他們分析的每一場實際颶風，這個模型都會提供大概100或200個理論上的變體。

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.

在屏幕上出現的圖中，實際颶風顯示為一條紅線，瑞再稱之為“媽媽”。所有理論變體都以黑線顯示，被稱為“女兒”或者“意大利面”，原因是它們有些像細細的面條。2017年的颶風瑪利亞給多米尼加、波多黎各和美屬維爾京群島造成了極大危害。葛魯爾翻著這場颶風的圖片，然后停在了一張寫有代碼的圖上，一位建模者在那上面寫了一句話，內容是“在不設強度指標的情況下創造一些意大利面”。

對每根“意大利面”，模型都會跟蹤一連串可能被颶風吹襲的地區，這個帶狀區域叫做“風場”。模型還會基于海面溫度調整對颶風頻率的預期。然后，它將這些數據和另一組信息結合起來，后者是對潛在客戶投保財產的量化值。從這里開始出現了瑞再真正關心的東西，即一條顯示某個颶風可能帶來多少保險損失的曲線，其中的每一個點都代表一個帶狀地區。瑞再用這些“損失頻率曲線”來計算保險價格，而按照該模型，這個價格既包括預期的賠付，也會帶來可以接受的利潤。

瑞銀目前的風暴建?；灸繕撕蛶资昵耙粯?，葛魯爾告訴我：“那就是繪制出這些意大利面，讓它們反映現在的氣候?！?/p>

不過，現在建模者考慮的是氣候變化可能會讓未來的局勢顯著有別于以往的情況

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.

這些年來瑞再一直在努力，想把自己的模型用于這個不斷變暖的世界。最初它在模型中假設氣候變化會讓每年的颶風數量增加1%，也就是每年歐洲風暴的頻率提高1%。隨后瑞再放棄了這種做法，因為它覺得驗證前者合理性的科學依據還不夠清晰。相反，它添加了一個調節因素，體現的是海面溫度對颶風頻率的影響方式，這個因素一直用到了今天。但近期災害成本大幅上升，特別是颶風災害增多已經清楚表明瑞再需要找到更好的辦法。

眼下瑞再正在幫助尋找資金，以便頻繁出現風暴的大西洋對岸的人們構建出新的模型，從而像瑞再期望的那樣真正實現氣候智能。在紐約市的Morningside Heights社區，或者說哥倫比亞大學工程學院應用數學和應用物理系，由前小號手、如今的大氣科學家亞當·索貝爾領導的團隊正在完善這個模型。他們沒有借鑒以前氣溫較低時出現的風暴，而是利用大規模計算能力來創造“人工”風暴。建模者希望以此更好地反映氣溫較高時期的實際情況。

索貝爾團隊采用的人造風暴方法由麻省理工學院的颶風專家凱利·伊曼紐爾開創。哥倫比亞大學團隊的秘笈則是它建立的模型，后者囊括了一些特定的物理學預期，旨在體現氣候變化影響颶風的方式。他們用的不是瑞再目前的標準做法，或者說一種自上而下的方法，它以此前颶風的路徑為起點，并且就像索貝爾所講的那樣，用歷史數據“輕輕地讓它搖擺一下”。哥倫比亞大學的建模者采取了自下而上的方式，把天氣相關因素的數據作為起點，而且是他們認為既和颶風有關，又有可能受全球變暖影響的數據。這些因素包括“風切變”，即在不同高度出現的速度和方向不同的風，以及海面溫度和空氣濕度。利用這些數據，他們的算法可以計算出颶風何時形成，如何移動以及有多大強度。理論上，這種更具前瞻性的方法有可能更為準確。

理論上是這樣。

到目前為止，由于不能確定哪些假設是對的，該模型產生了很多自相矛盾的結論。一個關鍵問題就是氣溫上升和濕度的相互影響。較高的氣溫會讓較多的海洋水汽進入大氣中，科學家因此普遍認為氣候變化會讓颶風變得更猛烈。還有許多科學家相信，較濕潤的空氣會讓颶風出現的更頻繁。

但氣溫上升不光會增加空氣濕度，它還會提高空氣的吸濕能力。哥倫比亞大學的科學家發現，該算法使用的兩個濕度指標會產生不同的結果。其中一個是“相對濕度”，即空氣含水量和吸濕能力的比例，此時模型顯示氣候變化會讓颶風出現的更頻繁。另一個指標則是“飽和差”，即空氣吸濕能力和含水量的絕對值之差，這個時候模型則表明氣候變化會降低颶風出現的頻率。海水溫度上升對這兩個指標都有影響，從而把哪個指標更重要的問題留給了科學家們。

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，索貝爾在他沒有窗戶的辦公室里告訴我，“我們差不多已經讓自己相信濕度差是更好”的風暴指標。這個辦公室的煤渣磚墻涂成了白色，其中的一面墻上掛著一幅顏色鮮亮的抽象畫，描繪的是颶風的移動路徑，這是索貝爾的母親為他畫的。他也坦率地說：“但我們還不能確定?！痹谝黄趯徍说目茖W論文中，索貝爾和他的同事們承認，按照他們的模型，氣候變化對颶風頻率的影響取決于建模者選擇強調哪個濕度指標。索貝爾說：“拿出這樣的結果基本上會讓我們覺得尷尬。讓我們不那么安心的是這就是行業所掌握知識的現狀?！?/p>

這讓要拿出真金白銀的一方陷入了成本頗高的兩難境地。和索貝爾同在哥倫比亞大學教學并且領導該團隊建模工作的李嘉婷說：“問題在于一個說‘增多’，另一個則說‘減少’，該相信誰呢？”

在蘇黎世，瑞再的巨災模型負責人伯托格也很想知道答案。他以帶著瑞士外交克制風格的口吻說：“我希望能夠更清楚一些?！睂τ诟鐐惐葋喆髮W團隊的研究結果，他表示瑞再計劃調整前者的模型，從而為颶風頻率“注入更多的不確定性”。同時，瑞再還將繼續尋求進一步的認知。

對努力推敲全球變暖對其利潤有何影響的瑞再來說，生活就是這樣，而且它要推敲的足夠具體，以便幫助自身業務重新定向。說到底，所有公司都面臨著同樣的策略性難題，它們的投資者和監管者也是如此。但作為全球經濟風向標，保險行業首當其沖，它們需要設法計算出氣溫的上升以及風的變化會怎樣影響自己的利潤。

我采訪瑞再的美洲業務主管史密斯的那個上午風和日麗。他的辦公室設在紐約州阿蒙克市，里面擺滿了藝術品，向窗外看去，整齊的草坪、樹木和水庫構成了壯麗的景觀。但有關颶風多里安的思緒讓空氣變得凝重，這場颶風剛剛橫掃在阿蒙克市以南1130英里（約1818.56千米）的巴哈馬群島。多里安消退后，據風險分析公司AIR Worldwide估算，它造成的災害給保險商帶來了15億美元至30億美元的損失。

如果沒有像那樣消散，颶風多里安或許會給瑞再的業績帶來更大的沖擊。吹著空調的史密斯放松地呼了口氣，他告訴我：“到目前為止，今年的情況還不壞?！碑斎?，今年還有幾個月才會結束。（財富中文網）

本文另一版本登載于《財富》雜志2019年11月刊，標題為《和漲潮賽跑》。

譯者：Charlie

審校：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.”