理想主義加經濟學 戰勝氣候危機的希望

Idealism combined with an intriguing application of economic theory may accomplish what international conferences have not: solving the seemingly intractable problem of global warming.

理想主義和經濟理論一個有趣應用的結合可能完成國際會議都沒有解決的、看似棘手的全球氣候變暖問題。

Despite periodic flurries of optimism, diplomacy has been largely disappointing. The 1997 Kyoto Protocol, for example, in which many nations agreed to impose strict taxes on carbon emissions, hasn’t accomplished much. And subsequent climate conferences haven’t come up with an effective solution. Secretary of State John Kerry summed up the diplomatic landscape in December at the United Nations climate change conference in Lima, Peru: “We’re still on a course leading to tragedy.”

儘管週期性地出現零星樂觀進展，但外交已經在很大程度上令人失望。例如，在1997年的《京都議定書》裏許多國家同意嚴格徵收碳排放稅，卻並沒有取得很大成就。隨後的氣候會議沒有提出有效的解決方案。美國國務卿克里12月在祕魯利馬的聯合國氣候變化會議上總結了外交政策的現狀：“我們仍然在一條導致悲劇的道路上。”

From an economic standpoint, international efforts until now have foundered on a fundamental “free rider problem.” In a nutshell, individuals and nations that bear the immediate costs of measures to protect the atmosphere will experience only a small fraction of the benefits, which are shared by all the people and nations on the planet. Why not just take a “free ride” and let others do the hard work?

從經濟的角度來看，國際努力到現在爲止已經失敗在基本的“搭便車問題”上。簡而言之，承擔採取措施保護環境的眼前成本的國家和個人，得到的福利卻只有一小部分。而這些福利是由地球上的全體人民和國家共享的。如此，爲什麼不乾脆“搭便車”，讓別人去辛勤工作呢？

In traditional economic theory, the benefits of reducing emissions take the form of an “externality,” meaning they are external to the local environment because they are spread over the whole world. Our own contributions are often too small to see or feel.

傳統的經濟理論認爲，減排福利採取了“外部性”的形式，這意味着它們和當地的環境是不相關的，因爲這些福利遍佈整個世界。我們自己的貢獻往往太小，無法看到或感覺到。

When the problem is an externality, it is, for the most part, futile to ask people to volunteer to fix it — by taking actions like car-pooling or riding a bike to work to cut back on emissions or, in the case of governments, by enacting laws and regulations.

當問題成了一個外部事物的時候，在大多數情況下，要求人們自願去修復它是徒勞的，比如通過拼車或騎自行車上班來削減排放量，或者政府制定法律法規。

Yes, some individuals with a strong moral compass will take action, and some nations will do so occasionally, but most people and countries will not do so consistently. That’s what the theory says, anyway.

是的，有些人用強烈的道德指向來採取行動，有些國家也會時不時地這麼做，但大多數國家和人民不會持續地採取措施。反正，這就是該理論講的內容。

But in a new book, “Climate Shock: The Economic Consequences of a Hotter Planet” (Princeton 2015), Gernot Wagner of the Environmental Defense Fund and Martin L. Weitzman, a Harvard economist, question that assumption. In a proposal that they call the Copenhagen Theory of Change, they say that we should be asking people to volunteer to save our climate by taking many small, individual actions.

但在他們的新書《氣候休克：全球變暖的經濟後果》（普林斯頓大學出版社，2015年）中，保護環境基金會的日爾諾特·瓦格納和哈佛大學經濟學家馬丁·L·魏茨曼對這個理論提出了質疑。兩人提出了他們所謂的哥本哈根改變理論，指出，我們應該要求人們主動採取許多個人行動，從小處着手，去拯救氣候。

Copenhagen has motivated half of its habitants to commute to work by bicycle every day, the Danish government says. How did that come about? A half-century ago, the city’s inhabitants were becoming almost as reliant on cars as people anywhere else. But after the oil crisis of the 1970s, the authors point out, many Copenhagen residents made a personal commitment to ride bicycles rather than drive, out of moral principle, even if that was inconvenient for them.

丹麥政府說，哥本哈根已經促使其一半的居民每天騎自行車上下班。這是怎麼發生的呢？半個世紀之前，全市居民和其他地方的人一樣幾乎都有汽車依賴症。但作者指出，上世紀70年代的石油危機之後，許多哥本哈根居民出於道德原則作出個人承諾要騎自行車而不是開汽車，即使這對他們來說是不方便的。

That happened in American cities, too, but in Copenhagen there was more social support and, perhaps, social pressure to join in the movement. The sight of so many others riding bikes motivated the city’s inhabitants and appears to have improved the moral atmosphere enough to surmount the free-rider problem.

美國的城市也是如此，但在哥本哈根有更多的社會支持，或者說是社會壓力來參加這個運動。這麼多人騎自行車的景象激勵着城市居民，這似乎增加了足夠的道德氛圍去克服搭便車的問題。

Elinor Ostrom won her Nobel in economics partly for observing that communities often solve free-rider problems. She was talking generally about contained communities like Copenhagen, not global ones. Its idealism about global warming has not spread worldwide. But she argued for a polycentric approach to climate change, with actions against global warming taken not just on a global scale but on a whole array of scales, involving smaller communities as well as the entire planet.

埃莉諾·奧斯特羅姆（Elinor Ostrom）贏得諾貝爾經濟學獎部分是因爲發現社區常常可以解決搭便車問題。她講的一般是像哥本哈根這樣的自成一體的社區，而不是全球社區的。它關於全球變暖的理想主義並沒有擴散到全球。但她主張用多中心的方法來應對氣候變化，不僅是在全球的規模而且要在各個規模上採取行動，包括小的社區，也包括整個星球。

There are communities based on shared interests, not on geography, and people who believe in socially responsible investing may be considered one such community. If ethical investing takes the form of investing only in “green” companies, for example, excluding companies that pollute the atmosphere, such measures may have a similar positive impact.

有的社羣是基於共同利益的，而非地理位置；有些人相信應該做出負有社會責任的投資，他們就構成了這樣的社羣。如果合乎道德的投資僅投資在“綠色”的公司上，例如，不包括污染大氣的公司，那麼這樣的措施可能具有相似的積極影響。

Of course, one might dismiss ethical investing as achieving nothing more than creating opportunities for unethical investors, who will be more than happy to step in if there is money to be made. But placing a deviant enterprise on a list of companies to be avoided by ethical investors could change the moral atmosphere, much as bicycling has in Copenhagen — increasing the likelihood of a broader, successful social movement against pollution of the world’s atmosphere.

當然，有人可能會認爲，道德的投資結果會一事無成，而更多的是爲非道德的投資者創造機會：只要有錢可以賺，非道德投資者就會很樂意參與。但是，把一個不守規矩的企業列在黑名單上，使它得不到合乎道德的投資，這種做法可以改變社會風氣，就像哥本哈根的自行車——增加爲抵制世界污染而發起的更廣泛、成功的社會運動的可能性。

The world is a diverse and complicated place, however. To combat global warming, social movements aren’t enough. We also need a concrete framework on a global scale.

然而，世界是一個多元又複雜的地方。爲應對全球變暖，僅社會運動是不夠的。我們還需要全球範圍內保護環境的具體架構。

In his presidential address before the American Economic Association in Boston in January, William D. Nordhaus of Yale proposed what he calls “climate clubs.” Here is a genuinely concrete idea that might work to stop global warming. As he defines it, a climate club is a group of countries that agree to create incentives for people to reduce carbon emissions, while also erecting tariff barriers on imports from countries that are not members of the club.

1月在波士頓面向美國經濟協會致辭的時候，耶魯大學的威廉·D·諾德豪斯提出了“氣候俱樂部”設想。這是個有可能阻止全球變暖的具體方案。諾德豪斯說，氣候俱樂部是指這樣一些國家，它們同意創造激勵措施，鼓勵人們減少碳排放，同時也會對來自俱樂部之外國家的商品進口設置關稅壁壘。

The tariff barriers contribute to a virtuous cycle: They provide an incentive for countries in the club to create incentives for individuals to reduce emissions. Professor Nordhaus’s analysis relies on the economic theory of clubs and on his own Coalition DICE model, which shows costs and benefits from reducing emissions for each country or region in the world today.

關稅壁壘有助於良性循環：它們爲俱樂部成員國獎勵減少碳排放的個人提供了動力。諾德豪斯的分析依賴於俱樂部的經濟理論和他自己的DICE聯合模型，該模型展示了當今世界上各個國家和地區減少碳排放的成本與收益。

A climate club may start with only a few countries and then grow as others join. The club may grow through time rather than collapse as we saw with the Kyoto Protocol. Now they will be coming into the club as they see, over the years, the advantages of membership.

氣候俱樂部開始可能只有少數幾個國家，然後其他國家逐漸加入。俱樂部規模可能會隨着時間不斷壯大，而不是像我們看到的《京都議定書》那樣走向崩潰。隨着時間推移，加入俱樂部的優勢顯現，就會有更多國家選擇加入。

In its pure form, the economic theory of clubs assumes that each country and individual is completely self-interested and has no interest in helping any others. But, in reality, people are not quite like that. There is some community feeling — including a sense of responsibility for the world community. Clubs might ultimately rely on such feelings to be successful.

純粹形式的俱樂部經濟理論認爲，每個國家和個人是完全自利的，他們對幫助別人沒有任何興趣。但實際上，人們並非如此。有一些社羣含有對國際社會的責任感。俱樂部可能最終會依靠這種責任感走向成功。

Club founders must overcome real-world obstacles, objections from climate change deniers and those who simply don’t understand the issues or the stakes we are facing. Who is going to undertake such difficult and expensive actions without some sense of moral principle?

俱樂部創始人必須克服現實障礙和反對意見，這些反對意見來自否認氣候變化的人以及那些不理解這件事情或者不理解其中利害關係的人。如果沒有某種意義上的道德原則感受，誰會去承擔這樣困難和代價巨大的行動？

To solve the extremely challenging problem of climate change, we may want to rely on both theories: the Copenhagen theory and the climate club theory. As with other things in life, good things can happen when there is a sense of idealism that creates an atmosphere for change. But it will also help to have a realistic structure that puts clear penalties on bad behavior by individuals and by entire countries.

要解決極具挑戰性的氣候變化問題，我們可能要依賴於兩種理論：哥本哈根理論和氣候俱樂部理論。就像生活中的其他事情，當理想主義創造了一個改變的環境時，好事就會發生。此外，個人和國家能有一個現實的機制，用明確的措施懲罰壞的行爲，那也將大有裨益。