環保節水 一廂情願的政策難奏效 Why wishful thinking doesn’t work

Three years ago, the University of Vermont in Burlington began to experiment with a few nudges towards a healthy, sustainable lifestyle. First, in 2012, campus outlets and the company operating the vending machines were required to make sure that at least 30 per cent of the drinks on offer were wholesome stuff such as vegetable juice, low-fat milk and water. A few months later, selling bottled water on campus was banned outright. The aim, pushed hard by student campaigners, was to encourage students to fill reusable bottles with tap water instead.

三年前，位於伯靈頓的佛蒙特大學(University of Vermont)開始嘗試一些推進健康、可持續生活方式的“輕推”(nudge)舉措。首先，在2012年，校園商店和經營自動售貨機的公司被要求確保它們提供的飲料中有至少30%是健康飲品，比如蔬菜汁、低脂牛奶和水。幾個月後，校園裏徹底禁售瓶裝水。這一舉動的目標是鼓勵學生用自來水灌入可重複使用的飲水瓶、以代替瓶裝水，學生倡導者也努力推動這一目標的實現。

So, how did the Vermont experiment go? A study by Elizabeth Berman and Rachel Johnson (of the University’s own Department of Nutrition and Food Sciences) was recently published in the American Journal of Public Health. The researchers found that “per capita shipments of bottles, calories, sugars and added sugars increased significantly when bottled water was bottled water sales dropped to zero, sales of sugar-free beverages and sugar-sweetened beverages increased.”

那麼，佛蒙特大學這一嘗試的結果如何？該校營養與食品科學部的伊麗莎白伯曼(Elizabeth Berman)和蕾切爾約翰遜(Rachel Johnson)最近在《美國公共健康雜誌》(American Journal of Public Health)上發表了一項研究。兩位研究者發現，“瓶裝水沒有了以後，瓶子、熱量、糖和添加糖的人均消耗量都顯著增加了……隨着瓶裝水銷量降至零，無糖飲料與含糖飲料的銷量都增加了。”

In other words, the policy backfired with both barrels. Students didn’t switch to tap water, they switched to the likes of Coke and Diet Coke instead. All this would be just an amusing curiosity — one more example of student campaigners who are all heart and no brains — if it weren’t for the fact that more mature policy makers often commit similar blunders on much broader canvases. We would do well to learn some lessons from the University of Vermont’s experience.

換句話說，該政策在兩個目標上都適得其反。學生們並未改喝飲用自來水，而是改喝可口可樂、健怡可樂之類的飲料。如果不是更多成熟的政策制定者在更廣闊的領域經常犯同樣錯誤的話，這一切只不過是有趣的奇聞異事，成爲學生倡導者一腔熱血但是不動腦子的又一個例證。我們最好從佛蒙特大學的例子中汲取一些教訓。

The first lesson is that when it comes to saving the planet, people focus on what they can see. Type “environmental impact of concrete” into a search engine and you are likely to see a page filled with scholarly analysis pointing out that the impact is very large indeed, because cement production releases vast volumes of carbon dioxide. Type “environmental impact of bottled water” instead and your search results will be packed with campaigning groups seeking to persuade you to change your ways.

第一個教訓是，當談到拯救地球時，人們專注於自己能看到的事。在搜索引擎中鍵入“水泥對環境的影響”，你可能會看到整個搜索結果頁面上全都是各種指出水泥對環境的影響確實很大（因爲水泥的生產過程釋放出大量二氧化碳）的學術分析。再鍵入“瓶裝水對環境的影響”，搜索結果肯定全都是各種活動團體試圖說服你改變生活方式。

This is understandable: I can’t do much about concrete but I can stop drinking bottled water. But being a logical target for campaigners is not the same as being a logical target for policy action.

這是可以理解的：我對水泥生產無能爲力，但我可以停止喝瓶裝水。但作爲活動人士的目標合乎邏輯，不等於它作爲政策行動的目標也合乎邏輯。

The second lesson is that we often struggle to deal with multiple goals. The University of Vermont wanted to reduce the flow of plastic water bottles to landfill but also wanted to encourage students to be healthy. There’s a clear conflict between these goals. Water is as healthy a drink as you can find, yet that was exactly what the University of Vermont was banning from vending machines. Wishful thinking provides a resolution — if everyone just drank tap water then there would be no problem. But wishful thinking is not an excuse for setting no priorities.

第二個教訓是，我們往往很難同時應對多個目標。佛蒙特大學既想減少需要填埋的塑料水瓶的數量，又想鼓勵學生培養健康的生活方式。這兩個目標存在明顯的矛盾。喝水最健康，但佛蒙特大學恰恰禁止自動售貨機出售瓶裝水。一廂情願的思維方式提供了一個答案——如果每個人都乾脆喝自來水，問題就解決了。但一廂情願的思維方式並非放棄設定優先順序的藉口。

We see this sharply in the debate over nuclear power. We want to reduce the greenhouse gas emissions that result from burning fossil fuels. We also want to avoid radioactive waste and the risk of radiation leaks. In response to a genuine policy dilemma, politicians have tended to plump for wishful thinking every time, typically involving wind turbines.

在關於核能的辯論中，我們更清楚地看到了同樣一幕。我們想減少燃燒化石燃料帶來的溫室氣體排放。我們也想避免放射性廢料以及輻射泄漏的風險。在迴應這一真正的政策兩難時，政客們每次都傾向於選擇一廂情願的思維方式，通常都涉及風力渦輪機。

The third lesson is that the much-vaunted notion of “nudging” doesn’t always help navigate a complicated policy maze. Nudging means using default options, information design and similar techniques to achieve policy goals. It can be very successful. But careless nudges are no more welcome in public policy than at a domino-toppling event. If you pick a questionable target (bottled water) and fudge a key policy dilemma (the environment vs health) then nudging isn’t going to solve your problems.

第三個教訓是，備受吹捧的“輕推”概念並不總能幫助我們走出政策迷宮。“輕推”意味着使用默認的選項、信息設計以及相似的技術來實現政策目標。它可以很成功。但粗心的“輕推”在公共政策領域不比它在推倒多米諾骨牌的遊戲中更受歡迎。如果你選擇了一個有問題的目標（瓶裝水）並隨隨便便製造出一個重要的政策困境（環境vs健康），那麼“輕推”將不會解決你的問題。

So what can be done? One approach is to try to reach policy goals with the help of market signals. The classic example of this is a carbon tax, levied on fossil fuels to reflect their carbon-dioxide emissions. The advantage of this approach is that it encourages everybody at any stage of production or consumption to take actions that reduce emissions, because those actions will save them money. A truck manufacturer might develop a cleaner engine, a logistics company might find a more efficient delivery algorithm, and the final consumer might decide to consume a little less.

那麼，我們能做什麼呢？一種方法是，設法在市場信號的幫助下達成政策目標。這方面的經典例子是碳稅——以化石燃料爲對象、按照其二氧化碳排放量徵收。這種方法的優點在於，它鼓勵處於生產或消費任何階段的每個人都採取行動減少碳排放，因爲這樣做可以省錢。卡車製造商或許會開發出更清潔的發動機，物流公司可能會找到更高效的投遞算法，而終端消費者可能會決定少消費一些。

The idea of using the price system to solve environmental problems is widely accepted by economists but, alas, it finds itself stranded in the policy doldrums. Ponder this: the Pope recently argued that climate change was a grave problem but he opposed market-based responses. Meanwhile the US Republican party likes market-based responses but isn’t so convinced about climate change.

利用價格體系解決環境問題的理念得到經濟學家們的廣泛認同，但可惜的是，這一理念自身被困在了政策內耗之中。思考一下：教皇最近稱，氣候變化是一個嚴重問題，但他反對基於市場的應對措施。與此同時，美國共和黨喜歡基於市場的措施，但並不怎麼相信氣候變化真實存在。

One other advantage of using environmental taxes is that people can decide on their own priorities. A lot of what we do has consequences for the planet — including breathing — and so part of the problem we face is deciding what is worth doing anyway.

採用環境稅的另一個好處是，人們可以決定自己的優先順序。我們的很多活動（包括呼吸）都對地球產生影響，因此，我們面臨的部分問題在於決定什麼事值得去做。

Perhaps it is time for a confession. I am writing this column on the hottest July day recorded in British history. At my left hand is a glass of chilled sparkling water, and next to the glass is a plastic bottle to top it up. If there had been a tax on that bottle, it is a tax I would willingly have paid.

或許我該坦白一下了。我正在英國曆史上有記錄以來7月最炎熱的一天寫這篇專欄，我左手邊是一杯冰鎮蘇打水，玻璃杯旁邊是一個塑料瓶，用來把杯中的蘇打水加滿。如果這個瓶子需要交稅的話，這稅我願意交。