Salvation Gets Cheap
Paul Krugman

The Intergovernmental Panel on Climate Change, which pools the efforts of scientists around the globe, has begun releasing draft chapters from its latest assessment, and, for the most part, the reading is as grim as you might expect. We are still on the road to catastrophe without major policy changes.

But there is one piece of the assessment that is surprisingly, if conditionally, upbeat: Its take on the economics of mitigation. Even as the report calls for drastic action to limit emissions of greenhouse gases, it asserts that the economic impact of such drastic action would be surprisingly small. In fact, even under the most ambitious goals the assessment considers, the estimated reduction in economic growth would basically amount to a rounding error, around 0.06 percent per year.

What’s behind this economic optimism? To a large extent, it reflects a technological revolution many people don’t know about, the incredible recent decline in the cost of renewable energy, solar power in particular.

Before I get to that revolution, however, let’s talk for a minute about the overall relationship between economic growth and the environment.

Other things equal, more G.D.P. tends to mean more pollution. What transformed China into the world’s largest emitter of greenhouse gases? Explosive economic growth. But other things don’t have to be equal. There’s no necessary one-to-one relationship between growth and pollution.

People on both the left and the right often fail to understand this point. (I hate it when pundits try to make every issue into a case of “both sides are wrong,” but, in this case, it happens to be true.) On the left, you sometimes find environmentalists asserting that to save the planet we must give up on the idea of an ever-growing economy; on the right, you often find assertions that any attempt to limit pollution will have devastating impacts on growth. But there’s no reason we can’t become richer while reducing our impact on the environment.

Let me add that free-market advocates seem to experience a peculiar loss of faith whenever the subject of the environment comes up. They normally trumpet their belief that the magic of the market can surmount all obstacles — that the private sector’s flexibility and talent for innovation can easily cope with limiting factors like scarcity of land or minerals. But suggest the possibility of market-friendly environmental measures, like a carbon tax or a cap-and-trade system for carbon emissions, and they suddenly assert that the private sector would be unable to cope, that the costs would be immense. Funny how that works.

The sensible position on the economics of climate change has always been that it’s like the economics of everything else — that if we give corporations and individuals an incentive to reduce greenhouse gas emissions, they will respond. What form would that response take? Until a few years ago, the best guess was that it would proceed on many fronts, involving everything from better insulation and more fuel-efficient cars to increased use of nuclear power.

One front many people didn’t take too seriously, however, was renewable energy. Sure, cap-and-trade might make more room for wind and the sun, but how important could such sources really end up being? And I have to admit that I shared that skepticism. If truth be told, I thought of the idea that wind and sun could be major players as hippie-dippy wishful thinking.

But I was wrong.

The climate change panel, in its usual deadpan prose, notes that “many RE [renewable energy] technologies have demonstrated substantial performance improvements and cost reductions” since it released its last assessment, back in 2007. The Department of Energy is willing to display a bit more open enthusiasm; it titled a report on clean energy released last year “Revolution Now.” That sounds like hyperbole, but you realize that it isn’t when you learn that the price of solar panels has fallen more than 75 percent just since 2008.

Thanks to this technological leap forward, the climate panel can talk about “decarbonizing” electricity generation as a realistic goal — and since coal-fired power plants are a very large part of the climate problem, that’s a big part of the solution right there.

It’s even possible that decarbonizing will take place without special encouragement, but we can’t and shouldn’t count on that. The point, instead, is that drastic cuts in greenhouse gas emissions are now within fairly easy reach.

So is the climate threat solved? Well, it should be. The science is solid; the technology is there; the economics look far more favorable than anyone expected. All that stands in the way of saving the planet is a combination of ignorance, prejudice and vested interests. What could go wrong? Oh, wait.

拚環保 可以兼顧經濟

聯合國跨政府氣候變遷問題小組（IPCC）最近開始公布最新的評估報告，內容令人擔心。我們仍然逐步迎向災難，政策未有大幅改變。

然而報告的部分內容卻也令人振奮。簡言之，是它對緩解問題所涉經濟層面的評估。這份報告呼籲以有力措施限制溫室氣體排放，同時又說，如此對經濟產生的衝擊其實很小。事實上，即使以最具企圖心的目標而言，經濟成長因而減緩的幅度預估平均每年約僅0.06%。

如此樂觀的根據是什麼？很大程度上反映許多人渾然不覺的科技革命，以及再生能源成本近年來大幅降低的趨勢，尤其是太陽能。

在說明這場革命前，容我解釋經濟成長與環境之間的整體關係。更多國內生產毛額（GDP）往往意味更多的汙染。導致中國大陸成為舉世最大溫室氣體排放國的原因是什麼？爆炸性的經濟成長。然而其他因素不必然等重。成長與汙染之間的關係不必然對等。

左右兩派經常未能明白這個道理。環保人士經常說，我們拯救地球的先決條件是，放棄不斷追求經濟成長的堅持。右派則說，任何限制汙染的企圖將對經濟成長產生嚴重衝擊。問題是，創造更多財富之餘，我們同時可以降低對自然環境造成的衝擊。

必須說明，每當環境課題浮上檯面時，提倡自由市場的人士似乎總是失去信心。他們經常說，市場的神奇力量足以克服一切障礙，民間企業的彈性與創新能力足以輕易應付各種造成限制的因素，例如土地或礦產的不足。然而，一旦提到對市場友善的環境措施可行性，例如碳稅或有關碳排放的總量管制交易制度，他們又會說，民間企業無力應付，因為成本必定驚人。

有關氣候變遷所涉經濟問題的合理立場是，與其他事物相同：如果我們為企業與個人賦予降低溫室氣體排放的誘因，他們一定會有回應。它的形式會是如何？直到幾年前，最理想的猜測是，它會在許多方面同時展開，涉及更好的隔絕技術、燃料效率更高的汽車與增加核電的使用等。

許多人並未認真考慮的是再生能源。總量管制許或許可為風力與太陽能創造更多空間，然而這些來源的終極重要性究竟如何？我必須承認，我也懷疑。坦白說，我認為，所謂風力與太陽能可扮演重要角色的說法，是一廂情願。

可是我錯了。

IPCC說，自從它2007年發表上一次的報告後，許多再生能源技術經證明已有相當的進展，成本也已降低。美國聯邦能源部願意展現更開放的積極態度。它去年發表的一項有關乾淨能源的報告題為「現在就革命」。這聽來有點誇張，然而如果你知道，太陽能板的價格2008年以來累計已經大降75%以上，這毫不誇張。

拜技術飛躍進展之賜，IPCC已經可將發電「去碳化」視為務實的目標，而由於火力發電廠是氣候問題的一大部分，這是現有的解方。

重點是，大幅減少溫室氣體排放量已在我們能力所及的範圍內。

如此說來，氣候威脅已經解決？應該是。相關科學很札實；技術已經具備，經濟也比任何人預期的好很多。無知、偏見與既得利益是當前的阻礙。

原文參照：
http://www.nytimes.com/2014/04/18/opinion/krugman-salvation-gets-cheap.html

紐約時報中文版翻譯：
http://cn.nytimes.com/opinion/20140422/c22krugman/zh-hant/

2014-04-20．經濟日報．A7．國際焦點．編譯陳世欽