世界邁向氣候安全的機會 會擦肩而過嗎?

Today’s US-China joint announcement on climate change and energy is the most important advance on the climate change agenda in many years. While the full ramifications will only be known at the climate summit in Paris in December 2015, the two largest C02 emitters have finally spoken, and most importantly, they’ve spoken together. What they’ve said gives the world a fighting chance – and no doubt the last one – for climate safety.

美國與中國週三就氣候變化和能源問題發表聯合聲明，這是全球氣候變化議程中多年來最重要的進展。雖然其全部意義要到2015年12月巴黎氣候大會上才能充分浮現，但是世界最大的兩個二氧化碳排放國終於作出了表態，最重要的是他們共同作出了表態。他們所發表的聲明給全球帶來了一次爲實現氣候安全而奮鬥的機會——毫無疑問也是最後一次機會。

The situation is stark. While the world’s governments agreed back in 2009 that we need to keep global warming below 2 degrees Celsius (relative to the pre-industrial era), in order to avoid massive damages from droughts, floods, extreme heat waves, and rising ocean levels, the brutal fact remains that the world is on course for a catastrophic rise of some 4 to 6 degrees by the end of the century. To avoid catastrophe, and stay below the 2 degree upper limit, CO2 emissions from energy use need to fall very sharply by mid century, and to reach net-zero emissions (“decarbonization”) by around 2070.

形勢是十分嚴峻的。早在2009年，世界各國政府就已達成共識，必須把全球氣溫上升幅度限制在2攝氏度以內（與工業化時代以前相比），才能避免乾旱、洪災、極端炎熱天氣及海平面上升導致的重大損失。儘管如此，一個依然存在的殘酷現實是，全球仍處於災難性的升溫過程中，到本世紀末氣溫將升高大約4到6度。爲避免災難性後果並讓溫度的升高保持在2度的上限之內，必須在本世紀中葉以前大幅減少因消耗能源而排放的二氧化碳，並在2070年前後達到接近零排放（也就是“脫碳”）的水平。

In short, the world will need to get almost entirely out of the fossil fuel business in the next half century or so, except for what can be continued safely with the use of carbon capture and storage (CCS). Such a deep transformation is feasible through a combination of three main steps: massive energy efficiency; a pervasive shift to low-carbon and zero-carbon electricity (notably wind, solar, geothermal, hydro, nuclear, and CCS); and the electrification of all vehicle transport and of heating and ventilation in residential and commercial buildings.

簡而言之，今後半個世紀左右全球必須接近完全擺脫化石燃料，只能繼續使用那些能應用碳捕獲與封存技術(CCS)的安全的化石燃料。這種深層次改革可以通過三個主要步驟來實現：大力提升能源使用效率；全面轉向低碳和零碳電力技術（特別是風力、太陽能、地熱、水力、核能以及碳捕獲與封存技術）；實現所有交通工具的電氣化，以及住宅和商用建築取暖和通風的電氣化。

Two kinds of breakthrough

兩大突破

First, China, the world’s largest emitter by far in absolute terms (roughly 28 per cent of the world’s CO2 emissions in 2014) has agreed a clear target to reach a peak of CO2 emissions no later than 2030, with the intention of trying to peak earlier than 2030. The US’s failure to act decisively on its own emissions for two decades has long been defended by the Senate on the basis that the US should act only if China does as well. That bottleneck and excuse is ending.

首先，中國同意設立明確目標，即二氧化碳排放量最晚在2030年達到峯值，並努力提前實現這一目標。中國是二氧化碳絕對排放量最大的國家，2014年中國約佔全球二氧化碳排放量的28%。20年來美國未能在自身減排上採取果斷措施，對此美國參議院的辯護理由一直是：只有中國採取了行動，美國纔會採取相應措施。這一阻礙和藉口已不復存在。

Second, the US-China agreement has the necessary three components for deep transformation by mid-century. The agreement calls for:

其次，美中協議包含本世紀中葉實現深層改革所需的三個必備組成部分。該協議規定了：

1) short-term commitments by both countries to 2030

1) 兩國到2030年的短期承諾

2) deep decarbonization by mid-century, with the US re-stating the goal of an 80 per cent CO2 reduction by the US by 2050

2) 本世紀中葉實現深度脫碳，美國重申了2050年二氧化碳減排80%的目標

3) a massive scale-up of research, development, demonstration, and diffusion (RDD&D) of low-carbon energy technologies. Specifically, China and the US committed to joint R&D in building efficiency, clean vehicles CCS, smart cities, and other areas.

3) 大舉擴大對低碳能源技術的研究、開發、示範和推廣(RDD&D)。具體來說，中國和美國承諾在建築節能、清潔能源汽車碳捕捉及碳封存、智能城市等領域展開研發合作。

What chance of success?

成功的機率有多大？

An announcement is just an announcement, of course. There are many crucial details and years of action that will make the difference between mere rhetoric and true climate safety. Both countries need to show how they intend to reach not only the short-term 2025-2030 goals, but also the mid-century deep decarbonization that is really the essence of the climate challenge. Short-term commitments are fine, but can easily be an illusion as well, with short-term steps of little long-term significance, unless the short-run measures are part of a long-term path out of carbon energy. The US and China have yet to put their cards on the table on how they intend to achieve deep decarbonization.

當然，一個聲明僅是聲明而已。就許多關鍵細節和需要持續多年的行動而言，冠冕堂皇的言辭和真實的環境安全之間是存在區別的。兩國都需要展示他們打算如何實現目標，不僅是到2025-2030年的短期目標，還有本世紀中葉的深層脫碳目標，後一個纔是應對氣候挑戰的關鍵。短期承諾固然不錯，但容易變成一種假象，只有短期措施而缺少長遠意義，除非這些短期措施是一項擺脫碳能源的長期計劃的組成部分。美國和中國尚未攤牌他們打算如何實現深度脫碳。

Still, the G2 has now spoken, and together with the EU, which made its own bold announcements just recently, the world’s three biggest economies and largest emitters are now on course for a serious agreement in Paris. Others will join. The three-part structure of today’s announcement can serve as the right blueprint for a serious and historic global deal in Paris. And the arithmetic is clear: if we fail in Paris, we will fail to stay below 2 degrees. Paris is the last chance.

不過，這兩個大國終於作出了承諾，再加上近期才作出大膽聲明的歐盟，全球三大經濟體兼三大碳排放地區終於朝着在巴黎達成重要協議的方向邁進。其他國家也會加入進來。今日這份聲明的三個部分可以作爲未來巴黎那份重要的、歷史性的全球協議的合適藍圖。而其中的得失也很清楚：如果我們不能達成巴黎協議，我們將無法把升溫幅度控制在2攝氏度以下。巴黎是最後的機會。

Not surprisingly, the incoming Republican Senate majority leader Mitch McConnell piped up immediately that he and his colleagues would oppose the deal. No doubt they will try. Yet my guess is that Mr McConnell and his buddies are soon going to learn a lesson in real democracy.

不出所料，即將上任的參議院多數派領袖、共和黨人米奇•麥康奈爾(Mitch McConnell)馬上放話稱，他和他的同僚將反對這一協議。他們當然會反對。但我的猜想是，麥康奈爾和他的夥計們將很快領會到什麼是真正的民主。

While the fossil fuel lobby may have helped finance the Republican victories last week, the US public cares about its own survival and the world that their children will soon inherit. The public has tasted reality with Superstorm Sandy, with California’s record-breaking droughts, unprecedented heat waves, and repeated flooding of the eastern seaboard. The Koch brothers may have bought some 44,000 paid ads this fall to help put favoured coal and oil candidates over the top, but they did not buy the souls of the American people, who by a large majority will be gratified today by the announcements from Beijing.

儘管共和黨上週在中期選舉中的勝利一定程度上或許得益於化石燃料說客提供的資金，但美國民衆在乎自己的生存，在乎他們的孩子將很快繼承的這個世界。氣候現實已經讓公衆體會切膚之痛——桑迪颶風(Superstorm Sandy)、加州一次次創紀錄的大旱、一次次前所未有的熱浪、以及東海岸地區反覆發生的洪災。科赫(Koch)兄弟或許買下了今秋的4.4萬個付費廣告，幫助他們青睞的、代表煤炭和石油業利益的候選人贏得了選舉，但兩兄弟沒有買下美國人的良心，今天聽到美中在北京發表的聯合聲明，大多數美國人會感到高興。

The climate is heating up but so too are the climate negotiations. Today’s announcement is a major step forward for the vast majority of humanity who are seeking a safer planet.

全球氣溫在升高，氣候談判的熱度同樣也在升高。在絕大多數希望地球變得更安全的人眼中，昨日的聲明是個巨大的進步。

Jeffrey Sachs is the director of The Earth Institute at Columbia University in New York and author of ‘To Move the World: JFK’s Quest for Peace

本文作者傑弗裏•薩克斯(Jeffrey Sachs)是位於紐約的美國哥倫比亞大學(Columbia University)地球研究所(Earth Institute)所長，著有《推動世界：肯尼迪對和平的追求》(To Move the World: JFK’s Quest for Peace)一書