近二十年前，《京都議定書》以具有法律約束力的方式為發達國家分配了減排目標。盡管表面上看起來裝有“牙齒”，但京都模式脫離各國國內政治現實的弊端也逐漸顯現。尤其是，這一“自上而下”的氣候治理方式在主要排放國國內遭遇重重阻力：美國國會從未核準該議定書，加拿大也于2011年宣布退出。2009年哥本哈根氣候大會之后，國際氣候制度的構建方式已經呈現出明顯變化，逐漸演進為以國家自主決定貢獻（INDC）為特征的“自下而上”模式。然而，這一新發展對于國際社會開展應對氣候變化合作、實現《公約》目標又帶來了諸多新的挑戰。

從自上而下到自下而上

《公約》及其《議定書》所搭建起來的國際氣候制度框架，在發達國家與發展中國家之間豎了一道“防火墻”，兩者責任、義務與權利顯著不同。在實現《公約》目標的前提下，并根據各國達成共識的原則和規則，發達國家需要率先承擔量化減排的氣候承諾、并對發展中國家提供支持。而發展中國家則需要在得到發達國家相關支持的情況下、根據國家自身國情采取積極行動。《京都議定書》是自上而下模式推進國際氣候制度構建的典型代表，這一模式一直延續到巴厘路線圖所確立的“雙軌談判”時期。

雙軌談判是指，一方面，簽署《京都議定書》的發達國家要在京都第二承諾的特設工作組中，談判形成2012年以后的大幅度量化減排指標；另一方面，發展中國家和未簽署《京都議定書》的發達國家（主要是指美國）則要在《聯合國氣候變化框架公約》下，在促進長期合作行動的特設工作組中談判討論進一步應對氣候變化的措施。

自上而下模式往往法律約束力強，伴有較為嚴格的遵約機制，核算規則統一，且設有嚴格的測量、匯報、核證規則以確保透明度，但是各方達成行動共識的難度大、進度慢。受制于主要談判締約方（主要是發達國家）國內政治的制約，尤其伴隨著全球政治經濟與排放格局的發展，并且受到全球金融危機的影響，2009年的哥本哈根大會并未達成既定成果，自上而下模式的發展遭遇重大挫折。

在上述國際背景之下，國際氣候合作呈現從“南北矛盾”向“大國博弈”和“大小之爭”過渡的趨勢。傘形國家集團所提出的“國家行動計劃表”、“允諾加審評”的模式更好地契合了關鍵締約方的國內政治，也更好地匹配了全球氣候博弈的國際政治，逐漸獲得了越來越多締約方的認可。以此為基礎，哥本哈根和坎昆兩次會議醞釀和開啟了公約締約方共同做出減排允諾的新規則。2013年，華沙大會啟動各國2020年后行動的INDC進程（即由各國自行提交的“自主貢獻預案”），表明了以自下而上模式推進國際氣候治理取得共識，也為2015年達成巴黎協議傳遞了重要的積極信號。新模式下，主要依靠各國自行提出各自的氣候行動或目標，而不再通過艱苦談判強制分配。匯總后的目標相應形成全球目標和共同行動。

相對于《公約》確立的原則與規則，以INDC進程為基礎的“自下而上”模式更多考慮到各國的自身國情，是一種在各國國家利益的最大公約數基礎上推進國際氣候合作、尋求實現公約目標的機制。該模式往往具有“非強迫”和“非侵入”的特征，各國行動與目標也通常是多元化和多樣性的，更有可能伴隨合作性和促成性機制的構建，更易于吸引各方積極參與；但由于可能缺乏統一核算規則，缺乏對目標力度的指導和強制性要求，因此難以保證行動的整體力度，各國間的政治互信與積極互動也有待進一步增強。

被打破的“防火墻”

INDC進程是國際氣候制度發展之路的重大轉折，對全球氣候治理會產生深遠影響。綜觀各國提交的INDC文件，這些“自主貢獻”五花八門、標準不一，且主要根據各國自身對其責任與能力的理解而自主提出，實際上已經打破了發達國家和發展中國家在公約及其議定書框架下關于各國責任、與責任相對應的承諾和行動的“防火墻”。INDC進程實質上是對共同但有區別的責任原則、各自能力原則、各自國情及其對應的“不對稱承諾”在公約框架之下的新的再平衡。

這一“自下而上”的進程引發了國家承諾與行動的本質變化。共同但有區別的責任原則和公平原則是國際氣候治理制度的核心基石。該原則將發達國家歷史上的排放責任與應盡義務，與發展中國家未來的發展訴求與排放空間需要協調起來，將發達國家的技術、資金優勢，與發展中國家亟待提高的能力以及全球應對氣候變化的整體需要聯系起來，最終以“二分法”和附件區分的形式，實現各國共同但有區別地承擔“不對稱承諾”。

然而在當前的INDC進程中，不管是發達國家還是發展中國家都共同地、自主地、不分先后地、甚至是在不論是否得到理應獲得支持的情況下，在同一個談判軌道中提出各自的目標與行動，且這樣的承諾還有可能逐步面臨統一的法律約束力與透明度要求。這一發展趨勢，對于發展中國家公約義務的未來發展產生新的、額外的壓力。在“防火墻”岌岌可危的情況下，如何處理好氣候責任的平衡，避免氣候責任的大國逃避責任與公約義務，是國際氣候制度未來所面臨的重大挑戰。

另一方面，根據締約方提交的INDC文件，各國的責任、承諾與行動均以各國“差異自表”的方式來體現。由此，各國開展氣候行動的法律基礎，從對于氣候責任的擔當，轉向了更多取決于國家自身能力和行動意愿。這一發展趨勢，是以實力為基礎的大國政治博弈和關鍵國家國內政治的產物。它繞開了以升溫目標和排放空間為基礎的多邊氣候規則的科學性、公平性和有效性，使氣候責任的大國得以擺脫自上而下的碳排放預算束縛。事實上，這種發展容易成為眾多締約方、尤其是發達國家逃避自身責任與義務的跳船平臺，也難以有力、有效、公平地控制住全球排放的趨勢。

不僅如此，目前發達國家的INDC文件以減緩為基本內容，不包括適應、資金、技術、能力建設以及行動與支持的透明度等要素，本質是對其公約下所需承擔義務的規避，實質上使得INDC進程無法反映國際氣候制度的所有核心要素，不利于達成全面、平衡、可持續實施的新協議?！豆s》對于減緩與適應的共同關注，以及對于氣候行動的力度、潛力、甚至是為發展中國家行動提供支持的安排，不僅是對于長期轉型與當下應對的權衡，也是對發達國家與發展中國家在責任、權利、能力與發展階段之間的權衡。當前“自下而上”的氣候治理進程所體現出的有所偏頗的議題推進，未必有利于構建公平正義的國際氣候制度，也難以真正提升全球行動力度，而全球行動力度則是實現《公約》目標的關鍵。

本文得到WWF中國氣候與能源項目的支持，文中觀點紕漏由作者自行承擔，對此作者深表感謝。

鄧梁春，世界自然基金會（WWF）項目顧問，主要研究方向為能源、環境與氣候變化政策，國際氣候治理制度。

The Paris climate change talks have just kicked-off, and there is general agreement amongst international society and the participants: a new global climate deal will be struck. That deal will be based on the UNFCCC, but different from the Kyoto Protocol in terms of degree of participation, strength of action taken, transparency and legal force.

Almost twenty years ago the Kyoto Protocol set legally binding emissions reduction targets for the developed nations. Despite appearing to have real force, it became increasingly apparent that Kyoto failed to take into account domestic political realities. As a result this “top-down” method of climate governance faced obstacle after obstacle in major carbon emitting nations: The US never ratified it; in 2011 Canada pulled out. After the Copenhagen talks in 2009 changes started to be seen in how international climate mechanisms were being put together, and the “bottom-up” INDC system took shape. But this development brings its own challenges for the world’s efforts to respond to climate change and implement the aims of the UNFCCC.

From top-down to bottom-up

The climate system put in place by the UNFCC and the Kyoto Protocol put a “firewall” in place between developed and developing nations: the two groups had different responsibilities, duties, and rights. The developed nations were to make earlier commitments to reduce emissions than developing nations, and to provide them with support. Meanwhile, on receiving that support the developing nations were to act on climate change in accordance with their national circumstances. The Kyoto Protocol was an example of a “top-down” approach to building a system of climate governance, an approach which continued until the “two-track negotiations” of the Bali Roadmap.

Those two-track negotiations meant the developed nation signatories to the Kyoto Protocol would set up special working groups during the second commitment period to set quantified targets for major emissions cuts post-2012; while developing nations and those developed nations not signed up to Kyoto (primarily the US) would discuss further climate change response measures in special working groups designed to foster long-term cooperation.

The top-down approach was legally binding and had strong enforcement mechanisms and a powerful measurement, reporting and verification system to ensure transparency. But reaching consensus was difficult and progress was slow. The domestic politics of key signatories (primarily the developed nations), particularly due to changes in the global political economy and the make-up of global emissions, and the impact of the financial crisis, meant no deal was reached in Copenhagen – a huge setback for the top-down approach.

Against this background we saw international climate interaction shift from north and south being in opposition, to a battle between the major powers, and between the large and small nations. The National Action Plans suggested by the Umbrella Group and the Commitment and Review approaches were found to better suit the needs of both international climate diplomacy and domestic politics. As such, these ideas became increasingly accepted and the Copenhagen and Cancun talks saw new rules for managing emissions commitments take shape.

In Warsaw in 2013 the INDC process was started – by 2020 each country would submit its own independently determined plans for emission cuts. There was now agreement on a new bottom-up approach, and the outlook for Paris was looking up. The new approach meant countries would put forward their own climate action plans and targets, rather than having this set through tortuous negotiations processes, and those plans and targets would, in the aggregate, represent joint action plans and global targets.

The INDC approach takes more account of national circumstances than the principles and rules embodied in the UNFCCC, representing an attempt to achieve the UNFCCC’s goals by relying on the individual national interest. It is voluntary and non-intrusive, and the action plans and targets it produces are diverse and varied, and may by accompanied with cooperative and facilitative mechanisms encouraging further participation. But a lack of a single verification method or a mechanism to encourage or require tougher targets mean it cannot ensure overall action with be powerful enough, and political trust and positive interactions still need to be strengthened.

Knocking down the firewall

The INDCs are a major change and will have a significant impact on global climate governance. The INDCs submitted are very varied and of different standards, and based on each country’s understanding of its own responsibilities and capabilities. In effect the UNFCCC’s distinction between the responsibilities of developed and developed nations, and the associated actions to be taken, has been broken down. The INDC process is in effect a rebalancing of the principles of common but differentiated responsibilities, respective capabilities, national circumstances and the corresponding “unequal commitments” of the UNFCC.

The new system changes the nature of national commitments and action. The principles of common but differentiated responsibility and fairness are the foundation of international climate governance, both coordinating the responsibility of the developed nations for their historical emissions with the need for future development and emissions of the developing world; and linking the technological and financial strengths of the developing nations with the urgent need for capacity building in developing nations and the overall global need to respond to climate change. This ultimately led to the “unequal commitments”, via the “dichotomy” and the annexes.

But in the current INDC process, both developed and developing nations are setting their own targets and action plans on one negotiating track: together, of their own accord, at the same time, and even without reference to whether or not support has been received. However, over time there will be calls for these targets to become legally binding and more transparent. That means new and unexpected pressure for developing nations. With the “firewall” at risk of collapse, there is a major new challenge for the global climate system: how to balance climate responsibilities and avoid major powers shirking their responsibilities under the UNFCCC.

Also, the INDCs allow each country to decide upon its own responsibilities, commitments and actions. This means the legal basis for national action is shifting from climate responsibility to respective capability and intent. That trend is the outcome of the realpolitik of major power diplomacy and the domestic politics of key countries. It bypasses the more scientific, fair and effective approach of a multilateral system based on limiting temperature rises, and allows major powers with climate responsibilities to avoid the limiting emission quotas of a top-down system. The change will make it easier for signatories, particularly the developed nations, to avoid their responsibilities and duties; and will make it more difficult to put in place strong, effective and fair controls on global emissions.

Moreover, the INDCs of developed nations are currently primarily about mitigation – adaptation, funding, technology and capacity building are missing, as are measures for transparency of actions taken and support given. This is in effect the avoidance of duties accepted under the UNFCCC, and means basic parts of the international climate system are missing from the INDC process. This will not help us reach a new powerful, balanced and sustainable agreement.

The UNFCCC’s coverage of both mitigation and adaptation, as well as the strength and potential for action of individual nations, and even the arrangements for support for action in developing countries, represented both a balancing of the need for long-term transitions and immediate response, and a consideration of the different responsibilities, duties, capabilities and stages of development of the developed and developing nations. The new bottom-up process has not advanced that agenda equally, which will not help build a fair and just system, or increase global efforts overall. And it is the strength of global efforts that will determine whether or not the aims of the UNFCC are achieved.

The author is grateful for support from WWF China’s Climate and Energy Programme for this article. The author is responsible for the views expressed in the article.