Deeply rooted in the old notions of fairness and equity,1 the idea of differential treatment between developed and developing countries started to appear in international environmental law in the last quarter of the twentieth century. It addresses the fact that environmental issues, such as climate change, have too much of a universal impact for the answer to be ‘solely a matter of domestic jurisdiction’,2 and acknowledges that ‘imposing equal obligations on subjects of law that are unequal in relevant ways may be perceived as unjust if they exacerbate inequalities or impose unfair burdens on those least able to bear them’.3 During the 1972 Stockholm and 1992 Rio Conferences, negotiators took hold of this idea. The preamble of the Stockholm Declaration states: ‘the developing countries must direct their efforts to development, bearing in mind their priorities and the need to safeguard and improve the environment. For the same purpose, the industrialized countries should make efforts to reduce the gap between themselves and the developing countries’ (emphasis added).4 In the twenty-year period between Stockholm and Rio, developing countries kept fighting to ensure different national situations were taken into account. Acknowledging historical differences as well as differences in terms of economic and social development, States then ‘crafted a burden-sharing arrangement rooted in differential treatment’5 in order to achieve a regime characterized by a universal scope rather than uniformity in parties' obligations.6 The 1992 Rio Declaration embodies this ‘burden-sharing arrangement’ in its Principle 7:7
States have common but differentiated responsibilities. The developed countries acknowledge the responsibility that they bear in the international pursuit to sustainable development in view of the pressures their societies place on the global environment and of the technologies and financial resources they command. (emphasis added)
At Rio, countries adopted the United Nations Framework Convention on Climate Change (UNFCCC),8 which was subsequently followed by the adoption of the Kyoto Protocol in 1997.9 Bringing together 195 Parties, the Convention today has a universal scope and constitutes the main legal instrument on climate change.10 The principle of common but differentiated responsibilities (CBDR), expressed in Article 3.1, helped make this universality possible. By addressing the demand of developing countries to see differences in national circumstances taken into account, the CBDR principle has become the basis of the differentiated obligations for developed and developing countries. Since 1992, the principle of common but differentiated responsibilities has been used repeatedly in the negotiations and has been reiterated in key texts structuring the regime, including the 1997 Kyoto Protocol. It has therefore been said that the principle of CBDR is ‘best reflected in the climate regime’.11
Still, the UNFCCC does not perfectly incorporate the Rio Declaration's definition of CBDR. Whereas the Rio Declaration clearly refers to historical contributions of developed countries to environmental degradation, these contributions are only mentioned in the preamble of the UNFCCC.12 Furthermore, the UNFCCC wording adds the mention of ‘respective capabilities’ to CBDR. Article 3.1 of the Convention, expressing CBDR, states that
[T]he Parties should protect the climate system for the benefit of present and future generations of humankind, on the basis of equity and in accordance with their common but differentiated responsibilities and respective capabilities. Accordingly, the developed country Parties should take the lead in combating climate change and the adverse effects thereof.
Since developed countries were strongly opposed to any reference to their historical emissions, it was important to put responsibilities and capabilities on an equal footing. Hence, the last sentence of Article 3.1, giving them ‘the lead’ in combating climate change, is more a reference to their larger obligations under the Convention and their greater technological and financial capacities than to their historical contribution to environmental degradation.
One of the main reasons why historical emissions were not taken into account in the Convention and the Protocol is because CBDR, as expressed in 1992, represented a political consensus on what should be the commitments and actions of developed and developing country parties. However, the multiplication of State groups within the developing countries category and the rise of emerging economies – some of them being today's major greenhouse gas emitters – have called this initial compromise into question. Trying to reach any new consensus comes down to a simple question: what is common and what is differentiated between developed and developing countries?13 While negotiating new differentiated obligations, questions concerning the legal nature and scope of the CBDR principle have re-emerged. Given that the formula of the principle is so general, however, it has led to diverging interpretations. For instance, the United States and some other developed countries have chosen to focus on ‘common’ responsibilities, asking emerging economies to take on commitments. Thus, for the United States, ‘developed and developing countries share common challenges in meeting all of their economic, social and environmental needs’14 and ‘all countries have a common responsibility to take actions that will promote’ clean development.15 Meanwhile, Australia considers that ‘if key developed country mitigation commitments … were separated from commitments and actions relating to non-Parties to the Kyoto Protocol and advanced developing economies … it would be more difficult to assess comparability of effort’.16
By contrast, emerging economies, small-island developing States and other developing countries emphasize ‘differentiated’ responsibilities, asking developed country parties to keep leading the fight against climate change. Thus, for Brazil, ‘significant steps must be taken to promote, facilitate and finance the transfer of, access to and development of environmentally sound technologies and know-how, particularly fromdeveloped countries to developing countries, for both mitigation and adaptation’.17 For Tuvalu, ‘the allocation of responsibility for emissions reductions should be based on historical emissions… . Annex I Parties have contributed approximately 75% of cumulative global emissions of CO2. A global breakdown of historical responsibility can be represented as: Kyoto Annex I Parties 45.75%, the United States 29.25%, Non-Annex I Parties 25%.’18 And Bolivia calls ‘on developed countries to commit to deep emission reductions in order to advance the objective of avoiding dangerous anthropogenic interference with the climate system and its consequences, to reflect their historical responsibility for the causes of climate change, and to respect the principles of equity and common but differentiated responsibilities in accordance with the UNFCCC’.19
At the fifteenth Conference of the Parties (COP) in Copenhagen in 2009, progress was obstructed ‘for one thing, by the continuing uncertainty about whether the United States will undertake serious action to curb its emissions [and] for another [because] Copenhagen negotiations for the first time have given serious attention to developing country [greenhouse gas] emissions’.20 Paradoxically, as the Copenhagen example shows, the CBDR principle, which made it possible to create the international climate regime in the 1990s, has also contributed to the post-2012 negotiation difficulties. More accurately, it is the question of how the principle would be implemented through differentiated obligations that led to difficulties in Copenhagen rather than its very existence. And on this point no consensus was reached. On the contrary, the Copenhagen Accord21 left ‘most substantive disagreements unresolved – in particular … the future of the Kyoto Protocol, the legal form and architecture of the future legal regime, and the nature and extent of differential treatment between developed and developing States’.22
After Copenhagen, the COP in Cancún gave ‘a new lease of life’23 to the climate regime. Still, the Cancún Agreements are characterized by the bottom-up/pledge and review approach that had already been sketched in Copenhagen.24 Moreover, an analysis of the pledges made so far reveals an ‘increasing parallelism between the mitigation commitments and actions taken by developed and (some) developing countries’,25 showing that the consensus reached only represents the lowest common denominator of parties' interests. The creation of the Ad Hoc Working Group on the Durban Platform for Enhanced Action in 2011 launched ‘a process to develop a protocol, another legal instrument or an agreed outcome with legal force under the Convention applicable to all Parties’.26 While not returning to a ‘targets and timetables’ approach as used in the Protocol, and without establishing the legal form of the future agreement, consenting to the launch of this new process has ensured the continuation of the climate regime, at least for the time-being.
Since differentiated obligations are at the core of the regime and since these obligations are ‘based on’ or ‘taking into account’ CBDR, it is obvious that the principle plays a central part in shaping the new texts of the regime and negotiating future obligations. Yet, when analyzing the wording of the Durban decisions, it seems that the practice of CBDR is changing. Indeed, while references to Decision 2/CP.1727 and the Bali Action Plan,28 which both contain the principle, can be found in it; Decision 1/CP.17 creating the Durban Platform makes no reference to CBDR as such. The objective to develop ‘a protocol, another legal instrument or an agreed outcome with legal force under the Convention’ (emphasis added) does link the future text to the UNFCCC and, therefore, indirectly to CBDR. However, this does not change the fact that the Decision does not refer to the principle as do all the important texts developed under the climate regime.29 More broadly, out of the eighteen other decisions adopted in Durban, only Decision 2/CP.17 quotes CBDR, Article 3 and the principles of the Convention,30 whereas Decision 3/CP.17 only refers to the latter.31 And yet, references to equity or special and national circumstances are more frequent in Decision 2/CP.17 than they were in Decision 1/CP.16. The question then arises whether or not this evolution of the CBDR practice through the Durban decisions is leading to changes in the principle's legal nature, scope and consequences, and whether this may have implications for the climate regime itself. At first blush, the answer would be ‘yes’. However, even though some major changes seem to take place with respect to the practice of the principle and the setting of common and differentiated obligations, one cannot help but noticing that vagueness and uncertainties that have characterized its legal nature remain unchanged.
In order to give a complete view of these elements of CBDR, the next part of this article assesses the legal nature and scope of the principle. The article then studies the impacts of the Durban decisions. The insights on CBDR drawn from this analysis are discussed in the conclusions, as they offer a glimpse of the future of the principle in the regime.