AbstractSince its modern inception in the 1960s, international environmental law (IEL) has faced three main challenges: (i) justifying the need for an international regulation of environmental issues (legitimacy); (ii) finding mechanisms to ensure compliance with IEL (effectiveness); and (iii) distributing equitably the benefits and burden of environmental protection (fairness). While it is nowadays possible to say that the legitimacy of IEL is no longer in question, the need to respond to challenges (ii) and (iii) has never been more pressing. This is particularly the case in the context of the redesign of the climate change regime (CCR), as the responses to (ii) and (iii) may conflict with each other. Industrialized countries who historically contributed the most to the artificial increase in greenhouse gases (GHGs) in the atmosphere have been matched, and even surpassed, in their level of GHG emissions by countries such as China, India, or Brazil, who are now being pressed to undertake real emissions-reduction commitments. Historically, however, none of these latter benefited from the emission laxity characterizing the nineteenth century and most of the twentieth century to further their development. While imposing specific emissions-reduction commitments on them would seem unfair, such commitments are nevertheless critical for the effectiveness of the regime both directly and indirectly (as without such commitments, industrialized countries may be reluctant to join or uphold a regime). The purpose of this article is to spell out in an orderly analytical manner the types of issue that must be addressed in seeking a balanced solution. This type of analysis can be conducted from several perspectives. The most directly relevant disciplines to deal with fairness considerations are admittedly ethics and political philosophy, and there is indeed a growing literature on climate fairness. Although this literature is briefly surveyed, the article focuses on the fairness dimensions of the existing legal arrangements or those currently being negotiated. There is a considerable gap between the theoretical approaches to climate fairness and the manner in which considerations of fairness operate in practice. This gap is mainly due to the need to account for political considerations or, in other terms, to balance fairness with political effectiveness. When such considerations are taken into account, the picture that emerges is quite different. The CCR is not built upon a single approach to fairness. Rather, fairness considerations are integrated through a patchwork of criteria used to distribute different objects (burden of emission reductions, emission rights, contribution to financial and technological assistance, and access to such assistance) among different actors situated at different levels.
Global CO<sub>2</sub> emissions from cement production, 1928–2018
