+ Add to my selection Routes to an ambitious climate agreement in 2015, Christian de Perthuis and André Jouvet 26 Jan. 2015 News Opinions& Debates In environmental matters, the multilateral framework has already made it possible to deal with global threats. The Montreal Protocol, signed in 1987, led the international community to virtually cease emissions of CFC1 gases whose accumulation in the atmosphere was causing the destruction of the ozone layer. The success of this universal agreement was based on three pillars: a strong political commitment from the governments concerned, a rigorous and independent monitoring system and appropriate economic instruments. More than twenty years of climate negotiations have so far failed to produce comparable results. Would what was possible for tropospheric ozone be out of reach for greenhouse gases? The implementation of an international climate agreement comes up against the very classic problem of the “free rider” (Olson (1965). For each actor taken in isolation, there is no direct correlation between the level of effort he agrees to make to reduce his emissions and the benefit he will derive from it in the form of less damage. Climate disruption is linked to the global stock of greenhouse gases, which is only weakly correlated to the annual emission flux of each country. Moreover, the most severe impacts are distant in time, which encourages each player to pass on the full costs of climate change to future generations. In such a context, each player has an interest in waiting for its neighbours to take action, the ideal position being that of the “free rider” who would make no effort when all others would commit to protecting the common good. Conversely, it is not in the interest of any actor to commit unilaterally until it is convinced that others will follow as part of a wider coalition (Nordhaus (2013)). Europe and the United States have so far reacted in opposite ways to the stowaway issue. The former has always considered that the unilateral commitment of the rich countries was likely to provoke a suction effect from other countries that would spontaneously join a broad international coalition. In contrast, the US Senate adopted in 1997, by an overwhelming majority, a resolution opposing the ratification of any climate treaty that would bind the United States without countries such as China or India being committed to equivalent efforts2 (105th Congress, 1997). This resolution made it impossible for the US to ratify the Kyoto Protocol and contributed to the stalemate in the climate negotiations. However, the lack of effective coordination is leading to worrying results: during the 2000s, global greenhouse gas emissions accelerated and are increasing our collective exposure to climate risk3 (IPCC, WGIII AR5, (2014), Boden and Andres (2014)). The central challenge of international negotiations is to go beyond the vision of “substitutable strategies” deployed by actors in the face of climate risk, to implement “complementary strategies” 4 (Sandler, T. (2004)). Get the English Version on page 28