Amphithéâtre Marguerite de Navarre, Site Marcelin Berthelot
En libre accès, dans la limite des places disponibles
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Interprétation simultanée en direct en français.

Résumé

How to design a climate agreement to get countries to limit their greenhouse gas emissions for the benefit of the whole world? Negotiators have been trying to do this since 1990, but ever since then atmospheric concentrations of greenhouse gases have continued to climb. Plainly, the world is doing something wrong.

The problem isn’t that countries can’t agree on what to do collectively. From the very beginning, countries agreed that atmospheric concentrations of greenhouse gases should be limited to avoid “dangerous” climate change. Later, they quantified this goal, saying that the increase in global mean temperature change should be kept under two degrees Celsius, relative to the pre-industrial level. Astonishingly, in a world in which countries seem to agree on very little, all countries agree about this. Support for this goal is universal.

The problem has been with how to meet this target. Two issues, in particular, need to be resolved. First, countries must agree on how to divide up the “carbon budget” implied by their collective goal. This “dividing up” is a constant sum game, and it should not be surprising that countries have disagreed on how to do this. Second, countries must enforce an agreement to keep within these limits. Enforcement is needed not only to punish countries that fail to fulfill their promises, but also to reassure every country that all countries will play their full part in achieving the collective goal.

Of these two problems, the first is easier to solve. In fact, countries solved it once before, in the Kyoto Protocol. The reason Kyoto failed is not that countries couldn’t agree how to meet their collective goal. The reason Kyoto failed is that this agreement could not be enforced. The United States declined to participate, without suffering any consequences. Canada ratified Kyoto, but did not adopt policies to implement it and later withdrew from the agreement—again, without suffering any material consequences. Other countries ratified and complied with the agreement, but in many cases this was because they were under no obligation to change their behavior.

Intervenant(s)

Scott Barrett

Columbia University, United States