Negotiating climate change, by Schmidt and Ockenfels in PNAS

 Now that there's light at the end of the Covid tunnel, we can turn our attention back to big problems:

Focusing climate negotiations on a uniform common commitment can promote cooperation  by Klaus M. Schmidt and  Axel Ockenfels, PNAS March 16, 2021 118 (11) e2013070118; https://doi.org/10.1073/pnas.2013070118

Edited by Lise Vesterlund, University of Pittsburgh, and accepted by Editorial Board Member Paul R. Milgrom

Abstract: International cooperation on the reduction of greenhouse gas emissions, disarmament, or free trade needs to be negotiated. The success of such negotiations depends on how they are designed. In the context of international climate change policy, it has been proposed [e.g., M. L. Weitzman J. Assoc. Environ. Resour. Econ. 1, 29–49 (2014)] that shifting the negotiation focus to a uniform common commitment (such as a uniform minimum carbon price) would lead to more ambitious cooperation. Yet, a proof-of-concept for this important claim is lacking. Based on game theoretical analyses, we present experimental evidence that strongly supports this conjecture. In our study, human subjects negotiate contributions to a public good. Subjects differ in their benefits and costs of cooperation. Participation in the negotiations and all commitments are voluntary. We consider treatments in which agreements are enforceable, and treatments in which they have to be self-enforcing. In both situations, negotiating a uniform common commitment is more successful in promoting cooperation than negotiating individual commitments (as in the Paris Agreement) and complex common commitments that tailor the commitment to the specific situation of each party (as attempted with the Kyoto Protocol). Furthermore, as suggested by our model, a uniform common commitment benefits most from being enforced.