The Climate Coordination Problem

The Climate Coordination Problem is the defining collective-action challenge of the twenty-first century. One hundred and ninety-six nations share a single atmosphere. Each nation benefits from emitting greenhouse gases (cheap energy, industrial growth) and bears only a fraction of the resulting climate damage. The incentive to free-ride — to let others cut emissions while continuing to pollute — is overwhelming. The Paris Agreement (2015) established a framework of voluntary national commitments, but voluntary commitments are not binding, and the aggregate pledges remain insufficient to limit warming to 1.5°C or even 2°C above pre-industrial levels. The game-theoretic structure is well understood. William Nordhaus's DICE and RICE models (Dynamic Integrated model of Climate and the Economy) model the problem as an intertemporal public goods game. Scott Barrett has shown that international environmental agreements tend to be either broad and shallow (many signatories, weak commitments) or narrow and deep (few signatories, strong commitments) — never both. Michael Oppenheimer and colleagues have modelled tipping points as irreversible threshold effects that make the game catastrophically non-linear. No known mechanism — carbon taxes, cap-and-trade, climate clubs, geoengineering governance — has solved the problem. The Academy hosts the Climate Coordination Problem in the World School because it is the largest game humanity has ever played: a coordination problem at planetary scale, with catastrophic payoffs, asymmetric players, and no enforcement mechanism.

Garrett Hardin, "The Tragedy of the Commons," Science 162(3859), 1968. William Nordhaus, "An Optimal Transition Path for Controlling Greenhouse Gases," Science 258(5086), 1992; The Climate Casino (Yale University Press, 2013). Scott Barrett, Environment and Statecraft (Oxford University Press, 2003). The Paris Agreement, adopted 12 December 2015, entered into force 4 November 2016. Michael Oppenheimer et al., "Discerning Experts" (Cambridge University Press, 2019). William Nordhaus, "Climate Clubs," American Economic Review 105(4), 2015. Nobel Prize 2018 to William Nordhaus for integrating climate change into economic analysis.