Plurilateral initiatives are again gaining importance in climate diplomacy as a complement to multilateral efforts – not least in view of the lack of progress in implementing the Paris Agreement and more difficult conditions in the UN process. New alliances are expected to facilitate agreement...

In this paper we argue that when a subgroup of countries cooperate on emission reduction, the optimal response of non-signatory countries reflects the interaction between three potentially opposing factors, the incentive to free-ride on the benefits of cooperation, the incentive to expand the...