We examine in this paper the formation and the stability of international environmental agreements when cooperation means to commit to a minimum abatement level. Each country decides whether to ratify the agreement and this latter enters into force only if it is ratified by a number of countries at least equal to some ratification threshold. We analyze the role played by ratification threshold rules and provide conditions for international environmental agreements to enter into force. We show that a large typology of agreements can enter into force among the one constituted by the grand coalition.

Financial support from the Barcelona Economics - CREA program is gratefully acknowledged.