The voluntary provision of a public good in an international commons

P>In a global commons, countries contribute to global welfare by limiting the environmental damage they do. Assuming this to be so, we examine the characteristics of equilibrium without international coordination, with particular focus on how control of damaging emissions relates to country size. There is some association between size and burden-sharing, with larger countries doing more to control emissions, but there remain important differences between this and a conventional 'subscription' public good.