The Evolution of Heterogeneity in Biodiversity and Environmental Regimes

Biodiversity and environmental protection are examples of international public goods problems that comprise a symmetrical system of rights and obligations. Moreover, the underlying scientific, economic, and political conditions do not necessarily lead to a prisoner's dilemma. Yet from this symmetrical beginning, voluntary (Nash) equilibria often require heterogeneous actions, the resolution of which is often couched as a North-South or East-West issue. The author uses evolutionary game theory to examine how heterogeneous behavior can emerge over time and finds that asymmetries need not be universally determined in terms of economic or technological differences. In particular, the author finds that the evolution of international environmental protocols is a function of scale: the ability to achieve a cooperative solution depends on the distribution of signatories (namely, nonparticipants in the population at large). Such scale considerations reveal an organizational pattern of collective action that does not require across-the-board contribution or abatement levels.