Do countries interact when they decide whether or not to ratify the Kyoto Protocol? If so, what is the nature of these interactions? To answer these questions, we provide a theoretical analysis based on the notions of strategic substitutability and strategic complementarity. Firstly, we analyze the nature of interactions between countries when they are merely seeking to provide a global public good. Secondly, we argue that countries have ties in several spheres in the real world and we try to shed light on the nature of the strategic interactions generated by geographic proximity, trade flows, and green investment flows. The empirical investigation is realized via the estimation of a parametric survival model, and our data sample covers 164 countries for the period from 1998 to 2009. We find evidence that, while countries' ratification decisions are originally strategic substitutes, they became strategic complements when we focus on the ratification decisions of specific peers.
