This article adapts a theory of ecological modernization to characterize countries by their economic, political, and cultural development to estimate their structural and strategic readiness to commit and comply with the Kyoto Protocol. Hypotheses logically derived from ecological modernization theory perform as expected, with substantial variation in Kyoto Protocol ratification explained by our variable pool. Results from logistic and Cox proportional hazards regression tests show that democratic openness, gross domestic product (GDP) output per unit of energy input, CO 2 emissions per capita, and record of international cooperation on transboundary environmental problems significantly predict whether or not a country is party to the Protocol, and how quickly a country submits an instrument of ratification.