Climate change has emerged as one of the most important issues of the twentyfirst century. Recent opinion polls show rising public awareness of climate change. Yet considerable cross-national variation exists in the intensity of public concern and in public willingness to pay for addressing climate change. Drawing on twelve multinational surveys, we examine two aggregate conditions—a country's affluence and its vulnerability to climate risks—as key factors underlying cross-national differences in public support for and commitment to costly climate policies. In contrast to the post-materialism thesis, we find “strong” concern about climate change to be higher in developing countries. Contrary to expectation, climate vulnerability had little effect on public concern, but did have significant impact on some measures of personal commitment and support for climate policies. The analysis indicates that, in most countries examined, high concern about climate change is only beginning to translate into personal commitment to action.