The failure of the 2009 Copenhagen Summit to produce a greenhouse gas emissions accord highlights the fact that consensus and expertise regarding the physical science of climate change exceeds the political science of changing human factors. We examined whether national differences in economic factors shape the extent to which perceptions of global warming are linked to self-reported intentions to make self-sacrifices to help protect the environment (N = 6,651 university students) in developing and developed nations (N = 34 nations). Perceptions of the importance of global warming predicted self-reported willingness to make sacrifices to help protect the environment, and this association was more pronounced in nations with a higher Human Development Index (HDI). There may be hope for the future, to the extent that young people in developed countries are prepared to match their convictions and intentions to sacrifice for the environment with action.