As public support is important for policy changes, it is crucial to understand how citizens construct their views toward climate policies. Based on the widely documented effect of descriptive social norms on human behavior, we hypothesized that individuals' support for climate policies to be implemented in their own country would be stronger when they perceive greater prevalence of climate action by national governments worldwide. Findings from two surveys with respondents from China and the United States provide supportive evidence for this hypothesis. In addition, four mediators underlying this effect (including informational influence, normative influence, and two forms of efficacy beliefs) were identified. In an experiment, with participants from the United States, we further found that a fact-based informational intervention effectively increased participants' perceptions of global prevalence of coal power phaseout, which, in turn, led to stronger support for a similar action in their own country. These findings introduce novel perspectives to the understanding of public attitudes toward climate policies and the study of climate change opinions. They also imply that communicators and policymakers can leverage the power of social influence, through messages built around narratives of a global norm, to garner public support for domestic climate efforts.