Personal and political action on climate change is traditionally thought to be motivated by people accepting its reality and importance. However, convincing the public that climate change is real faces powerful ideological obstacles, and climate change is slipping in public importance in many countries. Here we investigate a different approach, identifying whether potential co-benefits of addressing climate change could motivate pro-environmental behaviour around the world for both those convinced and unconvinced that climate change is real. We describe an integrated framework for assessing beliefs about co-benefits, distinguishing social conditions (for example, economic development, reduced pollution or disease) and community character (for example, benevolence, competence). Data from all inhabited continents (24 countries; 6,196 participants) showed that two co-benefit types, Development (economic and scientific advancement) and Benevolence (a more moral and caring community), motivated public, private and financial actions to address climate change to a similar degree as believing climate change is important. Critically, relationships were similar for both convinced and unconvinced participants, showing that co-benefits can motivate action across ideological divides. These relationships were also independent of perceived climate change importance, and could not be explained by political ideology, age, or gender. Communicating co-benefits could motivate action on climate change where traditional approaches have stalled.