The “common but differentiated responsibility” of developed and developing countries to mitigate climate change is a core principle of international climate politics—but there is disagreement about what this “differentiated responsibility” amounts to. We investigate how newspapers in developed countries (Australia, Germany, United States) and emerging economies (Brazil, India) covered this debate during the UN climate summits in 2004, 2009, and 2014. Newspapers in both types of countries attributed more responsibility to developed than to developing countries. In line with social identity theory, however, media in developed countries attributed less causal responsibility (blame) to other developed countries than media in emerging economies. The latter countries’ media, in turn, attributed less responsibility to other developing countries than media in developed countries. At the same time, in line with the “differentiated responsibility”, media in developed countries attributed more responsibility to their own countries than media in emerging economies.