For at least a decade, global climate change has been a very important topic in German mass media coverage. Theories of media effects such as “cultivation” and “agenda setting” lead us to expect that climate change reporting will have an impact on the risk perception of the media audience. Furthermore, because of the medialization of politics, media reporting of climate change may be assumed to have political effects. Based on a content analysis of about 1200 media stories, the “risk construct” of global climate change in the German mass media is analysed and its potential functions for the ways in which society copes with climate change are discussed. The empirical analysis finds that the media construct of climate change closely mirrors the position of the scientific community as documented in the IPCC reports. The article discusses likely effects of climate change coverage on individual behaviour and on policy. It concludes that the key effect is the legitimization of climate politics as a political field.