This paper studies early arguments in Sweden for combating climate change. We show how scientific results in relation to climate change entered the political sphere as part of the debate on energy in the 1970s, a process we propose to name energysation. We argue that the use of climate science by pro-nuclear political actors served as a way of maintaining a course set by a high-energy society while simultaneously trying to outmanoeuvre the growing environmental anti-nuclear and low-energy movement. When the pro-nuclear power side met with resistance, this led to a displacement of climate change knowledge away from the realm of the national political sphere and specific energy forms, a process we conceptualise as de-energysation. By highlighting conflicts and the political framings of climate change in the early years 1974–1983, we suggest that the history of these frames influences current delay in climate change mitigation and limits the range of actions and ways of addressing the ongoing climate emergency.