In this paper I reflect on a line of work that looked at climate geoengineering – an issue that has been largely framed by science and engineering – using social science techniques, but informed by an environmental-humanities sensibility. I suggest that, if we ever come to ‘make’ Earth climates, then we need an expanded way of thinking about two things, both of which should inform the other: what it means to make or compose something, and what it would be like to live in a made or composed world. I thus explore geoengineering as the ‘making of worlds’, asking how geoengineering might colour our relationship with the air, and what sort of world it might bring about.