In this progress report on climate change, I examine the growing literature dealing with the proposal to engineer global climate through the deliberate injection of aerosols into the stratosphere. This is just one of a wide range of technology proposals to geoengineer the climate, but one in particular which has gained the attention of Earth System science researchers and which is attracting wider public debate. I review the current status of this technology by exploring a number of different dimensions of the proposal: its history and philosophical and ethical implications; how it is framed in public discourse and perceived by citizens; its economic, political and governance characteristics; and how the proposed technology is being researched through numerical modelling and field experimentation. Unlike many other geoengineering interventions, stratospheric aerosol injection has no additional societal co-benefits: its sole raison d’etre would be to offset planetary heating caused by rising concentrations of greenhouse gases. The deployment of such a technology would have profound implications for the view humans have of themselves in relation to the non-human world.