Geoengineering is central to scenarios that limit global warming to 2 °C — for example, by removing carbon dioxide from the atmosphere or increasing the planet's albedo (see Nature 527, 436–438; 2015). However, the environmental and social implications of such technology are holding back research. Developing an international code of conduct could resolve this conundrum by ensuring that geoengineering proposals are subject to societal scrutiny and oversight.

The code would provide flexible governance for a wide range of projects, along with general principles and procedures to guide responsible research and to inform regulatory processes for technologies as they develop (see go.nature.com/2ceitmv).

As well as encouraging early cooperation and coordination of research, equity and sustainable development in the spirit of the 2015 Paris climate agreement, the code should promote precaution, risk assessment, public participation and transparency.