Setting targets for addressing major planetary concerns is an essential prerequisite for concerted global action (both inside and outside multilateral environmental agreements) and is necessarily a societal and political process, requiring negotiation and convergence among oftenconflicting interests. There is no such thing as a ‘scientific target’ applied in policy or business—operational targets are socio-political choices. However, this is not to say that targets cannot be ‘science-based’. What, then, does it mean for a target for addressing major planetary concerns to be ‘science-based’? First, recall that ‘science’ is ‘the organised, systematic enterprise that gathers knowledge about the world and condenses the knowledge into testable laws and principles’. Building from this, we propose the following characteristics as defining ‘science-based targets’...
