‘Planetary boundaries’ — exploring the challenges for global environmental governance

A range of studies from Earth system scientists argue that human activities drive multiple, interacting effects that cascade through the Earth system. Recent contributions state and quantify nine, interacting ‘planetaryboundaries’ with possible threshold effects. This article provides an overview of the globalgovernancechallenges that follow from this notion of multiple, interacting and possibly non-linear ‘planetaryboundaries’. Here we discuss four interrelated globalenvironmentalgovernancechallenges, as well as some possible ways to address them. The four identified challenges are related to, first, the interplay between Earth system science and global policies, and the implications of differences in risk perceptions in defining these boundaries; second, the capacity of international institutions to deal with individual ‘planetaryboundaries’, as well as interactions between them; third, the role of international organizations in dealing with ‘planetaryboundaries’ interactions; and fourth, the role of globalgovernance in framing social–ecological innovations.