We acknowledge the substantial contributions of researchers whose work was the basis of this expert assessment. G. Albistegui Adler and T. Carleton participated in trials of the elicitation protocol. This research was supported by the Alexander von Humboldt Foundation, the Stanford Woods Institute for the Environment, European Research Council grant no. 648291, the German Science Foundation Clusters of Excellence CliSAP and CliCCS, the National Science Foundation Interdisciplinary Behavioral Social Science Initiative and the Swedish Foundation for Strategic Environmental Research Mistra Geopolitics program.

Reviewer information

Nature thanks Geoff Dabelko, Vally Koubi and the other anonymous reviewer(s) for their contribution to the peer review of this work.