In this paper, Lenton et al introduced the term “tipping element” to describe large-scale components of the Earth system that may pass a tipping point. The authors have critically evaluated potential policy-relevant tipping elements in the climate system under anthropogenic forcing, drawing on the pertinent literature and a recent international workshop to compile a short list, and they assessed where their tipping points lie. An expert elicitation is used to help rank their sensitivity to global warming and the uncertainty about the underlying physical mechanisms. Then they explain how, in principle, early warning systems could be established to detect the proximity of some tipping points. The analyses suggest that rigorous study of potential tipping elements in human socioeconomic systems would also be welcomed, especially to address whether and how a rapid societal transition toward sustainability could be triggered, given that some models suggest there exists a tipping point for the transition to a low-carbon-energy system.