An analysis by Robbin Bastiaansen and Anna von der Heydt, the University of Utrecht, the Netherlands; and Peter Ashwin, the University of Exeter, UK, indicates that it might remain difficult to accurately find the equilibrium climate sensitivity in complex climate models. The equilibrium climate sensitivity is used to compare and evaluate models and is calculated using a limited set of data from a relatively short simulation. But such results could be heavily underestimating long-term warming as late climate tipping cannot be excluded by the commonly used methods to estimate equilibrium climate sensitivity, conclude the authors. The work is part of the European TiPES project on tipping points in the Earth system.