Earth System Models (ESMs) are used as inputs in impact models to estimate future climate risks. Hence, accurately representing the entire spectrum of uncertainty in ESMs is vital for comprehending the future co-evolution of the coupled human-natural system. Numerous ESMs are part of the CMIP6 suite and it is impossible to incorporate all of them in impact modeling. This study will help in selecting a suitable subset of ESMs that will reduce computing costs while preserving the range of uncertainty.

Concurrent temperature extremes are becoming common but there is no climatology of such extremes in the literature. This study provides a climatology for concurrent heatwaves and cold spells and a programming toolbox to study such phenomena. This dataset and toolbox will be of interest to a wide readership, expecially those interested in climate and climate change science.

This paper makes an important criticism about the visualisation of the planetary boundary concept. Hopefully, future publications will take up on the suggestions being made in this paper to communicate the concept more objectively in a scientific manner.

The paper gives a comprehensive overview on the current state of the societally important field of Earth system tipping point early warning signals across different fields. Relevant conclusions are drawn on promising avenues for further advancing the research field.