The planetary boundaries framework has been introduced to define “a safe operating space for humanity” in light of a multitude of existing anthropogenic pressures on vital components of the Earth system. Despite their considerable significance, Earth’s planetary boundaries remain inadequately defined and quantified; the difficulties that arise here are chiefly attributable to non-linear feedbacks in the Earth system and non-trivial interactions between the system’s various components. As national and international political decisions such as the Paris Agreement or the next steps toward a post-2020 global biodiversity framework require Earth system analyses, fundamental scientific progress on these questions is urgently necessary. This demands a novel and integrative Earth system modeling approach based on fast, modular coupled models that include advanced representation of the terrestrial biosphere.