With unabating climate extremes, evidence of waning biosphere buffering capacity, and surging ocean surface temperature, Earth system analysts are posing the question: is global environmental change accelerating, driven by the depletion of our planet's resilience? No scientist contributed more actively to addressing this question and thus defining sustainable development in the Anthropocene than the late Professor Will Steffen. His contributions to Earth system and global sustainability research gave birth to concepts such as the Planetary Boundaries, Hothouse Earth, Planetary Commons, and World-Earth resilience, and have become guideposts for how Earth system science can inform humanity's Earth stewardship in the Anthropocene.

Mounting evidence of accelerating global environmental change is driving scientists to question whether we are witnessing a breakdown in the resilience of our planet. Three lines of scientific enquiry have been important when studying the stability and resilience of the planet: the empirical evidence of the great acceleration of the human enterprise from the 1950s onwards resulting in planetary-scale pressures; the understanding that Earth is a complex biosphere-geosphere system with self-regulating interactions and feedbacks contributing to control its equilibrium state; and the emerging insight into the unique stability of the Holocene Epoch, the last 10,000 years of inter-glacial equilibrium, and its critical role in providing predictable (and for humanity agreeable) life conditions for the evolution of modern civilizations. Professor Will Steffen played a pivotal role in integrating and advancing these three Earth system research avenues and combining them into one integrated people-planet framework Earth system. State-of-the-art research on fully coupled Earth system models (ESMs) that also integrate non-linear dynamics and tipping-point behavior, and even human dynamics, is built in part on Will Steffen's pioneering work to observe and describe the Earth in the Anthropocene.

Prof. Will Steffen's legacy and how Earth system science can inform humanity's Earth stewardship in the Anthropocene