This module introduces Earth system science, taking a top-down approach to the Earth as a whole system, and tracing its development since its formation 4.5 billion years ago. The main focus is on the coupled evolution of life and its environment through a series of revolutions. Theoretical approaches are introduced, including Gaia, feedback mechanisms and systems theory, and practical sessions use models to build up conceptual understanding. The subject is inherently inter-disciplinary, including aspects of biology, chemistry and physics, and unifying the study of climate and global biogeochemical cycles. Co-taught with ENV-MA38.