Fifty years ago, Harte and Socolow edited Patient Earth: a collection of essays that addressed pressing environmental issues of the day. Their chapter reads as a retrospective piece following the introduction of the present volume, and is structured so as to compare and contrast Patient Earth with Earth 2020. Harte and Socolow carefully assess their choices of topics in Patient Earth, highlighting how environmentalism in 1970 was deeply intertwined with three other contemporary concerns – wilderness and the non-human environment, militarism and population – three topics which are scarcely present in Earth 2020. These three previous concerns have been replaced by two new ones: planetary-scale thinking and environmental justice. Harte and Socolow address the American-centric focus of Patient Earth’s case studies, their light treatment of the intersection between poverty and environment, and the three-component model of social change driving Patient Earth: science-policy-activism. While Earth 2020 addresses issues ignored by Patient Earth – e.g., sea level, ice, forests and fisheries – both books are silent on the overuse of antibiotics, and uncontrollable epidemics (topics which must also be brought into the discussion). They close their chapter with a measured consideration of the balance, or lack thereof, between scientific knowledge and public policy and activism.