For centuries we have been changing the natural world around us, through hunting and farming; building, mining, and engineering; and travelling and trading. But we can no longer take it for granted. ‘Origins’ outlines the rise of ecological science in the 20th century and the new awareness of the unexpected side-effects of human impacts on the environment raised by Aldo Leopold’s A Sand County Almanac (1949) and Rachel Carson’s Silent Spring (1962). It also describes the emergence of environmental ethics with the work of philosophers Richard Routley, Arne Naess, and Holmes Rolston III. One common feature of their contributions was their rejection of a human-interests-only or ‘anthropocentric’ approach to ethics.