Last month’s vote to formally recognize the ‘Anthropocene’ epoch (see Nature https://doi.org/10.1038/d41586-019-01641-5; 2019) recalls the visionary work of Ernst Haeckel, who died 100 years ago this August. In his book The History of Creation, published in 1868, he introduced the idea of an ‘Anthropozoic age’ to highlight humans’ profound impact on the environment.

More than a century later, the atmospheric chemist and Nobel laureate Paul J. Crutzen coined the term ‘Anthropocene’ to denote our present geological epoch, marked by humans’ ongoing effect on Earth’s atmosphere (see Nature 415, 23; 2002 and Nature 467, S10; 2010). For Crutzen, this started in the eighteenth century, but Haeckel maintained that human influence began much earlier, with the “era of cultivated forests”.