In the News & Views article “Global change: Plankton cooled a greenhouse” by Birger Schmitz (Nature 407, 143–144; 2000), the period of ‘superwarm’ conditions at the Palaeocene/Eocene boundary should have been cited as lasting about 60,000 (not 150,000) years. Proof corrections made to the paper concerned (by S. Bains et al. Nature 407, 171–174;2000) were not passed on to the News & Views author.