The illustration used with the article ‘US warms to carbon sequestration research’ (see Nature 401, 315; 1999) should have been referenced to “Direct experiments on the ocean disposal of fossil fuel CO2” by Peter G. Brewer, Gernot Friederich and Edward T. Peltzer of the Monterey Bay Aquarium Research Institute, and Franklin M. Orr of Stanford University (see Science 284, 943–945; 1999).