Nature 408, 184— 187 (2000).

In this paper, part of the labelling of Figs 2–4 was printed incorrectly. In Fig. 2, the year 2950 should have been 2050. In Figs 2 and 3, the year 1050 should have been 1950. In Fig. 4, the numbers on the y axis should have been labelled sequentially from -200 to +400; in addition, in Fig. 4a the y axis should have been labelled ‘Changes in vegetation carbon (Gt C)’.