Correction to: Nature https://doi.org/10.1038/s41586-018-0589-x, published online 17 October 2018.
In this Letter, the position of the y axes in Fig. 3b was altered during the production process, and the carbon isotope label ‘δ13C’ was inadvertently changed to ‘δ18C’. In addition, the x axis in Fig. 3b is on a different scale; whereas this extends to 40 kyr in Fig. 3a and c, it extends to 50 kyr in Fig. 3b. This figure has been corrected online.
Deceased: Robert Thunell.