Most geologists would argue that geoscientific knowledge, experience, and guidance is critical for addressing many of society's most acute environmental challenges, yet few geologists are directly engaged in current discourses around sustainable development. That is surprising given that several attributes make modern geoscience well placed to make critical contributions to contemporary sustainability thinking. Here, we argue that if geoscientists are to make our know-how relevant to sustainability science, two aspects seem clear. Firstly, the geoscience community needs to substantially broaden its constituency, not only forging interdisciplinary links with other environmental disciplines but also drawing from the human and behavioural sciences. Secondly, the principles and practices of 'sustainability' need to be explicitly integrated into geoscience education, training and continued professional development. Dear Editor Many thanks for the opportunity to revise this manuscript based on the two reviews provided. As you noted, the review by Mark Maslin was especially constructive, and we have attempted to weave in most of his broader points. We have also included a specific statement about the extent to which 'sustainability'exists in UK university geoscience departments, although a wider systematic examination of this issue, with real data is beyond the sope of the present article. We have followed your advice and retained the images, although we acknowledge Maslin's comment that they are not essential to the paper. There is some restructuring of the argument to reflect the changes made, and a couple of references have been added, including those indicated by Maslin. Overall we feel that the argument has been sharpened up, though we take heart from the positive endorsements by both referees. I hope you like the new improved version. regards, Iain