Nature 446, 646–649 (2007)

It has been brought to our attention that there was some ambiguity in the wording of the first boldface paragraph of this Letter regarding our prediction of the change in temperature on Mars that would have resulted from changes in albedo. As is clear from Table 1, we predict a total change of 0.65 degrees Celsius over the period from the 1970s to the 1990s, rather than 0.65 degrees Celsius per year.