Climate policy is typically seen as informed by scientific evidence that anthropogenic carbon emissions require reducing in order to avoid dangerous consequences. However, agreement on these matters has not translated into effective policy. Using interviews with local authority officials in the UK's East Midlands region, this paper argues that the ideas, arguments and data informing local climate policy have been grounded in evidence from the natural sciences. Focusing on carbon emissions data demonstrated a consensus around scientific knowledge, not local policy responses to this knowledge. Acknowledging this "mistaken consensus" provides the potential to utilise evidence more attentive to local contexts.