Anthropogenic emissions are rapidly altering Earths climate, pushing it toward a warmer state for which there is no historical precedent. Although no perfect analog exists for such a disruption, Earths history includes past climate states—“paleoclimates”— that hold lessons for the future of our warming world.  In a recent paper in the journal Science (see: Tierney et al. make a strong case that information from the past is vital to a more appropriate understanding of present-day and future environments – especially so in these times of rapid anthropogenic change.  Several IGU Commissions, including those on Climate, Geomorphology and Society, and Future Earth, have researchers who are using knowledge of past changes to inform future conditions.