Abstract

Climate-change velocity describes the rate of movement of climate conditions over Earth’s surface. It is a function of both the temporal and spatial gradients in climate conditions; velocities can be high if change through time is rapid, or if local conditions are homogenous. As a measure of climate instability it has several advantages, including describing the minimum migration rate required to track changing conditions and explicitly capturing the buffering effect of topography on climate change. Variation in climate stability has long been hypothesized as a possible driver of large-scale ecological patterns including diversity and range size gradients. We calculated a global map of climate-change velocity since the Last Glacial Maximum and used this measure of climate instability to address a number of classic hypotheses.

Historical climate-change velocity is related to a wide range of characteristics of modern distributions and communities. Some key results include apparent extinctions of small-ranged and weakly-dispersing vertebrate species from high-velocity regions, more specialized mutualistic networks in low-velocity regions and an increased importance of stability where current conditions are wet, productive and aseasonal. In general, climate-change velocity appears to influence a wide variety of features in the modern distributions of species and structure of communities. Understanding the role of historical climate instability improves our understanding of the origin of ecological patterns and our ability to predict changes in patterns under anthropogenic warming.