Background/Question/Methods Climate-change velocity is a measure of the rate of climate change that incorporates small-scale climate variation such as that found along topographic gradients. 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. Results/Conclusions We show that historical climate-change velocity is related to a wide range of characteristics of modern distributions and communities, typically more so than traditionally used climate anomalies. Some key results include apparent extinctions of small-ranged and weakly-dispersing 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 since the LGM appears to explain a wide variety of phenomena in the modern distributions of species and structure of communities, and we propose that its applications could be quite wide. 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.