A longstanding question in ecology and biogeography is can organisms keep pace with climate change? To address this question, scientists have studied two facets of the problem: 1) How fast can organisms disperse? and 2) How fast are climates being displaced across landscapes? Here I review the latter by describing new approaches to quantifying the rate of climate change. In particular I focus on new approaches that account for climatic connectivity – the ability of landscapes to promote or hinder species movement in response to a changing climate. Here we propose a set of modifications to distance-based climate velocity estimates that: 1) assume organisms will follow paths that minimize their exposure to dissimilar climates, and 2) account for inter-annual variability in climate at a site. Using this approach we calculate climate velocity and minimum cumulative exposure (MCE) along climate trajectories for North America.
Results/Conclusions
We find that velocity is weakly related to MCE; each metric identifies contrasting areas of vulnerability to climate change. Notably, velocity underestimates climate change exposure in mountainous regions where climate trajectories often traverse dissimilar climates, resulting in high MCE. In contrast, in flat regions velocity is high where MCE is low, as these areas have low climatic resistance to movement. We also find that regions with high inter-annual variability in climate have lower velocity estimates than regions with low variance, all else being equal. We suggest that more nuanced assessments of climate change exposure are warranted - approaches which explicitly account for climatic connectivity in a rapidly changing world.