Overheated amphibians

Uncertainties related to species’ physiological requirements and microclimatic fluctuations hinder predictions of the effects of climate change on biodiversity. A study published in Nature tackles both of these gaps for amphibians, which are particularly sensitive to warming and aridification. Pottier et al. combined a database of empirical observations with phylogenetic model-based imputation to quantify thermal limits for 5,203 amphibian species. This provided estimates of the temperatures that these animals can physiologically tolerate. Next, Pottier et al. leveraged recent advances in microenvironmental data and biophysical modelling to quantify the environmental temperatures that amphibians actually experience in the wild. By estimating the hourly microclimates experienced by amphibians around the world, they found that 104 species are already likely to experience fatal overheating despite retreating to microclimatic refugia. This number is projected to quadruple under future climate conditions in a high-emissions scenario, driven particularly by the growing exposure of arboreal and terrestrial species to extreme temperatures. Pottier et al. found that many species would overheat even under vegetation shade. Notably, the study reports a nonlinear relationship between thermal safety margins — the difference between species’ temperature tolerance and the environmental temperature — and overheating risk. In other words, species with apparently similar thermal vulnerability can face markedly different probabilities of overheating. Such an insight underscores the importance of accounting for small-scale spatiotemporal variation in climate.

Original reference: Nature 639, 954–961 (2025)