Asymmetry of thermal sensitivity and the thermal risk of climate change

Aim. Understanding and predicting the biological consequences of climate change requires considering the thermal sensitivity of organisms relative to environmental temperatures. One common approach involves “thermal safety margins” (TSMs), which are generally estimated as the temperature differential between the highest temperature an organism can tolerate (CTmax) and the mean or maximum environmental temperature it experiences. Yet, organisms face thermal stress and performance loss at body temperatures below their CTmax, and the steepness of that loss increases with the asymmetry of the thermal performance curve (TPC). Location. Global Time period. 2015-2019. Major taxa studied. Ants, fish, insects, lizards, and phytoplankton. Methods. We examine variability in TPC asymmetry and the implications for thermal stress for 384 populations from 289 species across taxa and for metrics including ant and lizard locomotion, fish growth, and insect and phytoplankton fitness. Results. We find tha...