Can leaf net photosynthesis acclimate to rising and more variable temperatures?

Under future climates, leaf temperature ( T l ) will be higher and more variable. This will affect plant carbon (C) balance because photosynthesis and respiration both respond to short‐term (subdaily) fluctuations in T l and acclimate in the longer term (days to months). This study asks the question: To what extent can the potential and speed of photosynthetic acclimation buffer leaf C gain from rising and increasing variable T l ? We quantified how increases in the mean and variability of growth temperature affect leaf performance (mean net CO 2 assimilation rates, A net ; its variability; and time under near‐optimal photosynthetic conditions), as mediated by thermal acclimation. To this aim, the probability distribution of A net was obtained by combining a probabilistic description of short‐ and long‐term changes in T l with data on A net responses to these changes, encompassing 75 genera and 111 species, including both C3 and C4 species. Our results show that (a) expected increases in T l variability will decrease mean A net and increase its variability, whereas the effects of higher mean T l depend on species and initial T l , and (b) acclimation reduces the effects of leaf warming, maintaining A net at >80% of its maximum under most thermal regimes.