Thermodynamic constraints on changes in temperature persistence and variance under climate change

The effects of extreme temperature events depend critically on both the length and amplitude of the events. Here I review numerical evidence from a range of climate models - including complex Earth System Models and highly simplified aquaplanet models - that indicates robust changes in both temperature persistence and variance under climate change. The most robust changes are found over ocean areas and appear to arise from fundamental thermodynamic constraints on atmospheric water vapor concentrations, the moist atmospheric lapse rate, and longwave radiative cooling. It is argued that such constraints will drive robust changes in the persistence and amplitude of temperature variability over the next century that will be superposed on any other changes due to, say, land-surface processes or variations in the ENSO phenomenom.