Land climate under warming in radiative-convective equilibrium simulations

A simple way to model Earth’s climate is to assume radiative-convective equilibrium (RCE), where surface fluxes transport heat and water vapor away from the surface, and radiative cooling balances this energy in the atmosphere. This framework has provided basic insight into the effect of warming on climate over oceans with both fixed and interactive surface temperatures, but it is seldom applied over land. Unlike oceans, land surfaces have a limited water supply and a small heat capacity, and may respond quite differently given these features. Here, we run a suite of cloud-permitting simulations in RCE over land both with interactive soil moisture and fixed at saturation. In contrast to the most relevant previous studies, our simulations span a wide range of climates, obtained by varying the top-of-atmosphere insolation and atmospheric CO₂ concentrations. Several notable patterns emerge as surface temperatures rise including non-monotonic trends in precipitation and steady declines in soil moisture, neither of which can be explained with existing theory. The results demonstrate distinctions between land and ocean responses to warming, with implications for land climate sensitivity and hydrological sensitivity.