Underestimated Land Heat Uptake Alters the Global Energy Distribution in CMIP6 Climate Models

Abstract

Current global warming results in an uptake of heat by the Earth system, which is distributed among the different components of the climate system. However, current‐generation climate models deliver heat inventory and partitioning estimates of Earth system components that differ from recent observations. Here we investigate the global heat distribution under warming by using fully‐coupled CMIP6 Earth system model experiments, including a version of the MPI‐ESM with a deep land model component, accommodating the required space for more realistic terrestrial heat storage. The results show that sufficiently deep land models exert increased subsurface land heat uptake, leading to a heat uptake partitioning among the Earth system components that is closer to observational estimates. The results are relevant for the understanding of Earth's heat partitioning and highlight the importance of the land heat sink in the Earth heat inventory.

Permafrost Cloud Feedback May Amplify Climate Change

“…Furthermore, there is an increase in the heat uptake in the region of Atlantic deep water formation and the subsequent distribution across the global oceans (Figure S9 in Supporting Information S1). By the end of our simulations this resulted in an additional ocean heat uptake of about 100 ZJ, which, while small in comparison to the overall change in energy storage, exceeds the continental heat uptake projected for the twenty-first century (Steinert et al, 2024). Despite this buffer, the feedback's impact on global surface temperatures is far from negligible.…”