Physical Processes Leading to Extreme Day-to-day Temperatures Changes: Future Climate

Extreme temperature changes from one day to the next, whether warming or cooling, have profound impacts on human health, ecosystems, and socio-economic, and their potential future changes can result in even more significant challenges. In the previous study, we quantified the physical processes—advection, adiabatic, and diabatic heating or cooling—that drive extreme day-to-day temperature (DTDT) changes in present-day climate. However, the role of these processes in projected changes of DTDT extremes under future warming scenarios has remained unexplored. This study addresses this gap by examining these processes globally using the Community Earth System Model (CESM) Large Ensemble under a high-emission scenario together with Lagrangian backward trajectory calculations. The findings reveal that reduced temperature changes due to advection and altered diabatic processes primarily drive the projected decreases in DTDT extremes in the extratropics during December-February (DJF) and June-August (JJA). In contrast, increases in DTDT extremes in the tropics are primarily caused by enhanced local processes, such as radiative heating during DJF, and mostly by intensified diabatic processes during JJA, with advection playing a minor role. Therefore, there is a strong need for adaptive strategies and informed decision-making in response to climate change, particularly in underdeveloped countries in the tropics and subtropics.