Trends and Drivers of Cold Extremes in a Changing Climate

Cold extremes — also referred to as cold air outbreaks, cold spells, or cold snaps — have received less attention in the scientific literature than hot extremes, largely because their frequency and intensity are projected to decrease under climate change. Nevertheless, cold extremes continue to exert substantial impacts across a wide range of sectors, including human health, agriculture, and infrastructure. Superimposed on their overall global decline is pronounced regional and seasonal variability, driven by variability in the underlying physical mechanisms, which themselves may be influenced by climate change. Here, we provide an overview of global and regional trends in cold extremes, examine their key drivers in both present and future climates, and discuss outstanding questions related to the dynamical forcing of cold extremes and their projected evolution under climate change.