Summertime Temperature Variability Increases With Local Warming in Midlatitude Regions
Duo Chan, Alison Cobb, Lucas R. Vargas Zeppetello, David S. Battisti, Peter Huybers
Abstract
Abstract Climate change presents risks both in terms of warming and increased variability that are heightened when compounded. It is thus notable that the simulations in the Coupled Model Intercomparison Project Phase 5 (CMIP5) showing greater Northern midlatitude continental warming also show a greater increase in monthly average temperature variance, particularly in Europe. European variability increases with warming at a rate of 0.40°C 2 /°C (95% C.I. [0.28, 0.50]), with local warming rates explaining 71% of the intermodel difference in variability changes. Coupling between warming and variance increases the probability of high temperatures compared to a scenario where variance is stable. If warming were to reach 6°C, the risk of monthly average temperature exceeding a 30°C threshold is 4 times greater in the increased‐variance scenario. Despite the simple scaling across models suggesting some common origin, changes in model temperature and variance potentially involve a range of mechanisms whose contributions remain unclear.