End-of-century heat and drought stress approaching Europe swiftly

Abstract Extreme heat and drought levels typical of an end-of-century climate could occur swiftly, and repeatedly. Despite the European climate being potentially prone to multi-year successive extremes due to the influence of the North Atlantic variability, it remains unclear how the likelihood of such successive extremes changes under warming, how early they could reach end-of-century levels, and how this is affected by internal climate variability. Using the MPI Grand Ensemble, we find that even under moderate warming, end-of-century heat and drought levels virtually impossible 20 years ago reach 1-in-10 likelihoods as early as the 2030s. By 2050-2075, two successive years of single or compound end-of-century extremes, unprecedented to date, exceed 1-in-10 likelihoods; while Europe-wide 5-year megadroughts become plausible. Whole decades of end-of-century heat stress could start by 2040, by 2020 for rain-deficit drought, and end-of-century decades starting as early as 2030 become twice as likely under a warm North Atlantic state.