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Name: Erich Fischer
Talk Title: Increasing probability of record-shattering climate extremes
Abstract: Recent climate extremes have broken long-standing records by large margins. Such extremes unprecedented in the observational period often have substantial impacts due to a tendency to adapt to the highest intensities, and no higher, experienced during a lifetime. Here we show climate models project not only more intense extremes but also events that break previous records by much larger margins. These record-shattering extremes, nearly impossible in the absence of warming, are likely to occur in the coming decades. We provide an analytical solution to show that the changes in probability of record-shattering extremes simulated by numerical climate models is well understood and can be accurately reproduced in a purely statistical approach. The increase in record-shattering extremes can be reproduced with an analytical solution assuming normally distributed random uncorrelated variables or assuming a non-stationary GEV distribution with time-varying location and scale parameter for the random variables.
Based on this analytical solution we demonstrate that the probability of occurrence of record-shattering extremes depends on warming rate, rather than global warming level, and is thus emission pathway-dependent. In high-emission scenarios, week-long heat extremes that break records by three or more standard deviations are 2–7 times more probable in 2021–2050 and 3–21 times more probable in 2051–2080, compared to the last three decades. In 2051–2080, such events are estimated to occur about every 6–37 years somewhere in the northern mid-latitudes.
This talk is an invited talk at EVA 2021. View the programme here.