Increasing extreme precipitation variability plays a key role in future record-shattering event probability

TL;DR

The study finds that climate change will significantly increase the likelihood of extreme precipitation events that break records by large margins, especially in tropical regions.

Contribution

The paper introduces a framework to quantify how changes in both mean and variability of precipitation influence the probability of extreme record-shattering events.

Findings

High emission scenarios project much higher probabilities of extreme precipitation events by the end of the century.

Increasing variability in precipitation is a key driver of rising record-shattering event probabilities.

Tropical regions face the strongest increases in vulnerability to extreme precipitation events.

Abstract

Climate events that break records by large margins are a threat to society and ecosystems. Climate change is expected to increase the probability of such events, but quantifying these probabilities is challenging due to natural variability and limited data availability, especially for observations and very rare extremes. Here we estimate the probability of precipitation events that shatter records by a margin of at least one pre-industrial standard deviation. Using large ensemble climate simulations and extreme value theory, we determine empirical and analytical record shattering probabilities and find they are in high agreement. We show that, particularly in high emission scenarios, models project much higher record-shattering precipitation probabilities in a changing relative to a stationary climate by the end of the century for almost all the global land, with the strongest increases in vulnerable regions in the tropics. We demonstrate that increasing variability is an essential driver of near-term increases in record-shattering precipitation probability, and present a framework that quantifies the influence of combined trends in mean and variability on record-shattering behaviour in extreme precipitation. Probability estimates of record-shattering precipitation events in a warming world are crucial to inform risk assessment and adaptation policies.

The probability of record-shattering extreme precipitation events is projected to be higher in a changing than a stationary climate at the end of the century, with the steepest rise in vulnerability in the tropics, according to climate model simulations.

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