Precipitation disaster hotspots depend on historical climate variability

TL;DR

The paper shows that areas with low historical precipitation records are most at risk for future extreme rain events, which could affect 250 million people by 2050.

Contribution

The study reveals that historical precipitation patterns and climate change interact to shape future disaster risks, with low-record regions being most vulnerable.

Findings

Regions with low current precipitation records face higher risk of future extreme events.

High current records show the steepest risk increase under climate change.

Low preparedness and vulnerability in high-risk areas amplify disaster threats.

Abstract

Record-high precipitation events are relevant for impacts since they are more severe than any observed event and can lead to unforeseeable consequences. Climate change increases average record-breaking probability, but the current, local record-breaking probability and local disaster preparedness are dependent on observed precipitation history as well. Here, we show that historical variability shapes current and future record-breaking probabilities: regions with low current records are more at risk. Climate change modifies this pattern non-linearly: moderate climate change (SSP2-4.5) increases average record-breaking probability by 2050 by 40%, but high current records are most sensitive to climate change with a record-breaking probability increase of up to 75%. Thus, regions with low current records are most at risk, but regions with high current records see the steepest risk increase with climate change. Disaster risk is further increased by low preparedness. If the last record-breaking event is long ago, local society is more likely to be unprepared for the next one. Vulnerability and exposure in many regions with high record-breaking probability is high due to poverty and rapid urbanisation, resulting in a major imminent threat.

This study shows that historical precipitation variability shapes current and future record-breaking precipitation probabilities, with regions with low current records being more at risk. High-risk regions are abundant around the world, leading to a quarter billion people facing potential precipitation disasters by 2050.

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