What is it about?

Extreme weather events rarely occur but can have devastating impacts. This paper introduces an analysis method that determines whether one-in-a-hundred-years events are becoming more frequent. Based on a 41-year record in the continental United States, the change in frequency of extreme temperature events is determined with statistical confidence. We found it is possible to aggregate extreme event data over geographical locations with different climate zones for meaningful inference. The risk of high-temperature extremes has increased twofold. The risk of low-temperature events did not change much. The results for extreme rainfall risk change vary with season.

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Why is it important?

Extreme weather events incur large costs to society and damage the environment. We characterize extreme weather event data over geographical locations with different climate zones. The work makes meaningful inferences of the changes in 100-year extreme event risks from year to year for each individual month using only 41 years’ worth of data. The future possibilities involve regional analyses of the extreme events in temperature and rainfall, or other types of extreme events. Given the importance of monitoring changes in the frequency and intensity of extreme events, there are broad benefits from this type of data-driven modeling of heat waves, floods, and threats to local agriculture and water supplies.


Estimating how risk of extreme weather events changes from year to year is a challenging task due to the limited availability of data. We hope our work would be a valuable asset for governments globally to asses climate risks and combat the existential threat to our planet. While we do plan to carry this work forward, we expect this work can be a harbinger for future research worldwide.

Saahil Shenoy
Stanford University

Read the Original

This page is a summary of: Trends of extreme US weather events in the changing climate, Proceedings of the National Academy of Sciences, November 2022, Proceedings of the National Academy of Sciences,
DOI: 10.1073/pnas.2207536119.
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