Amplified warming of North American cold extremes linked to human-induced changes in temperature variability

Abstract How global warming is impacting winter cold extremes is uncertain. Previous work has found decreasing winter temperature variability over North America which suggests a reduction in frequency and intensity of cold extremes relative to mean changes. However, others argue that cold air outbre...

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Bibliographic Details
Published in:Nature Communications
Main Authors: Russell Blackport, John C. Fyfe
Format: Article in Journal/Newspaper
Language:English
Published: Nature Portfolio 2024
Subjects:
Q
Online Access:https://doi.org/10.1038/s41467-024-49734-8
https://doaj.org/article/3c815edc42744fbb9511078f6c778985
Description
Summary:Abstract How global warming is impacting winter cold extremes is uncertain. Previous work has found decreasing winter temperature variability over North America which suggests a reduction in frequency and intensity of cold extremes relative to mean changes. However, others argue that cold air outbreaks are becoming more likely because of Arctic-induced changes in atmospheric circulation. Here we show that cold extremes over North America have warmed substantially faster than the winter mean temperature since 1980. This amplified warming is linked to both decreasing variance and changes in higher moments of the temperature distributions. Climate model simulations with historical forcings robustly capture the observed trends in extremes and variability. A pattern-based detection and attribution analysis shows that the changes in variability are detectable in observations and can be attributed to human influence. Our results highlight that human emissions are warming North American extreme cold temperatures beyond only shifting the winter mean temperature.