Warming Trends in Summer Heatwaves
Journal Article - Open Access
WARWICK UNIV COVENTRY (UNITED KINGDOM) WARWICK United Kingdom
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The frequency and severity of heatwaves is expected to increase as the global climate warms. We apply crossing theory for the first time to determine heatwave properties solely from the distribution of daily observations without timecorrelation information. We use Central England Temperature time series to quantify how the simple increased occurrence of higher temperatures makes heatwaves consecutive summer days with temperatures exceeding a threshold more frequent and intense. We find an overall twofold to threefold increase in heatwave activity since the late 1800s. Weeklong heatwaves that on average return every 5 years were typically below approximately 28 deg C and now typically exceed it. Our analysis takes as inputs average userspecific heat wave properties. Its output pinpoints the range of temperatures for which changes in the distribution must be well resolved statistically in order to track how these heatwave properties are changing. This provides a quantitative benchmark for models used for the attribution of heat waves.