Record-breaking and unprecedented compound hot and dry summers in Europe under different emission scenarios

• Published in: Environmental Research: Climate Vol. 2; no. 4; pp. 45009 - 45026
• Main Authors: Dosio, Alessandro, Spinoni, Jonathan, Migliavacca, Mirco
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.12.2023
• Subjects: compound hot and dry event; Europe; record-breaking
• DOI: 10.1088/2752-5295/acfa1b
• ISSN: 2752-5295

After analysing observed summer compound hot and dry (CHD) events over Europe from 1950 to 2022, we employ a large ensemble of high-resolution regional climate model simulations to investigate CHD events under different emission scenarios. By the end of the century, even under a low-emission scenario, model results show a likely increase in the frequency and extension of CHD events over most (60%) of Europe. In particular, the fraction of land projected to be hit once every two years nearly doubles (at least 15%, likely range 6–21) compared to the historical period (8%, 6.5–10), and at least 5,3% (1–7) of land will be hit every year. Under a high-emission scenario, 50% of the Iberian Peninsula is projected to be hit at least twice every three years (20.3 times in 30 years, likely range 17.2–24.2), compared to 1 in ten years in the historical period, whereas 50% of the British Islands, France, and the Mediterranean will be hit more than once every two years. Moreover, 10% of European land will be hit nearly once every 7 years (4.2 times, 3.2–5.6) by CHD events whose intensity equalled or even surpassed the maximum recorded during 1950–2022, and 20% of the Iberian Peninsula once every 5 years. The increase in record-breaking or unprecedented CHD events is mostly related to the increase in record-breaking heatwaves, which is likely over most regions even for the low-emission scenario. In contrast, the increase in record-breaking drought events is limited to southern Europe under the medium- and high-emission scenarios.