Unprecedented Europe Heat in June–July 2019: Risk in the Historical and Future Context

Abstract

Western‐central Europe experienced the most severe June–July heat on record in 2019, with several heatwaves occurring over the most densely populated regions. Highest 3‐day averaged daily mean temperature in June–July averaged over the region exceeds normal by 4.7°C, which is estimated to be a 1‐in‐283‐year event over the 1950–2014 climate. The driver and future likelihood of this extreme heat in a changing climate have drawn extensive attention. Based on the newly released climate model data from the sixth Coupled Model Intercomparison Project (CMIP6), we find that anthropogenic climate change has caused a sevenfold increase in the likelihood of the extreme heat over 1950–2014 climate, and even a 23‐fold increase since 1980s. Such extreme heat will become more frequent in the future, with return periods of 1.8–7.2 years under future emission and societal development scenarios. Without sufficient adaptation strategies, such extreme heat would become more widespread, long‐lasting, and severe over Europe.

Spatial and Temporal Variation Characteristics of Heatwaves in Recent Decades over China

“…Since the 1960s, the frequency, intensity, and duration of HW in the US evidently increased [6,17]. Europe experienced severe heatwaves in June and August of 2003, July of 2006, July-August of 2010 and 2018, and even an unprecedented heatwave in June-July 2019 [18]. Severe heatwaves were experienced in China since the beginning of the 21st century.…”

Distinct influences of large-scale circulation and regional feedbacks in two exceptional 2019 European heatwaves

“…Although extremely warm conditions for the 2019 summer were mainly confined to western and some central areas of the continent, temperature anomalies were large enough to produce an overall continental anomaly close to +2°C (with respect to 1981-2010). Recent results estimate a return period of nearly 300 years for a similar event, taking into account recent climatic conditions 18 . As seen in Fig.…”

“…Contrasting with the lack of robust projections in dynamical changes 17 , recent works indicate robust and significant increases in maximum HW magnitude over large regions, even for 1.5°C global warming targets 8 . Moreover, anthropogenic forcing has already caused a 7fold increase in the likelihood of extreme heat events 18 . In addition to direct radiative effects of increasing greenhouse gases concentrations, the potential contribution of enhanced local land-atmosphere feedbacks has also been acknowledged 19 .…”

Analysis of historical heatwaves in the United Kingdom using gridded temperature data

“…Exceptionally high temperatures were also recorded in Scotland and large parts of central, eastern and southern England at the same time. The heatwave of July 2019, like its counterpart in 2018, was part of a wider event where unprecedented temperatures were recorded over large parts of western Europe (Ma et al ., 2020). On the 31 July 2020, a temperature of 37.8°C was recorded at Heathrow, which is the third hottest day on record in the UK (Kendon, 2020).…”