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Consistent geographical patterns of changes in high-impact European heatwaves


Climate-change projections suggest that European summer heatwaves will become more frequent and severe during this century1,2,3,4, consistent with the observed trend of the past decades5,6. The most severe impacts arise from multi-day heatwaves, associated with warm night-time temperatures and high relative humidity. Here we analyse a set of high-resolution regional climate simulations and show that there is a geographically consistent pattern among climate models: we project the most pronounced changes to occur in southernmost Europe for heatwave frequency and duration, further north for heatwave amplitude and in low-altitude southern European regions for health-related indicators. For the Iberian peninsula and the Mediterranean region, the frequency of heatwave days is projected to increase from an average of about two days per summer for the period 1961–1990 to around 13 days for 2021–2050 and 40 days for 2071–2100. In terms of health impacts, our projections are most severe for low-altitude river basins in southern Europe and for the Mediterranean coasts, affecting many densely populated urban centres. We find that in these locations, the frequency of dangerous heat conditions also increases significantly faster and more strongly, and that the associated geographical pattern is robust across different models and health indicators.

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Figure 1: Climate-change scenarios for daily summer temperature statistics.
Figure 2: Heatwave frequency and amplitude.
Figure 3: Increasing health risk.

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This research was supported by the Swiss National Science Foundation (NCCR Climate) and by the ENSEMBLES project, funded by the European Commission’s 6th Framework Programme (contract GOCE-CT-2003-505539). Computational resources for the ETH climate simulations have been provided by the Swiss Center for Scientific Computing (CSCS).

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Both authors contributed extensively to the work presented in this letter.

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Correspondence to E. M. Fischer.

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Fischer, E., Schär, C. Consistent geographical patterns of changes in high-impact European heatwaves. Nature Geosci 3, 398–403 (2010).

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