EGU2020-20192, updated on 25 Sep 2023
EGU General Assembly 2020
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

A global attribution study on historical heat-related mortality impacts attributed to climate change.

Ana Maria Vicedo Cabrera1,2,3, Francesco Sera, Rochelle Schneider dos Santos, Aurelio Tobias, Christopher Astrom, Yuming Guo, Yasushi Honda, Anna Delucca, David Hondula, Dolores Ibarreta, Veronika Huber, and Antonio Gasparrini
Ana Maria Vicedo Cabrera et al.
  • 1Institute of Social and Preventive Medicine, University of Bern, Switzerland (
  • 2Oeschger Center for Climate Change Research. University of Bern, Switzerland
  • 3Department of Public Health, Environments and Society, London School of Hygiene & Tropical Medicine, London, United Kingdom

On behalf of the Multi-Country Multi-City Collaborative (MCC) Research Network.

Background & Aim: Climate change is considered the most important environmental threat to human health. Substantial mortality and morbidity burden have been directly or indirectly attributed to climate-sensitive environmental stressors. However, limited quantitative evidence exists on how much of this burden can be attributed to man-made influences on climate. In this large health attribution study, we aimed at quantifying the proportion of excess heat-related mortality attributed to anthropogenic climate change in recent decades across 626 locations across 41 countries in various regions of the world included in MCC database.

Methods: We first estimated the location-specific heat-mortality associations through two-stage time-series analyses with quasi-Poisson regression with distributed lag non-linear models and multivariate multilevel meta-regression using observed data. We then quantified the heat-related excess mortality in each location using daily modelled series derived from historical (factual) and preindustrial control (counterfactual) simulations from 5 general circulation models (ISIMIP2b database) in the period between 1991 and 2019. We finally computed the proportion of heat-related excess mortality attributable to anthropogenic influences as the difference between the two scenarios, with associated measures of uncertainty.

Results: We found a steep increase in level of warming, expressed as the difference in annual average temperature between scenarios, with an average increase of 1.0°C (from 0.7°C  to 1.2°C) across the 626 locations between 1991 and 2019. Overall excess heat-mortality fractions of 1.92% [95% confidence interval: 0.41, 3.25] and 1.28% [0.20, 2.50] were estimated under the factual and counterfactual scenarios, respectively, with an overall difference of 0.76% [0.25,1.74]. This translates to 33% of historical heat-excess mortality that can be attributed to anthropogenic climate change. Larger proportions were found in North America (46%), Central America (47%), South America (43%), South Africa (48%), Middle-East Asia (61%), South East-Asia (50%) and Australia (42%), although highly imprecise in most of cases.

Conclusions: Our findings suggest that current warming driven by anthropogenic influences is already responsible for a considerable proportion of the heat-related mortality burden. These results stress the importance of strengthening current mitigation strategies to reduce further warming of the planet and related health impacts.

How to cite: Vicedo Cabrera, A. M., Sera, F., Schneider dos Santos, R., Tobias, A., Astrom, C., Guo, Y., Honda, Y., Delucca, A., Hondula, D., Ibarreta, D., Huber, V., and Gasparrini, A.: A global attribution study on historical heat-related mortality impacts attributed to climate change., EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20192,, 2020.


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