1.1.5Active indicatorHeat-Related Mortality
1.1Heat and health
1.2Health and extreme weather-related events
1.3Climate suitability for infectious disease transmission
Indicator 1.1.5 · Hazards
Heat-Related Mortality
Exposure to heat has a range of health consequences, including heat stress and heat stroke, worsening heart disease, acute kidney injury, and an increased risk of premature death. Older adults, women, and people with underlying health conditions are particularly vulnerable to these adverse health effects. This indicator tracks heat-related mortality worldwide and the proportion attributed to human-caused climate change.
Headline finding
In 2023, heat was associated with a record-high 710,000 estimated deaths globally, with 71.5% attributed to climate change
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Figure 1
Heat-Related Mortality
Heat-related mortality by Human Development Index (HDI) group, World Health Organization (WHO) region, or Lancet Countdown region, from 2006 to 2023. The figure presents estimates based on observed climate conditions, and results are shown as either the annual number or percentage of deaths related to heat.
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Figure 2
Estimated and Counterfactual Heat-Related Mortality
Heat-related mortality by Human Development Index (HDI) group, World Health Organization (WHO) region, or Lancet Countdown region, from 2006 to 2023. The figure shows the annual number of heat-related deaths under counterfactual conditions and the additional mortality attributed to human-caused climate change, comparing the 2006–15 and 2016–23 averages with 2023.
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Figure 3
Heat-Related Deaths Attributed To Climate Change
Percentage of estimated heat-related deaths that are attributed to climate change for the world, by Human Development Index (HDI) group, World Health Organization (WHO) region, or Lancet Countdown region, from 2006 to 2023. The percentage is calculated as the difference between the estimated annual number of heat-related deaths with the observed climate minus that with the counterfactual climate, divided by that with the observed climate. This gives the proportion of heat-related deaths attributed to human-caused climate change.
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About this indicator
Description
This indicator has two parts. Part (1) monitors heat-related mortality using a newly-developed model framework built on a mortality database covering 129 countries. State-of-the-art meta-prediction models estimate the temperature-mortality association for all countries globally, combined with yearly mortality estimates from the Global Burden of Disease, producing the most comprehensive global estimate of heat-related mortality yet. Part (2) quantifies the contribution of human-induced climate change by comparing this factual burden against heat-related mortality estimated under a counterfactual scenario, with temperatures as they would have been without anthropogenic climate change.
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Caveats
The analysis for heat-related mortality assumes that the exposure-response function does not change over time, thus not accounting for processes of adaptation or maladaptation. Not capturing these changes could result in an over-estimation of heat-related deaths in later years in case of adaptation, or an under-estimation in case of maladaptation.
This indicator was last updated in September 2026
Data sources
- European Centre for Medium-Range Weather Forecasts Reanalysis 5th Generation monthly averaged data on single levels from 1959 to present. Copernicus Climate Change Service Climate Data Store.
- Gridded Population of the World Version 4, 2021. Socioeconomic Data and Applications Center, National Aeronautics and Space Administration.
- Yearly, country-level mortality and population data obtained from the Global Burden of Disease 2023
- All-cause mortality from the United Nations Statistics Division Demographic Statistics Database, Eurostat Mortality Statistics and the World Mortality Dataset