This is a series of articles examining heatwaves from every angle, exploring their causes, consequences, and the science behind them. It includes eight parts:
- Introduction
- Heatwave patterns
- Impacts on human health
- Impacts on urban areas
- Extreme heat in 2024
- Are heatwaves linked to climate change?
- Adapting to more frequent periods of extreme heat
- Temperature, apparent temperature, and heat indices
According to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), human-induced climate change has led to an increase in the frequency, intensity, and duration of heatwaves since the 1950s. Further warming is expected to reinforce this trend, as every 0.5 °C increase in global temperature significantly raises both the occurrence and severity of extreme temperature events, including heatwaves.
According to estimates, human-induced climate change led to an average of 26 additional days of extreme heat across all monitored locations worldwide between May 2023 and May 2024, compared to what would have occurred without global warming.
In the following year, climate change at least doubled the number of extreme heat days in 195 countries and territories, compared to a world without its influence.
The WMO warns that global warming is currently occurring at an exceptionally rapid pace. Every year between 2015 and 2024 ranked among the ten warmest years on record, and global temperatures are expected to continue approaching record highs between 2025 and 2029.
According to forecasts, average global temperatures during this period are projected to be 1.2 °C to 1.9 °C higher than in the pre-industrial era (1850–1900), with an 80% probability that at least one of these years will surpass the current record set in 2024.
According to the IPCC, this increase is expected to be most pronounced in polar regions and in the mid-latitudes.
It is uncertain how rising global temperatures will affect the occurrence of heatwaves in different regions. While warming increases the likelihood of extreme temperature events, their underlying causes are not yet fully understood. In some areas, heatwaves are recurring that exceed the projections of current climate models, raising questions about how accurately these models can estimate regional risks associated with global warming.
Annual average area (land, ocean, or both) between 0° and 70°N in the Northern Hemisphere that experienced extreme heat events during the months of May to September, for the period 1950–2023. A grid cell is classified as experiencing an extreme heat event if its daily maximum temperature exceeds the smoothed 90th percentile threshold for the corresponding calendar day, based on the 1981–2010 reference period. Area is expressed in million square kilometres and is derived from ERA5 reanalysis data. Graphic by Oliver Indra.
This situation highlights the urgency of researching climate change as well as the occurrence and intensity of heatwaves. It also underscores the importance of continuous monitoring, evaluation, and the search for solutions that can help mitigate the risks associated with extreme heat.
Explore how our tools help you prepare for heatwaves: Urban Heat Maps offer hyper‑local temperature insights tailored to city planning and public health, climate+ provides long-term modelled and observed climate data for strategic adaptation, and point+ delivers precise, customisable weather forecasts for any location.
This article is based in part on original work provided by Jaroslava Sochorova (Windy.com), which has been adapted and edited by meteoblue.
