Summary:
Extreme heat across Europe has increased roughly tenfold in recent decades due to human-induced climate change, according to a new study published in Weather and Climate Extremes. Researchers at the University of Graz, led by climate scientist Gottfried Kirchengast, developed a new computational method to measure the full hazard of weather and climate extremes, including heatwaves, floods and droughts.
The approach introduces a class of threshold-exceedance metrics that track not only how often extreme events occur, but also their duration, intensity, spatial extent and timing. These individual indicators can be combined into a single measure described as total event extremity. Using daily maximum temperature data from 1961 to 2024, the team compared the period 2010–2024 with a 1961–1990 reference baseline.
For Austria and most of Central and Southern Europe, the total extremity of heat events increased by about a factor of 10, with regional amplification ranging from fivefold to 25-fold. The researchers report that this rise clearly exceeds natural climate variability. They argue that the method can also support impact assessments, attribution studies and legal analyses related to climate-related damages.
New computation method for climate extremes: Researchers at the University of Graz reveal tenfold increase of heat over Europe
How much will heat, flooding, drought and storms increase as a result of human-induced climate change? In a groundbreaking study, climate researcher Gottfried Kirchengast and his team at the University of Graz have developed a new method for computing the hazards from extreme events: it can compute all relevant hazard metrics for events such as heat waves, floods and droughts in any region worldwide with unprecedented information content. Using it for Europe, the researchers found that anthropogenic climate change has caused a tenfold increase in extreme heat in recent decades. The study, published in the journal Weather and Climate Extremes, also provides a basis for better quantifying the damage to people, ecosystems and infrastructure.
Whether in health, construction, agriculture, forestry or the energy sector, many areas are affected by the impacts and damages caused by weather and climate extremes. For example, temperatures above 30 degrees Celsius put heat stress on the body and weaken the fitness of many people. How well the severity of these hazards can be calculated is, for example, crucial for climate impact computations and corresponding adaptation measures.
“Our new, universally applicable method is suitable for all hazard measures defined by the exceedance of critical thresholds. It can be used to compute the frequency, duration, intensity, spatial extent and other variables of extreme events, up to the combination of all metrics in the total extremity,” explains Gottfried Kirchengast from the Wegener Center and Department of Physics at the University of Graz, main author of the work.
Versatile “computation tool” for weather and climate extremes
The researcher found a general mathematical solution to the underlying high-dimensional threshold exceedance problem and, together with Stephanie Haas and Jürgen Fuchsberger from the Wegener Center, implemented the method as a widely applicable computation tool.
“If suitable long-term climate data are available, the development of climate hazard metrics for extremes of interest can be tracked year by year and decade by decade – in European countries and any other region worldwide,” says Kirchengast, emphasising the versatility of the method. It can thus serve a wide variety of purposes – from providing comprehensive hazard data on weather extremes for climate impact analyses to supporting attribution of the extent to which emission-intensive actors such as states or companies are responsible for the increasing climate damages and risks. The latter is of great importance in the context of climate lawsuits, among other things.
Extreme heat in Europe increased tenfold due to climate change
In their study, the researchers used the new method to investigate changes in extreme heat events in Austria and across Europe. The computations were based on datasets of daily maximum temperatures over 1961 to 2024. The threshold for “extreme” was taken as the temperature at each location that was exceeded by only one percent of the daily values in the period from 1961 to 1990. For Austria, this threshold value is about 30 degrees, in southern Spain it is over 35 degrees and in Finland it is around 25 degrees.
“We found that the total extremity of heat in Austria and most regions of Central and Southern Europe has increased about tenfold in the current climate period from 2010 to 2024 compared to 1961 to 1990. This has been caused by increases in both the frequency and duration of events, as well as in the threshold exceedance magnitude and spatial extent of the events,” explains Kirchengast, adding: “This massive increase in the total extremity metric goes far beyond its natural variability and shows the influence of human-made climate change with a clarity that even I as a climate researcher have never seen before.”
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The new hazard metrics for heat extremes in Austria and Europe, as well as other key data on the development of weather and climate extremes, are freely available and accessible via the Graz Climate Change Indicators – ClimateTracer web portal (as of March 2026 in the data domain ‘Extremes’).
Journal Reference:
Gottfried Kirchengast, Stephanie J. Haas, Jürgen Fuchsberger, ‘A new class of climate hazard metrics and its demonstration: revealing a ten-fold increase of extreme heat over Europe’, Weather and Climate Extremes 51, 100855 (2026). DOI: 10.1016/j.wace.2026.100855
Article Source:
Press Release/Material by University of Graz
Featured image credit: vwalakte | Freepik
