Researchers reveal tenfold increase of heat over Europe
To what extent are climate hazards such as heat extremes, flooding, drought and storms (icons at left) intensified by anthropogenic climate change? The study answers this question by introducing a new holistic class of hazard metrics (illustrated by the chart in the middle) that can track the amplification of the extremity of such events, from just frequency change to their total extremity, with a level of rigor not attained before. Based on this diagnostic power, the metrics enable better quantification and attribution of climate impacts, such as quantifying the harm to people, property, ecosystems and infrastructure (icons at right). University of Graz/Wegener Center
University of Graz – A new method for computing the hazards from extreme events has been developed by researchers in Austria. It can compute all relevant hazard metrics for events such as heat waves, floods and droughts in any region worldwide with unprecedented information content.
Researchers from the University of Graz found that anthropogenic climate change has caused a tenfold increase in extreme heat in Europe in recent decades. The study 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,” said Gottfried Kirchengast of the Department of Physics at the University of Graz.
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,” said Kirchengast, emphasizing 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 per cent 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,” explained Kirchengast.
“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,” he added.
