A new study has revealed that heatwaves in Eastern North America and Central Europe could become twice as intense as previously predicted, driven by variations in soil moisture. Published in Nature Communications, the research, led by Professor Douglas Maraun at the University of Graz with contributions from the University of Reading, highlights the potential for devastating temperature surges if global warming reaches 2°C.
The study warns that extreme heat events in these regions could rise by up to 4°C, significantly outpacing moderate heatwave projections. This alarming trend mirrors the catastrophic heatwaves that hit Canada in 2021, India in 2022, and the Mediterranean in 2023.
Reinhard Schiemann, a co-author of the study from the University of Reading, explained “While it’s known that heatwaves become more intense as average temperatures rise, the rarest and most extreme heatwaves could intensify disproportionately. The critical factor is how soil moisture interacts with heat during these events.”
Soil moisture plays a dynamic role in heatwaves by altering the land’s cooling effect. The research identified three soil states:
- Very Wet Soil: Minimal influence on temperature.
- Very Dry Soil: Limited cooling effect.
- Middle State: Strongest impact on amplifying temperatures.
Regions transitioning into this middle state, like Central Europe and the Eastern US, could experience extreme heat events far exceeding earlier projections. Conversely, already arid regions may see less intense increases if they receive more rainfall.
The researchers used multiple climate models to assess soil moisture’s impact on peak temperatures during the hottest days of the year. These models show that shifts in rainfall patterns, driven by climate change, will significantly influence soil moisture and, consequently, the severity of heatwaves.
For example:
Wet regions becoming drier may enter the middle state, amplifying heatwave intensity.
Dry regions receiving more rainfall might mitigate temperature spikes.
Rethinking Climate Risk Assessments
The findings suggest that existing climate risk models may underestimate the true intensity of future heatwaves in regions like Eastern North America and Central Europe. These insights highlight the urgent need for updated assessments to better prepare for and mitigate the impacts of extreme heat events.
As the planet warms, understanding the complex interactions between soil moisture and temperature will be vital to safeguarding communities from increasingly severe climate threats.