A recent large-scale European study has revealed that heat waves can temporarily reduce the number of antibiotic resistance genes in soil, but they also cause lasting damage to soil and ecosystems—especially in cold, wet regions like the Netherlands. The research, led by soil ecologist Franciska de Vries from the University of Amsterdam, was published in the Proceedings of the National Academy of Sciences. Scientists examined how soil organisms react to extreme weather conditions, including severe drought, flooding, alternating frost and thaw, and intense heat waves. To do this, they collected soil samples from across Europe, from Iceland to Greece and from Sweden to Spain and the Russian steppe, and exposed them to these extreme conditions in controlled climate chambers. The study found that soils from warm, dry countries are more accustomed to heat and drought, and their organisms remain relatively stable under extreme weather. In contrast, cold, wet soils—like those in Sweden, Iceland, and the Netherlands—are more vulnerable to disruption by heat and drought, leading to a loss of important functions such as carbon storage. Researchers also looked at how extreme weather affects the type and number of resistance genes in the soil. Droughts, floods, and freeze-thaw cycles caused only mild and predictable changes in the resistance genes, based on the local climate and soil type. However, heat waves triggered the most unpredictable responses, with bacteria entering survival mode, producing fewer antibiotics, and exchanging fewer resistance genes. These genes did not quickly return to their original levels after the heat wave. Geography was the most significant factor in how soil responds to extreme weather. Wet soils had a harder time coping with drought and heat, while soils from warmer countries like Greece and Spain contained higher quantities of resistance genes. Although heat waves temporarily reduce the number of resistance genes in the soil, de Vries warns that the damage caused by heat and drought to soils and ecosystems is serious. The temporary drop in resistance genes does not mean the health risks from antibiotic resistance are gone. The study highlights that climate extremes affect antibiotic resistance in different ways depending on the region. This knowledge can help predict where the real risks lie and guide targeted policies and monitoring efforts for specific soils and regions.