What happens when two severe weather events combine. A study shows that the effects are far worse than the sum of them
Episodes in which extreme heat and drought will overlap will become more frequent and longer, according to a climate study cited by InfoClima.ro. The risk of fires increases, and agricultural production is compromised very quickly, according to the study to which a researcher from Romania also contributed.
What is a composite heat-drought event and why is it so dangerous
The study estimates that 28% of the global population will be exposed to combined heat-drought phenomena under current policies by 2090. The frequency of these episodes will increase by 2.4 times compared to current levels.
Moreover, the duration of a composite heat-drought event will increase by 2.7 times.
In order to have a composite heat wave-drought event, two conditions must be met simultaneously.
- Be a day that is warmer than 90% of the days recorded at that place and at that time of year.
- Accumulated rainfall in a month to indicate a moderate or severe drought. Extreme temperatures are strongly correlated with the intensification of these compound episodes.
“The combination is not a simple addition of two problems: the effects are much worse than their sum. The risk of fires increases exponentially, agricultural production is compromised in record time, heat-related mortality is escalating, and water reserves are running out,” explains Monica Ioniță, researcher at the Alfred Wegener Institute in Bremerhaven and co-author of the study.
The study is signed by Gerrit Lohmann, Xianyao Chen and Monica Ionita and published in AGU (Advancing Earth and Space Science).
Tropical regions and low-income countries will be most affected, although they contribute the least to global greenhouse gas emissions.
Using 152 simulations based on eight climate models and observational data from global sources, the research team demonstrated that greenhouse gas emissions from human activity are the main driver of this intensification. Without anthropogenic influence, there is no significant trend.
