Dr. Samuel Jonson Sutanto

Extreme event isn’t just about single extreme events anymore, it’s about events stacking up, one after another, or even overlapping at the same time. Our new study analyzed how two types of hazards, droughts and heatwaves, may intensify across Europe in the coming decades.

What are the Key findings?

• Both drought and heatwave events are projected to increase in number, duration, and frequency, and more importantly so are compound and consecutive drought and heatwave (CnC) events.
• For compound events (where drought and heatwave coincide) under SSP5-8.5: up to 6× more compared with the historic period. For consecutive events (one followed by the other): up to ~3.5× more.
• Drought hotspots: historically Western Europe; future: expanding to South & East under moderate warming, and across almost all Europe (except far north) under high warming. For heatwaves: already strong in southern & eastern Europe (Russia, Italy, Portugal); the Mediterranean region remains a key future hotspot.
• Drought impacts (economic, ecosystem, non‐economic) are projected to double while heatwave impacts on human (health, mortality) may increase nine‐fold by 2100.

Why does this matter?

We often prepare for “one extreme event,” like a drought or a heatwave, but this study shows the risk of multiple hazards arriving in quick succession or simultaneously, which can have far greater impacts on sectors like agriculture, water supply, human health, ecosystems. Each hazard alone is bad but concurrent and consecutive hazards are even worse.

Key takeaways for policy & planning

• Adaptation and mitigation are urgent. Under lower warming (SSP1-2.6) the increase is smaller, reinforcing the benefit of limiting warming.
• Risk assessments should move beyond single hazards and consider compound & consecutive events.
• Hotspot mapping helps target adaptation; e.g., southern & eastern Europe will need robust heatwave and drought strategies.
• Impact modelling (especially using ML) shows promise but is constrained by limited historic data, especially for heatwaves.

Final thoughts

This work adds important nuance to how we think about climate risk: it’s not just about “will there be more” droughts or heatwaves, but “will they occur in concurrent and consecutive?” By highlighting where (and how much) risk could escalate, especially under high warming, it sends a clear message: the future of extreme climate impacts is already and we need to prepare much more comprehensively.

If you want to know more, you can read our paper: https://nhess.copernicus.org/articles/25/3879/2025/