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Publication Date
14 April 2023

Advancing Research on Compound Weather and Climate Events via Large Ensemble Model Simulations

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We use a collection of large ensembles to present six different compound event case studies that illustrate the benefit and limitations of large ensembles, from precipitation-wind extremes to temporally compounding crop failures in bread-basket regions.


Compound events are increasingly recognized as particularly damaging extreme events. Studying their change under warming is thus urgent, yet complicated by the limited sample size in observations. Large ensembles can help reduce projection uncertainties or serve as test beds to better quantify uncertainties and develop statistical methods. We expect this paper to be an important reference for the compound event community moving forward.


Compound hot–dry events—co-occurring hot and dry extremes—frequently cause damage to human and natural systems, often exceeding separate impacts from heatwaves and droughts. Strong increases in the occurrence of these events are projected with warming, but associated uncertainties remain large and poorly understood. Here, using climate model large ensembles, we show that mean precipitation trends exclusively modulate the future occurrence of compound hot–dry events over land. This occurs because local warming will be large enough that future droughts will always coincide with at least moderately hot extremes, even in a 2°C warmer world. By contrast, precipitation trends are often weak and equivocal in sign, depending on the model, region, and internal climate variability. Therefore, constraining regional precipitation trends will also constrain future compound hot–dry events. These results help to assess future frequencies of other compound extremes characterized by strongly different trends in the drivers.

Point of Contact
Flavio Lehner
National Center for Atmospheric Research (NCAR)
Funding Program Area(s)