Disentangling aerosol-cloud interactions with causality

A large part of the uncertainty around future global warming is due to the cooling effect of aerosol-liquid cloud interactions, and in particular to the elusive sign of liquid water path (LWP) adjustments to aerosol perturbations. We quantify this adjustment with a novel causal approach that combines physical knowledge in the form of a causal graph with geostationary satellite observations of stratocumulus clouds. This allows us to remove confounding from large-scale meteorology, to resolve feedback loops and to disentangle counteracting physical processes such as cloud-top entrainment enhancement and precipitation suppression due to aerosol perturbations. Accounting for environmental confounding via this approach yields weak LWP adjustments that are time-dependent (positive then negative) and regime-dependent. These results suggest that time-aware causal analyses are key to reconcile conflicting studies concerning the sign and magnitude of LWP adjustments across different data sources.




13:30 h


Bundesstr. 53, room 022/023
Seminar Room 022/023, Ground Floor, Bundesstrasse 53, 20146 Hamburg, Hamburg


Emilie Fons


Ann-Kristin Naumann

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