Investigating Aerosol-Cloud-Climate Interactions with a Heuristic Counterfactual Model

Clouds play a crucial role in Earth’s climate due to their high albedo. Aerosols, essential for cloud formation, can modify cloud albedo and coverage. When aerosols come from human activities, they act as a climate forcing, similar to greenhouse gases. However, while greenhouse gases warm the planet, anthropogenic aerosols cool it by modifying the cloud radiative properties. The magnitude of this cooling remains one of the largest uncertainties in future climate projections. 

In this talk, I will present a heuristic model, grounded in fundamental cloud physics, that re-casts satellite-observed cloud properties into a counterfactual, non-polluted world. Our results show that the negative radiative effect due to aerosol-cloud interactions (i.e., cooling) changes approximately linearly with anthropogenic aerosol emissions. The ongoing decline in global anthropogenic aerosol emissions could therefore amplify greenhouse gas-induced warming, potentially contributing to the accelerated warming observed in the past two years.