Natural Experiments

Uncertainties in how airborne particles (aerosol) influence cloud reflectivity hinder our understanding of anthropogenic climate change. The study of aerosol-cloud interactions (ACI) is complicated by the difficulty of disentangling aerosol effects from other phenomena like meteorological variability. “Natural experiments” in which a phenomenon of interest may be clearly separated from other sources of variability offer promising means to better understand causality in ACI. My group has studied natural experiments like international shipping and lockdowns in response to the COVID-19 pandemic to learn what they can, and can’t, tell us about aerosol-cloud interactions.