Aerosols, Clouds and Recent Trends in Earths Energy Imbalance

Differences in modeling the effective radiative forcing from aerosol-cloud interactions represents the largest source of uncertainty in historical anthropogenic forcing. This uncertainty limits our ability to constrain estimates of climate sensitivity and make accurate projections of future climate change. The forcing from aerosols, even in recent decades, is not well known, but evidence suggests that the cooling effect of aerosols has weakened over the past several decades. This reduction in aerosols is believed to be a key contributor to the growing imbalance in Earth’s energy budget, which has nearly doubled over the past two decades. We use satellite observations of aerosol and cloud properties with a modified “cloud controlling factor” analysis in an attempt to: i) better constrain climate model estimates of the effective radiative forcing from aerosol-cloud interactions; and ii) quantify the contributions of aerosol-cloud interactions to the recent trends in Earth’s Energy Imbalance.