17 June 2016

Improving Our Fundamental Understanding of the Role of Aerosol-Cloud Interactions in the Climate System

Colloquium summary suggests a path forward to reduce uncertainty in estimates of a key mechanism driving climate change.

Science

Attempts to estimate the change in the Earth’s energy balance due to the influence of human-caused aerosols on clouds are fraught with uncertainty because of the many processes involved, the wide range of spatial and temporal scales, and the inability to measure the changes since the dawn of the industrial era.  This uncertainty drives a three-fold uncertainty in the radiative forcing of climate change since pre-industrial times, making it difficult to use the observed warming since then as a test of climate models.

Impact

This overview paper suggests a path forward involving planned field experiments, improved understanding of aerosol-cloud interactions from cloud-scale modeling, multi-scale global modeling, and multi-scale analysis of simulations and data.

Summary

A Sackler Colloquium on “Improving Our Fundamental Understanding of the Role of Aerosol- Cloud Interactions in the Climate System,” was held June 23–24, 2015 in Irvine, California. This manuscript provides an overview of the papers published in the Proceedings of the National Academy of Sciences as a result of the colloquium.  Aerosol effects on cold (mixed-phase) as well as warm clouds are addressed.

Contact
Steven J. Ghan
Pacific Northwest National Laboratory (PNNL)
Publications
2016.  "Improving our fundamental understanding of the role of aerosol−cloud interactions in the climate system."  Proceedings of the National Academy of Sciences of the United States of America 113(21): 5781-5790, doi:10.1073/pnas.1514043113.