Role of Chemistry in Climate Forcing and Climate Change Impacts

Earth’s climate and its changes are controlled by a large number climate forcing agents.  The abundance of these forcing agents depends on various atmospheric processes and variables.  Undoubtedly, many physical processes play crucial roles in controlling and changing climate.  However, there are many chemical processes that also play critical roles in the climate system.  This is especially true when it pertains to the human-induced climate change since many of the changes are brought forth by the emission of chemicals into the atmosphere.

This talk will briefly cover how chemistry in the gas phase, on particles, and in particles influences climate and its changes.  Specifically, the following three areas will be explored: (1). How chemical transformations plays a key role in determining forcing of the climate system; and (2) the roles played by chemical transformations in determining the impact of changes and variability in climate; and (3) how chemical transformations interconnect many important issues related to adaptation and mitigation strategies. 

Role of aerosols in these processes will be emphasized.  Aerosols play key roles in many aspects of Earth’s climate through their interactions directly with the incoming radiation, by altering the cloudiness and thus alter the radiation balance, and by altering the chemical composition that further influences the radiation field.  Chemical processes are at the center of each of the three ways aerosols exert their influence on climate and its changes.  Yet, each of these roles is not well quantified and thus the role of aerosols in the atmosphere is one of the largest uncertainties in the climate system, especially as it relates to human induced changes. This talk will also explore the phenomenology of these roles played by aerosols.  The talk will exemplify some of the issues by using results from our laboratory.