Climate Sensitivity and Feedbacks

The extent to which Earth's climate will change as a result of human activities depends in large part on it's sensitivity to the radiative forcing from increased greenhouse gases.

We use numerical climate models and a wide assortment of observational data sets to better understand the physical processes that regulate the Earth's climate sensitivity. Particular emphasis is placed on understanding the radiative feedbacks that can serve to amplify or dampen changes in climate to an external forcing. Most of the warming that results from increasing CO2 is a direct result of these internal feedbacks rather than the radiative effects of the increased CO2 itself. Therefore, an accurate representation of these feedbacks is essential to reliable projections of future climate change.

We test the fidelity of these feedback processes in climate models using a combination of satellite observations and in-situ measurements to evaluate changes in water vapor, clouds, temperature and precipitation on time-scales ranging from months to decades. These changes are closely-linked to changes in both the local thermodynamic state, as well as the large-scale circulation patterns. In addition to the global-scale response, we also consider the manifestation of these large-scale changes in dynamic and thermodynamic state on the frequency and intensity of extreme weather events, such as tropical cyclones, floods, and droughts.