[PAOCQ] Nadir Jeevanjee (GFDL)

“Perspectives on Climate Sensitivity”

The notion of climate sensitivity has become synonymous with Equilibrium Climate Sensitivity (ECS), or the equilibrium response of the Earth system to a doubling of CO2. But, there is actually a hierarchy of measures of climate sensitivity, some of which probe important physics beyond that of ECS and which are more relevant to 21st century warming. This talk will focus on two of them, the Transient Climate Response (TCR) and Transient Climate Response to Cumulative Emissions (TCRE), using the two-box model for ocean heat uptake as a common theoretical framework. We emphasize that i) TCR can be scaled by the forcing to estimate transient temperature change across a variety of scenarios, ii) the two-box model predicts a linear relationship between ocean heat content and surface temperature which is inconsistent with most models, and iii) the TCRE depends critically on the airborne fraction of cumulative emissions, which appears to be constrained to values of 0.5-0.6 but for which a theoretical understanding is lacking.

PAOC Colloquium —

Interdisciplinary seminar series that brings together the whole PAOC (Program in Atmospheres, Oceans, and Climate) community. Seminar topics include all research concerning the physics, chemistry, and biology of the atmospheres, oceans and climate, as well as talks about societal impacts of climatic processes.

Contact: paoc-colloquium-comm@mit.edu