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Climate and Carbon Responses to a Restoration Scenario of Idealized CO2 Emissions Reversal

Presentation Date
Thursday, December 15, 2022 at 2:56pm - Thursday, December 15, 2022 at 3:06pm
McCormick Place - S501bcd



We explore the response of the Earth’s climate and carbon system to an idealized sequential addition and removal of CO2 to the atmosphere, following a symmetric and continuous emissions pathway, using both an Earth System Model and an ensemble of simple climate model realizations. Here we show that, under this idealized restoration scenario, there is a proportionality of warming to cumulative emissions that roughly holds through most of the emissions reversal phase from positive to negative emissions, subject to an asymmetry that is governed by the zero emissions commitment (ZEC). The ZEC, much of which actually occurs before reaching zero emissions, also controls the timing between peak cumulative CO2 emissions and peak temperature, such that peak temperature may occur before peak cumulative emissions. As cumulative CO2 emissions approach zero through negative CO2 emissions, CO2 concentrations drop below preindustrial values, while residual long-term climate change continues, governed by multicentennial dynamical processes.

Funding Program Area(s)