Abstract
The ability to rapidly simulate the climate implications of a large
number of CO2 emissions trajectories is helpful for implementing
mitigation and adaptation policies. A key variable of interest is
near-surface air temperature, which is approximately proportional to
cumulative CO2 emissions. We take advantage of this relationship,
diagnosing Green’s Functions for the spatial temperature response to CO2
emissions based on CMIP6 experiment data, creating an emulator that can
be used across emissions scenarios to estimate local temperature
responses. As compared to CMIP6 experiments, this approach captures the
spatial temperature response with some limited accuracy in polar
regions. It incorporates emissions path dependency and is useful for
evaluating large ensembles of policy scenarios that are otherwise
prohibitively expensive to simulate using earth system models. We apply
this emulator to show differing local temperature responses when a
global mean of 2ºC is reached and to varying trajectories with the same
cumulative emissions.