Aggressive aerosol mitigation policies reduce chances of keeping global warming to below 2C

Differences are likely explained by location shifts of aerosol-impacting emissions and their resultant influences on susceptible clouds. Despite weaker changes, implementation of aggressive aerosol cleanup policies will have a major impact on global warming rates over 2020-2050. APRP-derived aerosol radiative forcings are used together with a forcing and impulse response model to estimate global temperature trends.

Strong mitigation of GHGs, as in SSP1-2.6, likely prevents warming exceeding 2C since preindustrial but the strong aerosol cleanup in this scenario increases the probability of exceeding 2C by 2050 from near zero without aerosol changes to 6% with cleanup. When the same aerosol forcing is applied to a more likely GHG forcing scenario (i.e., SSP2-4.5), aggressive aerosol cleanup more than doubles the probability of reaching 2C by 2050 from 30% to 80%.

It is thus critical to quantify and simulate the impacts of changes in aerosol radiative forcing over the next few decades.