Editing IPCC:AR6/SRCCL/Chapter-2 (section)

==== 2.4.2.3 Future changes of carbonaceous aerosol emissions ====

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Due to the short atmospheric lifetime of carbonaceous aerosols in the atmosphere, of the order of a few days, most studies dealing with the future concentration levels have a regional character (Cholakian et al. 2018 <sup>[[#fn:r900|900]]</sup> ; Fiore et al. 2012 <sup>[[#fn:r901|901]]</sup> ). The studies agree that the uncertainties in changes in emissions of aerosols and their precursors are generally higher than those connected to climate change itself. Confidence in future changes in carbonaceous aerosol concentration projections is limited by the reliability of natural and anthropogenic emissions (including wildfires, largely caused by human activity) of primary aerosol as well as that of the precursors. The Aerosol Chemistry Model Intercomparison Project (AerChemMIP) is endorsed by the Coupled-Model Intercomparison Project 6 (CMIP6) and is designed to quantify the climate impacts of aerosols and chemically reactive gases (Lamarque et al. 2013 <sup>[[#fn:r902|902]]</sup> ). These simulations calculated future responses to SLCF emissions for the RCP scenarios in terms of concentration changes and radiative forcing. Carbonaceous aerosol emissions are expected to increase in the near future due to possible increases in open biomass-burning emissions (from forest, savannah and agricultural fires), and increase in SOA from oxidation of BVOCs ( ''medium confidence'' ) (Tsigaridis et al. 2014 <sup>[[#fn:r903|903]]</sup> ; van Marle et al. 2017b <sup>[[#fn:r904|904]]</sup> ; Giglio et al. 2013 <sup>[[#fn:r905|905]]</sup> ).

More robust knowledge has been produced since the conclusions reported in AR5 (Boucher et al. 2013 <sup>[[#fn:r906|906]]</sup> ) and all lines of evidence now agree on a small effect on carbonaceous aerosol global burden due to climate change ( ''medium confidence'' ). The regional effects, however, are predicted to be much higher (Westervelt et al. 2015 <sup>[[#fn:r907|907]]</sup> ). With respect to possible changes in the chemical composition of PM as a result of future climate change, only a few sparse data are available in the literature and the results are, as yet, inconclusive. The co-benefits of reducing aerosol emissions due to air quality issues will play an important role in future carbonaceous aerosol emissions ( ''high confidence'' ) (Gonçalves et al. 2018 <sup>[[#fn:r908|908]]</sup> ; Shindell et al. 2017 <sup>[[#fn:r909|909]]</sup> ).

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