%0 Journal Article
%A Polvani, L. M.
%A Wang, L.
%A Ábalos Álvarez, Marta
%A Butchart, N.
%A Chipperfield, M. P.
%A Dameris, M.
%A Deushi, M.
%A Dhomse, S. S.
%A Jöckel, P.
%A Stone, K. A.
%T Large impacts, past and future, of ozone‐depleting substances on Brewer‐Dobson circulation trends: a multimodel assessment
%D 2019
%@ 2169-897X
%U https://hdl.handle.net/20.500.14352/108238
%X Substantial increases in the atmospheric concentration of well-mixed greenhouse gases(notably CO_(2)), such as those projected to occur by the end of the 21st century under large radiative forcingscenarios, have long been known to cause an acceleration of the Brewer-Dobson circulation (BDC) inclimate models. More recently, however, several single-model studies have proposed that ozone-depletingsubstances might also be important drivers of BDC trends. As these studies were conducted with differentforcings over different periods, it is difficult to combine them to obtain a robust quantitative picture of therelative importance of ozone-depleting substances as drivers of BDC trends. To this end, we hereanalyze—over identical past and future periods—the output from 20 similarly forced models, gatheredfrom two recent chemistry-climate modeling intercomparison projects. Our multimodel analysis revealsthat ozone-depleting substances are responsible for more than half of the modeled BDC trends in the twodecades 1980–2000.We also find that, as a consequence of the Montreal Protocol, decreasingconcentrations of ozone-depleting substances in coming decades will strongly decelerate the BDC until theyear 2080, reducing the age-of-air trends by more than half, and will thus substantially mitigate the impactof increasing CO_(2). As ozone-depleting substances impact BDC trends, primarily, via thedepletion/recovery of stratospheric ozone over the South Pole, they impart seasonal and hemisphericasymmetries to the trends which may offer opportunities for detection in coming decades.
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