Reappraisal of the Climate Impacts of Ozone‐Depleting Substances

Morgenstern, Olaf; O’Connor, Fiona M.; Johnson, Ben; Zeng, Guang; Mulcahy, Jane; Williams, J.; Teixeira, J.; Michou, Martine; Nabat, Pierre; Horowitz, Larry W.; Naik, Vaishali; Sentman, Lori T.; Deushi, Makoto; Bauer, Susanne E.; Tsigaridis, Kostas; Shindell, D. T.; Kinnison, Douglas E.

doi:10.1029/2020gl088295

Cited by 18 publications

(69 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The anthropogenic aerosol ERF evaluated from the "all" (piClim-aer) experiment is −1.09 ± 0.04 W m −2 , which is identical to the ERF of −1.10 W m −2 from the physical model HadGEM3-GA7.1 and lower in magnitude than the ERF of −1.45 W m −2 derived from HadGEM3-GA7.1 with CMIP5 emissions (Mulcahy et al, 2018). The estimate fits well within the likely range of −1.60 to −0.65 W m −2 (16 %-84 % confidence level) provided by a recent major assessment of aerosol ERF (Bellouin et al, 2020) and the −1.5 to −0.4 W m −2 likely range previously assessed by AR5 (Myhre et al, 2013a).…”

Section: Aerosols and Aerosol Precursorsmentioning

confidence: 52%

“…The model resolution is N96L85; this is equivalent to a horizontal resolution of roughly 135 km and the 85 terrain-following model levels cover an altitude range up to 85 km above sea level. The physical atmosphere model, HadGEM3-GA7.1, already includes the UKCA prognostic aerosol scheme called GLOMAP-mode (Mann et al, 2010;Mulcahy et al, 2018), in which secondary aerosol formation makes use of prescribed oxidant fields. Here, the UKCA chemistry and aerosol schemes are coupled, with oxidants from the stratosphere-troposphere chemistry scheme (Archibald et al, 2020) influencing secondary aerosol formation rates.…”

Section: Model Descriptionmentioning

confidence: 99%

“…A full description and evaluation of the UKCA chemistry and aerosol schemes in UKESM1 can be found in Archibald et al (2020) and Mulcahy et al (2020), respectively. Mulcahy et al (2018) also implemented a number of aerosol process improvements in HadGEM3-GA7.1, which helped reduce the aerosol ERF at the present day (year 2000) from −2.75 ± 0.06 W m −2 in its predecessor model (i.e. HadGEM3-GA7.0; Walters et al, 2019) to −1.45 ± 0.04 W m −2 ; the aerosol ERF in HadGEM3-GA7.0 previously led to an unrealistic negative total anthropogenic ERF of −0.60 W m −2 .…”

Section: Model Descriptionmentioning

confidence: 99%

“…Table 1 gives a full list of the fSST ERF experiments carried out with UKESM1 for this study. The only experiment omitted from the fSST ERF experiments specified in the RFMIP and AerChemMIP protocols is piClim-NH3; this is because UKESM1's aerosol scheme, GLOMAP-mode (Mann et al, 2010;Mulcahy et al, 2018Mulcahy et al, , 2020 To test this, we created an ensemble of short runs on each machine by perturbing selected variables in their initial conditions, using a perturbation with a numerical value comparable to the machine's precision. The spread of results (at each point in time and space) on each platform was then used to determine whether they could each have been sampled from the same ensemble of results generated on either machine.…”

Section: Model Setup and Experimentsmentioning

confidence: 99%

See 3 more Smart Citations

Assessment of pre-industrial to present-day anthropogenic climate forcing in UKESM1

et al. 2021

Self Cite

View full text Add to dashboard Cite

Abstract. Quantifying forcings from anthropogenic perturbations to the Earth system (ES) is important for understanding changes in climate since the pre-industrial (PI) period. Here, we quantify and analyse a wide range of present-day (PD) anthropogenic effective radiative forcings (ERFs) with the UK's Earth System Model (ESM), UKESM1, following the protocols defined by the Radiative Forcing Model Intercomparison Project (RFMIP) and the Aerosol and Chemistry Model Intercomparison Project (AerChemMIP). In particular, quantifying ERFs that include rapid adjustments within a full ESM enables the role of various chemistry–aerosol–cloud interactions to be investigated. Global mean ERFs for the PD (year 2014) relative to the PI (year 1850) period for carbon dioxide (CO2), nitrous oxide (N2O), ozone-depleting substances (ODSs), and methane (CH4) are 1.89 ± 0.04, 0.25 ± 0.04, −0.18 ± 0.04, and 0.97 ± 0.04 W m−2, respectively. The total greenhouse gas (GHG) ERF is 2.92 ± 0.04 W m−2. UKESM1 has an aerosol ERF of −1.09 ± 0.04 W m−2. A relatively strong negative forcing from aerosol–cloud interactions (ACI) and a small negative instantaneous forcing from aerosol–radiation interactions (ARI) from sulfate and organic carbon (OC) are partially offset by a substantial forcing from black carbon (BC) absorption. Internal mixing and chemical interactions imply that neither the forcing from ARI nor ACI is linear, making the aerosol ERF less than the sum of the individual speciated aerosol ERFs. Ozone (O3) precursor gases consisting of volatile organic compounds (VOCs), carbon monoxide (CO), and nitrogen oxides (NOx), but excluding CH4, exert a positive radiative forcing due to increases in O3. However, they also lead to oxidant changes, which in turn cause an indirect aerosol ERF. The net effect is that the ERF from PD–PI changes in NOx emissions is negligible at 0.03 ± 0.04 W m−2, while the ERF from changes in VOC and CO emissions is 0.33 ± 0.04 W m−2. Together, aerosol and O3 precursors (called near-term climate forcers (NTCFs) in the context of AerChemMIP) exert an ERF of −1.03 ± 0.04 W m−2, mainly due to changes in the cloud radiative effect (CRE). There is also a negative ERF from land use change (−0.17 ± 0.04 W m−2). When adjusted from year 1850 to 1700, it is more negative than the range of previous estimates, and is most likely due to too strong an albedo response. In combination, the net anthropogenic ERF (1.76 ± 0.04 W m−2) is consistent with other estimates. By including interactions between GHGs, stratospheric and tropospheric O3, aerosols, and clouds, this work demonstrates the importance of ES interactions when quantifying ERFs. It also suggests that rapid adjustments need to include chemical as well as physical adjustments to fully account for complex ES interactions.

show abstract

Section: Aerosols and Aerosol Precursorsmentioning

confidence: 52%

Section: Model Descriptionmentioning

confidence: 99%

Section: Model Descriptionmentioning

confidence: 99%

Section: Model Setup and Experimentsmentioning

confidence: 99%

See 2 more Smart Citations

Assessment of pre-industrial to present-day anthropogenic climate forcing in UKESM1

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…Dust is modelled independently using the bin scheme of Woodward (2001). A full description and evaluation of the chemistry and aerosol schemes in UKESM1 can be found in Archibald et al (2020) and Mulcahy et al (2020) respectively.…”

Section: Modelsmentioning

confidence: 99%

Effective radiative forcing from emissions of reactive gases and aerosols – a multi-model comparison

et al. 2021

Self Cite

View full text Add to dashboard Cite

Abstract. This paper quantifies the pre-industrial (1850) to present-day (2014) effective radiative forcing (ERF) of anthropogenic emissions of NOX, volatile organic compounds (VOCs; including CO), SO2, NH3, black carbon, organic carbon, and concentrations of methane, N2O and ozone-depleting halocarbons, using CMIP6 models. Concentration and emission changes of reactive species can cause multiple changes in the composition of radiatively active species: tropospheric ozone, stratospheric ozone, stratospheric water vapour, secondary inorganic and organic aerosol, and methane. Where possible we break down the ERFs from each emitted species into the contributions from the composition changes. The ERFs are calculated for each of the models that participated in the AerChemMIP experiments as part of the CMIP6 project, where the relevant model output was available. The 1850 to 2014 multi-model mean ERFs (± standard deviations) are −1.03 ± 0.37 W m−2 for SO2 emissions, −0.25 ± 0.09 W m−2 for organic carbon (OC), 0.15 ± 0.17 W m−2 for black carbon (BC) and −0.07 ± 0.01 W m−2 for NH3. For the combined aerosols (in the piClim-aer experiment) it is −1.01 ± 0.25 W m−2. The multi-model means for the reactive well-mixed greenhouse gases (including any effects on ozone and aerosol chemistry) are 0.67 ± 0.17 W m−2 for methane (CH4), 0.26 ± 0.07 W m−2 for nitrous oxide (N2O) and 0.12 ± 0.2 W m−2 for ozone-depleting halocarbons (HC). Emissions of the ozone precursors nitrogen oxides (NOx), volatile organic compounds and both together (O3) lead to ERFs of 0.14 ± 0.13, 0.09 ± 0.14 and 0.20 ± 0.07 W m−2 respectively. The differences in ERFs calculated for the different models reflect differences in the complexity of their aerosol and chemistry schemes, especially in the case of methane where tropospheric chemistry captures increased forcing from ozone production.

show abstract

Attribution of stratospheric and tropospheric ozone changes between 1850 and 2014 in CMIP6 models

Zeng

Abraham

Archibald

et al. 2022

Preprint

View full text Add to dashboard Cite

We quantify the impacts of halogenated ozone-depleting substances (ODSs), methane, N2O, CO2, and short-lived ozone precursors on total and partial ozone column changes between 1850 and 2014 using CMIP6 Aerosol and Chemistry Model Intercomparison Project (AerChemMIP) simulations. We find that whilst substantial ODS-induced ozone loss dominates the stratospheric ozone changes since the 1970s, the increases in short-lived ozone precursors and methane lead to increases in tropospheric ozone since the 1950s that make increasingly important contributions to total column ozone (TCO) changes. Our results show that methane impacts stratospheric ozone changes through its reaction with atomic chlorine leading to ozone increases, but this impact will decrease with declining ODSs. The N2O increases mainly impact ozone through NOx-induced ozone destruction in the stratosphere, having an overall small negative impact on TCO. CO2 increases lead to increased global stratospheric ozone due to stratospheric cooling. However, importantly CO2 increases cause TCO to decrease in the tropics. Large interannual variability obscures the responses of stratospheric ozone to N2O and CO2 changes. Substantial inter-model differences originate in the models' representations of ODS-induced ozone depletion. We find that, although the tropospheric ozone trend is driven by the increase in its precursors, the stratospheric changes significantly impact the upper tropospheric ozone trend Posted on 22 Nov 2022 -CC-BY-NC 4 -https://doi.org/10.1002/essoar.10510050.1 -This a preprint and has not been peer reviewed. Data may be preliminary.through modified stratospheric circulation and stratospheric ozone depletion. The speed-up of stratospheric overturning (i.e. decreasing age of air) is driven mainly by ODS and CO2; increases. Changes in methane and ozone precursors also modulate the cross-tropopause ozone flux.

show abstract

Reappraisal of the Climate Impacts of Ozone‐Depleting Substances

Cited by 18 publications

References 33 publications

Assessment of pre-industrial to present-day anthropogenic climate forcing in UKESM1

Assessment of pre-industrial to present-day anthropogenic climate forcing in UKESM1

Effective radiative forcing from emissions of reactive gases and aerosols – a multi-model comparison

Attribution of stratospheric and tropospheric ozone changes between 1850 and 2014 in CMIP6 models

Contact Info

Product

Resources

About