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These are the intended use-case/justification for one or multiple variable groups. Opportunities are linked to relevant experiment groups. Identifying opportunities helps to provide a structure to map variables against requirements. Each opportunity description will convey why this combination of variables and experiments is important and how they contribute to impact.
| Attribute | Value |
|---|---|
| description | This represents the list of variables from experiments that are most relevant for scientific investigations into trace gas and aerosol budgets, the role of trace gas and aerosol short-lived climate forcers (SLCFs) in atmospheric composition changes, including air quality, and their impact on climate forcing and climate responses, including any effects from climate feedbacks on sources and sinks of SLCFs. Specifically, this opportunity addresses the four primary objectives of Phase 2 of the Aerosol and Chemistry Model Intercomparison Project (AerChemMIP2): 1) How has process understanding and associated impact assessments advanced for global and regional atmospheric composition changes, radiative forcing, and climate responses? 2) How important are climate feedbacks on natural SLCF emissions and sinks, in addition to changes in atmospheric composition and their radiative effects? 3) What is the relative importance of climate change and emissions of SLCFs for atmospheric composition and air quality over the historical period and into the future? 4) What future climate benefits and trade-offs are expected from improving air quality and/or from policies for improved sustainability? This opportunity builds on the success of AerChemMIP in CMIP6 and aims to exploit new model capability that was not available in the CMIP6 ensemble of models. It will also address new scientific questions. |
| expected_impacts | Analysis of the AerChemMIP simulations in CMIP6, along with the use of the DECK, historical and ScenarioMIP simulations led to advancing our understanding of the role of SLCFs in climate forcing, atmospheric composition, air quality, climate feedbacks and climate responses. As an example, AerChemMIP provided the first consistent calculation of Effective Radiative Forcing (ERF) for a wide range of speciated forcing agents, which was a vital contribution to the sixth Assessment Report of the Intergovernmental Panel on Climate Change (AR6). Inclusion of these diagnostics and experiments will facilitate that assessment for AR7. A review paper by Griffiths et al. 2024 (https://egusphere.copernicus.org/preprints/2024/egusphere-2024-2528/) provides an assessment of how many of these variables and experiments were used to advance our understanding of the role of SLCFs. Quoting from that paper, "AerChemMIP contributed to the development of the WGI IPCC AR6, being referenced in the Summary for Policymakers, Chapters 4, 6, 7, and the Atlas, as well as contributing important assessment/evaluation papers that underpin the Report. " Here, we reviewed the CMIP6 data request (some variables were removed) and add new variables to exploit new model capability (e.g., nitrate aerosol, methane emissions-driven capability, interactive fires, hydrogen) in CMIP7 and to address new scientific questions (e.g., climate mitigation potential of volatile organic compounds). For example, high frequency output of air quality relevant constituents over the historical period and in the future pathways will be used in health impact assessments. |
| justification_of_resources | The resource requirements of this opportunity are high. However, this is the only opportunity that will advance our understanding of the role of short-lived climate forcers in atmospheric composition, climate forcing and climate responses. Using AerChemMIP from CMIP6 as a guide, only this opportunity will be able to provide an assessment of present-day effective radiative forcings (and climate responses) for speciated short-lived climate forcers for AR7. Analysis of historical and future air quality will only be possible with this opportunity, with relevant high frequency atmospheric constituent output from these experiments vital for conducting health impact and vegetation damage assessments. |
| lead_theme | Atmosphere |
| minimum_ensemble_size | 3 |
| name | Understanding the role of atmospheric composition for air quality and climate change |
| opportunity_id | 5 |
| data_request_themes | Impacts & Adaptation, Atmosphere, Earth System |
| experiment_groups | deck, fast-track, scenarios, historical, aerchemmip |
| mips | AerChemMIP2, DCPP, FireMIP, PMIP |
| time_subsets | 80ac3156-a698-11ef-914a-613c0433d878 |
| variable_groups | aerchemmip_2d_daily, aerchemmip_2d_monthly, aerchemmip_2d_subdaily, aerchemmip_2dZ_monthly, aerchemmip_3d_daily, aerchemmip_3d_monthly, aerchemmip_CFsites, aerchemmip_fixed, aerchemmip_ocean_salt_and_heat_transport_variables_monthly, baseline_monthly |