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Air quality modelling advances to support revision of the Gothenburg Protocol

Air quality modelling advances to support revision of the Gothenburg Protocol

Air pollution

Following the decision of Parties to the UNECE Convention on Long-range Transboundary Air Pollution (Air Convention) to revise the Protocol to Abate Acidification, Eutrophication and Ground-Level Ozone (Gothenburg Protocol), which is expected to further strengthen efforts to reduce air pollution in Europe and North America, technical and scientific work has begun to support the revision process.   

The revision process will include the following issues, among others: new emission reduction commitments for the pollutants currently covered by the Protocol; potential revisions of technical annexes including with regard to their level of ambition and scope; how to deliver further reductions of black carbon emissions; whether and how to address methane emissions; how to achieve additional ammonia emission reductions; new flexibilities, and other approaches for non-Parties to facilitate ratification and subsequent implementation of the Protocol; overarching, collective risk-based target(s) to reduce risk to health and ecosystems in the region; how to achieve integrated approaches among climate, energy and air policies.  

Having been instrumental in developing emission scenarios in the Greenhouse Gas Air Pollution Interactions and Synergies (GAINS) model – that have supported the negotiations of the Gothenburg Protocol – the Convention’s Task Force on Integrated Assessment Modelling (TFIAM) met in Paris last week for its 53rd meeting to discuss the status of work in support of the Protocol’s revision process. TFIAM brings together the best available science within the Convention on emissions, air quality, health and ecosystem impacts, and cost-effectiveness of abatement measures. The GAINS model uses scenario analysis to show future developments in air quality up to 2050 with current policies and with additional policy measures and identifies cost effective solutions to reduce air pollution.  

At its meeting, TFIAM presented updated scenarios aimed at a 50% reduction of air quality related health impacts and showed initial assessment of feasibility achieving a similar reduction in threats to biodiversity. These scenarios are intended to further support the policymaking process, specifically as it relates to setting overarching, collective risk-based target(s) to reduce risk to health and ecosystems in the region. In addition, to support the revision process, further progress in modelling, including on methane, health impacts, and inputs on critical loads and levels was also discussed.  

While technical measures will remain part of the solution to reduce emissions, non-technical and structural measures, including behavioural change (e.g. such as dietary change) and synergies with other policy fields will also be needed. Therefore, TFIAM discussed non-technical and structural measures, which includes a complex mix of policy instruments, such as pricing, research investments, infrastructural planning and awareness raising. While structural and non-technical measures can bring a lot of benefits, as they will likely have larger synergetic reduction potentials, taking into account developments in other policy areas, there are also some challenges. These concern, e.g. the actual application and the cost of certain measures related to behavioural changes, which are not easily predictable and hence difficult to include into decision support. 

In addition to presentations on other research projects in the area of integrated assessment modelling, TFIAM also discussed examples of national integrated assessment studies. The main recommendations and conclusions of the task force’s work will be presented to the Working Group on Strategies and Review in Geneva on 27-31 May 2024.