Taking up some of the main results of the recent review report, which assessed the effectiveness of the amended Protocol to Abate Acidification, Eutrophication and Ground-Level Ozone (Gothenburg Protocol) under the UNECE Convention on Long-range Transboundary Air Pollution, experts discussed mitigation potentials for methane (CH4) as a precursor to ground-level ozone and air pollution effects on biodiversity this week (11-15 September 2023).
The review report finds that since current legislation will not be sufficient to achieve the long-term objectives of the Gothenburg Protocol, additional action is needed. Specifically, the scenario calculations show that if other pollutants and environmental concerns such as climate change, biodiversity loss, energy, transport, agricultural and nitrogen management policies are further integrated, these policies could offer substantial, cost-effective emission reductions of air pollutants covered by the Protocol (sulphur dioxide (SO2), nitrogen oxides (NOx), ammonia (NH3), volatile organic compounds (VOCs) and fine Particulate Matter (PM2.5)).
At the ninth joint session (Geneva, 11-15 September 2023) of the scientific bodies under the UNECE Convention on Long-range Transboundary Air Pollution, the Steering Body to the Cooperative Programme for Monitoring and Evaluation of the Long-range Transmission of Air Pollutants in Europe (EMEP) and the Working Group on Effects (WGE), experts discussed methane emissions, which prove to be the main driver behind increasing background ozone levels. This not only has consequences for health, but also for crops. For example, in 2015, estimated total wheat production losses for Europe due to ozone were 23.8M tonnes, greater than the annual production of Ukraine (21.8 M tonnes).
In the future, increases in global methane are expected to more than offset projected reductions of nitrogen oxides (NOx) and volatile organic compounds (VOCs) emissions – precursors of ground-level ozone – in Europe and at least partially offset reductions of NOx and VOC emissions in North America. This means that ambitious ozone reduction targets become more dependent on global cooperation to reduce ozone precursors, including methane. Experts highlighted the need to make policymakers aware of non-technical measures, such as dietary change, as an important part of methane control policies.
Experts also discussed air pollution effects on biodiversity, with nitrogen emissions still contributing to air, soil and water pollution with knock-on damages to human health, and biodiversity of forests and rivers. In soils and water bodies, too much nitrogen can lead to nutrient overloads or eutrophication. Earth system scientists say that the world’s planetary boundaries for interference with the nitrogen cycle have already been surpassed, meaning that there is a high risk of non-linear changes to ecosystems and biodiversity, which are likely eroding the resilience of important sub-systems of the Earth System.
Latest assessments of nitrogen depositions from atmosphere into European ecosystems show that in large parts of the region, thresholds (critical loads) for eutrophication are exceeded. The bad news, as confirmed by a recent report published by the Coordination Center for Effects, is that the recovery of ecosystems from eutrophication is relatively slow and the share of ecosystems in Europe, where this threshold is exceeded, remains above 60% for 2020. The highest exceedances are found in the Po Valley in Italy, the Dutch-German and German-Danish border areas and in north-eastern Spain.
In addition, findings from International Cooperative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests) show that climate change-related events, such as droughts, heat waves and storms and ensuing insect infestations, have caused damage to forest ecosystems, adding additional pressures.
New impetus for ambitious action to further reduce nitrogen emissions might come from the new Kunming-Montreal Global Biodiversity Framework under the Convention on Biological Diversity (CBD).
The discussions will feed into discussions on policy options to address the review of the Gothenburg Protocol at the Executive Body at its 43rd session (11-14 December 2023).
About the Air Convention
The UNECE Convention on Long-range Transboundary Air Pollution was adopted in 1979. Over the years, it has been extended by eight protocols that identify specific measures to be taken by Parties to cut their emissions of air pollutants. The Convention has 51 Parties, covering North America and almost the entire European continent.
The amended Gothenburg Protocol establishes legally binding emissions reduction commitments for 2020 and beyond for the major air pollutants: sulphur dioxide (SO2), nitrogen oxides (NOx), ammonia (NH3), volatile organic compounds (VOCs) and fine Particulate Matter (PM2.5). Entering into force in 2019 and with 27 Parties to date, the amended Protocol is already supporting action for clean air in a number of countries.