Focus on the changing concentrations, emissions, and sinks of both climate forcers (N₂O, CH₄, F-gases) and (cooling or warming) air pollutants (NH₃, NOₓ, BC, PM, etc.). This includes both measurement-based studies and those reported in emission inventories. Depending on the submitted papers, the theme will include sub-sessions grouping contributions related to agriculture, industrial areas, domestic sectors, and terrestrial and marine ecosystems.

Long-term monitoring studies, trend analyses, and innovative methods for interpretation or visualization are also covered under this theme. Most contributions will originate from the natural and technical sciences. Integrative studies with a strong focus on specific sources or sinks can also be presented here if contributors prefer this theme over Theme 2.

Examples of special sessions could include:

• Monitoring and measurement techniques or strategies, as well as methods for reporting and verification of emission data.
• Studies in the agricultural domain focusing on CH₄ and N₂O, including net GHG exchange in natural environments and the link with reactive nitrogen.
• Emissions of CH₄, N₂O, and F-gases from various sectors, including industry and waste.
• The role of NH₃ and the transition to H₂, and their impact on climate.
• IPCC emission report on emissions of short lived climate forcers.

Concentrate on the large-scale assessment of emissions and concentrations of NCGGs, focusing on atmospheric processes, including the physics and chemistry related to the radiative aspects of the atmosphere. In addition to modelling, this theme includes monitoring concentrations of non-CO₂ greenhouse gases, studying atmospheric processes, and exploring the relationships between greenhouse gases and other air pollutants (e.g., aerosols or reactive nitrogen species).
Contributions to this theme may include innovations in both models and atmospheric measurements. We also aim to host a special session dedicated to satellite observations.

Examples of topics for this session could include:

• The use of satellite data in studies of CH₄ and short-lived climate forcers, as well as presentations of planned new satellite programs.
• The modelling and observation of the physics and chemistry related to the radiative aspects of the atmosphere.
• The monitoring of concentrations of non-CO₂ greenhouse gases and atmospheric processes, as well as the application of inverse modelling.
• The interactions between greenhouse gases and other air pollutants (e.g., aerosols or reactive nitrogen species).

This third theme invites contributions from integrative studies aimed at connecting the pieces of the puzzle and discussing whether measures/actions are potential "game changers" or false illusions. The theme welcomes integrative and innovative studies on sources of non-CO₂ greenhouse gases, their effects, and strategies to reduce these effects.

Possible session topics could include:

•  The energy transition in progress: Which new sources of emissions are emerging? What non-CO₂ substances are involved? How can we prevent these new emission sources from emerging in the first place (safety by design)? Integrated assessment studies and cost-benefit analyses are also invited.
• The interaction between climate policies and policies regarding air pollution, land use, and biodiversity and their impact on non-CO₂ GHGs. How will reductions in NO_x and NH₃ emissions, aimed at reducing impacts on human health (by decreasing aerosol concentrations) and ecosystems (by reducing N deposition), affect the non-CO₂ GHG balance?
• Geo-engineering and gas removal options that include non-CO₂ GHGs and/or short-lived climate forcers: assessment of the potential impact of geo-engineering techniques, including potential experiments, process understanding, modeling, as well as governance and ethical discussions related to geo-engineering.

This will concentrate on policy implementation and decision making.
Contributions within this theme will be from both natural sciences (e.g. reporting on new emission reduction technologies) and social sciences (e.g. on the economic or institutional feasibility of environmental measures, and the perception of our response to climate change). Contributions on technological issues and industries’ perspectives are welcomed, as well as contributions or plans for financial, technological and capacity building support for developing countries and their options for climate change control. We also welcome transdisciplinary studies under this theme, aiming for co-production of new and actionable knowledge together with stakeholders.

Examples of topics for this session could include:

• Scenario modelling, integrated assessment studies and governance related studies brought together.
• The global methane pledge, what measures are currently taken; how will it be monitored and where does it work or does it fail?
• Proper GHG stock taking, transparency and accountability rules have become increasingly important policy tools ever since the Paris Agreement.
• Developments in geopolitics and the impact on non-CO₂ GHG emission reductions.