The global nitrogen cycle is a fundamental component of the Earth system, influencing terrestrial and marine ecosystem productivity, atmospheric chemistry and climate dynamics. Anthropogenic perturbations have profoundly altered this cycle, leading to environmental challenges such as greenhouse gas emissions, air pollution, and eutrophication. Despite decades of research, significant uncertainties remain in quantifying the key fluxes and transformations of nitrogen across the terrestrial, aquatic, and atmospheric domains. Addressing these challenges requires an Earth system perspective that integrates diverse insights into a coherent global framework and ensures robust representation of nitrogen–carbon–climate interactions in Earth System Models (ESMs).
This session invites contributions that advance understanding of the global nitrogen cycle, its regional and global budget closure, its interactions with carbon, water and climate, including studies that:
• Quantify nitrogen fluxes (N₂O, NH₃, NOx, N₂, BNF, lateral N) across atmosphere, vegetation, soil, and aquatic/marine systems.
• Reconcile regional and global nitrogen budgets using observations, inversions, process-based models, and data-driven approaches.
• Evaluate uncertainties, benchmarking strategies, and emergent constraints for nitrogen–carbon and nitrogen–climate interactions in ESMs and Integrated Assessment Models.
• Assess nitrogen’s role in regulating air and freshwater pollution, land carbon sinks, climate feedbacks, and mitigation pathways.
• Provide synthesis-level insights relevant to global assessments (e.g., IPCC).
By emphasizing budget closure, cross-domain integration, and benchmarking frameworks, this session provides a platform for advancing global nitrogen cycle research and strengthening its connections to Earth system modeling and sustainability challenges.
Sian Kou-Giesbrecht