Human activities have doubled the global nitrogen cycle since pre-industrial times. While nitrogen is essential for agriculture, excess nitrogen causes environmental harm, including air pollution, biodiversity loss, and climate impacts. The Nutrient Cycling research theme addresses the balance of nitrogen use, informing the GAINS model on emissions of N2O, NH3, and NOx.

Background

Nitrogen serves as an important plant nutrient and thus stands for the foundation of agriculture and human nutrition. We have estimated that, globally, half of the human population depends on mineral fertilizers produced by chemical industry (Erisman et al., 2008). Yet, different forms of nitrogen cause multiple damage in the environment, from air pollution to biodiversity loss, from drinking water toxicity to climate impacts. The research theme Nutrient Cycling deals with the dichotomy of a “too little – too much” with regard to nutrients, specifically nitrogen nutrients. It informs the GAINS model on parameters, emission factors and activities needed to understand the release of nitrous oxide (N2O), ammonia (NH3) and nitrogen oxides (NOx). Due to the pollutant sources, there is a strong focus on agriculture, but sectors like industry, combustion, and waste are also very relevant.

Activities

Air Pollution

Human health impacts from air pollution are strongly influenced by nitrogen compounds, hence deep reduction of air pollution requires a strong commitment to nitrogen reduction (Amann et al., 2020). Using GAINS, Gu et al. (2022) investigated prioritizing NH3 over NOx abatement, pointing out the decisive impact of NH3. A detailed analysis on a European level (Liu et al., 2023) identified different chemical regimes depending on the NOx and NH3 level, appearing differently by region and time. Using hypothetical emission reductions of 25 and 100%, the concept was extended by Guo et al. (2024, in press). Using the scenarios developed under the INMS project (Kanter et al., 2020), a global extension on the impacts to human health and on ecosystems was provided by Guo et al. (2024).

 

Nitrogen Budgets on Different Scales

Using mass balance considerations, assessing the stocks and fluxes of nitrogen compounds supports a more exact attribution of the underlying causes of visible pollution effects. Nitrogen budgets are established for specific scales, like individual countries (Hayashi et al., 2021), for the INMS project and under the LRTAP convention, with IIASA co-chairing the Expert Panel on Nitrogen Budgets that has been fundamental in establishing the UNECE National N Budget guidance document. Urban scale budgets have also been developed (Winiwarter et al., 2020; Kaltenegger et al., 2023; Suchowska-Kisielewicz et al., 2024) as part of the UNCNET project, and budgets on globally gridded data have been established for agricultural areas by Kaltenegger and Winiwarter (2020) and Kaltenegger et al. (2021), with the latter activities contributing to the GELUC project.

 

Budgeting Nitrous Oxide Emissions

Nitrous oxide is a stable compound in the atmosphere, with a lifetime of around 115 years. This makes it specifically prone to being dealt with in budget approaches, especially when considering the considerable uncertainties involved in flux assessment. IIASA contributed in a leading role to the global budgets established by Tian et al. (2020, 2024). Analysis of regional situations (Xu et al., 2021) or the temporal trends in relation to inverse modelling (Thompson et al., 2019) led to more thorough investigation of individual sectors and emission parameters, leading to improved modelling of soil processes (Del Grosso et al., 2022) and machine learning approaches (Li et al., 2024). Specific attention was given to options to reduce sectoral N2O emissions, such as for industry (Davidson and Winiwarter, 2023) using inexpensive end-of-pipe solutions, or agriculture (Hiis et al., 2024) based on bioengineering potentials.

Agriculture and fertilization © Meryll | Dreamstime.com

 

Relevant Projects

Above results have been achieved in part or predominantly in a number of research projects, with external partners, and often with more information available on specific project websites. IIASA is in the steering team of the “Towards an Integrated Nitrogen Management System (INMS)” project, coordinated by CEH Edinburgh and spanning a global team of researchers with more than 70 participating institutions under funding of the Global Environment Facility. On a smaller scale (both in terms of project size and spatial entity addressed), IIASA coordinated the “Urban Nitrogen Cycles – New Economy Thinking to Master the Challenges of Climate Change (UNCNET)” project with Chinese, Austrian and Polish partners funded by the NSFC on the Chinese side and JPI Urban Europe for the European partners. The “Greenhouse gas effects of global land-use competition (GELUC) project, coordinated by the Institute of Social Ecology of BOKU University, Vienna, and funded by Austria’s National Science Foundation FWF, allowed the integration of nitrogen into land use considerations on a global scale, allowing for gridded representation. Finally, all activities in connection with European national nitrogen budgets, such as the contributions to the Expert Panel on Nitrogen Budgets have been supported by the LRTAP Convention’s Working Group on Strategies and Review as the work of the Center for Integrated Assessment Modelling (CIAM).

Visitors

Activities of the research theme Nutrient Cycling are particularly attractive for international visitors. The following scientists have spent time at IIASA, with resulting joint publications.

  • Yixin Guo (PKU-IIASA PostDoc, 2021-22)
  • Zehui Liu (PKU PhD student, 2022)
  • Ulli Dragosits (CEH Edinburgh, 4/2023)
  • Crystal Lu (Iowa State University, 9-11/2023)
  • Xiuming Zhang (Zhejiang University under an MSC postdoctoral fellowship, 2024-26)

Relevant Publications

2024

Guo, Y., Zhao, H., Winiwarter, W. , Chang, J. , Wang, X., Zhou, M., Havlik, P. , Leclere, D., Pan, D., Kanter, D., & Zhang, L. (2024). Aspirational nitrogen interventions accelerate air pollution abatement and ecosystem protection. Science Advances 10 (33) eado0112. 10.1126/sciadv.ado0112.

Hiis, E.G., Vick, S.H.W., Molstad, L., Røsdal, K., Jonassen, K.R., Winiwarter, W. , & Bakken, L.R. (2024). Unlocking bacterial potential to reduce farmland N2O emissions. Nature 10.1038/s41586-024-07464-3. (In Press)

Suchowska-Kisielewicz, M., Greinert, A., Winiwarter, W. , Kaltenegger, K. , Jędrczak, A., Myszograj, S., Płuciennik-Koropczuk, E., Skiba, M., & Bazan-Krzywoszańska, A. (2024). The fate of nitrogen in the urban area – The case of Zielona Góra, Poland. Science of the Total Environment 915 e169930. 10.1016/j.scitotenv.2024.169930.

Tian, H., Pan, N., Thompson, R. L., Canadell, J. G., Suntharalingam, P., Regnier, P., Davidson, E. A., Prather, M., Ciais, P., Muntean, M., Pan, S., Winiwarter, W. , Zaehle, S., Zhou, F., Jackson, R. B., Bange, H. W., Berthet, S., Bian, Z., Bianchi, D., Bouwman, A. F., Buitenhuis, E. T., Dutton, G., Hu, M., Ito, A., Jain, A. K., Jeltsch-Thömmes, A., Joos, F., Kou-Giesbrecht, S., Krummel, P. B., Lan, X., Landolfi, A., Lauerwald, R., Li, Y., Lu, C., Maavara, T., Manizza, M., Millet, D. B., Mühle, J., Patra, P. K., Peters, G. P., Qin, X., Raymond, P., Resplandy, L., Rosentreter, J. A., Shi, H., Sun, Q., Tonina, D., Tubiello, F. N., van der Werf, G. R., Vuichard, N., Wang, J., Wells, K. C., Western, L. M., Wilson, C., Yang, J., Yao, Y., You, Y., & Zhu, Q. (2024). Global nitrous oxide budget (1980--2020). Earth System Science Data 16 (6) 2543-2604. 10.5194/essd-16-2543-2024.

2023

Davidson, E. A. & Winiwarter, W. (2023). Urgent abatement of industrial sources of nitrous oxide. Nature Climate Change 13 599-601. 10.1038/s41558-023-01723-3.

Kaltenegger, K. , Bai, Z., Dragosits, U., Fan, X., Greinert, A., Guéret, S., Suchowska-Kisielewicz, M., Winiwarter, W. , Zhang, L., & Zhou, F. (2023). Urban nitrogen budgets: Evaluating and comparing the path of nitrogen through cities for improved management. Science of the Total Environment 904 e166827. 10.1016/j.scitotenv.2023.166827.

Liu, Z., Rieder, H.E., Schmidt, C., Mayer, M., Guo, Y., Winiwarter, W. , & Zhang, L. (2023). Optimal reactive nitrogen control pathways identified for cost-effective PM2.5 mitigation in Europe. Nature Communications 14 (1) e4246. 10.1038/s41467-023-39900-9.

2022

Del Grosso, S.J., Ogle, S.M., Nevison, C., Gurung, R., Parton, W.J., Wagner-Riddle, C., Smith, W., Winiwarter, W. , Grant, B., Tenuta, M., Marx, E., Spencer, S., & Williams, S. (2022). A gap in nitrous oxide emission reporting complicates long-term climate mitigation. Proceedings of the National Academy of Sciences 119 (31) e2200354119. 10.1073/pnas.2200354119.

2021

Gu, B., Zhang, L., Van Dingenen, R., Vieno, M., Van Grinsven, H.J.M., Zhang, X., Zhang, S. , Chen, Y., Wang, S., Ren, C., Rao, S., Holland, M., Winiwarter, W. , Chen, D., Xu, J., & Sutton, M.A. (2021). Abating ammonia is more cost-effective than nitrogen oxides for mitigating PM 2.5 air pollution. Science 374 (6568) 758-762. 10.1126/science.abf8623.

Kaltenegger, K. , Erb, K.-H., Matej, S., & Winiwarter, W. (2021). Gridded soil surface nitrogen surplus on grazing and agricultural land: Impact of land use maps. Environmental Research Communications 3 (5) e055003. 10.1088/2515-7620/abedd8.

Xu, R., Tian, H., Pan, N., Thompson, R.L., Canadell, J.G., Davidson, E.A., Nevison, C., Winiwarter, W. , Shi, H., Pan, S., Chang, J., Ciais, P., Dangal, S.R.S., Ito, A., Jackson, R.B., Joos, F., Lauerwald, R., Lienert, S., Maavara, T., Millet, D.B., Raymond, P.A., Regnier, P., Tubiello, F.N., Vuichard, N., Wells, K.C., Wilson, C., Yang, J., Yao, Y., Zaehle, S., & Zhou, F. (2021). Magnitude and Uncertainty of Nitrous Oxide Emissions From North America Based on Bottom‐Up and Top‐Down Approaches: Informing Future Research and National Inventories. Geophysical Research Letters 48 (23) e2021GL095264. 10.1029/2021GL095264.

2020

Amann, M. , Kiesewetter, G. , Schöpp, W. , Klimont, Z. , Winiwarter, W. , Cofala, J., Rafaj, P. , Höglund-Isaksson, L. , Gomez-Sanabria, A. , Heyes, C. , Purohit, P. , Borken-Kleefeld, J. , Wagner, F. , Sander, R. , Fagerli, H., Nyiri, A., Cozzi, L., & Pavarini, C. (2020). Reducing global air pollution: the scope for further policy interventions. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378 (2183) e20190331. 10.1098/rsta.2019.0331.

Kaltenegger, K. & Winiwarter, W. (2020). Global Gridded Nitrogen Indicators: Influence of Crop Maps. Global Biogeochemical Cycles 34 (12) e2020GB006634. 10.1029/2020GB006634.

Kanter, D.R., Winiwarter, W. , Bodirsky, B.L., Bouwman, L., Boyer, E., Buckle, S., Compton, J.E., Dalgaard, T., de Vries, W., Leclere, D., Leip, A., Müller, C., Popp, A., Raghuram, N., Rao, S., Sutton, M.A., Tian, H., Westhoek, H., Zhang, X., & Zurek, M. (2020). A framework for nitrogen futures in the shared socioeconomic pathways. Global Environmental Change 61 e102029. 10.1016/j.gloenvcha.2019.102029.

Winiwarter, W. , Amon, B., Bai, Z., Greinert, A., Kaltenegger, K. , Ma, L., Myszograj, S., Schneidergruber, M., Suchowski-Kisielewicz, M., Wolf, L., Zhang, L., & Zhou, F. (2020). Urban nitrogen budgets: flows and stock changes of potentially polluting nitrogen compounds in cities and their surroundings – a review. Journal of Integrative Environmental Sciences 17 (1) 57-71. 10.1080/1943815X.2020.1841241.

2019

Thompson, R., Lassaletta, L., Patra, P., Wilson, C., Wells, K., Gressent, A., Koffi, E., Chipperfield, M., Winiwarter, W. , Davidson, E.A., Tian, H., & Canadell, J.G. (2019). Acceleration of global N2O emissions seen from two decades of atmospheric inversion. Nature Climate Change 9 993-998. 10.1038/s41558-019-0613-7.

2008

Erisman, J.W., Sutton, M.A., Galloway, J.N., Klimont, Z. , & Winiwarter, W. (2008). How a century of ammonia synthesis changed the world. Nature Geoscience 1 (10) 636-639. 10.1038/ngeo325.