EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Synthesis, homogenisation and regionalisation of inland water greenhouse gas budget estimates for the RECCAP2 initiative

Ronny Lauerwald1, George H. Allen2, Bridget R. Deemer3, Shaoda Liu4,5, Taylor Maavara4,6, Pete Raymond4, Lewis Alcott7, David Bastviken8, Adam Hastie9, Meredith A. Holgerson10, Matthew S. Johnson11, Bernhard Lehner12, Peirong Lin13, Alessandra Marzadri14, Lishan Ran15, Hanqin Tian16, Xiao Yang17, Yuanzhi Yao18, and Pierre Regnier19
Ronny Lauerwald et al.
  • 1Université Paris-Saclay, UMR EcoSys, Eco&Phy, Palaiseau, France (
  • 2Department of Geosciences, Virginia Tech, VA, USA
  • 3U.S. Geological Survey, Southwest Biological Science Center, Flagstaff AZ, USA
  • 4Yale School of the Environment, Yale University, New Haven, CT, USA
  • 5State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875 China
  • 6School of Geography, University of Leeds, Leeds, LS2 9JT, UK
  • 7Department of Earth & Planetary Sciences, Yale University, New Haven, CT, USA
  • 8Department of Thematic Studies - Environmental Change, Linköping University, Linköping, Sweden
  • 9School of GeoSciences, University of Edinburgh, Edinburgh, UK
  • 10Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA
  • 11Earth Science Division, NASA Ames Research Center, Moffett Field, CA, USA
  • 12Department of Geography, McGill University, Montreal, H3A 0B9, QC, Canada
  • 13Institute of Remote Sensing and GIS, School of Earth and Space Sciences, Peking University, China
  • 14University of Trento, Department of Civil, Environmental and Mechanical Engineering, Trento, Italy
  • 15Department of Geography, The University of Hong Kong, Pokfulam Road, 999077, Hong Kong, China
  • 16Schiller Institute for Integrated Science and Society, Department of Earth and Environmental Sciences, Boston College, Chestnut Hill, MA, USA
  • 17Southern Methodist University, Department of Earth Sciences, Dallas, TX-75275, USA
  • 18School of Geographic Sciences, East China Normal University, Shanghai 200241, China
  • 19Department Geoscience, Environment & Society - BGEOSYS, Université Libre de Bruxelles, 1050 Bruxelles, Belgium

Inland waters are important sources of the greenhouse gasses (GHGs) carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) to the atmosphere. While a growing number of global estimates of inland water GHG emissions exists, the integration of inland waters into regional GHG budgets is often hampered by the lack of adequate geo-spatial datasets. Moreover, existing estimates diverge substantially, in part due to persisting uncertainties related to the size and distribution of effective inland water surface areas.  In the framework of the 2nd phase of the REgional Carbon Cycle Assessment and Processes (RECCAP-2) initiative, we synthesize existing estimates of GHG emissions from streams, rivers, lakes and reservoirs, and homogenize them with regard to underlying global maps of inland water surface areas and the effects of seasonal ice cover. We then produce estimates of inland water GHG emissions for 10 extensive land regions that are used for the regional land budgets of RECCAP2. According to our synthesis, global inland waters emit 5.6 (3.5-9.1) Pg CO2 yr-1, 101 (83-135) Tg CH4 yr-1 and 326 (254-592) Gg N2O yr-1. South American rivers contribute about one third of global inland water CO2 emissions. North-American and Russian lakes contribute together one third of global inland water CH4 emissions. Finally, North America alone contributes one fourth of global inland water N2O emissions.

The global inland water emissions sum up to a global warming potential (GWP) of an equivalent emission of 13.6 (10.0-20.3) and 8.3 (5.8-12.7) Pg CO2 yr-1 at a 20- and 100-year horizon, respectively. At 100-year horizon, the contribution of CO2 dominates the GWP of global inland water GHG emissions, with rivers being the largest emitters. At the 20-year horizon, on the contrary, lakes and rivers are equally important emitters, and the contributions of CH4 to the GWP of inland water GHG emissions even exceed those of CO2. Contributions of N2O to the GWP appear to be less significant at both time horizons. Normalized to the area of the RECCAP-2 land regions, South America and South East Asia show the highest inland water emission rates in terms of GWP, dominated by riverine CO2 emissions.

How to cite: Lauerwald, R., Allen, G. H., Deemer, B. R., Liu, S., Maavara, T., Raymond, P., Alcott, L., Bastviken, D., Hastie, A., Holgerson, M. A., Johnson, M. S., Lehner, B., Lin, P., Marzadri, A., Ran, L., Tian, H., Yang, X., Yao, Y., and Regnier, P.: Synthesis, homogenisation and regionalisation of inland water greenhouse gas budget estimates for the RECCAP2 initiative, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-1333,, 2023.