The past and the future of the tropical forest carbon sink: insights from permanent forest inventory plots
- 1University of Leeds, School of Geography, Leeds, UK (whubau@gmail.com; S.L.Lewis@leeds.ac.uk; o.phillips@leeds.ac.uk)
- 2Royal Museum for Central Africa, Service of Wood Biology, Tervuren, Belgium (wannes.hubau@africamuseum.be; hans.beeckman@africamuseum.be)
- 3Ghent University, Department of Environment, Laboratory of Wood Technology Ghent, Belgium (wannes.hubau@ugent.be)
- 4University College London, Department of Geography, London, UK (s.l.lewis@ucl.ac.uk)
- *A full list of authors appears at the end of the abstract
Structurally intact tropical forests sequestered ~1 Pg C yr-1 over the 1990s and early 2000s, equivalent to ~15% of fossil fuel emissions. Climate-driven vegetation models typically predict that this carbon sink will continue for the remainder of the 21st century. However, recent plot inventories from Amazonia show a declining rate of carbon sequestration, potentially signaling an imminent end to the sink. Here we assess whether the African tropical forest sink is also declining.
Records from 244 multi-census plots across 11 countries reveal that the African tropical forest sink in aboveground live biomass has been stable for three decades, at 0.66 Mg C ha-1 yr-1, from 1985-2015 (95% CI, 0.53-0.79). Thus, the carbon sink responses of Earth’s two largest expanses of tropical forest have diverged over recent decades. A statistical model including CO2, temperature, drought, and forest dynamics can account for the trends. Despite the past stability of the African carbon sink, our data and model show that very recently the sink has begun decreasing, and that it will continue to decline in the future. This implies that the intact tropical forest carbon sink on both continents is set to end decades sooner than even the most extreme vegetation model estimates.
Published independent observations of inter-hemispheric atmospheric CO2 concentration indicate increasing carbon uptake into the Northern hemisphere landmass, offsetting a weakening of the tropical forest sink, which reinforces our conclusion that the intact tropical forest carbon sink has already saturated. Nevertheless, continued on-the-ground monitoring of the world’s remaining intact tropical forests will be required to test our prediction that the intact tropical forest carbon sink will continue to decline. Our findings were recently published in Nature (March 2020) and have important policy implications: given tropical forests are likely to sequester less carbon in the future than Earth System Models predict, an earlier date to reach net zero anthropogenic greenhouse gas emissions will be required to meet any given commitment to limit the global heating of Earth.
AfriTRON consortium: W. Hubau, S.L. Lewis, O.L. Phillips, K. Affum-Baffoe, H. Beeckman, A. Cuní-Sanchez, A.K. Daniels, C.E.N. Ewango, S. Fauset, J.M. Mukinzi , D. Sheil, B. Sonké, M.J.P. Sullivan, T.C.H. Sunderland, H. Taedoumg, S.C. Thomas, L.J.T. White, K.A. Abernethy, S. Adu-Bredu, C.A. Amani, T.R. Baker, L.F. Banin, F. Baya, S.K. Begne, A.C. Bennett, F. Benedet, R. Bitariho, Y.E. Bocko, P. Boeckx, P. Boundja, R.J.W. Brienen, T. Brncic, E. Chezeaux, G.B. Chuyong, C.J. Clark, M. Collins, J.A. Comiskey, D.A. Coomes, G.C. Dargie, T. de Haulleville, M. Djuikouo Kamdem, J. Doucet, A. Esquivel-Muelbert, T.R. Feldpausch, A. Fofanah, E.G. Foli, M. Gilpin, E. Gloor, C. Gonmadje, S. Gourlet-Fleury, J.S. Hall , A.C. Hamilton, D.J. Harris, T.B. Hart, M.B.N. Hockemba, A. Hladik, S.A. Ifo, K.J. Jeffery, T. Jucker, E. Kasongo Yakusu, E. Kearsley, D. Kenfack, A. Koch, M.E. Leal, A. Levesley, J.A. Lindsell, J. Lisingo, G. Lopez-Gonzalez, J.C. Lovett, J. Makana, Y. Malhi, A.R. Marshall, J. Martin, E.H. Martin, F.M. Mbayu, V.P. Medjibe, V. Mihindou, E.T.A. Mitchard, S. Moore, P.K.T. Munishi, N. Nssi Bengone, L. Ojo, F. Evouna Ondo, K.S.-H. Peh, G.C. Pickavance, A.D. Poulsen, J.R. Poulsen, L. Qie, J. Reitsma, F. Rovero, M.D. Swaine, J. Talbot, J. Taplin, D.M. Taylor, D.W. Thomas, B. Toirambe, J. Tshibamba Mukendi, D. Tuagben, P.M. Umunay, G.M.F. Van Der Heijden, H. Verbeeck, J. Vleminckx, S. Willcock, H. Woell, J.T. Woods, L. Zemagho RAINFOR consortium: R.J.W. Brienen, O.L. Phillips, T.R. Feldpausch, E. Gloor, T.R. Baker, J. Lloyd, G. Lopez-Gonzalez, A. Monteagudo-Mendoza, Y. Malhi, S.L. Lewis, R. Vásquez Martinez, M. Alexiades, E. Álvarez Dávila, P. Alvarez-Loayza, A. Andrade, L.E.O.C. Aragão, A. Araujo-Murakami, E.J.M.M. Arets, L. Arroyo, G.A. Aymard C., C. Baraloto, J. Barroso, D. Bonal, R.G.A. Boot, J.L. Camargo, C.V. Castilho, V. Chama, K.J. Chao, J. Chave, J.A. Comiskey, F. Cornejo Valverde, L. da Costa, E.A. Oliveira, A. Di Fiore, T.L. Erwin, S. Fauset, M. Forsthofer, D.R.Galbraith, E.S. Grahame, N. Groot, B. Hérault, N. Higuchi, E.N. Honorio Coronado, H. Keeling, T.J. Killeen, W.F. Laurance, S. Laurance, J. Licona, W.E. Magnusson, B.S. Marimon, B.H. Marimon-Junior, C. Mendoza, D.A. Neill, E.M. Nogueira, P. Núñez, N.C. Pallaqui Camacho, A. Parada, G. Pardo, J. Peacock, M. Peña-Claros, G.C. Pickavance, N.C.A. Pitman, L. Poorter, A. Prieto, C.A. Quesada, F. Ramírez, H. Ramírez-Angulo, Z. Restrepo, A. Roopsind, A. Rudas, R.P. Salomão, M. Schwarz, N. Silva, J.E. Silva-Espejo, M. Silveira, J. Stropp, J Talbot, H. ter Steege, J. Teran-Aguilar, J. Terborgh, R. Thomas-Caesar, M. Toledo, M. Torello-Raventos, R.K. Umetsu, G.M.F. van der Heijden, P. van der Hout, I.C. Guimarães Vieira, S.A.Vieira, E. Vilanova, V. Vos, R.J. Zagt
How to cite: Hubau, W., Lewis, S. L., Phillips, O. L., and Beeckman, H. and the AfriTRON consortium & the RAINFOR consortium: The past and the future of the tropical forest carbon sink: insights from permanent forest inventory plots, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11069, https://doi.org/10.5194/egusphere-egu2020-11069, 2020
