Abstract
Reforestation is considered an important nature-based climate solution to help achieve net-zero CO2 emissions. However, strategies using reforestation-based CO2 removal to offset fossil fuel emissions may not lead to the same climate outcome as avoiding the fossil fuel emissions. Here, we use an Earth System model of intermediate complexity to compare the climate outcome of different pathways: a reference pathway, and net-zero pathways where additional fossil fuel CO2 emissions relative to the reference pathway are balanced by reforestation-based CO2 removals (“Reforestation Net-zero pathways”). Results show that model simulations of Reforestation Net-zero pathways yield a higher atmospheric CO2 and warmer climate outcome than the reference simulation. The higher atmospheric CO2 results from carbon cycle feedbacks. The additional global warming from higher atmospheric CO2 is further amplified by biogeophysical effects of reforestation. These findings highlight the need for improved methods to account for the carbon cycle and climate effects of reforestation.
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Data availability
The data and Python code to re-create the figures in this manuscript and the Supplementary Information are available at this repository: https://doi.org/10.20383/103.01572.
Code availability
The model code for version 2.10 of the UVic ESCM is available on the official UVic ESCM webpage at http://terra.seos.uvic.ca/model/2.10/.
References
UNFCCC. The Paris Agreement. United Nations Framework Convention on Climate Change. UNFCCC https://unfccc.int/documents/184656 (2016).
Rogelj et al. Mitigation pathways compatible with 1.5 °C in the context of sustainable development. In: Global Warming of 1.5 °C (Cambridge University Press, in press, 2018).
Riahi, K. et al. Mitigation pathways compatible with long-term goals. In IPCC 2022: Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (Cambridge University Press, in press, 2022).
Allen, M. R. et al. Framing and Context. In: Global Warming of 1.5 °C (Cambridge University Press, in press, 2018).
Fankhauser, S. et al. The meaning of net zero and how to get it right. Nat. Clim. Change 12, 15–21 (2022).
Zickfeld, K. et al. Net-zero approaches must consider Earth system impacts to achieve climate goals. Nat. Clim. Change 13, 1298–1305 (2023).
Smith, P. et al. Biophysical and economic limits to negative CO2 emissions. Nat. Clim. Change 6, 42–50 (2016).
Griscom, B. W. et al. Natural climate solutions. Proc. Natl. Acad. Sci. USA 114, 11645–11650 (2017).
Minx, J. C. et al. Negative emissions - Part 1: Research landscape and synthesis. Environ. Res. Lett. 13, https://doi.org/10.1088/1748-9326/aabf9b (2018).
IUCN. Global standard for nature-based solutions: a user-friendly framework for the verification, design and scaling up of NbS. IUCN https://doi.org/10.2305/IUCN.CH.2020.09.en (2020).
Seddon, N. et al. Understanding the value and limits of nature-based solutions to climate change and other global challenges. Philos. Trans. R. Soc. B Biol. Sci. 375, 20190120 (2020).
Smith, H. B., Vaughan, N. E. & Forster, J. Long-term national climate strategies bet on forests and soils to reach net-zero. Commun. Earth Environ. 3, 1–12 (2022).
Smith, S.M. et al. The State of Carbon Dioxide Removal (2024)—2nd Edition https://doi.org/10.17605/OSF.IO/F85QJ (2024).
Koch, A., Brierley, C. & Lewis, L. S. Effects of Earth system feedbacks on the potential mitigation of large-scale tropical forest restoration. Biogeosciences 18, 2627–2647 (2021).
Littleton, E. W. et al. Dynamic modelling shows substantial contribution of ecosystem restoration to climate change mitigation. Environ. Res. Lett. 16, 124061 (2021).
Dooley, K. & Nicholls, Z. Carbon removals from nature restoration are no substitute for steep emission reductions. One Earth 5, 812–824 (2022).
Matthews, H. D. et al. Temporary nature-based carbon removal can lower peak warming in a well-below 2 °C scenario. Commun. Earth Environ. 3, 1–8 (2022).
Jayakrishnan, K. U. & Bala, G. A comparison of the climate and carbon cycle effects of carbon removal by afforestation and an equivalent reduction in fossil fuel emissions. Biogeosciences 20, 1863–1877 (2023).
Boysen, L. R. et al. The limits to global-warming mitigation by terrestrial carbon removal. Earths Future 5, 463–474 (2017).
Harper, A. B. et al. Land-use emissions play a critical role in land-based mitigation for Paris climate targets. Nat. Commun. 9 https://doi.org/10.1038/s41467-018-05340-z (2018).
Pugh, T. A. M. et al. Role of forest regrowth in global carbon sink dynamics. Proc. Natl. Acad. Sci. USA 116, 4382–4387 (2019).
Cook-Patton, S. C. et al. Mapping carbon accumulation potential from global natural forest regrowth. Nature 585, 545–550 (2020).
Koch, A. & Kaplin, J.O. Tropical forest restoration under future climate change. Nat. Clim. Change 12, 279–283 (2022).
Moustakis et al. No compromise in efficiency from the co-application of a marine and terrestrial CDR method. Nat. Commun. 16, 4709 (2025).
Guo et al. Remote carbon cycle changes are overlooked impacts of land cover and land management changes. Earth Syst. Dyn. 16, 631–666 (2025).
Allen, M. et al. Geological Net Zero and the need for disaggregated accounting for carbon sinks. Nature 638, 343–350 (2025).
Bonan, G. B. Forests and climate change: forcings, feedbacks, and the climate benefits of forests. Science 320, 1444–1449 (2008).
Arora, V. K. & Montenegro, A. Small temperature benefits provided by realistic afforestation efforts. Nat. Geosci. 4, 514–518 (2011).
Perugini, L. et al. Biophysical effects on temperature and precipitation due to land cover change. Environ. Res. Lett. 12 https://doi.org/10.1088/1748-9326/aa6b3f (2017).
Forzieri, G. et al. Increased control of vegetation on global terrestrial energy fluxes. Nat. Clim. Change 10 https://doi.org/10.1038/s41558-020-0717-0 (2020).
Cerasoli, S., Yin, J. & Porporato, A. Cloud cooling effects of afforestation and reforestation at midlatitudes. Proc. Natl. Acad. Sci. USA 118, 1–7 (2021).
Windisch, M. G., Davin, E. L. & Seneviratne, S. I. Prioritizing forestation based on biogeochemical and local biogeophysical impacts. Nat. Clim. Change 11, 867–871 (2021).
Lawrence, D., Coe, M., Walker, W., Verchot, L. & Vandecar, K. The unseen effects of deforestation: biophysical effects on climate. Front. For. Glob. Change 5, 1–13 (2022).
De Hertog, S. J. et al. The biogeophysical effects of idealized land cover and land management changes in Earth system models. Earth Syst. Dyn. 14, 629 (2023).
Anderegg, W. R. L. et al. Climate-driven risks to the climate mitigation potential of forests. Science 368 https://doi.org/10.1126/science.aaz7005 (2020).
Landry, J. S., Matthews, H. D. & Ramankutty, N. A global assessment of the carbon cycle and temperature responses to major changes in future fire regime. Clim. Change 133, 179–192 (2015).
Seidl, R. et al. Forest disturbances under climate change. Nat. Clim. Change 7, 395–402 (2017).
Choat, B. et al. Triggers of tree mortality under drought. Nature 558, 531–539 (2018).
Jones, M. W. et al. Global and regional trends and drivers of fire under climate change. Rev. Geophys. 60, 1–76 (2022).
Runde, I., Zobel, Z. & Schwalm, C. Human and natural resource exposure to extreme drought at 1.0°C-4.0°C warming levels. Environ. Res. Lett. 17 https://doi.org/10.1088/1748-9326/ac681a (2022).
Burton, C. et al. Global burned area increasingly explained by climate change. Nat. Clim. Change https://doi.org/10.1038/s41558-024-02140-w (2024).
Mengis, N. et al. Evaluation of the University of Victoria Earth System Climate Model version 2.10 (UVic ESCM 2.10). Geosci. Model Dev. 13, 4183–4204 (2020).
Portmann, R. et al. Global forestation and deforestation affect remote climate via adjusted atmosphere and ocean circulation. Nat. Commun. 13, 5569 (2022).
Verified Carbon Standard: Methodology for Afforestation, reforestation, and revegetation Projects https://verra.org/wp-content/uploads/imported/methodologies/VCS-ARR-Methodology.pdf (2021).
Roe, S. et al. Contribution of the land sector to a 1.5 °C world. Nat. Clim. Change 9, 817–828 (2019).
Boysen, L. R. et al. Global climate response to idealized deforestation in CMIP6 models. Biogeosciences 17, 5615–5638 (2020).
Weaver, A. J. et al. The UVic Earth System Climate Model: Model description, climatology, and applications to past, present and future climates. Atmos. Ocean 39, 361–428 (2001).
Cox, P. M. Description of the TRIFFID dynamic global vegetation model. Hadley Centre Technical Note. Theor. Appl. Climatol. 24, 16 (2001).
Clark, D. B. et al. The Joint UK Land Environment Simulator (JULES), model description – Part 2: Carbon fluxes and vegetation dynamics. Geosci. Model Dev. 4, 701–722 (2011).
Avis, C. A., Weaver, A. J. & Meissner, K. J. Reduction in areal extent of high-latitude wetlands in response to permafrost thaw. Nat. Geosci. 4, 444–448 (2011).
MacDougall, A., Avis, C. & Weaver, A. Significant contribution to climate warming from the permafrost carbon feedback. Nat. Geosci. 5, 719–721 (2012).
MacDougall, A. H. & Knutti, R. Enhancement of non-CO2 radiative forcing via intensified carbon cycle feedbacks. Geophys. Res. Lett. 43, 5833–5840 (2016).
Meissner, K. J., Weaver, A. J., Matthews, H. D. & Cox, P. M. The role of land surface dynamics in glacial inception: a study with the UVic Earth System Model. Clim. Dyn. 21, 515–537 (2003).
Eyring, V. et al. Overview of the coupled model intercomparison project phase 6 (CMIP6) experimental design and organization. Geosci. Model Dev. 9, 1937–1958 (2016).
Riahi, K. et al. The shared socioeconomic pathways and their energy, land use, and greenhouse gas emissions implications: an overview. Glob. Environ. Change 42, 153–168 (2017).
Meinshausen, M. et al. The shared socio-economic pathway (SSP) greenhouse gas concentrations and their extensions to 2500. Geosci. Model Dev. 13, 3571–3605 (2020).
MacIsaac, A. J. et al. Temporary nature-based carbon removal can lower peak warming in a well-below 2 C scenario – Supplementary data. Federated Research Data Repository https://doi.org/10.20383/102.0552 (2022).
Mathesius, S. et al. CMIP6 scenarios’ radiative forcing of non-CO2 greenhouse gases and aerosols for UVic ESCM simulations (1850–2500). Zenodo https://doi.org/10.5281/zenodo.11061150 (2023).
Acknowledgements
This project was undertaken with the financial support of the Government of Canada. Ce projet a été réalisé avec l’appui financier du governement du Canada. This research was enabled in part by support provided by BC Digital Research Infrastructure and the Digital Research Alliance of Canada (alliancecan.ca).
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A.J.M. developed the research questions, designed the study, performed model simulations, analyzed the model output, produced the figures, and led the writing of the manuscript. K.Z. conceived the research, assisted in data analysis and interpretation, and edited the manuscript. P.E.B. and H.D.M. provided editorial feedback throughout the writing process.
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Communications Earth and Environment thanks Charles Koven and the other anonymous reviewer(s) for their contribution to the peer review of this work. Primary handling editors: Charlotte Kendra Gotangco Gonzales and Mengjie Wang. A peer review file is available.
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Supplementary Information for: Imbalances in climate outcomes in net-zero pathways with fossil fuel CO2 emissions and reforestation-based CO2 removals
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MacIsaac, A.J., Zickfeld, K., Banville, P.E. et al. Imbalances in climate outcomes in net-zero pathways with fossil fuel CO2 emissions and reforestation-based CO2 removals. Commun Earth Environ (2026). https://doi.org/10.1038/s43247-026-03329-x
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DOI: https://doi.org/10.1038/s43247-026-03329-x
