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Advertisement Advertisement Nature * View all journals * Search * My Account Login * Explore content * About the journal * Publish with us Subscribe * Sign up for alerts * RSS feed 1. nature 2. articles 3. article * Article * Published: 13 April 2022 Realization of Paris Agreement pledges may limit warming just below 2 degC * Malte Meinshausen ORCID: orcid.org/0000-0003-4048-3521^1,2, * Jared Lewis^2,3, * Christophe McGlade^4, * Johannes Gutschow ORCID: orcid.org/0000-0001-9944-3685^2,5, * Zebedee Nicholls ORCID: orcid.org/0000-0002-4767-2723^1,2,3, * Rebecca Burdon^2,6, * Laura Cozzi^4 & * Bernd Hackmann^7 Nature volume 604, pages 304-309 (2022)Cite this article * 551 Altmetric * Metrics details Subjects * Climate-change mitigation * Projection and prediction Abstract Over the last five years prior to the Glasgow Climate Pact^1, 154 Parties have submitted new or updated 2030 mitigation goals in their nationally determined contributions and 76 have put forward longer-term pledges. Quantifications of the pledges before the 2021 United Nations Climate Change Conference (COP26) suggested a less than 50 per cent chance of keeping warming below 2 degrees Celsius^2, 3,4,5. Here we show that warming can be kept just below 2 degrees Celsius if all conditional and unconditional pledges are implemented in full and on time. Peak warming could be limited to 1.9-2.0 degrees Celsius (5%-95% range 1.4-2.8 degC) in the full implementation case--building on a probabilistic characterization of Earth system uncertainties in line with the Working Group I contribution to the Sixth Assessment Report^6 of the Intergovernmental Panel on Climate Change (IPCC). We retrospectively project twenty-first-century warming to show how the aggregate level of ambition changed from 2015 to 2021. Our results rely on the extrapolation of time-limited targets beyond 2030 or 2050, characteristics of the IPCC 1.5 degC Special Report (SR1.5) scenario database^7 and the full implementation of pledges. More pessimistic assumptions on these factors would lead to higher temperature projections. A second, independent emissions modelling framework projected peak warming of 1.8 degrees Celsius, supporting the finding that realized pledges could limit warming to just below 2 degrees Celsius. Limiting warming not only to 'just below' but to 'well below' 2 degrees Celsius or 1.5 degrees Celsius urgently requires policies and actions to bring about steep emission reductions this decade, aligned with mid-century global net-zero CO [2] emissions. Access through your institution Buy or subscribe This is a preview of subscription content Access options Access through your institution Access through your institution Change institution Buy or subscribe Subscribe to Nature+ Get immediate online access to the entire Nature family of 50+ journals $29.99 monthly Subscribe Subscribe to Journal Get full journal access for 1 year $199.00 only $3.90 per issue Subscribe All prices are NET prices. VAT will be added later in the checkout. Tax calculation will be finalised during checkout. Buy article Get time limited or full article access on ReadCube. $32.00 Buy All prices are NET prices. Additional access options: * Log in * Learn about institutional subscriptions Fig. 1: Number of countries that have NDCs, long-term targets and net-zero emission targets and their share of global CO[2] emissions. [41586_2022_4553_Fig1_HTML] Fig. 2: Although some near-term pledges are estimated to be very weak, implying potentially substantial overachievement (hot air), countries with long-term targets envisage substantial per capita emission reductions. [41586_2022_4553_Fig2_HTML] Fig. 3: Global mean temperature projections based on 2030 NDCs show a wide range, whereas those based also on long-term targets stay just around or below 2 degC--with limited additional effects by the GMP. [41586_2022_4553_Fig3_HTML] Fig. 4: Pledges submitted at the time of the Paris Agreement (2015) and up to after COP26 show a strong recent decrease in projected cumulative emissions. [41586_2022_4553_Fig4_HTML] Fig. 5: Pledges submitted at the time of the Paris Agreement (2015) and up to after COP26 indicate the possibility of emission peaking before 2030 and lowering median warming. [41586_2022_4553_Fig5_HTML] Data availability The data archive for this study is available at https://doi.org/ 10.5281/zenodo.5886866, which includes the scenario data, temperature outcomes and supplementary tables^48. Country-level emission quantifications of NDCs and LT-LEDs (the 'NDC Factsheets')^49 are available at https://doi.org/10.5281/zenodo.5768669 and are also interactively available at https://climate-resource.com/tools/ndcs. The source data PRIMAP-hist CR is provided at https://doi.org/10.5281 /zenodo.5494497. Source data are provided with this paper. Code availability The analysis code used in this study is provided by Silicone (version 1.2.1) for the infilling, available at https://github.com/ GranthamImperial/silicone, and by the Anaeris package (version 0.2.0+41.g6ddf6e5) for the harmonization, available at https:// github.com/iiasa/aneris. The climate model MAGICC7.5 is in the process of becoming open source (re-factoring ongoing), the model is available as an interactive mode at http://live.magicc.org. The source code for extrapolating and infilling of the NDC scenarios are available at https://gitlab.com/climate-resource/ ndc-realisations-2021. References 1. UNFCCC. Glasgow Climate Pact https://unfccc.int/documents/310475 (United Nations Framework Convention on Climate Change, 2021). 2. Ou, Y. et al. Can updated climate pledges limit warming well below 2 degC? Science 374, 693-695 (2021). CAS Article Google Scholar 3. UNEP. 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Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (eds V. Masson-Delmotte et al.) Ch. 2 (Cambridge Univ. Press, 2021). 48. Meinshausen, M. et al. Data for study "Realisation of Paris Agreement climate pledges may limit warming just below 2 degC". Zenodo https://doi.org/10.5281/zenodo.5886866 (2022). 49. Meinshausen, M., Lewis, J., Nicholls, Z. & Guetschow, J. NDC factsheets. Zenodo https://doi.org/10.5281/zenodo.5768669 (2021). 50. Climate Action Tracker. Temperatures https:// climateactiontracker.org/global/temperatures/ (2021). Download references Acknowledgements We acknowledge discussions and collaborations with several colleagues of the UNEP Gap report team and the IAM modellers contributing to the SR1.5 and ENGAGE scenario databases. M.M. is the recipient of an Australian Research Council (ARC) Future Fellowship (grant number FT130100809). C.M., L.C. and B.H. state that the views expressed in this article are in the author's personal capacity and do not necessarily reflect the views of the United Nations, United Nations Climate Change or the International Energy Agency. Author information Affiliations 1. Climate & Energy College, School of Geography, Earth and Atmospheric Sciences, The University of Melbourne, Melbourne, Victoria, Australia Malte Meinshausen & Zebedee Nicholls 2. Climate Resource, Melbourne, Victoria, Australia Malte Meinshausen, Jared Lewis, Johannes Gutschow, Zebedee Nicholls & Rebecca Burdon 3. International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria Jared Lewis & Zebedee Nicholls 4. International Energy Agency, Paris, France Christophe McGlade & Laura Cozzi 5. Potsdam Institute for Climate Impact Research, Potsdam, Germany Johannes Gutschow 6. Melbourne Climate Futures, The University of Melbourne, Melbourne, Victoria, Australia Rebecca Burdon 7. United Nations Climate Change, Bonn, Germany Bernd Hackmann Authors 1. Malte Meinshausen View author publications You can also search for this author in PubMed Google Scholar 2. Jared Lewis View author publications You can also search for this author in PubMed Google Scholar 3. Christophe McGlade View author publications You can also search for this author in PubMed Google Scholar 4. Johannes Gutschow View author publications You can also search for this author in PubMed Google Scholar 5. Zebedee Nicholls View author publications You can also search for this author in PubMed Google Scholar 6. Rebecca Burdon View author publications You can also search for this author in PubMed Google Scholar 7. Laura Cozzi View author publications You can also search for this author in PubMed Google Scholar 8. Bernd Hackmann View author publications You can also search for this author in PubMed Google Scholar Contributions All authors contributed to writing the study. M.M. designed the study and quantified the NDCs for the bottom-up NDC analysis; J.L. performed the global harmonization, climate model runs and analysis; C.M. and L.C. provided the analysis of net-zero emission targets and the IEA scenarios; Z.N. provided the code base for the probabilistic climate model analysis and analysis of the ENGAGE database; and J.G. provided the PRIMAP-hist data. Corresponding author Correspondence to Malte Meinshausen. Ethics declarations Competing interests The authors declare no competing interests. Peer review Peer review information Nature thanks Kalyn Dorheim, Zeke Hausfather and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Additional information Publisher's note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Extended data figures and tables Extended Data Fig. 1 CO[2] emissions for various scenarios. Total CO[2] emissions of the considered scenarios A and B, the 2030 extension scenarios 'a' to 'h' (Extended Data Table 2), the SSP scenarios (dashed grey lines) and the SR1.5 scenario database. As in Fig. 3b, but for total CO[2] emissions instead of GHG emissions. Source data Extended Data Fig. 2 Sensitivity test of database temperature projections in the ENGAGE database^31. The 25 closest scenarios in terms of their 2050 GHG emissions (GWP-100 AR6, excluding LULUCF) to this study's scenario A (thick blue line, Extended Data Table 2) are selected (thin coloured lines). For the respective emission level around 30 GtCO[2]e by 2050, more of the selected ENGAGE scenarios suggest lower post-2050 GHG emission levels than our scenario A, which had been extrapolated using an equal-quantile-walk approach on the basis of the SR1.5 scenario database^7. Source data Extended Data Table 1 2100 warming relative to 1850-1900 of comparison studies shown in sidebars of Fig. 3a, c Full size table Extended Data Table 2 Overview of shown pathways and their characteristics Full size table Source data Source Data Fig. 1 Source Data Fig. 2 Source Data Fig. 3 Source Data Fig. 4 Source Data Fig. 5 Source Data Extended Data Fig. 1 Source Data Extended Data Fig. 2 Rights and permissions Reprints and Permissions About this article Verify currency and authenticity via CrossMark Cite this article Meinshausen, M., Lewis, J., McGlade, C. et al. Realization of Paris Agreement pledges may limit warming just below 2 degC. Nature 604, 304-309 (2022). https://doi.org/10.1038/s41586-022-04553-z Download citation * Received: 26 November 2021 * Accepted: 16 February 2022 * Published: 13 April 2022 * Issue Date: 14 April 2022 * DOI: https://doi.org/10.1038/s41586-022-04553-z Share this article Anyone you share the following link with will be able to read this content: Get shareable link Sorry, a shareable link is not currently available for this article. Copy to clipboard Provided by the Springer Nature SharedIt content-sharing initiative Comments By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate. Access through your institution Buy or subscribe Access through your institution Change institution Buy or subscribe Associated Content Net-zero commitments could limit warming to below 2 degC * Zeke Hausfather * Frances C. 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