Long-term climate implications of twenty-first century options for carbon dioxide emission mitigation

ABSTRACT Long-term future warming is primarily constrained by cumulative emissions of carbon dioxide1,2,3,4. Previous studies have estimated that humankind has already emitted about 50% of

the total amount allowed if warming, relative to pre-industrial, is to stay below 2 °C (refs 1, 2). Carbon dioxide emissions will thus need to decrease substantially in the future if this

target is to be met. Here we show how links between near-term decisions, long-term behaviour and climate sensitivity uncertainties constrain options for emissions mitigation. Using a model

of intermediate complexity5,6, we explore the implications of non-zero long-term global emissions, combined with various near-term mitigation rates or delays in action. For a median climate

sensitivity, a long-term 90% emission reduction relative to the present-day level is incompatible with a 2 °C target within the coming millennium. Zero or negative emissions can be

compatible with the target if medium to high emission-reduction rates begin within the next two decades. For a high climate sensitivity, however, even negative emissions would require a

global mitigation rate at least as great as the highest rate considered feasible by economic models7,8 to be implemented within the coming decade. Only a low climate sensitivity would allow

for a longer delay in mitigation action and a more conservative mitigation rate, and would still require at least 90% phase-out of emissions thereafter. Access through your institution Buy

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OTHERS NEAR-TERM TRANSITION AND LONGER-TERM PHYSICAL CLIMATE RISKS OF GREENHOUSE GAS EMISSIONS PATHWAYS Article 13 December 2021 PATH TO NET ZERO IS CRITICAL TO CLIMATE OUTCOME Article Open

access 12 November 2021 OPPORTUNITIES AND CHALLENGES IN USING REMAINING CARBON BUDGETS TO GUIDE CLIMATE POLICY Article 30 November 2020 REFERENCES * Allen, M. et al. Warming caused by

cumulative carbon emissions towards the trillionth tonne. _Nature_ 458, 1163–1166 (2009). Article  CAS  Google Scholar  * Zickfeld, K., Eby, M., Matthews, H. D. & Weaver, A. J. Setting

cumulative emissions targets to reduce the risk of dangerous climate change. _Proc. Natl Acad. Sci. USA_ 106, 16129–16134 (2010). Article  Google Scholar  * Matthews, H. D., Gillett, N. P.,

Stott, P. A. & Zickfeld, K. The proportionality of global warming to cumulative carbon emissions. _Nature_ 459, 829–832 (2009). Article  CAS  Google Scholar  * Raupach, M. R. et al. The

relationship between peak warming and cumulative CO2 emissions, and its use to quantify vulnerabilities in the carbon-climate-human system. _Tellus B_ 63, 145–164 (2011). Article  CAS 

Google Scholar  * Stocker, T. F., Wright, D. G. & Mysak, L. A. A zonally averaged, coupled ocean-atmosphere model for paleoclimate studies. _J. Clim._ 5, 773–797 (1992). Article  Google

Scholar  * Joos, F., Plattner, G-K., Stocker, T. F., Marchal, O. & Schmittner, A. Global warming and marine carbon cycle feedbacks on future atmospheric CO2 . _Science_ 284, 464–467

(1999). Article  CAS  Google Scholar  * UNEP _The Emissions Gap Report: Are the Copenhagen Accord Pledges Sufficient to Limit Global Warming to_ 2 °_C_ _or_ 1.5 °_C_? (UNEP, 2010); available

at http://www.unep.org/publications/ebooks/emissionsgapreport/. * den Elzen, M. G. J., van Vuuren, D. P. & van Vliet, J. Postponing emission reductions from 2020 to 2030 increases

climate risks and long-term costs. _Climatic Change_ 99, 313–320 (2010). Article  Google Scholar  * UNFCCC, _Communications Received from Parties in Relation to the Listing in the Chapeau of

the Copenhagen Accord_ (UNFCCC, 2010); available at http://unfccc.int/meetings/cop_15/copenhagen_accord/items/5276.php. * Friedlingstein, P. et al. Update on CO2 emissions. _Nature Geosci._

3, 811–812 (2010). Article  CAS  Google Scholar  * Hegerl, G. C. et al. in _IPCC Climate Change 2007: The Physical Science Basis_ (eds Solomon, S. et al.) 663–745 (Cambridge Univ. Press,

2007). Google Scholar  * Hourcade, J-C. & Crassous, R. Low-carbon societies: A challenging transition for an attractive future. _Clim. Policy_ 8, 607–612 (2008). Article  Google Scholar

  * Van Vuuren, D. P. et al. Stabilizing greenhouse gas concentrations at low levels: An assessment of reduction strategies and costs. _Climatic Change_ 81, 119–159 (2007). Article  Google

Scholar  * Van Vuuren, D. P., Bellevrat, E., Kitous, A. & Isaac, M. Bio-energy use and low stabilization scenarios. _Energy J._ 31, 193–222 (2010). Google Scholar  * Van Vuuren, D. P. et

al. RCP2.6: Exploring the possibility to keep global mean temperature change below 2 °C. _Climatic Change_ 109, 95–116 (2011). Article  Google Scholar  * Edenhofer, O. et al. The economics

of low stabilization: Model comparison of mitigation strategies and costs. _Energy J._ 31, 11–48 (2010). Google Scholar  * Clarke, L. et al. International climate policy architectures:

Overview of the EMF 22 international scenarios. _Energy Econ._ 31, S64–S81 (2009). Article  Google Scholar  * Edmonds, J., Clarke, L., Lurz, J. & Wise, M. Stabilizing CO2 concentrations

with incomplete international cooperation. _Clim. Policy_ 8, 355–376 (2008). Article  Google Scholar  * Richels, R., Blanford, G. J. & Rutherford, T. F. International climate policy: A

‘second best’ solution for a ‘second best’ world? _Climatic Change_ 97, 289–296 (2009). Article  Google Scholar  * Davis, S. J., Caldeira, K. & Matthews, H. D. Future CO2 emissions and

climate change from existing energy infrastructure. _Science_ 329, 1330–1333 (2010). Article  CAS  Google Scholar  * Bosetti, V., Carraro, C. & Tavoni, M. Climate change mitigation

strategies in fast-growing countries: The benefits of early action. _Energy Econ._ 31, S144–S151 (2009). Article  Google Scholar  * Weaver, A. J., Zickfeld, K., Montenegro, A. & Eby, M.

Long term climate implications of 2050 emission reduction targets. _Geophys. Res. Lett._ 34, L19703 (2007). Article  Google Scholar  * Meehl, G. A. et al. in _IPCC Climate Change 2007: The

Physical Science Basis_ (eds Solomon, S. et al.) 747–845 (Cambridge Univ. Press, 2007). Google Scholar  * Solomon, S., Plattner, G-K., Knutti, R. & Friedlingstein, P. Irreversible

climate change due to carbon dioxide emissions. _Proc. Natl Acad. Sci. USA_ 106, 1074–1079 (2009). Article  Google Scholar  * Solomon, et al. Persistence of climate changes due to a range of

greenhouse gases. _Proc. Natl Acad. Sci. USA_ 107, 18354–18359 (2010). Article  CAS  Google Scholar  * Knutti, R. & Hegerl, G. C. The equilibrium sensitivity of the Earth’s temperature

to radiation changes. _Nature Geosci._ 1, 735–743 (2008). Article  CAS  Google Scholar  * Lunt, D. J. et al. Earth system sensitivity inferred from Pliocene modeling and data. _Nature

Geosci._ 3, 60–64 (2010). Article  CAS  Google Scholar  * Marchal, O., Stocker, T. F. & Joos, F. A latitude-depth circulation-biogeochemical ocean model for paleoclimate studies. Model

development and sensitivity. _Tellus B_ 50, 290–316 (1998). Article  Google Scholar  * Siegenthaler, U. & Oeschger, H. Biospheric CO2 emissions during the past 200 years reconstructed by

convolution of ice core data. _Tellus B_ 39, 140–154 (1987). Article  Google Scholar  * Archer, D. Fate of fossil fuel CO2 in geologic time. _J. Geophys. Res._ 110, C09S05 (2005). Article 

Google Scholar  * Friedlingstein, P. et al. Climate-carbon cycle feedback analysis: Results from the C4MIP model intercomparison. _J. Clim._ 19, 3337–3353 (2006). Article  Google Scholar  *

Gregory, J. M., Jones, C. D., Cadule, P. & Friedlingstein, P. Quantifying carbon cycle feedbacks. _J. Clim._ 22, 5232–5250 (2009). Article  Google Scholar  * Knutti, R., Stocker, T. F.,

Joos, F. & Plattner, G-K. Probabilistic climate change projections using neural networks. _Clim. Dyn._ 21, 257–272 (2003). Article  Google Scholar  Download references ACKNOWLEDGEMENTS

The authors wish to thank D. Matthews, J. Daniel and T. Sanford for helpful discussions and R. Flecker for creating Fig. 3. AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * College of

Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF, UK P. Friedlingstein * Department of Atmospheric and Oceanic Sciences, University of Colorado, Boulder,

Colorado 80309, USA S. Solomon * Climate and Environmental Physics, Physics Institute, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland G-K. Plattner * Institute for Atmospheric

and Climate Science, ETH Zurich, Universitätstrasse 16, CH-8092 Zürich, Switzerland R. Knutti * Laboratoire des Sciences du Climat et de l’Environment, UMR CEA-CNRS-UVSQ, Bat. 709, CE,

L’Orme des Merisiers, 91191 Gif-sur-Yvette, France P. Ciais * CSIRO Marine and Atmospheric Research, Clunies Ross Street, Black Mountain, Acton, Australian Capital Territory 2601, Australia

M. R. Raupach Authors * P. Friedlingstein View author publications You can also search for this author inPubMed Google Scholar * S. Solomon View author publications You can also search for

this author inPubMed Google Scholar * G-K. Plattner View author publications You can also search for this author inPubMed Google Scholar * R. Knutti View author publications You can also

search for this author inPubMed Google Scholar * P. Ciais View author publications You can also search for this author inPubMed Google Scholar * M. R. Raupach View author publications You

can also search for this author inPubMed Google Scholar CONTRIBUTIONS P.F. and S.S. designed the work and the experiments, P.F. performed the model simulations, G-K.P. provided the model

code, G-K.P. and R.K. gave guidance on the use of the model, P.F. led the writing of the paper with contributions from all other authors. CORRESPONDING AUTHOR Correspondence to P.

Friedlingstein. ETHICS DECLARATIONS COMPETING INTERESTS The authors declare no competing financial interests. SUPPLEMENTARY INFORMATION SUPPLEMENTARY INFORMATION (PDF 733 KB) RIGHTS AND

PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Friedlingstein, P., Solomon, S., Plattner, GK. _et al._ Long-term climate implications of twenty-first century

options for carbon dioxide emission mitigation. _Nature Clim Change_ 1, 457–461 (2011). https://doi.org/10.1038/nclimate1302 Download citation * Received: 20 May 2011 * Accepted: 31 October

2011 * Published: 20 November 2011 * Issue Date: December 2011 * DOI: https://doi.org/10.1038/nclimate1302 SHARE THIS ARTICLE Anyone you share the following link with will be able to read

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