Science and policy characteristics of the Paris Agreement temperature goal

Journal name:
Nature Climate Change
Volume:
6,
Pages:
827–835
Year published:
DOI:
doi:10.1038/nclimate3096
Received
Accepted
Published online

Abstract

The Paris Agreement sets a long-term temperature goal of holding the global average temperature increase to well below 2 °C, and pursuing efforts to limit this to 1.5 °C above pre-industrial levels. Here, we present an overview of science and policy aspects related to this goal and analyse the implications for mitigation pathways. We show examples of discernible differences in impacts between 1.5 °C and 2 °C warming. At the same time, most available low emission scenarios at least temporarily exceed the 1.5 °C limit before 2100. The legacy of temperature overshoots and the feasibility of limiting warming to 1.5 °C, or below, thus become central elements of a post-Paris science agenda. The near-term mitigation targets set by countries for the 2020–2030 period are insufficient to secure the achievement of the temperature goal. An increase in mitigation ambition for this period will determine the Agreement's effectiveness in achieving its temperature goal.

At a glance

Figures

  1. Projected impacts at 1.5 [deg]C and 2 [deg]C GMT increase above pre-industrial levels for a selection of indicators and regions.
    Figure 1: Projected impacts at 1.5 °C and 2 °C GMT increase above pre-industrial levels for a selection of indicators and regions.

    a, Increase in global occurrence probability of pre-industrial 1-in-a-1000 day extreme temperature events17. b, Increase in extreme precipitation intensity (RX5Day) for the global land area below 66° N/S and South Asia21. c, Reduction in annual water availability in the Mediterranean21. d, Share of global tropical coral reefs at risk of long-term degradation37. e, Global sea-level rise commitment for persistent warming of 1.5 °C and 2 °C over 2000 years44. f, Changes in local crop yields for present-day tropical agricultural areas21 (below 30° N/S, model dependent implementation of present day management24). Dashed boxes: no increase in CO2 fertilization (No CO2). Panels b, c and f display median changes that are exceeded for over 50% of the respective land areas.

  2. GMT projections for emission scenarios assessed by the IPCC and UNEP.
    Figure 2: GMT projections for emission scenarios assessed by the IPCC54 and UNEP68.

    a, Probability of holding warming below 2 °C during the entire twenty-first century and below 1.5 °C by 2100 (allowing for overshoot any time before 2100, if probability by 2100 is at least 50%). b, Maximum median warming above 1.5 °C for scenarios that reach zero globally aggregated GHG emissions in the second half of the twenty-first century (horizontal axis). Empty (filled) circles indicate scenarios for which median warming returns below 1.5 °C before or by 2100 (after 2100). Scenarios have been extended beyond 2100 assuming constant 2100 emission levels. A list of all scenarios included in b is given in Supplementary Table 2.

  3. Absolute contribution of bioenergy to total primary energy supply in literature scenarios with below 3 [deg]C of warming relative to pre-industrial levels by 2100.
    Figure 3: Absolute contribution of bioenergy to total primary energy supply in literature scenarios with below 3 °C of warming relative to pre-industrial levels by 2100.

    a, Bioenergy contributions to primary energy in 2050 (black dots represent individual scenarios). Sustainable potentials highlighted in green and light green are based on ref. 63. b, As with a, but for the 2100 primary bioenergy contribution. A list of all scenarios included is given in Supplementary Table 2.

  4. Characteristics of below 2 [deg]C and 1.5 [deg]C pathways.
    Figure 4: Characteristics of below 2 °C and 1.5 °C pathways.

    a, Global emissions trajectories for likely below 2 °C warming scenarios70, and scenarios limiting warming to below 1.5 °C by the end of the century51, 68. Trajectories are based on integrated scenarios that simulate least-cost pathways for obtaining climate protection from 2020 onward. Current estimates of GHG levels implied by INDCs (orange, data from ref. 70) and current policies (purple, minimum–maximum range from ref. 99) by 2025 and 2030 are indicated. Differences in the historical emissions of both scenario sets are due to differences in the underlying models and arbitrary model sampling. b, Timing of globally aggregated emissions reaching zero for total Kyoto-GHG emissions, total CO2 emissions, and CO2 emissions from energy and industry, respectively. The colours of the ranges correspond to the scenarios shown in panel a. A list of all scenarios included is given in Supplementary Table 2.

References

  1. United Nations Framework Convention on Climate Change (UNFCCC, 1992).
  2. Knutti, R., Rogelj, J., Sedláček, J. & Fischer, E. M. A scientific critique of the two-degree climate change target. Nature Geosci. 9, 1318 (2015).
  3. Adoption of the Paris Agreement FCCC/CP/2015/10/Add.1 (UNFCCC, 2015).
  4. Hare, W. L., Cramer, W., Schaeffer, M., Battaglini, A. & Jaeger, C. C. Climate hotspots: key vulnerable regions, climate change and limits to warming. Reg. Environ. Change 11, 113 (2011).
  5. IPCC Climate Change 2001: Impacts, Adaptation, and Vulnerability (eds McCarthy, J. J., Canziani, O. F., Leary, N. A., Dokken, D. J. & White, K. S.) (Cambridge Univ. Press, 2001).
  6. Smith, J. B. et al. Assessing dangerous climate change through an update of the intergovernmental panel on climate change (IPCC) “reasons for concern”. Proc. Natl Acad. Sci. USA 106, 41334137 (2009).
  7. Oppenheimer, M. et al. in Climate Change: Impacts, Adaptation, and Vulnerability (eds Field, C. B. et al.) 10391099 (IPCC, Cambridge Univ. Press, 2014).
  8. IPCC Climate Change 2007: Synthesis Report (eds Pachauri, R. K. & Reisinger, A.) (Cambridge Univ. Press, 2007).
  9. Submissions from Parties FCCC/KP/AWG/2009/MISC.1/Add.1 (UNFCCC, 2009).
  10. The Copenhagen Accord FCCC/CP/2009/11/Add.1 (UNFCCC, 2009).
  11. The Cancun Agreements FCCC/CP/2010/7/Add.1 (UNFCCC, 2010).
  12. Report on the Structured Expert Dialogue on the 2013–2015 Review FCCC/SB/2015/INF.1 (UNFCCC, 2015).
  13. Seneviratne, S. I., Donat, M. G., Pitman, A. J., Knutti, R. & Wilby, R. L. Allowable CO2 emissions based on regional and impact-related climate targets. Nature 529, 477483 (2016).
  14. IPCC Climate Change 2013: The Physical Science Basis (eds Stocker, T. F. et al.) (Cambridge Univ. Press, 2013).
  15. IPCC Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (eds Field, C. B. et al.) (Cambridge Univ. Press, 2012).
  16. Seneviratne, S. I., Donat, M. G., Mueller, B. & Alexander, L. V. No pause in the increase of hot temperature extremes. Nature Clim. Change 4, 161163 (2014).
  17. Fischer, E. M. & Knutti, R. Anthropogenic contribution to global occurrence of heavy-precipitation and high-temperature extremes. Nature Clim. Change 5, 560564 (2015).
  18. Greve, P. et al. Global assessment of trends in wetting and drying over land. Nature Geosci. 7, 716721 (2014).
  19. Westra, S., Alexander, L. V. & Zwiers, F. W. Global increasing trends in annual maximum daily precipitation. J. Clim. 26, 39043918 (2013).
  20. Lehmann, J., Coumou, D. & Frieler, K. Increased record-breaking precipitation events under global warming. Climatic Change 132, 501515 (2015).
  21. Schleussner, C.-F. et al. Differential climate impacts for policy relevant limits to global warming: the case of 1.5 °C and 2 °C. Earth Syst. Dynam. 7, 327351 (2016).
  22. Sedláček, J. & Knutti, R. Half of the world's population experience robust changes in the water cycle for a 2 °C warmer world. Environ. Res. Lett. 9, 044008 (2014).
  23. Schewe, J. et al. Multimodel assessment of water scarcity under climate change. Proc. Natl Acad. Sci. USA 111, 32453250 (2014).
  24. Rosenzweig, C. et al. Assessing agricultural risks of climate change in the 21st century in a global gridded crop model intercomparison. Proc. Natl Acad. Sci. USA 111, 32683273 (2013).
  25. McGrath, J. M. & Lobell, D. B. Regional disparities in the CO2 fertilization effect and implications for crop yields. Environ. Res. Lett. 8, 014054 (2013).
  26. Tai, A. P. K., Martin, M. V. & Heald, C. L. Threat to future global food security from climate change and ozone air pollution. Nature Clim. Change 4, 817821 (2014).
  27. Challinor, A. J. et al. A meta-analysis of crop yield under climate change and adaptation. Nature Clim. Change 4, 287291 (2014).
  28. Elliott, J. et al. Constraints and potentials of future irrigation water availability on agricultural production under climate change. Proc. Natl Acad. Sci. USA 111, 32393244 (2013).
  29. Bodirsky, B. L. et al. Reactive nitrogen requirements to feed the world in 2050 and potential to mitigate nitrogen pollution. Nature Commun. 5, 3858 (2014).
  30. Deryng, D., Conway, D., Ramankutty, N., Price, J. & Warren, R. Global crop yield response to extreme heat stress under multiple climate change futures. Environ. Res. Lett. 9, 034011 (2014).
  31. Nelson, G. C. et al. Agriculture and climate change in global scenarios: why don't the models agree. Agric. Econ. 45, 85101 (2014).
  32. Lesk, C., Rowhani, P. & Ramankutty, N. Influence of extreme weather disasters on global crop production. Nature 529, 8487 (2016).
  33. Asseng, S. et al. Rising temperatures reduce global wheat production. Nature Clim. Change 5, 143147 (2015).
  34. Pörtner, H.-O. et al. in Climate Change 2014: Impacts, Adaptation, and Vulnerability (Field, C. B. et al.) Ch. 6 (IPCC, Cambridge Univ. Press, 2014).
  35. Gattuso, J.-P. et al. Contrasting futures for ocean and society from different anthropogenic CO2 emissions scenarios. Science 349, aac4722 (2015).
  36. Meissner, K. J., Lippmann, T. & Sen Gupta, A. Large-scale stress factors affecting coral reefs: open ocean sea surface temperature and surface seawater aragonite saturation over the next 400 years. Coral Reefs 31, 309319 (2012).
  37. Frieler, K. et al. Limiting global warming to 2 °C is unlikely to save most coral reefs. Nature Clim. Change 3, 165170 (2013).
  38. Hezel, P. J., Fichefet, T. & Massonnet, F. Modeled Arctic sea ice evolution through 2300 in CMIP5 extended RCPs. Cryosphere 8, 11951204 (2014).
  39. Burke, M., Hsiang, S. M. & Miguel, E. Global non-linear effect of temperature on economic production. Nature 527, 235239 (2015).
  40. Mathesius, S., Hofmann, M., Caldeira, K. & Schellnhuber, H. J. Long-term response of oceans to CO2 removal from the atmosphere. Nature Clim. Change 5, 11071113 (2015).
  41. Schewe, J., Levermann, A. & Meinshausen, M. Climate change under a scenario near 1.5 °C of global warming: monsoon intensification, ocean warming and steric sea level rise. Earth Syst. Dynam. 2, 2535 (2011).
  42. Clark, P. U. et al. Consequences of twenty-first-century policy for multi-millennial climate and sea-level change. Nature Clim. Change 6, 360369 (2016).
  43. Schneider von Deimling, T. et al. Estimating the near-surface permafrost-carbon feedback on global warming. Biogeosci. 9, 649665 (2012).
  44. Levermann, A. et al. The multimillennial sea-level commitment of global warming. Proc. Natl Acad. Sci. USA 110, 1374513750 (2013).
  45. Dutton, A. et al. Sea-level rise due to polar ice-sheet mass loss during past warm periods. Science 349, aaa4019 (2015).
  46. Mace, M. J. Mitigation commitments under the Paris Agreement and the way forward. Clim. Law 6, 2139 (2016).
  47. Decision IPCC/XLIII-7 (IPCC, 2016).
  48. Clarke, L. et al. in Climate Change 2014: Mitigation of Climate Change (Edenhofer, O. et al.) Ch. 6 (IPCC, Cambridge Univ. Press, 2014).
  49. IPCC Climate Change 2014: Synthesis Report (Cambridge Univ. Press, 2014).
  50. Mastrandrea, M. D. et al. The IPCC AR5 guidance note on consistent treatment of uncertainties: a common approach across the working groups. Climatic Change 108, 675691 (2011).
  51. Rogelj, J. et al. Energy system transformations for limiting end-of-century warming to below 1.5 °C. Nature Clim. Change 5, 519527 (2015).
  52. Statement of the CVF Chair at the UNFCCC COP21 Ministerial Dialogue on the Long-Term Goal (Climate Vulnerable Forum, 2015); http://go.nature.com/29DRiRy
  53. Rogelj, J. et al. Zero emission targets as long-term global goals for climate protection. Environ. Res. Lett. 10, 105007 (2015).
  54. IPCC Climate Change 2014: Mitigation of Climate Change (eds Edenhofer, O. et al.) (Cambridge Univ. Press, 2014)
  55. Rogelj, J. et al. Differences between carbon budget estimates unravelled. Nature Clim. Change 6, 245252 (2016).
  56. Meinshausen, M. et al. The RCP greenhouse gas concentrations and their extensions from 1765 to 2300. Climatic Change 109, 213241 (2011).
  57. Fuss, S. et al. Betting on negative emissions. Nature Clim. Change 4, 850853 (2014).
  58. Smith, P. et al. Biophysical and economic limits to negative CO2 emissions. Nature Clim. Change 6, 4250 (2015).
  59. Williamson, P. Scrutinize CO2 removal methods. Nature 530, 153155 (2016).
  60. Obersteiner, M. et al. Managing climate risk. Science 294, 786787 (2001).
  61. Kriegler, E. et al. The role of technology for achieving climate policy objectives: overview of the EMF 27 study on global technology and climate policy strategies. Climatic Change 123, 353367 (2014).
  62. Lobell, D. B. & Tebaldi, C. Getting caught with our plants down: the risks of a global crop yield slowdown from climate trends in the next two decades. Environ. Res. Lett. 9, 074003 (2014).
  63. Creutzig, F. et al. Bioenergy and climate change mitigation: an assessment. GCB Bioenergy 7, 916944 (2014).
  64. Smith, P. et al. in Climate Change 2014: Mitigation of Climate Change (Edenhofer, O. et al.) Ch. 11 (IPCC, Cambridge Univ Press, 2014).
  65. Havlik, P. et al. Global land-use implications of first and second generation biofuel targets. Energy Pol. 39, 56905702 (2011).
  66. Lotze-Campen, H. et al. Impacts of increased bioenergy demand on global food markets: an AgMIP economic model intercomparison. Agric. Econ. 45, 103116 (2014).
  67. Riahi, K. et al. Locked into Copenhagen Pledges — Implications of short-term emission targets for the cost and feasibility of long-term climate goals. Technol. Forecast. Soc. Change 90A, 823 (2013).
  68. The Emission Gap Report 2015: A UNEP Synthesis Report (UNEP, 2015).
  69. Rogelj, J., McCollum, D. L., O'Neill, B. C. & Riahi, K. 2020 emissions levels required to limit warming to below 2 °C. Nature Clim. Change 3, 405412 (2013).
  70. Synthesis Report on the Aggregate Effect of the Intended Nationally Determined Contributions FCCC/CP/2015/7 (UNFCCC, 2015).
  71. Rogelj, J. et al. Paris Agreement climate proposals need a boost to keep warming well below 2 °C. Nature 534, 631639 (2016).
  72. Jaeger, C. C. & Jaeger, J. Three views of two degrees. Reg. Environ. Chang. 11, 1526 (2011).
  73. Schellnhuber, H. J. Rahmstorf, S. & Winkelmann, R. Why the right climate target was agreed in Paris. Nature Clim. Change 6, 649653 (2016).
  74. Rogelj, J. & Knutti, R. Geosciences after Paris. Nature Geosci. 9, 187189 (2016).
  75. Mitchell, D. et al. Realizing the impacts of a 1.5 °C warmer world. Nature Clim. Change 6, 735737 (2016).
  76. James, R. & Washington, R. Changes in African temperature and precipitation associated with degrees of global warming. Climatic Change 117, 859872 (2013).
  77. Hallegatte, S. et al. Mapping the climate change challenge. Nature Clim. Change 6, 663668 (2016).
  78. Chadwick, R. & Good, P. Understanding nonlinear tropical precipitation responses to CO2 forcing. Geophys. Res. Lett. 40, 49114915 (2013).
  79. Hawkins, E., Joshi, M. & Frame, D. Wetter then drier in some tropical areas. Nature Clim. Change 4, 646647 (2014).
  80. Bouttes, N., Gregory, J. M. & Lowe, J. A. The reversibility of sea level rise. J. Clim. 26, 25022513 (2013).
  81. Schleussner, C.-F., Levermann, A. & Meinshausen, M. Probabilistic projections of the Atlantic overturning. Climatic Change 127, 579586 (2014).
  82. Drijfhout, S. et al. Catalogue of abrupt shifts in Intergovernmental Panel on Climate Change climate models. Proc. Natl Acad. Sci. USA 112, 43 (2015).
  83. Joughin, I., Smith, B. E. & Medley, B. Marine ice sheet collapse potentially underway for the Thwaites Glacier Basin, West Antarctica. Science 344, 735738 (2014).
  84. Rignot, E., Mouginot, J., Morlighem, M., Seroussi, H. & Scheuchl, B. Widespread, rapid grounding line retreat of Pine Island, Thwaites, Smith and Kohler glaciers, West Antarctica from 1992 to 2011. Geophys. Res. Lett. 41, 35023509 (2014).
  85. Favier, L. et al. Retreat of Pine Island Glacier controlled by marine ice-sheet instability. Nature Clim. Change 4, 117121 (2014).
  86. Feldmann, J. & Levermann, A. Collapse of the West Antarctic Ice Sheet after local destabilization of the Amundsen Basin. Proc. Natl Acad. Sci. USA 112, 1419114196 (2015).
  87. Mengel, M. & Levermann, A. Ice plug prevents irreversible discharge from East Antarctica. Nature Clim. Change 4, 451455 (2014).
  88. Spence, P. et al. Rapid subsurface warming and circulation changes of Antarctic coastal waters by poleward shifting winds. Geophys. Res. Lett. 41, 46014610 (2014).
  89. Hellmer, H. H., Kauker, F., Timmermann, R., Determann, J. & Rae, J. Twenty-first-century warming of a large Antarctic ice-shelf cavity by a redirected coastal current. Nature 485, 225228 (2012).
  90. Vuuren, D. P. et al. A new scenario framework for climate change research: scenario matrix architecture. Climatic Change 122, 373386 (2014).
  91. Steffen, W. et al. Planetary boundaries: guiding human development on a changing planet. Science 347, 1259855 (2015).
  92. Lomax, G., Lenton, T. M., Adeosun, A. & Workman, M. Investing in negative emissions. Nature Clim. Change 5, 498500 (2015).
  93. Meinshausen, M. et al. National post-2020 greenhouse gas targets and diversity-aware leadership. Nature Clim. Change 5, 10981106 (2015).
  94. Edenhofer, O. King Coal and the queen of subsidies. Science 349, 12861287 (2015).
  95. The Coal Gap: Planned Coal-Fired Power Plants Inconsistent with 2 °C and Threaten Achievement of INDCs (Climate Action Tracker, 2015).
  96. Lelieveld, J., Evans, J. S., Fnais, M., Giannadaki, D. & Pozzer, A. The contribution of outdoor air pollution sources to premature mortality on a global scale. Nature 525, 36771 (2015).
  97. Rogelj, J. et al. Air-pollution emission ranges consistent with the representative concentration pathways. Nature Clim. Change 4, 245252 (2014).
  98. Hulme, M. 1.5 °C and climate research after the Paris Agreement. Nature Clim. Change 6, 222224 (2016).
  99. INDCs Lower Projected Warming to 2.7 °C: Significant Progress But Still Above 2 °C (Climate Action Tracker, 2015).

Download references

Author information

Affiliations

  1. Climate Analytics, 10969 Berlin, Germany

    • Carl-Friedrich Schleussner,
    • Michiel Schaeffer,
    • Tabea Lissner &
    • William Hare
  2. Potsdam Institute for Climate Impact Research, 14473 Potsdam, Germany

    • Carl-Friedrich Schleussner,
    • Tabea Lissner,
    • Anders Levermann,
    • Katja Frieler &
    • William Hare
  3. Energy Program, International Institute for Applied Systems Analysis, 2361 Laxenburg, Austria

    • Joeri Rogelj
  4. Institute for Atmospheric and Climate Science, ETH Zurich, 8092 Zürich, Switzerland

    • Joeri Rogelj,
    • Erich M. Fischer &
    • Reto Knutti
  5. Environmental Systems Analysis Group, Wageningen University and Research Centre, 6708 PB Wageningen, the Netherlands

    • Michiel Schaeffer
  6. Woodrow Wilson School of Public and International Affairs, Princeton University, Princeton, New Jersey 08544, USA

    • Rachel Licker
  7. Institute of Physics and Astronomy, University of Potsdam, 14476 Potsdam, Germany

    • Anders Levermann
  8. Lamont-Doherty Earth Observatory, Columbia University, New York 10964-1000, USA

    • Anders Levermann

Contributions

C.F.S, J.R., M.S. and W.H. led the writing of the paper with significant contributions from all authors. C.F.S, J.R., M.S. and W.H. designed the manuscript structure and content. C.F.S., J.R. and M.S. carried out the analysis presented and produced the figures.

Competing financial interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to:

Author details

Supplementary information

PDF files

  1. Supplementary Information (266 KB)

    Supplementary Information

Additional data