Template:AR6 SSP table
| SSP | Scenario |
Estimated warming (2041–2060) |
Estimated warming (2081–2100) |
Very likely range in °C (2081–2100) |
|---|---|---|---|---|
| SSP1-1.9 | very low GHG emissions: CO2 emissions cut to net zero around 2050 |
1.6 °C | 1.4 °C | 1.0 – 1.8 |
| SSP1-2.6 | low GHG emissions: CO2 emissions cut to net zero around 2075 |
1.7 °C | 1.8 °C | 1.3 – 2.4 |
| SSP2-4.5 | intermediate GHG emissions: CO2 emissions around current levels until 2050, then falling but not reaching net zero by 2100 |
2.0 °C | 2.7 °C | 2.1 – 3.5 |
| SSP3-7.0 | high GHG emissions: CO2 emissions double by 2100 |
2.1 °C | 3.6 °C | 2.8 – 4.6 |
| SSP5-8.5 | very high GHG emissions: CO2 emissions triple by 2075 |
2.4 °C | 4.4 °C | 3.3 – 5.7 |
The IPCC Sixth report did not estimate the likelihoods of the scenarios.[1]: 12
In 2020, a commentary described SSP5–8.5 as highly unlikely, SSP3–7.0 as unlikely, and SSP2–4.5 as likely.[2]
In January 2025, a revised assessment by Hausfather estimated median warming under current policies at about 2.7 °C by 2100, with the 5th–95th percentile of central estimates spanning 2.3–3.0 °C; including emissions and climate-system uncertainties widens the range to roughly 1.9–3.7 °C. The paper also states that current-policy emissions pathways tend to align most closely with, or fall slightly below, SSP2-4.5 rather than SSP3-7.0.[3]
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- ↑ 1.0 1.1 IPCC, 2021: Summary for Policymakers. In: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 3−32, doi:10.1017/9781009157896.001.
- ↑ Hausfather, Zeke; Peters, Glen P. (2020-01-29). "Emissions – the 'business as usual' story is misleading". Nature. 577 (618–620): 618–620. Bibcode:2020Natur.577..618H. doi:10.1038/d41586-020-00177-3. PMID 31996825. S2CID 256819346. Retrieved 2021-09-03.
- ↑ Zeke Hausfather, “An assessment of current policy scenarios over the 21st century and the reduced plausibility of high-emissions pathways,” Dialogues on Climate Change, January 13, 2025, https://doi.org/10.1177/29768659241304854.