Publication Abstracts

Hansen et al. 2023

Hansen, J.E., M. Sato, L. Simons, L.S. Nazarenko, I. Sangha, P. Kharecha, J.C. Zachos, K. von Schuckmann, N.G. Loeb, M.B. Osman, Q. Jin, G. Tselioudis, E. Jeong, A. Lacis, R. Ruedy, G. Russell, J. Cao, and J. Li, 2023: Global warming in the pipeline. Oxford Open Clim. Change, 3, no. 1, kgad008, doi:10.1093/oxfclm/kgad008.

Improved knowledge of glacial-to-interglacial global temperature change yields Charney (fast-feedback) equilibrium climate sensitivity 1.2±0.3°C (2σ) per W/m2, which is 4.8°C±1.2°C for doubled CO2. Consistent analysis of temperature over the full Cenozoic era — including 'slow' feedbacks by ice sheets and trace gases — supports this sensitivity and implies that CO2 was 300-350 ppm in the Pliocene and about 450 ppm at transition to a nearly ice-free planet, exposing unrealistic lethargy of ice sheet models. Equilibrium global warming for today's GHG amount is 10°C, which is reduced to 8°C by today's human-made aerosols. Equilibrium warming is not 'committed' warming; rapid phaseout of GHG emissions would prevent most equilibrium warming from occurring. However, decline of aerosol emissions since 2010 should increase the 1970-2010 global warming rate of 0.18°C per decade to a post-2010 rate of at least 0.27°C per decade. Thus, under the present geopolitical approach to GHG emissions, global warming will exceed 1.5°C in the 2020s and 2°C before 2050. Impacts on people and nature will accelerate as global warming increases hydrologic (weather) extremes. The enormity of consequences demands a return to Holocene-level global temperature. Required actions include: (1) a global increasing price on GHG emissions accompanied by development of abundant, affordable, dispatchable clean energy, (2) East-West cooperation in a way that accommodates developing world needs, and (3) intervention with Earth's radiation imbalance to phase down today's massive human-made 'geo-transformation' of Earth's climate. Current political crises present an opportunity for reset, especially if young people can grasp their situation.

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BibTeX Citation

@article{ha09020b,
  author={Hansen, J. E. and Sato, M. and Simons, L. and Nazarenko, L. S. and Sangha, I. and Kharecha, P. and Zachos, J. C. and von Schuckmann, K. and Loeb, N. G. and Osman, M. B. and Jin, Q. and Tselioudis, G. and Jeong, E. and Lacis, A. and Ruedy, R. and Russell, G. and Cao, J. and Li, J.},
  title={Global warming in the pipeline},
  year={2023},
  journal={Oxford Open Climate Change},
  volume={3},
  number={1},
  pages={kgad008},
  doi={10.1093/oxfclm/kgad008},
}

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RIS Citation

TY  - JOUR
ID  - ha09020b
AU  - Hansen, J. E.
AU  - Sato, M.
AU  - Simons, L.
AU  - Nazarenko, L. S.
AU  - Sangha, I.
AU  - Kharecha, P.
AU  - Zachos, J. C.
AU  - von Schuckmann, K.
AU  - Loeb, N. G.
AU  - Osman, M. B.
AU  - Jin, Q.
AU  - Tselioudis, G.
AU  - Jeong, E.
AU  - Lacis, A.
AU  - Ruedy, R.
AU  - Russell, G.
AU  - Cao, J.
AU  - Li, J.
PY  - 2023
TI  - Global warming in the pipeline
JA  - Oxford Open Clim. Change
JO  - Oxford Open Climate Change
VL  - 3
IS  - 1
SP  - kgad008
DO  - 10.1093/oxfclm/kgad008
ER  -

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