Knutti & Hegerl (2008)
Also: Knutti & Hegerl 2008
The equilibrium sensitivity of the Earth's temperature to radiation changes
Knutti, R., & Hegerl, G. C. (2008). The equilibrium sensitivity of the Earth's temperature to radiation changes. Nature Geoscience, 1(11), 735-743. Link to paper
DOI: https://doi.org/10.1038/ngeo337
References
All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.