ECS
ECS (Equilibrium climate sensitivity)
Refers to the equilibrium (steady-state) change in global average surface temperature that would result from a sustained doubling of the atmospheric carbon dioxide concentration.
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.