c104.
The IPCC explains its strict definitions of terms such as “unlikely”, “very likely” and “virtually certain” at www.ipcc.ch/publications_and_data/ar4/wg1/en/ch1s1-6.html (see box 1.1). “Very likely” means a likelihood of more than 90%. For more on the strengths and limitations of the IPCC reports, see Shaun Chamberlin (2009), The Transition Timeline, chapter 18: “Climate Change—The IPCC”.