False Analogy
Also: False Analogy
Logical Fallacy: False Analogy
Assuming that because two things are alike in some ways, they are alike in some other respect.
Graphics Resource page
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.