The IPCC’s working groups talk about scientific uncertainty in a different way, the report by the InterAcademy Council found. How confidence on particular uncertainty – namely about climate adaptation and vulnerability – is handled is also not quite right, it says.

“By making vague statements that were difficult to refute, authors were able to attach ‘high confidence’ to the statements,” the report says, adding that such statements are “not supported sufficiently in the literature, not put into perspective, or not expressed clearly.”

IPCC reports should be consistent in their expression of issues and use a “level of understanding scale” that describes the amount of evidence available and the degree of agreement among experts, the report says.