The IPCC's landmark assessment reports have expressed increasing certainty about climate change impact
change in the approximate times each phrase was used per 10,000 words, in the 2001 and 2021 reports:
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
50.0
55.0
60.0
high confidence
medium confidence
likely
very likely
very high confidence
virtually certain
low confidence
extremely likely
very/exceptionally/extremely unlikely
unlikely
about as likely as not
2001|
2021|
