"It is likely (IPCC defines the word "likely" as 66% probability) that there has been significant anthropogenic warming over the past 50 years averaged over each continent"
"It is very likely (IPCC defines the "very likely" as 90% probability) that hot extremes, heat waves, and heavy rains will continue to become more frequent.
You can find it here
Now you have to remember that in developing their climate modals they use the weather data from the last 150 years to test the modals, if the model is a close match to the climate over the last 150 years, then they use the modal to predict the future. So what they are saying is that their models match the past with a 66% probability, but for some reason even though their confidence in the models is only 66% they are 90% confidante of the answer (future climate).
So in summary, what would you say if I showed you a mathematical formula and said to you that I'm 66% percent confident that the formula is accurate, and then proceeded to tell you that although I'm only 66% confident of the formulas accuracy, I'm 90% confident of the result are right. Would that make any sense?