Actually I have figured out what this means
To gain this degree of certainty, the report was compiled according to a ‘consensus’-based model which posed some problems for evaluating the contribution of human-caused climate change to phenomena such as tropical cyclones, where data gaps appear before the middle of the last century.It means, simply stated They didn't know what to think because nothing made any sense, so they voted on how to fudge the numbers to try and prove their theory.