Actually, that's not what it says. Well, it is, but that's if you believe the conservative paper and not the article it references. In the paper by Professor Hulme, he states "That particular consensus judgement, as are many others in the IPCC reports, is reached by only a few dozen experts in the specific field of detection and attribution studies; other IPCC authors are experts in other fields.". In other words, a few dozen experts that actually study the specific field of detection and attribution came to that conclusion, but the other hundreds of climatologists and other scientists who specialize in other fields still agree.