Let's say I ask a scientist to give me a report on human saliva. In the report, the scientist says that saliva is swallowed by humans in small amounts. Now, let's say I ask another scientist for a report on how many people swallow saliva in small amounts, and I get a report back saying "all of them". Now, let's say I ask a third scientist about human mortality rates, and he reports that all people eventually die.
With much fanfare, I issue a report saying that swallowing saliva in small amounts over a long period of time leads to death in 100% of the cases, and list the three scientists as contributors to the report. One of the scientists demands in no uncertain terms that his name be taken off the report on the grounds that the information he supplied in no way supports the conclusions in my report. The other two scientists are funded by the spittoon manufacturing lobby, and don't object.
This, in essence, is what we have in the UN's Intergovernmental Panel on Climate Change report.