This isn't an issue I care much about, so I hope you won't mind a quick treatment. The 5-second version is that more is on the line for the researchers personally with climate change research than other sorts of science, that scientific reports have consequences for politics which forces the scientists to be more involved in politics than other sorts of scientists, and that this corroding influence of politics adds friction to the processes that pump errors out of science. Here's an incomplete list with more details:

The most visible one is media pressure, which rewards more shocking possibilities. (Did you ever hear about clathrate gun hypothesis? Did you hear that further research didn't pan out?) In most other fields, the media rarely if ever comes calling, and so more of the incentives come from other researchers. (I remember a historian, who was called up because Sarah Palin had made a correct but non-obvious comment about Paul Revere, who pointed out that he had never been interviewed until Palin had mentioned Revere.)

Relatedly, the funding and visibility of climatology depends in large part on how much people care about climatology. This is true for many fields- NASA seems to find asteroids whose paths take them close to Earth whenever Congress debates NASA's funding- but seems particularly true for climatology.

There is also a lot of money and influence going against climate change research. The decision to not fly DSCOVR, for example, was almost certainly political and did significant harm to our understanding of the climate and its dynamics. There are claims of data suppression during the Bush era which are harder to evaluate, but are suggestive of politicization of research.

The existence of climate deniers acting in bad faith poisons the well for normal scientific bug-checking. The Lenski affair happened in evolution, but the same sort of dynamic can show up between climatologists and skeptics. There is no social benefit in providing data to people acting in bad faith, and so it's easier to just not give them your data, even though people acting in bad faith can identify scientific errors that you would need to correct. But this prevents normal criticism from taking place, and (as a general human tendency) scientists are more likely to see others as acting in bad faith if their work is being criticized. (This is pretty neatly captured by Climategate. Most critics stupidly focused on things that were benign- like the phrase "trick"- while the emails included evidence of data withholding and stonewalling, which are not benign.)