Some people complain that the IPCC is intransparent. David Holland is a good example. Such sentiments are often expressed with a suggestion that this is because the IPCC is arrogant or malign. There is a third explanation: The IPCC has not quite woken up to this internet thingy.
One example is the IPCC policy to keep draft assessment reports under wraps and release them with a big bang. That was never possible. I recall excited journalists waving faxed copies of draft pages of AR2. Technology has moved on. The 0th order draft of AR5 will soon be available in its entirety on the internet. The problem with the IPCC policy is that stimulates uncontrolled leaks. The first rule of PR is to keep control over the message.
I think that the IPCC has stuck to its policy because the Bureau is full of people who are not particularly internet savvy.
The same seems to be true of IPCC authors. Search engines, reference management software, and document management software are science fiction to some of my colleagues. That affects transparency. If properly managed, you can release the entire history of a document with a few clicks of a mouse. If your documents are not properly managed, you'd be hard-pressed to do that. It also affects quality. Without a search engine, you quote the papers you know -- and the papers you know are by the people you know. With a search engine, you cite all papers -- not necessarily unbiased, but at least comprehensive.