Trying to explain the IPCC "Theory" ( which , in and of itself doesn’t "belong" to the IPCC , but is a synthesis of many years of scientific research by hundreds if not thousands of climate specialists )
If the IPCC were solely a scientific organization the scientists would write a report, hand it over to governments, and that would be the end of the matter. But that’s not what happens. After IPCC reports are finished, a series of meetings take place. Called plenaries, they are attended by some of the senior authors/scientists as well as by representatives of the world’s governments (again, these are often Environment Ministry people rather than normal diplomats).
During the plenaries, all the governments present must accept, adopt, and approve the IPCC reports (see the definitions on page 2 here). There must be unanimous agreement that the information these reports contain is true and correct. Why? Because, as I’ve previously reported, IPCC reports serve a dual purpose.
The public has been told these reports establish what is known about climate change. But they also pave the way for a political goal. Before a treaty mandating new measures to fight climate change can be negotiated it is necessary that all the world’s countries first “buy in” to a particular set of scientific conclusions.
For each of the IPCC’s three working groups, a Summary for Policymakers is drafted by IPCC scientists. But the wording of these documents is not considered final until the text has been unanimously agreed to at a plenary.
It is important to understand that the 2007 IPCC report is 3,000 pages long. The only documents that decision-makers such as legislators, policy wonks, and regulators (in addition to opinion-makers such as journalists) are ever likely to read therefore are these Summaries.
This means that the most influential IPCC documents are not scientific statements at all. Rather, they are the result of a messy, arduous process that pits scientists against politicians. They are the result of a process in which the integrity of the scientific message is wholly dependent on the ability of individual scientists to stand firm in the face of a political onslaught.
