The IPCC does not do its own scientific research. They review all the research on the subject that is being published and make current scientific consensus accessible to the public.
The greenhouse effect is a scientific fact and well known for over 150 years (Joseph Fourier, 1824). The increase of the greenhouse effect from combustion of fossil fuels (the Callendar effect) is somewhat newer (Svante Arrhenius 1896), but no longer disputed by serious scientists either. The questions now are "how much warmer" and "what are the consequences".
The idea that the leading scientists of the world are corrupt and just go for the easiest money, while industry and money men are honest and responsible is absolutely preposterous.
One of the greatest achievements in science is to prove your most respected colleagues wrong. If you publish a mistake, your mistake will be gleefully, repeatedly, dissected in public. If you're caught cheating, your career is dead. Such a conspiracy is impossible.
When you try to find out whether you can trust someone, you should review their track record. Here are some historical facts for you:
The Romans knew that asbestos was dangerous. Scientists warned of exceptionally short life expectancies for asbestos workers in the 1880ies. As the decennia went by, more and more scientific evidence piled up: The link between asbestos and lung fibrosis was established in the 1920ies in the UK (Nellie Kershaw). Asbestos causes cancer, asbestos causes illness also in family members of the workers, people living in the vicinity of asbestos factories also die early, even occasional contact with asbestos is dangerous, there seems to be no lower limit to what constitutes dangerous exposure... Even today, in spite of massive scientific evidence of the consequences of asbestos exposure, only 60 countries have banned its use, mostly during the nineties and early 2000s. Canada has banned use of the stuff, but still happily exports it to poor countries. They even tried to force it upon the French by demanding that the WTO overturn their ban, arguing that their chrysotile was less dangerous than previously thought, even though 95% of asbestos used in the USA was chrysotile. Tens of millions have died from asbestos, tens of millions more will, even though safe and better alternatives exist. The first industry to act upon the dangers of asbestos was the insurance business - by denying their product to asbestos workers.
Lead has been known to be extremely poisonous since ancient times. Most European countries banned white lead early in the 20th century, because it regularly poisoned painters and children. Even so, GM and Standard Oil got the go-ahead, against dire warnings from the scientific community, to add tetraethyl lead to gasoline to avoid knocking. All the way up until the ban was introduced, the automotive and oil industries insisted that lead was safe up to concentrations of 50 micrograms per liter of blood. As it turned out, this was based on thin air. Average blood lead in the American population eventually rose to almost 20 micrograms/l. The fact is that there is no safe level, and blood levels of 7 micrograms/l have measurable impact on mental health and abilities. The average American was suffering from chronic lead poisoning for decades because it was cheaper for the automotive industry to continue using lead, rather than build engines that didn't need it.
It's the same story with DDT, PCB, acid rain and the ozone hole. The arguments and tactics against reform are always the same: Overlook all signs of danger, conceal what you know from the public, deny all links and responsibility and throw up as much FUD as possible. We don't know for sure that it's dangerous, there's no alternative, and besides, you're a bunch of hysterical treehuggers anyway. When forced to, they always come up with a solution right away.
In every one of these cases, science and the environmental movement were right, the industry was wrong, often criminally so, and politicians were completely disinterested until public outrage was imminent.
Why would anybody trust these people?
