Comments on the cited IPCC
Some additional notes on the IPCC as a single source
As mentioned, a lot on this site is seemingly based on a single source (the IPCC's reports), which might make the whole reasoning obsolete, in case it turns out the source is not credible.
However, the IPCC as mentioned does not do studies, it assesses existing research and standpoints. That means it evaluates (much) more than just one source. According to their website, "hundreds of scientists all over the world contribute to the work of the IPCC as authors, contributors and reviewers". Being part of the UN, the IPCCs reports can be considered - to put it a bit dramatic - the "mouthpiece of mankind's science" (uhhh ...).
Now you can certainly find opinions which question if this organization is credible at all. E.g. Prof. Richard Lindzen is often cited in this context. He claims that there is a hype only and "no 'consensus' on global warming" at all.
Also, as with every disputed topic, it is easily possible to find single contradictory opinions. They e.g. refer to global warming as "not an observable phenomenon" . Note they are mostly just that: single opinions, not a consensus.
If these opinions and the people behind are correct, why didn't they participate in the IPCC's procedure to form a common standpoint? Why couldn't they convince more scientists of their opinion?
In fact, the above mentioned professor did participate in IPCC reports! This means he had been heard, he had a chance to make his point and his opinion went into the discussions. However he could not get the others to (largly) agree. Why?
How much more certainty do we need?
I don't advocate to blindly follow an opinion given from an organization with a somewhat respected name. Skepticism is sure required, but i.m.o. (with limited time and means available) there is enough evidence that there is no "conspiracy" behind the IPCC, as some sites suggest.
Actually, if you do some more research, you can even find the almost opposite is true! It turns out that the above mentioned R. Lindzen seems to be on the payroll of the well known oil company Exxon Mobil - along with some other interesting personal details . That does not only tell something about R. Lindzen, but also the oil companies. See the "exxonsecrets.org" main site as well. As comparison, this instantly brings to mind the efforts of the tobacco industry trying to play down health risks of smoking. Or likewise, the efforts of chemical industry against DDT bans.
On my part: if it turns out the IPCC was completely wrong, I could as well distrust anyone else making any statements on this topic. So be it. I will take this page off the site then :-)
I consider it a fair assumption that both sides - supporters and sceptics - had been heard and all opinions were balanced, including the oil and automotive lobby, as (rather unintended for scientific, i.e. unpolitical reports!) the opinions from China or the USA. It's a democratic process after all! If there is a "conspiracy" on such a high level (consider the IPCC is an organization of the United Nations, with e.g. explicit agreement of the "G8") - again - one can as well distrust any other source.
Thank you for reading all this.
Let us know any comments.