Presumably because you recognize that scientists overwhelmingly say it is happening? You're not a climate scientist yourself, so you have to defer to the experts.The phrase "what the scientists overwhelmingly say" may not be worded with mathematical precision, but no matter how many subquestions you divide it into, you know what it means, and you know that "what the scientists overwhelmingly say" is that AGW is real.

No I don't. Convince me.

Ok.

Who do you trust as a reliable source of information on this subject?

Of what? You already believe AGW is real. Did you come by that belief independently of scientists warning us of it?

Convince me that "what the scientists overwhelmingly say" is that AGW is real. I am not yet convinced of that.

Maybe this will help?



http://iopscience.iop.org/1748-9326/8/2/024024/article




ABSTRACT:
We analyze the evolution of the scientific consensus on anthropogenic global warming (AGW) in the peer-reviewed scientific literature, examining 11 944 climate abstracts from 1991–2011 matching the topics 'global climate change' or 'global warming'. We find that 66.4% of abstracts expressed no position on AGW, 32.6% endorsed AGW, 0.7% rejected AGW and 0.3% were uncertain about the cause of global warming. Among abstracts expressing a position on AGW, 97.1% endorsed the consensus position that humans are causing global warming. In a second phase of this study, we invited authors to rate their own papers. Compared to abstract ratings, a smaller percentage of self-rated papers expressed no position on AGW (35.5%). Among self-rated papers expressing a position on AGW, 97.2% endorsed the consensus. For both abstract ratings and authors' self-ratings, the percentage of endorsements among papers expressing a position on AGW marginally increased over time. Our analysis indicates that the number of papers rejecting the consensus on AGW is a vanishingly small proportion of the published research.

Who paid for those? just curious if there was a financial incentive for their conclusions.

Well done, I was expecting either that, or the 2004 Science editorial. This is a stronger piece IMO.

What do you think of the major criticisms of this study?

It's a literature review, no money required.

for the abstracts or for the review? or both?

Plus, see the wiki page of counterexamples. First, it's a short list, though of course, it is undoubtedly incomplete. Second, it contains multiple references to what the scientific consensus is that they are objecting to, including especially another wiki page specifically listing a large number of statements of consensus on the subject. That page includes this statement:

Of course, that revised statement is somewhat equivocal, but they had been the last holdout (as a group; there are individuals, as mentioned in the first link) who been explicitly denying AGW.

Oh, of the abstracts 1991-2011, those were mostly paid for. The review is free. But given the scope of all academia I really doubt that who paid for the studies is important. If we're talking about one study that's one thing, this is a review of many many studies and the money is mostly from academia I'd expect.

If we want to be careful, Wikipedia is out, right? We should agree on that.

My line of question was because I wondered if many of the abstracts were paid for by a small number of "entities" As you were.

The pages I linked were lists of non-Wikipedia references.