The people who know this best in all the world have written extensively on the matter and you can read them on-line. Take a look at the Summary of the Scientific Basis from the Third Assessment Report of the Intergovernmental Panel on Climate Change.Over the past decade, everyone knowlegeable in the field who was at all accessible to persuasion has been persuaded—there are no legitimate scientific critics left. The establishment of consensus on this matter is quite remarkable; I do not think there has been anything like it in scientific history. For anyone who would like a broader overview of the history of climate science and the personalities involved in the debate, I recommend William K. Stevens, The Change in the Weather. Anyone interested in some of the political water-muddying that surrounds this issue, take a look at Ross Gelbspan's web site. It occurs to me, however, that there has been oddly little art addressing this. Oh, there's Bruce Sterling's Viridian list, and now website, and there has been political debate. But in terms of serious art on the subject...nothing is coming to mind, though a world under climate change has been a background of several SF novels.
For a long time, I've been comparing the situation with the science-fictional scenarios of world-wide disaster I grew up with. And the differences are so striking I think they deserve comment. It is not a lone scientist, or even group of scientists, or outcast scientists. Though there are scientific critics of the IPCC's work, there are no more climatologists among them--the last holdout, Lindzen, wrote a chapter in the Third Assessment (he still claims it probably will not be a problem, however.) And heroic businessmen? Nowhere to be found, though the current CEO of BP is fairly reasonable about the issue. Villanous businessmen and politicians, on the other hand, we have in large numbers, most notably US Vice President Dick Cheney. And European politicians are taking the lead. Who'd'a thunk it?
Which all sounds pleasantly perplexing, at least when I am not quaking in my boots. But I think the differences bear some examination. The people who wrote those novels had what are in retrospect, big gaps in their thinking and I think those gaps are the gaps in our culture's thinking. What else have we missed?