Okay, the Wikipedia article again....

Wikipedia on Global Warming

It is therefore not correct to say that there is a debate between those who "believe in" and "oppose" the theory that adding carbon dioxide or methane to the Earth's atmosphere will, absent any mitigating actions or effects, result in warmer surface temperatures on Earth. Rather, the debate is about what the net effect of the addition of carbon dioxide and methane will be, when allowing for compounding or mitigating factors.

(my italics)

In other words, the question is not "Are human activities contributing to global warming?" (Or even "Is global warming happening?") The question among scientists is: "How much is human activity affecting global warming?" At billions of pounds of atmospheric carbon dioxiode per year, I find it hard to believe that it's a minimal effect.

...

The extent of the scientific consensus on global warming—that "most of the observed warming over the last 50 years is likely to have been attributable to human activities"[21]—has been investigated. In the journal Science in December 2004, Dr Naomi Oreskes published a study of the abstracts of 928 refereed scientific articles in the ISI citation database identified with the keywords "global climate change". This study concluded that 75% of the 928 articles either explicitly or implicitly accepted the consensus view — the remainder of the articles covered methods or paleoclimate and did not take any stance on recent climate change.[22] [23]. The study did not report how many of the 928 abstracts explicitly endorsed the hypothesis of human-induced warming.

(my italics)

So, in a 2004 study, 75% of scientists studying global climate change agreed with the consensus that it's caused by humans. The other 25% weren't covering a topic that related to today's issue.



This graph shows different studies' reconstructed temperatures across the last several hundred years.



This shows what we know with more certainty - the rate of changes in temperature since the 1860's.