Cawacko,
Global warming, and the anthropogenic contribution, is one of the most firmly established scientific facts in modern times. It's virtually as firmly acknowledge as the link between second hand cigarrete smoke and respiratory illness.
And you know what? There's still some tobacco company-funded scientists, and self-appointed "experts" who deny the link between tobacco and respiratory illness or cancer. Note: you won't find any of the "experts" published in peer-reviewed scientific journals, with research pertaining to global warming.
Every single scientific organization and body on the planet, with expertise in climate science, is in agreement: humans are changing the climate. And those bodies include the National Academy of Science, AGU, and every single top american science organization.
Can it be proven beyond every shadow of a doubt that humans are influencing climate? No. Science can't ever prove anything beyond a shadow of a doubt. But, the entire scientific community has concluded with 90% certainty that humans are changing the climate. 90% is science, is considered a scientific fact.