To what extent is climate change caused by human factors?

While there may not be any evidence to suggest that CO2 warms the climate, I'd have to argue that humans absolutely have caused aspects of climate change. Take nitrous oxide, for instance, which NASA's research states is "produced by soil cultivation practices, especially the use of commercial and organic fertilizers, fossil fuel combustion, nitric acid production, and biomass burning." All of those realeasants are human-made and proven to contribute to climate change, hence they're all ways of life campaigners are trying to change. Of course, to an extent there is some organic climate change that occurs (that's just how it is), but it would be ludicrous to deny that climate change isn't at least accelerated by human factors. Take this statement from NASA: "In its Fifth Assessment Report, the Intergovernmental Panel on Climate Change, a group of 1,300 independent scientific experts from countries all over the world under the auspices of the United Nations, concluded there's a more than 95 percent probability that human activities over the past 50 years have warmed our planet." It would be absurd to deny the research of so many; it's fact.