Speaking as someone who has formal training in geosciences and atmospheric physics that relates to climate change, I have given up on the denial brigade. The sad fact is: people don't know what they don't know and are very easily swayed by tiny slivers of information (usually way out of context) that have been spun into a lie. Lots of money can buy any industry the shills they need to promote their lies.
And, though it's pointless to go into this, it ain't just CO2. Methane has 10 to 20 times the potency, as a greenhouse gas, that CO2 does. Rice farming, livestock, landfills, and well releases are all hugely ramping up the level of methane in the atmosphere. Diesel soot is also a major player, because it deposit on ice fields and glaciers and hastens their melting by slightly darkening them and thus increasing their absorption of solar radiation. There's also the fact that the ocean is losing its ability to absorb excess CO2 in the atmosphere, for various reasons. Warming and acidification of seawater is destroying coral reefs, which are also a carbon sink we need. Rainforest (especially bog forest, which stores 12 times the carbon per acre of regular rainforest) is being chopped down and burned off at horrifying speed in places like Indonesia where big multinationals are going all in on oil palm plantations. Et fucking cetera.