Earlier quoted context omitted.
If “it all keeps changing”, which thwarts their attempts to “model an insanely complex system”, then wouldn’t that mean any claim about “global warming” is actually a claim to possessing a priori knowledge?
We know very well how carbon dioxide interacts with infrared radiation (easily tested with an IR spectrometer), and we know human activity releases enormous quantities of carbon dioxide into the atmosphere, which does not magically disappear. Precise predictions are hard, but the general direction of travel cannot be seriously disputed without arguing against the above simple facts.
Btw, CO2 does 'magically' disappear. Into the oceans. Alas, from what I've read it'll take about 2,000 years to do so.
> [...], but the general direction of travel cannot be seriously disputed without arguing against the above simple facts.
I don't want to argue against global warming, but I want to argue that can't argue against global warming without arguing against your 'simple facts'.
Your 'simple fact' about CO2 could be true, but global warming could still be a myth. (I don't think it is; but your argument is far from sufficient. It's a complex system. Eg from time to time volcanic eruptions produce a lot of CO2, but they are typically associated with a cooling of the climate, because of other factors.
Similarly, burning coal releases a lot of CO2, but it also used to release a lot of SO2. Locally, SO2 is pretty bad (ever heard of acid rain?), but SO2 converts to sulfuric acid aerosols that can block solar radiation. These days most coal fired power plants have measure to avoid spewing so much SO2.
It's conceivable someone could find a coal so 'dirty' with sulphur, that burning it would decrease temperatures. I don't think it's very likely, but it's conceivable. So you need more empirical observations, than just your simple facts to make your argument.)