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Well there definitely is greenhouse effect from CO2 and the line-by-line models show more energy reflected back as the CO2 increases. The problem with those models is they model just one small column in the atmosphere to see what happens with more CO2, but the same amount of sun, clouds, other weather like updrafts, etc. So while those simple models say there will be warming under more CO2, the effects are unknown. Before the current hysteria, the papers from the 70's show the overall effect between 0.5 and 2C. So not only not a big deal, but a definite benefit.

As for mankind's CO2, there is either a very strange coincidence of natural increases from the biosphere and volanoes or there is the manmade explanation of the rise from 280 to 400.

There are some who say the rise came from warming. That is partly correct, we had natural warming after the end of the Little Ice Age and that warming can explain 10ppm of that rise. But it can't explain the whole rise. There are also claims that CO2 was higher in recent centuries. But those old measurements invariably are from morning with CO2 off-gased from vegetation overnight, or from cities or both. The most reliable estimates come from Greenland ice cores which have annual resolution for the past 20k years. They show the current rise to be fairly unique in that interval. But, (there's always a but) other measurements show the current rise to not be so unique, with a few natural spurts reaching about 1/2 the current observed CO2 spurt.

So bottom line there is probably some warming from rising CO2, the rising CO2 is almost certainly manmade and that's about it for the science. Most everything else I read is propaganda. For example talking about weather as if the minor amount of global warimng could change the weather (even if that was possible it would be negative feedback). Lots of propaganda about melting icecaps but the fact is that it is too cold to snow in Antarctica and not warming, but if it did, it would result in more snow and ice accumulation.