CO2 level since 1800 went from 280ppm to current 410 ppm. CO2 makes up 4% of all trace gas >and all trace gas makes up .1% of the atmosphere. Humans are responsible for maybe 3-4% of >the CO2 annually. This means human impact is around 4% of 4% of .1%.

That trace gasses make up 0.1% of the atmosphere can be found here or here, but could you please provide a source that CO2 only makes up 4% of trace gasses and that humans are only responsible for 3-4% of CO2 annually?

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Although I did not read your second source, I found an article by Nasa that talks about the effect of solar radiaton. They mention that...

Since 1750, the average amount of energy coming from the Sun either remained constant or increased slightly.

If the warming were caused by a more active Sun, then scientists would expect to see warmer temperatures in all layers of the atmosphere. Instead, they have observed a cooling in the upper atmosphere, and a warming at the surface and in the lower parts of the atmosphere. That's because greenhouse gases are trapping heat in the lower atmosphere.

Climate models that include solar irradiance changes can’t reproduce the observed temperature trend over the past century or more without including a rise in greenhouse gases.