Climate Action Now, page-160

"Your argument is specious, CO2 levels are at an historically low level (time from the first Humans)"

CO2 levels remained relatively consistent between ~180ppm and ~290ppm for at least the last 800,000 years. (First humans are from around 200,000 years ago - homo sapiens). From the graph below, you can see that CO2 levels are indeed historically high when it comes to 'recent' history.




"humans could not significantly alter the natural cycle most influenced by Solar Activity,"

It was carbon dioxide in the past, and its carbon dioxide now. Solar irradiance and Carbon Dioxide are the two long term drivers of the climate on Earth.




Purple line is CO2
Blue line is Temperature.

No correlation - sure.

Now, the sun has become about 6% stronger in the last 500 million years.

I have put in the red line myself to illustrate the gradual increase in solar irradiance (it doesn't matter how steep it is, you can flatten it out, make it steeper, the result is the same)

Red line is solar irradiance.
Blue line is temperature.

No correlation.

It would be incorrect to then conclude that the sun has no influence on the earths temperature.

So, when you combine both CO2 and solar irradiance, this is what you get.



A pretty good correlation.