I'm guessing it's some variation of "we know of climate change in the past that was not caused by humans, therefore no climate change is caused by humans". For

I'm guessing it's some variation of "we know of climate change in the past that was not caused by humans, therefore no climate change is caused by humans". For the record, we do know of at least one instance of positive climate change in the past caused by humans. Genghis Khan famously went on a huge murderous rampage (some estimate that he directly and indirectly caused the death of ~10% of the world population), causing massive forest regrowth in previously populated areas, which in turn scrubbed CO2 out of the atmosphere. https://carnegiescience.edu/news/war-plague-no-match-deforestation-driving-co2-buildup https://carnegiescience.edu/news/war-plague-no-match-defores...