Discussing a thought pattern

SUPPLEMENTARY MATERIALS to Steffen et al. 2015 Science 1259855

My grandfather used to have a little poem.

A man convinced against his will
Will have the same opinion still.

Believe it or not, some people disagree with me, especially regarding topics that have been so politicized, such as COVID and Climate Change. Today, I tried explaining to people how I got my opinion. One of the first arguments I heard was that CO2 levels had been the highest for hundreds of thousands of years. They pull out the charts of the Vostok Ice Core data. They point at the chart and compare the current world CO2 levels with data from ice cores harvested from Vostok Antarctica.

Looking at the chart, I saw that there is a pattern that the temperature rises every hundred thousand years (roughly). If humans cause climate change, does that mean that multiple human civilizations have risen and fallen every hundred thousand years, or is there some natural event causing this?

Another thing that I observed was that the maximum temperature in this current epoch is less than or equal to previous epochs. I marked it with a yellow line. What does that mean to the current narrative? If humans are responsible for increased temperatures, shouldn't they be higher than in previous cycles?

I marked another piece of evidence using the green lines. The argument is that CO2 controls the temperature. Between the lines, CO2 was in a plateau. Despite this, temperatures plummeted. Doesn't this go against the narrative?

Continued.