Did you know what causes Ice Ages?
It is the Earth’s orbital cycles, known since Milanković computed them in the 1920s.

When you drive a climate model with these cycles, it will correctly reproduce the sequence of Ice Ages as we know it from paleoclimate data.

https://www.realclimate.org/index.php/archives/2019/04/first-successful-model-simulation-of-the-past-3-million-years-of-climate-change/