evidence: As CO2 has had no noticeable effect on climate in 600 million years, until 15- 20 years ago, when carbon tax was invented, any alleged climatic effects can be ignored. [...] Scientists have actually long known that something something other than CO2 sets things in motion when Earth enters and emerges from ice ages: shifts in solar radiation reaching Earth due to variations in the Earth’s orientation to the Sun. (These are known as Milankovitch cycles). Then other natural feedbacks kick in — most especially changes in carbon dioxide. [...] Here, too, commenters on this blog often claim that since recent periods in Earth’s past were almost as warm as it is now, we can’t know for sure that the CO2 we’ve added to the atmosphere is responsible for the observed recent warming.