Check an article about periods of greenhouse and icehouse period on Earth. https://en.wikipedia.org/wiki/Greenhouse_and_icehouse_Earth.

All major climate changes could be explained by tectonic moves that changed currents in oceans.

Why do we neglect the presently observed tectonic moves as a possible cause of climate changes now?

My argument was as well that naturally caused climate changes could be much more rapid than we observe now, supposedly caused by humans.