The Ice Ages are well confirmed scientifically, but not understood.
The dominant climate of the earth is cold. We get relatively brief warm periods, "interglacials", of which we are in one now. Ice ages are theorized to be prompted by shifts in the Earth's orbit[0].
CO2 is measured in hundredths of a percent for impact on the climate. Does it really seem reasonable that our little human technology, an infinitesimal fraction of the energy at work in the Solar System is making a huge difference?