Some possibilities... earth orbit variations,moon orbit variations, earth tilt variations,slowdown of rotation, magnetic field variations
etc. etc. etc.
Why don't you tell me as you seem to know it all...
I have said I believe the warming is caused (mostly) by the same natural causes that have occurred many times in the earths past history before mankind existed.
Are mankind's activities increasing the warming maybe, possibly
are the proposed countermeasures more detrimental to mankind than the warming maybe, possibly.
Does Co2 increase warming yes it seems to was Co2 much higher in the past yes say the "scientist's" was the earth greener supporting a huge explosion of plant and animal species
was it warmer yes they say all before humans existed.
https://clintel.org/there-is-no-climate-emergency-a-message-to-the-people/