I guess my thinking is more along the lines of the right sun spots and solar events in the right places - i.e. with enough energy directed in the right plane to affect earth systems. Maybe it could be fruitful to explore radio blackouts caused by solar storms - to see if correlation with temperatures could exist. That could falsify or verify such a correlation and further analysis as well. Just a thought
Also the troposphere is warming rapidly while the stratosphere is cooling. Which is only something you expect from greenhouse gas related warming.
Also night time temps are increasing faster than daytime temps. Another fingerprint of greenhouse gas induced warming.
Also the earth is hotter than it's been in 100,000 years and scientists predicted that greenhouse gasses would cause exactly this much warming with this level of greenhouse gasses 50 years ago well before it was obvious what was going to happen.
So yeah. Not the sun. Good question though.