Heat transport to the arctic - or lack thereof - is what will end this debate. There's a lot of interesting work around how solar variability - whether because of orbital forcing, solar cycle or both - affects wind patterns and how wind patterns affect ocean currents which can affect heat transport to the arctic. It's really the only viable explanation for the glacial cycles.You'll do well there.
A natural.
So when the AMOC collapses, like they did for D-O events, the climactic impact will be swift and undeniable. And that's when the real study of earth's climate will begin in earnest. As we will have a new and very real climate threat that will allow the climate community the cover to ditch their current CO2 bias.