The current models for climate focus on CO2 and cannot explain the medieval warming period.

The argument I throw is that this may be true, but it does not invalidate AGW, it only says there are other sources of warming, than CO2. It does not mean all warmings are because of Ocean current movements, or are unrelated to CO2 or anthropogenic pressures. It does not invalidate climate models which cannot explain the medieval warm period, it simply shows another potential source of warming at that time. Of course the question of why the currents shifted has to be asked. And in like sense, the question about the strength of current day ocean currents has to be asked. But there is no necessary nexus for why they changed then, and why they change now. On the other hand, the component of change over time which does track rise in global CO2 and other effects is large. I believe as others do, compellingly large.

I don't see how that fits your Analogy.