which certainly doesn't speak to any semblance of long-term feedback influence... let alone a true representation of shorter-term. Notwithstanding, of course, the so-called warming that still remains "in the pipe" and hasn't yet come forward to effect an impact on surface temperature.
I'm not trying to speak to a long-term climate influence. I'm saying the observed climate sensitivity to date, based on the instrumental temperature recod, is significantly lower than the IPCC approximation. End o' story. Maybe that warming is "in the pipe." Maybe we could stop emissions right now and it would continue to warm. Maybe. Maybe not. But based on current observations, the climate sensitivity is low, and therefore that is what I believe.
As for the distant past, the uncertainties are quite high, so I prefer more recent evidence.
again, you can't argue for low(er) climate sensitivity without providing a rationalization (vis-a-vis sensitivity) for the significant warming observed in the distant past. Your bifurcate point is suggestive of a "tipping point"... please sir, a certain brand of denier goes absolutely wonky when "tipping points" are spoken of!
I can argue for lower climate sensitivity based on the observable evidence from the instrumental temperature record. Tipping points is generally how complex systems work, fro checmial reactiobns, to lake ecology to atmospheric physics. The problem is that they tipping points aren't very predictable. We could oxidize all the fossil fuels and not hit a tipping point. Or it could happen next year.