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Over time periods in excess of 10K years this is a reasonable caveat. For more human-oriented timelines, there's no negative feedback mechanism I'm aware of that would do anything close to producing an actual oscillation.

Edit: I'd be happy for you to educate me how I'm wrong btw, since that would mean I've missed something significant, which would make me happy! So please do tell me if you know of such a mechanism.

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I really meant to say that there's no way to really know of any region of the CO2 vs. temperature graph if there's positive or negative feedback dominating. You're proposing it all runs away in one lump, and I'm saying that there can be chunks of runaway and then damping. An extreme case would be if things are really underdamped somewhere and we spiral down to one of these points.

There are all kinds of things that have time lags from years to centuries, though, that could cause ringing (ocean heat uptake, rates of carbon uptake as the biosphere adapts and shifts, etc).

Indeed, we have evidence of ringing in the geologic climate record-- like Dansgaard-Oeschger events. We also live with ringing in weather systems like El Nino. Warming intensifying or creating new modes of oscillation would not be that surprising.

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