First, what is "too quickly" with reference to CO2 removal from the atmosphere? At present, human civilization emits over 40 gigatons - or 40 trillion kilograms - of CO2 per year. And that increases the atmospheric burden by about 2.5 parts per million per year. So today, before you even start _reducing_ atmospheric CO2, you need to be sucking down at least 40 trillion kilograms of CO2. I struggle to imagine a scenario outside of total science fiction where that would be remotely possible.
Second, the equilibrium climate response to changes in greenhouse gas forcing take on the order of decades or centuries to realize. This is because the dynamics of the climate system are heavily buffered. For example, the ocean acts as a giant heat capacitor that slowly interchanges with the atmosphere. Were you to instantaneously halve the CO2 in the atmosphere, you'd likely see a pretty classic exponential decay in global average temperature (and other more nuanced responses); in the present climate, it's not clear we have already passed specific "tipping points" that would induce that hysteresis I described in the previous comment (in fact - one could read "climate tipping point" as a synonym for dynamical system hysteresis). Theoretically, one could try to "dial in" some particular equilibrium climate state, but it's not obvious over what timescale you'd have to intervene and what the cost of such an intervention would be.
The cool thing is none of this needs to be purely "theoretical." You could simulate all of this _today_ if you had a setup to run a global climate model. A "4X CO2" experiment where you branch from an equilibrium spin-up climate state and immediately apply a global quadrupling of CO2 has been a completely standard experiment as part of CMIP for over two decades. The opposite experiment is an established protocol for both the Carbon Dioxide Removal Intercomparison Project [1], which features an annual ramp down of CO2 at a 1% per year rate, and the Cloud Feedback Model Intercomparison Project [2], which features a more direct counterpart, with an abrupt decrease of atmospheric CO2 by 50%. There is a large body of literature discussing the results of these classes of experiments, but this is outside of my primary research focus and I can't turn you to particularly good papers off-hand. But they're easy enough to find.
First, what is "too quickly" with reference to CO2 removal from the atmosphere? At present, human civilization emits over 40 gigatons - or 40 trillion kilograms - of CO2 per year. And that increases the atmospheric burden by about 2.5 parts per million per year. So today, before you even start _reducing_ atmospheric CO2, you need to be sucking down at least 40 trillion kilograms of CO2. I struggle to imagine a scenario outside of total science fiction where that would be remotely possible.
Second, the equilibrium climate response to changes in greenhouse gas forcing take on the order of decades or centuries to realize. This is because the dynamics of the climate system are heavily buffered. For example, the ocean acts as a giant heat capacitor that slowly interchanges with the atmosphere. Were you to instantaneously halve the CO2 in the atmosphere, you'd likely see a pretty classic exponential decay in global average temperature (and other more nuanced responses); in the present climate, it's not clear we have already passed specific "tipping points" that would induce that hysteresis I described in the previous comment (in fact - one could read "climate tipping point" as a synonym for dynamical system hysteresis). Theoretically, one could try to "dial in" some particular equilibrium climate state, but it's not obvious over what timescale you'd have to intervene and what the cost of such an intervention would be.
The cool thing is none of this needs to be purely "theoretical." You could simulate all of this _today_ if you had a setup to run a global climate model. A "4X CO2" experiment where you branch from an equilibrium spin-up climate state and immediately apply a global quadrupling of CO2 has been a completely standard experiment as part of CMIP for over two decades. The opposite experiment is an established protocol for both the Carbon Dioxide Removal Intercomparison Project [1], which features an annual ramp down of CO2 at a 1% per year rate, and the Cloud Feedback Model Intercomparison Project [2], which features a more direct counterpart, with an abrupt decrease of atmospheric CO2 by 50%. There is a large body of literature discussing the results of these classes of experiments, but this is outside of my primary research focus and I can't turn you to particularly good papers off-hand. But they're easy enough to find.
[1]: https://www.geomar.de/en/cdrmip [2]: https://www.cfmip.org/experiments/cfmip3cmip6