If all of this were true, and there is pretty hard evidence that the huge masses (relatively) of CO2 increase come from oceans that have warmed,-if all of this were true then that would suggest that with an inexorable return of the cold side of the cycle we should be producing as much CO2 as we can to protect the plant life when the naturally produced CO2 is curtailed.
Yes. In fact, former Greenpeace ecologist Patrick Moore points out that if left alone, the Earth would eventually suffocate all life in only about 2 million more years. (And we got really close to this in the last ice age). This is because living things suck carbon dioxide out of the atmosphere and use it in ways that do not naturally return to the atmosphere.
For example: Chalk
The fossil fuels and cement industry have been blamed for destroying the Earth. However, ironically, they are the two major industries that are putting carbon back into the atmosphere. The fossil fuels that we have burned so far have added 11 million years to life on Earth.
The TRUTH about carbon dioxide (C02): Patrick Moore, Sensible Environmentalist