See an item at Anthony Watt’s site which graphs the amount of atmospheric carbon dioxide by geologic time period. We currently live in the “Anthropocene” era. They show how in the “Last Glacial Maximum”, e.g. the last Ice Age which was only about 10,000 years ago and an age from which the earth is still recovering, how there was less carbon dioxide than now in the atmosphere.
This demonstrates the variability of carbon dioxide in the atmosphere is large and sustained across eons. Yet we are still here. Further, if we reduce carbon dioxide (if we could and if we can afford it), do we get the climate of the last Ice Age? I don’t think the answer is known.