The important issue is that the increase of CO2 is accelerating. There have been times with more CO2 in the atmosphere and oceans, but when their introduction is slow, it can be accommodated. However, when rapid, the usual processes are not able to handle it. We have an historical event showing us what happens when the CO2 concentration accelerates, the PETM boundary, the Paleoeocene-Eocene Boundary, where 55.8 million years ago, the oceans and atmosphere were filled with greenhouse gases over a very short period of time. The oceans acidified resulting on the largest loss of sea life in our planet's history. Daytime temperatures at the North Pole in the summer were 75 degrees Fahrenheit -- there was serious global warming.
We are pumping more than 20 times of CO2 at 10 times the rate as then. What we will experience, if nothing is done, will be far worse than what happened then.
One thing we can look forward to is that there will be jelly fish in abundance, which incidentally are mostly edible. As our food stocks begin to disappear from global warming, I believe jelly fish will be found to take their place.