Except that anthropogenic climate forcing is more than just the CO2 emissions from releasing previously locked-up carbon. Human industry and even agricultural practices have significantly rearranged the chemistry of above-ground minerals and chemicals, so that atoms that were previously bound up in harmless arrangements are now rearranged to form gases that have unnaturally high greenhouse trapping capabilities. Cutting down forests has reduced the planet's CO2 absorption capacity, and other land use changes have had a net forcing effect on climate.
From memory the IPCC report concluded that burning fossil fuels was only responsible for about half of anthropogenic climate forcing, presumably meaning (extending your logic) that if we did manage to burn them all, AND continue our other practices, we could be looking at 12 degrees warming in total. Obviously that's not going to happen, but if it did, it's too hard to say for sure that it couldn't somehow trigger a runaway greenhouse effect. And I would think a runaway greenhouse effect could in principle be triggered by more than just a simple temperate-tipping point - it could also be caused by an excessively quick rise in temperature. Further, with or without mankind's activities, the biosphere's composition now compared to 200 million years ago is significantly different - for all we know, it may be capable of absorbing far less CO2.

We intelligent ones have created fluorocarbons, a GHG that never existed before. We should get back to 1960 levels by 2400 or so since we are phasing them out.

We can create a "methane burp" that does more GW than CO2. Methane is short-lived (less than a decade half-life), so things should cool down a generation after the methane burp.

You may be right VERY long term, in geological time frames. But even a century is a LONG time for civilization and me personally.

Best Hopes for minimal GW,

Alan

When the CO2 was 2% of the air, the sun was a little less bright compared to now. That would mean that a higher amount of CO2 compared to now would have to be in the air to make the temp the same as now. If we burnt all the fossil fuel, the 2% CO2 would make for air that'll cause us (and animals) to breathe more heavily as CO2 builds up in blood. I'd invest in oxygen bar equipment companies in that case as people would want relief from the emphysema-like breathing symptom.

Worse, even without global warming, a "creamy nougat" of oil would cause "peak air" and our own suffocation! An atmosphere of 15% oxygen and 5% CO2 would be extremely unhealthy. You do NOT want a "creamy nougat" of oil!

We must get over our addiction to fossil fuel, one way or another. Start building the solar and wind power plants!

Petrol prices high enough yet? Just wait!