> I don't see how that would be possible (and at least the scientists at the ICPP don't believe it would be possible either That's down to the fact that emitti

> I don't see how that would be possible (and at least the scientists at the ICPP don't believe it would be possible either That's down to the fact that emitting more than 8.5 RCP requires some insane choices. Like, as you say, burning pretty much everything. A low-end runaway greenhouse can happen with 12 W/m^2 forcing[1], which would mean temperature changes ~20 C compared to 4-8, and multiple times more CO2. > At the end of the day, it is believed that all or almost all of the oil, coal and natural gas we use comes from biogenic sources, meaning it used to be in the atmosphere at some point in the past. That is a very, very silly way to look at it. The total weight of carbon in the air is 870 gigatons. There are 1000 gigatons in ocean life, 2000 gigatons in the terrestrial biosphere, and 4000 gigatons in fossil fuel reserves. The fact that it was in the atmosphere at one point is irrelevant; I've drunk thousands of gallons of water in my lifetime. If you were to return those to my body all at once, I would explode. [1]: https://en.wikipedia.org/wiki/Runaway_climate_change https://en.wikipedia.org/wiki/Runaway_climate_change