From the video linked in another comment it seems like drastic is basically impossible. The speaker, Stuart Scott, had said that we'd have to just drop $28 trillion worth of fossil fuel assets on the floor and walk away today. It seems more likely that we're going to hit at least 5 degrees over the next 100 years which, if I'm not mistaken, means mass extinction events and the collapse of civilization as we know it.
2 degrees, from what I understand, is drastic enough to destabilize our current geo-political situation and threaten humanity with large-scale famine, water shortages, and mass migrations. It doesn't seem like we can even avoid 2 degrees at this point. It's just going to happen even if we do stop everything today if I'm understanding this news right.
The IPCC reports don't substantiate those figure. RCP8.5 which assumes increasing co2 emmisions until 2080 results in 2.6-4.8 degrees by 2100. But Rcp8.5 is considered pretty much worst case. It is basically what happens if we just continue to use fossil fuels and have no climate policy.
RCP4.5 which is a somewhat optimistic but still realistic plan would only have 1.1-2.6.
RCP6 which is a realistic scenario where fossil fuels are used heavily but by 2060 we start heavily switching to carbon neutral sources. That leads to 1.4-3.1 degrees by 2100.
There also isn't any scientific consensus on what level of rise would lead to collapse of civilization. But I'm pretty sure it wouldn't be 5 degrees by 2100.
Even with 5 degrees the bread baskets of the world should still be producing a ton of food. There would need to be engineering solutions. GMO modified crops to survive droughts better. Better irrigation in California and the Midwest.
The dooms day projections all assume we just sit around while food production drops and just starve to death. That's a bad assumption.
It would cause famine in parts of the world where rising food costs means they can't afford food. But food could go up 5x in America before we'd have problems affording it.
The estimates are still loose on the methane situation and how that would affect the IPCC reports. Isn't it called the "methane crisis" because it's likely going to rapidly accelerate warming?
2 degrees, from what I understand, is drastic enough to destabilize our current geo-political situation and threaten humanity with large-scale famine, water shortages, and mass migrations. It doesn't seem like we can even avoid 2 degrees at this point. It's just going to happen even if we do stop everything today if I'm understanding this news right.