Zeke Hausfather has a useful update on how real-world GHG emissions compare with estimates in IPCC models, and the implications for future warming:
So what should our takeaway from all of this be? First, there is some good news here. The world is no longer heading toward the worst-case outcome of 4C to 6C warming by 2100. Current policies put us on a best-estimate of around 2.6C warming.
At the same time, a world of 2.6C by 2100 is still a giant mess to leave to the future, including today’s young people, who will live through that, and warming continues after 2100 in these current policy scenarios. Climate system uncertainties mean that we could still end up with close to 4C warming if we get unlucky with climate sensitivity and carbon cycle feedbacks.
A lot of this optimism depends on governments keeping their promises when all the costs come due. We are all still fighting to keep a world stable enough to sustain something like our current global civilization.
