The best estimates (and very likely ranges) for 2081-2100 in the two scenarios that I believe are widely considered to correspond to our current situation are 2.7C (2.1-3.5C) and 3.6C (2.8-4.6C).
Could another 15-25 years of emissions around today's levels mean 3-4C by 2090?
3/
1.5C-2.5C is already catastrophic enough to leave 100,000s or millions of species struggling, including humans in my opinion.
I ask whether and under what conditions 3-4C by 2090 would be plausible in light if this conversation from yesterday:
'We have already observed impacts of climate change on agriculture. We have assessed the amount of climate change we can adapt to. There’s a lot we can’t adapt to even at 2C. At 4C the impacts are very high and we cannot adapt to them'
There's every reason to think we can't avoid 2.3-2.8C.
Can this be delayed for many centuries or beyond (which may help species to adapt) or will it hit by 2050-2150 which would be too fast for species to cope?
2. 'Planetary boundaries represent thresholds in major Earth system processes that are sensitive to human activity and control global-scale habitability and stability
critical oxygen thresholds are being approached at rates comparable to other.. processes'
An amazing news story totally ignored by state-corporate media: according to even the most conservative and optimistic consensus assumptions there had to be 'immediate action' years ago at the very latest with emissions peaking and falling by now to avoid utterly catastrophic 2C.
BREAKING: scientists warn we're beginning to feel the effects of a geologically instantaneous 21st century shift into extreme and unsurvivable conditions 🧵
1. 'We are starting to feel the effects of transitioning to a hothouse climate (ΔT +4-5 °C) in a geological instant'
The global change happening now is potentially like the Permian extinction which occurred in just a few centuries.
2. "In my view it is impossible to survive that sort of change (4°C by 2100). That is beyond human physiology. But that is the trajectory we are on now.. No matter what we do with all the whiz-bang technology.. physiologically we cant survive that."
Even establishment climate scientists who organise consensus views (and often downplay catastrophe) show we can anticipate 2.1°C by (2035- ) 2050 at which point impacts become too severe to manage.
Scientists now know today's capitalist economic system can't limit global warming to well below 2°C meaning human adaptation will not be feasible as the conditions for modern agriculture disappear forever in the coming years. Most scientists accept this. Some aren't ready yet. 🧵
Officially, CO2 emissions would have needed to be reduced by a staggering 70% in the 2020s to limit global warming to well below 2°C (when CDR fails). This is obviously not feasible: economic growth has left us with record high emissions approaching 2025.