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?
COLLAPSE/EXTINCTION: scientists fear global warming of 3.5°C, which wipes out 33-70% of species (IPCC AR4 2007, IPCC AR6 2022), will likely hit by the 2060s give or take a decade or two 🧵
1. IPCC scenario SSP3-7.0 shows 3.5°C by 2080 or from 2062 (not the worst-case scenario). Even a moderate emissions scenario can lead to 3.5°C this century (new research shows 2060s-80s possible).
2. A new pre-print from highly respected climate scientists implies 3.5°C by 2065-77 at current rates of warming. The authors warn this rate could increase or decrease perhaps suggesting 3.5°C by around 2055-2087 rather like IPCC high emissions scenarios. researchsquare.com/article/rs-607…
BREAKING: scientists say Earth's major systems are undergoing abrupt changes — and soon we'll all feel them 🧵
1. 'prepare for a future of abrupt change.. choices made now will determine whether we face a future of worsening impacts and irreversible change or one of managed resilience to the changes already locked in.' phys.org/news/2025-08-s…
2. Society must now brace for catastrophic impacts.
Destruction of habitats and wildlife has intensified and accelerated to an almost unimaginable degree during the capitalist era. Scientists say the 40-50% of plant species now facing extinction will be obliterated in a handful of decades. It didn't have to be like this. Rethink.
'previous mass extinctions.. took 10,000s, 100,000s, even millions of years to happen. this is happening so fast, now in just two, three decades..' google.com/amp/s/www.cbsn…
2. Current estimates of plant extinctions are, without a doubt, gross underestimates. Extinctions will surpass background rates by 1000s of times over the next 80 years. universityofcalifornia.edu/news/plants-ar…
BREAKING: as tropical forests show increasingly clear signs they are entering a collapse phase scientists warn irreversible mass extinction conditions are on the horizon 🧵
1. rapid warming & collapse
".. warming could continue to accelerate.. even if we reach zero human emissions. We will have fundamentally changed the carbon cycle in a way that can take geological timescales to recover, which has happened in Earth’s past.”scitechdaily.com/mass-extinctio…
2. “There will be a point in the not too distant future when we suddenly see and feel this mass extinction all around us very clearly”
“A key point of extinction crises is that life has always recovered.. However..we most likely won’t be there to see it."
The Greenland ice sheet is now losing around 9 billion litres of ice an hour [Geological Survey of Denmark &Greenland]
With the ice sheet at “a tipping point of irreversible melting”, scientists currently expect an unavoidable sea level rise of 1-2 metres.weforum.org/stories/2025/0…
4 to 10 m sea level rise committed in the coming 2000 years, with the majoroty of that in the coming decades/centuries it would appear. science.org/doi/10.1126/sc…
BREAKING: horrific worst-case scenarios firmly back on the table as scientists confirm large-scale Earth systems such as forests, ice sheets, and ocean currents may already be collapsing 🧵
'large-scale Earth systems may be experiencing gradual collapses that are easy to miss, with profound implications
"we may already be crossing tipping points without realizing"