Climate Emergency Institute
July 2019 Most complete list.
Climate feedbacks in the Earth system and prospects for their evaluation
The IPCC has always used only a mean for its single fixed sensitivity
For the IPCC AR6 the IPCC rejected the latest model results that put the sensitivity higher, and downgraded it to 3°C again.
2021 IPCC AR6 sensitivity models result is 3.8°C,
but IPCC improperly pegged it back at 3°C (same as 1990), rejecting risk in the entire assessment.
For the IPCC AR6 the IPCC rejected the latest model results that put the sensitivity higher, and downgraded it to 3°C again.
2021 IPCC AR6 sensitivity models result is 3.8°C,
but IPCC improperly pegged it back at 3°C (same as 1990), rejecting risk in the entire assessment.
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IPCC AR6 climate sensitivity
This single metric determines all IPCC
projections. There is no one number
that is the climate sensivity
Using only one number, ignores any possibility
of anything higher than this 3°C
There has always been a wide range of estimates
for the value, but the IPCC has only used a
single fixed metric (3°C)m which for long term
equilibrium warming runs contrary to climate
system science and to risk assessment.
Here is the big question for climate science .
If the climate change science, that policy makers rely on, turns about to be a large underestimate what happens to the future of the planet and of humanity?
The answer is runaway climate change (chaos) hot house Earth, because multiple enormous sources of amplifying are triggered. The big one is permafrost thaw, that is already releasing all three main GHGs -methane, CO2 and nitrous oxide. This is irreversible, and furthermore permafrost thaw become self-reinforcing. Thawing permafrost emits carbon by frozen microbes coming back to life and digesting organic material. This produces heat, which makes the thaw unstoppable and increasing.
The models that project the wide ranging sensitivity do not (still) include any any of these large feedbacks.
This the worst fundamental fatal flaw in climate change science- it's incredible.
The science has always agreed that higher climate sensitivity (than 3°C) is possible.
The 1st 1990 IPCC assessment piu it at 3°C , a range up to 4.5°C
If it is, all the global warming impacts will be earlier and larger (we are already finding this) than projected at 3°C. That risk must be excluded using a higher sensitivity. This was explained by in 2009 by economist Martin Weitzman his paper On modeling and interpreting catastrophic climate change. Catastrophic impacts were mentioned in IPCC 2021 TAR and 2007 AR4, but not since. The IPCC in effect has excluded catastrophic climate change impacts.
In addition, the sensitivity will increase with temperature, because of the many amplifying feedback responses to warming. As the planet surface warms large feedbacks come into play. which are all positive (amplifying) the global temperature increase. We already have methane and nitrous oxide that will increase with further warming, making the climate more sensitive. The IPCC excludes these from the projections by not adding extra feedback warming to climate sensitivity based on its warming projections. We know these feedbacks will happen and indeed they have started, but the IPCC acts as if they don't exist.
projections. There is no one number
that is the climate sensivity
Using only one number, ignores any possibility
of anything higher than this 3°C
There has always been a wide range of estimates
for the value, but the IPCC has only used a
single fixed metric (3°C)m which for long term
equilibrium warming runs contrary to climate
system science and to risk assessment.
Here is the big question for climate science .
If the climate change science, that policy makers rely on, turns about to be a large underestimate what happens to the future of the planet and of humanity?
The answer is runaway climate change (chaos) hot house Earth, because multiple enormous sources of amplifying are triggered. The big one is permafrost thaw, that is already releasing all three main GHGs -methane, CO2 and nitrous oxide. This is irreversible, and furthermore permafrost thaw become self-reinforcing. Thawing permafrost emits carbon by frozen microbes coming back to life and digesting organic material. This produces heat, which makes the thaw unstoppable and increasing.
The models that project the wide ranging sensitivity do not (still) include any any of these large feedbacks.
This the worst fundamental fatal flaw in climate change science- it's incredible.
The science has always agreed that higher climate sensitivity (than 3°C) is possible.
The 1st 1990 IPCC assessment piu it at 3°C , a range up to 4.5°C
If it is, all the global warming impacts will be earlier and larger (we are already finding this) than projected at 3°C. That risk must be excluded using a higher sensitivity. This was explained by in 2009 by economist Martin Weitzman his paper On modeling and interpreting catastrophic climate change. Catastrophic impacts were mentioned in IPCC 2021 TAR and 2007 AR4, but not since. The IPCC in effect has excluded catastrophic climate change impacts.
In addition, the sensitivity will increase with temperature, because of the many amplifying feedback responses to warming. As the planet surface warms large feedbacks come into play. which are all positive (amplifying) the global temperature increase. We already have methane and nitrous oxide that will increase with further warming, making the climate more sensitive. The IPCC excludes these from the projections by not adding extra feedback warming to climate sensitivity based on its warming projections. We know these feedbacks will happen and indeed they have started, but the IPCC acts as if they don't exist.
Climate sensitivity is the fundamental metric determining all projections in climate change science. It is a single fixed metric, but it is bound to increase with global temperature due to inevitable amplifying feedbacks.
It is defined as the equilibrium warming resulting from a doubling of atmospheric CO2.
There has always been a very large range from the models used.
The IPCC just takes (only) the middle of the range. It has been 3°C since the fits 1990 IPCC Assessment. The IPCC 6th Assessment kept it at 3°C, even though the models had 3.8°C.
It is defined as the equilibrium warming resulting from a doubling of atmospheric CO2.
There has always been a very large range from the models used.
The IPCC just takes (only) the middle of the range. It has been 3°C since the fits 1990 IPCC Assessment. The IPCC 6th Assessment kept it at 3°C, even though the models had 3.8°C.
Video 2011, AGU panel presentation
Paleoclimate record points toward potential rapid climate change
There is no one number that is climate sensitivity
Paleoclimate record points toward potential rapid climate change
There is no one number that is climate sensitivity
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IPCC AR6 Climate Sensitivity
