How does the global average temperature increase compare to atmospheric CO₂ concentrations in the last ~100 years?
It is quite a linear relationship, with a 2.7°C increase for a doubling of CO₂ concentration.
This includes non-CO₂ effects, which approximately cancel.
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This tweet was inspired by a comment by @GregFlato based on this figure by @RARohde
"If you multiply by 270ppm to make it comparable to TCR & ECS, you get something we might call ‘instantaneous climate sensitivity’ (ICS) which comes out to be 2.7C"
(try to follow the discussion on the various threads)
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A problem is that it includes non-CO₂ as it is based on observations.
TCR, TCRE, & ECS are often (not always) model based, but then they become like a model metric as they don't include non-CO₂ (are they practically useful).
Basically, non-CO₂ is a pain (& important)...
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It becomes a trade-off:
* Something based on observations that mixes CO₂ and non-CO₂
* Something based on models that can clearly isolate the CO₂ effect?
Have we become obsessed with model based metrics, & less so on more complex empirical metrics?
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Then there is the question of reversibility. How does the relationship change in the future, & does it help anything?
Global CO₂ emissions grew at 2.6%/yr in the 2000s, but this dropped to 1.0%/yr in the 2010s.
Can we see this in the atmosphere?
If emissions growth continued at 2.6%/yr in the 2010s, it would lead to ~0.3ppm difference in 2019, or cumulatively 1.3ppm over the 2010s.
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How did I do this? 1. Assume emissions continued at 2.6%/yr from 2010 2. Get difference with current emissions 3. Multiply by airbourne fraction (AF, estimated 1960-2010, 0.43) to estimate atmospheric increase 4. Convert to ppm (1ppm = 2.124GtC, GtCO2 = 3.664 GtC).
Simple!
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We should see this in the atmosphere, but how confidently given variability?
The effective difference in growth rates is ~2%, which we should be able to detect after 5-10 years. Though, note in the commentary, we compared 1% & -1%, not 2.5% & 1%. rdcu.be/buifD
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"It is not obvious that the cheapest resources with the lowest carbon footprint lie in the resources already discovered... To stop exploration at this time would cause a major threat to the world's energy security", are the arguments from the Norwegian Oil & Gas lobby
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"Recent polls have shown that 60% to 70% of voters continue to support future Norwegian oil & gas production"
[Perhaps the political niche is threading the needle between investment for old & new fields, taking the IEA's lead]
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THREAD: Bioenergy use in the @IEA Net Zero 2050 scenario
I have seen a few comments that the IEA uses loads of bioenergy. Let's have a look...
First up, overall, bioenergy use is lower than in equivalent scenarios assessed by the IPCC, particularly in 2050.
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2. An important detail is that the IEA assumes traditional biomass is gone by 2030. Traditional bioenergy "is unsustainable, inefficient & polluting, & was linked to 2.5 million premature deaths in 2020"
The IPCC only has a slow drop, so the IEA must build up modern bioenergy.
3. In terms of modern bioenergy, the IEA has similar levels as the IPCC up until 2050.
* Rapid growth to 2030 is to compensate traditional bioenergy
* Slowdown to 2050 is to limit to 100EJ per year, view by many as sustainable.
The new @IEA Net Zero by 2050 report is crystal clear on what is needed.
"All the technologies needed to achieve the necessary deep cuts in global emissions by 2030 already exist, & the policies that can drive their deployment are already proven."
"Clean energy innovation must accelerate rapidly, with governments putting R&D, demonstration and deployment at the core of energy and climate policy."
In 2030 only existing technologies needed, by 2050 new technologies also come to market.
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Net Zero 2050 is a jobs bonanza.
JOBS. JOBS. JOBS.
"The transition to net zero brings substantial new opportunities for employment, with 14 million jobs created by 2030 in our pathway thanks to new activities and investment in clean energy"