🧵 on alternatives to "net-zero"
"CO₂-induced global warming stops when anthropogenic CO₂ emissions balance with anthopogenic CO₂ removals"
is a long version of
"CO₂-induced global warming stops with (net-)zero CO₂ emissions"
1/
"CO₂-induced global warming stops when anthropogenic CO₂ emissions balance with anthopogenic CO₂ removals"
is a long version of
"CO₂-induced global warming stops with (net-)zero CO₂ emissions"
1/
In short-form: "...emissions balance with removals"
In long-form: "anthropogenic emissions from sources balance with anthropogenic removals from sinks"
I have basically used UNFCCC language, not IPCC language. These policy makers had it right all along!
2/
In long-form: "anthropogenic emissions from sources balance with anthropogenic removals from sinks"
I have basically used UNFCCC language, not IPCC language. These policy makers had it right all along!
2/
Twitter was very divided on zero versus net-zero. Though, there are many reasons. Clearly, science & policy are getting blurred here. Many say "zero" because "net" means continued use of fossil fuels.
I suspect technically, "net" is more correct, but not sure 100% correct.
3/
I suspect technically, "net" is more correct, but not sure 100% correct.
3/
The UNFCCC carefully defines the terms, & this allows explicit text to be written: "anthropogenic emissions by
sources and removals by sinks of all greenhouse gases"
emissions are positive, removals are negative, no talk of "net".
4/
sources and removals by sinks of all greenhouse gases"
emissions are positive, removals are negative, no talk of "net".
4/
The Paris Agreement uses the same definitions. With this, the intent of "achieve a balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases" is clear.
(one could debate if it means "anthropogenic removals", but on previous use ... yes)
5/
(one could debate if it means "anthropogenic removals", but on previous use ... yes)
5/
The IPCC seems to be more ambiguous. Here, emissions include LULUCF, which is clearly a net concept (LULUCF is both emissions & removals). This is from SR15, but is much the same in AR5.
6/
6/
The most famous sentence in SR15, uses "net zero" or "net anthropogenic CO₂ emissions".
Elsewhere it is explained that net-zero means balance of emissions & removals.
So really, "net zero" is scientific shorthand?
7/
Elsewhere it is explained that net-zero means balance of emissions & removals.
So really, "net zero" is scientific shorthand?
7/
After all that, back to the first tweet.
* It is best to drop the scientific short hand...
* Probably important to include "anthropogenic" to be unambiguous, noting anthropogenic is ambiguous!
8/
* It is best to drop the scientific short hand...
* Probably important to include "anthropogenic" to be unambiguous, noting anthropogenic is ambiguous!
8/
"CO₂-induced global warming stops when anthropogenic CO₂ emissions balance with anthopogenic CO₂ removals"
or at least
"CO₂-induced global warming stops when CO₂ emissions balance with removals"
Not sure what people will think of this?
Comments welcome...
/end
or at least
"CO₂-induced global warming stops when CO₂ emissions balance with removals"
Not sure what people will think of this?
Comments welcome...
/end
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