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/

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/

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/

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/

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/

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/

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/

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/

"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