Thread by @anlomedad

@GlobalEcoGuy Increasing land carbon sink for offset projects –
this doesn't work. Net-zero with🌳is a logical fallacy ppl believe in.
General mechanics of carbon sinks AND under AGW stress can't compensate continued emissions.
A TRUE-zero world has to increase carbon sink annually to stay 0

@GlobalEcoGuy German forests reduced sink capacity by 86% since 1990 and 🇩🇪biosphere was already a net CO2 source from 2016-2020. At 1.1C.

* at local 24C/34C, respiration/photosynthesis balance in C3 / C4 plants is a net CO2 source
* stress from🪲🔥💧=CO2e source
* ++˚C =ocean store less CO2

@GlobalEcoGuy The 3 * above show: land&ocean carbon sinks are more and more reduced under AGW stress.
Now to the general mechanics. Positive emissions in a "net-zero" world will still add to the atmosphere each year. As shown above, more so under progressing AGW stress.
++ CO2ppm = ++˚C

@GlobalEcoGuy Biosphere slowly adopts to the new regional climate regime. In doing so, it emits CO2e. Whether it dies from pests bc bug larvae don't die in warmer winters, from drought or from fires, it emits CO2e.

And by now, it's fossil CO2. CO2 which doesn't belong in the current cycle.

@GlobalEcoGuy The plants now alive have stored those x% of human caused emissions. That's what they grew their plant matter from. This fossil CO2 didn't show in ppm readings, so far.
But when the plants die from AGW stress, their stored fossil CO2 ends up in the atmo.
All of a sudden. 💣

@GlobalEcoGuy One might say, CO2 from dying plants is only temporarily added to the atmo, and other plants which so far didn't die from AGW stress take it up, as do oceans.

But only x% of added fossil CO2 from dying plants is taken up, y% do stay in atmo.
And while x decreases, y increases!

@GlobalEcoGuy So, as we progress into changed climate regimes, land & oceans take up less and less, and the fossil CO2 emissions currently stored in plants eventually are released and will raise CO2ppm.

Hence, a true-zero world has to measure that rise and increase NET annually to stay at 0.

@GlobalEcoGuy As long as fossil CO2e emissions continue, including methane from oil and gas industry, which they do in a net-zero world, plant-stored fossil CO2 is increased and eventually ends up in the atmo, anyway. Where it doesn't belong. And where smaller land&ocean sinks won't reduce it.

@GlobalEcoGuy Already under 1.1˚C,🌳are more often a net source bc local ˚C exceeds 24/34˚C (sources below), and bc AGW stress lets them die. If we stop emissions today at 1.1˚C, newly planted trees only buffer fossil CO2 in the air, and with a biosphere uptake capacity already reduced by 20%.

@GlobalEcoGuy That's my take of the general mechanics under AGW stress.
Well managed BECCS can help. But not as tool to meet basic energy demand. That wd stress biocapacity even further. BECCS can only be used to reduce fossil CO2 from the carbon cycle. And only once the world is at true-zero

@GlobalEcoGuy These are the sources I drew from. Both are real-data studies, not model fantasies.

AGW stress 💧🪲🔥of 1.1˚C reduced CO2 sinks: nature.com/articles/s4146…
Photosynthesis/CO2 respiration in C3/C4 plants already reduced sinks by 20% due to rising local ˚C: advances.sciencemag.org/content/7/3/ea….

@GlobalEcoGuy German source for German biosphere being a net CO2 source 2016-2020 and loss of forests's carbon sink capacity by 86% since 1990: klimareporter.de/images/dokumen…
or klimareporter.de/erdsystem/auf-…

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