[photochemsyn]

Forestry carbon credits have always been a bad joke, comparable to 'clean zero-emission coal plants' in terms of their effectiveness in slowing the rate of CO2 increase in the atmosphere. Such concepts are really borderline, if not actual, scientific fraud.

The guilty parties here are politicians, bureaucrats and corporations who wanted to be seen as 'doing something' or selling 'responsible stewardship' to the public while actually doing nothing. I honestly have more respect for the outfits that didn't even bother with such bogus PR claims (ExxonMobil) vs the shady fraudsters who tried to greenwash their image this way (BP 'Beyond Petroleum', Chevron's 'sustainability program'). Politicians like Al Gore hyped these schemes as well, while not doing much that would actually decrease fossil fuel use (like a massive increase in solar/wind/storage technology R&D and manufacturing support). Countries like Canada used this nonsense to justify continuing with the dirtiest fossil fuel production system on the planet, i.e. Alberta tar sand mining, all while portraying themselves as green enviromentalists.

Such opportunistic politicization of the issue has resulted in major problems ever since when it comes to explaining the science to skeptics, who understandably started to think it was all about politics.

Even 30 years ago when these schemes were first trotted out as 'cap and trade' scientists knew they were bogus. Forests weren't capable of expanding to absorb fossil carbon being pumped into the atmosphere and predictions of continental drying (reduced growth rates), warmer winters (allowing insect infestations), and longer fire seasons (burning down the forests) all pointed to steady reductions in standing biomass, not increases.

[alexose]

Note that most of the carbon offsets offered by airlines are forestry-related. Any time you see offsets for less than $50/ton, proceed with an abundance of caution.

I do think the general state of offsets is improving. There are more high-quality offsets hitting the market every day. They're much too expensive, but I'd rather see "real" offsets at a high price than the complete make-believe we've had up until recently.

[photochemsyn]

The only mechanisms at the CDR Database that look like actual long-term offsets are in the mineralization category, meaning the production of carbonate rocks from atmospheric CO2. The problem is you need the counterion to make these rocks, i.e. calcium or magnesium, and these are often already locked up in rocks. Mine tailings have been proposed as a source, I don't know.

https://en.wikipedia.org/wiki/Carbonate_rock

The sci-fi approach that would be great is pulling atmospheric CO2 out of the air and making diamond from it. The technology is sort of there already but the costs are ludicrous. The pathway is atmospheric CO2 + water -> methane -> synthetic diamond production. That last is a slow energy-intensive process, but such diamonds would be easily distinguishable from the 'real' geologic diamonds (as they'd have the same amount of carbon-14 as the atmospheric CO2 does). Worth someone writing a business plan I think.

[etrautmann]

Can you provide links? I’m very curious to learn more about real offsets even if expensive.

[alexose]

Sure! I usually point people at Carbonplan's CDR database: https://carbonplan.org/research/cdr-database

[mistrial9]

good on them to provide reproducible parts here; interesting to see the research trends of [json|csv] , [python|R] consistently..

[etrautmann]

Thanks! +1 to Carbonplan

[danielfoster]

Not sure what airlines are offering now, but when I checked in 2019, United’s offset scheme included funding for sustainable tourism and education in developing countries. Great causes, but not an offset.

[briantakita]

The grift is even bigger than that. Scapegoating a naturally occurring gas for all of the world's problems is a huge opportunity for grifters, greenwashers, & con artists. I wonder if theres a study of scientists who add "the effects of global warming on..." to their paper titles for some career sustaining $$$. Don't get me wrong, there's plenty of great work out there...however the incentives seem to invite unethical behavior.