One adult tree captures 25kg per year. One transatlantic flight releases 500kg per passenger. Twenty trees, per person, per flight. Get serious.
IPCC projections for a "good" scenario still depend on magical BECCS processes that don't yet exist., not flue scrubbing, which I think if anything will be away to keep coal plants online for _longer_.
It's still valuable science, but don't get excited until there are major, major advancements in non-flue DAC/CCS.
You're failing to put things in perspective. There are 500 trees on earth for each human being. That would mean they can absorb 12500 kg per year.
Also, tree are NOT the largest natural CO2 sink, oceans absorb more.
Overall, the biosphere absorbs about 50% of total human emissions (25% by land plants and 25% by oceans). I think that once we drop the CO2 emissions enough, the nature will quickly scrub it out of the air, we don't need to get negative ourselves, just drop close to zero and nature should balance itself pretty quick.
It's a carbon _cycle_. We've spent a hundreds of years adding new carbon to that cycle as fast as our technology will allow, which is now very fast. It will remain in the cycle unless we sequester it back into the ground. Plants (for the most part) aren't CO2 limited, they're nitrogen limited.
The climate also isn't something that will just snap happily back into place. We're in a local minima. If we climb up this hill, we won't like what we find in the next valley.
Oceans absorbing CO2 results in acidification which is already harming the oceanic life cycle. We really want to tilt the balance away from the oceans, because the consequences of a dead ocean are dire.
At the power plant it is a matter of putting together technology that already exists. All of the elements such as amine strippers, pyrolysis, oxy-fuel combustion, etc. have been around since the 1970s. The literature has a "stopped clock" appearance in that people have talked about these things in the context of "clean coal" and biofuels for a long time without anything being built.
There are two problems with it.
One of them is that any kind of carbon capture is expensive and competes directly with a power plant (maybe the same power plant) without the CCS equipment. To win that competition, the operator of the power plant either needs to be fined for emitting CO₂ or has to be paid for capturing it, to the tune of $50-$100 per tonne.
Another is that the ecological accounting for biofuels is frequently not favorable. When you consider water consumption, effects of land use, and the effects of inputs, many biofuel schemes (such as Ethanol from corn in the US) seem to be a net negative.
The cheapest BECCS scheme is to capture CO₂ from the alcohol fermentation process, this has been implemented with great success
Ethanol from sugarcane in Brazil is much better from an ecological and economic perspective and it would cost something like $30 a tonne to capture CO₂ and inject it into a saline aquifer but politically it seems impossible given that most international bodies think that the real problem in Brazil is deforestation and that somehow promoting agriculture in Brazil is going to cause deforestation despite the fact that the Ethanol industry is mostly around São Paulo and nowhere near the rainforest.
In principle there might be some agreement that Brazil gets credits for BECCS and also gets credits for protecting the rainforest but the latter is somewhat nonsensical in that there is a mismatch in time between processes that emit CO₂ (say you spend 5 hours on a plane) and the need to protect a forest forever to sequester a finite amount of CO₂.
> but politically it seems impossible given that most international bodies think that the real problem in Brazil is deforestation and that somehow promoting agriculture in Brazil is going to cause deforestation despite the fact that the Ethanol industry is mostly around São Paulo and nowhere near the rainforest.
It's not like Bolsonaro's term hasn't proven that deforestation is a massive problem. No one is trusting Brazil on a geopolitical stage at all, particularly as it looks like Lula is heading off in a lame-duck term against parliament and regional governors being dominated by Bolsonaro allies, who are bought off by Big Ag.
agriculture has been the most contentious issue in world trade and it is the reason why the World Trade Organization has been deadlocked since 1999. A while back Brazil asked the question: "What industries can we lead the world in?" and one of the answers was meatpacking so they got behind
That is, JBS is to Brazil what Boeing or Apple Computer are to the US and it is by no means anomalous that it has a great deal of political influence.
When we tell them what to do with their land they react the same way we'd react if they said "It's unfair that we have to pay royalties for software like Microsoft Windows and Hollywood Movies, not to mention GMO seeds".
Most of the people in the US I talk to who rightly want to see a stop to deforestation in the Amazon are ignorant about agriculture in Brazil (e.g. they think that JBS is backwards, not the fiercely competitive corporation it is) and ignorant about agriculture in general and not particularly understanding of the process by which deforestation happens in Brazil.
It doesn't help that many questions are not well understood such as the relationship between land use in the area south of the Amazon and local climate changes that could cause the rainforest to recess northward.
There could be some compromise but so long as developed country NGOs are speaking to Brazilians in a patronizing way it isn't going to happen.
Why is sugarcane in Brazil any better than corn in the US? If they use petrochemical fertilizer, the problem is the same.
You cannot sequester a ton of CO2 for $30/tn anywhere in the world right now. You can't even do it for five times that. If what you say were true, I'd be able to clean up after my own existence right now, which I can't do. I can only buy scammy "credits" and "offsets".
The advantage of corn over other crops is that it flourishes in the presence of nitrogen fertilizer. Sugarcane is not so hungry.
The cost of capturing fermentation CO₂ is low because fermentation CO₂ is almost pure with very little nitrogen in it. Thus almost all of the cost is the cost of compressing the CO₂, pumping it, and injecting it underground which is about $30 a tonne. Even a few percent of nitrogen will cause the CO₂ to misbehave while pumping, so capturing CO₂ from a combustion stream requires some kind of separation which historically has been an aniline stripper or something like the rectisol process, but maybe it will be aluminum formate or something else in the future. The aniline stripper costs about $50 a tonne.
The trouble with capturing fermentation CO₂ is that it is not scalable. There is a certain amount of it produced and it isn't enough to "save the Earth" but it is a low hanging fruit and it would help in the process in validating sequestration, as there are all kinds of questions about the permanence and safety of saline aquifer injection. (Don't get me started about the CarbFix water sequestration project...)
As for why you can't buy any good carbon credits it is the proliferation of junk carbon credits at low prices that keeps good ones off the market. Another problem is that many schemes are using the CO₂ to produce more oil
which on one hand is a real market for the CO₂ (in Texas you can drill and get CO₂ in some places and since the 1980s they will pump it sideways and use it for enhanced oil recovery) but doing so seems to be more problem than solution and it ties the project economically to the up-and-down cycles of the oil industry.
This is quite interesting, thanks for sharing. I had written off ethanol because of how gunked up it got with the American corn industry and the stupid fact that Iowa votes first in the US primary elections. Maybe there's something to this.
