So you want to use plants to reduce COâ‚‚
86 points - today at 6:31 PM
SourceTrees respire. They breath in and out. At night time, many trees emit more CO2.
And trees don't exist in isolation as these napkin calculation articles consider them (spherical cows and all that). Every single tree on earth relies on mycorrhizal fungi for the vast majority of its nutrients. Fungi break things down release CO2.
Most of our oxygen comes not from forest but from oceans (specifically from phytoplankton, algae, and photosynthetic bacteria). Between 50-80% of it in fact. Likewise, most of the CO2 that has been captured has been captured by the ocean not by forests. About 25-30% of all human emissions have been captured by the ocean.
Forests (and grasslands) are tremendously important for ecosystems and our health but I think this focus on CO2 and oxygen is simply misleading. If that's your concern you should really be focusing on the ocean. Which IMO is in an even more dire strait than our forests
msftgreed
today at 8:44 PM
Forests do net sequester carbon. But if you want to really sock away the carbon you harvest the trees and pyrolize it. It will give you energy (heat) you can use and elemental carbon (biochar). You could bury that a few feet under or innoculate it with microorganisms and work it into fields. Carbon in that form will sit in the soil for hundreds of years. Thousands or millions if you bury it.
The ocean breathes in and out too. Very little carbon sinks down to the sea floor. The ocean does happen to absorb a lot of CO2, but that's from acidification rather than photosynthesis.
theandrewbailey
today at 8:17 PM
> Most of our oxygen comes not from forest but from oceans (specifically from phytoplankton, algae, and photosynthetic bacteria). Between 50-80% of it in fact.
That fact checks out: about 70% of the earth's surface is covered by oceans. It follows that most photosynthesis, thus oxygen comes from oceans.
simonebrunozzi
today at 8:24 PM
> Which IMO is in an even more dire strait than our forests
I think you are probably right, but could you kindly elaborate and provide more details? Very curious to hear your view and learn more.
If the ocean is the main hero there, why is the forest still important to our health?
davidkwast
today at 8:13 PM
Rainfall
And at least the forest soil has the same amount of carbon stored.
(Author here) I've added the word "indoor" to the title, which will hopefully make it harder to miss that this is not about climate change or carbon sequestration.
As somebody who works on carbon dioxide removal at planetary scale, I was excited about your article about indoor air… but nearly every comment here seems to want to talk about the changing climate!
I don't want to stop anyone from debating the merits of using plants for carbon sequestration. But the ones explaining why my article did such a bad job of explaining those merits are kind of eye-opening, yes.
asdfman123
today at 8:24 PM
You can sequester carbon with plants, but you can't let them decay or it will release it back into the environment (it's called the "carbon cycle" of a reason).
A startup has solved this problem the following way (for example): grow microalgae near a very dry desert, and bury it in trenches. It never decays and thus never releases CO2 due to lack of water.
Basically, we'd have to permanently stick it back underground again.
You don't necessarily have to bury the plants to sequester the carbon. A lot of oceanic carbon just sinks to the bottom and is eventually covered over, especially near estuaries that spew silt.
To me, this is great that demonstrates how ridiculous carbon capture and storage is. I just can't imagine us paying to do something like this at scale, when we have a much more straightforward alternative: Stop burning fossil fuels, and use clean energy instead. Right? Like why even both going through the effort of carbon capture, when we're still going to have to stop burning fossil fuels anyways, in order to fix the climate?
asdfman123
today at 8:46 PM
If you can find a way to get other people to stop burning carbon, let us know.
I know that sounds dismissive but I mean it. There's no magic wand.
Carbon capture is already done at scale because CO2 is commercially valuable.
The proposed carbon storage is permanent in the form of carbonates. This is a variant of the Solvay process used to make washing powder.
Chalk cliffs were once the shells of sea creatures. That's a whole load of sequestered carbon right there.
We'll have to do both I imagine by the time we realize it's too late.
Think of it like a battery. We pour sunlight into the plant at one end and then we take this gasoline from the other side of the battery and burn it. The end-result is that we have full fuel cycle powered by the Sun.
This kind of battery is useful. All human hearts together produce about the same power in beating as a Falcon 9 in the final stage but you can't use hearts like that.
Just popping in here to say that the IPCC has no model for a stable climate that doesn’t involve removing many billion tons of carbon dioxide alongside complete decarbonization, so unfortunately simply stopping emissions at this point isn’t enough. Some level of carbon dioxide removal is required to maintain a stable climate.
I'm a big proponent of transitioning to no-till agriculture when it makes sense. Perennial plants have deeper roots, which means they require significantly less water and fertilizer, all while sequestering more carbon.
Two examples:
-Switchgrass for ethanol. Currently, ~15% of irrigation water in the US goes towards corn, and more than 1/3rd of that is converted into ethanol for gasoline. Studies show that perennial switchgrass would be a 5x more efficient source of ethanol.
- Salish Blue - a perennial wheat-wheatgrass hybrid. I made savory crepes last week with pure salish blue flower, and they were excellent!
ninefathom
today at 7:32 PM
The BBC did this in their 2012 documentary mini-series "How to Grow a Planet" with Iain Stewart. It was a lovely series; I highly recommend it.
The vast interior of the world's oceans are a nutrient desert. It has been proposed to grow algae by spreading silt, the same way that Saharan winds do.
I’ve always wanted to jam on how to create an indoor carbon dioxide removal system. (I think that’s what this article is about but perhaps it’s indirectly about the changing climate)
1 kg per day of material adds up fast but that assumes zero ventilation. If I simply wanted a system to keep my office below 500 ppm all day, I wonder how much material that would produce.
Anyone ever build a little carbon dioxide zapping system for indoor air quality? I’ve also heard that indoor CO2 isn’t actually all that bad but it’s VOCs that are what make me feel sluggish.
sephamorr
today at 8:52 PM
I think what you really want is an Energy Recovery Ventilator. It cycles in fresh air and uses an intercooler to limit the heat and humidity loss.
That’s cool. Is that something that you’ve built or installed?
Even if that is a better solution, I am personally curious about an indoor carbon dioxide zapper, since what I work on is carbon dioxide removal at planetary scale.
moebrowne
today at 7:39 PM
What if the plants were algae?
I did some of the napkin math on algae a couple years ago... The fun realization is that the physical carbon has to go somewhere. So if we're trying to sequester the average american's 14 tons a year of carbon or whatever it is these days, that means you're going to have at least 14 tons of dead algae to deal with. (And a lot more weight if the algae isn't dehydrated.). That's a lot of dead algae, which demonstrates the difficulty of the problem...
In other news, have you considered ditching your car and becoming a vegetarian?
Not emitting the carbon in the first place is much easier!
yjftsjthsd-h
today at 7:12 PM
Bamboo it is.
davidkwast
today at 8:14 PM
Best comment
michaelfm1211
today at 7:09 PM
How is it that 132.5 watts is 3 light bulbs but 918 watts is 765 light bulbs? Is there a typo?
It might not be clearly worded, but 132.5 watts is the power used by 2 incandescent light bulbs, whereas 918 watts is the power present in the light produced by 765 light bulbs. The factor of 50 comes from the fact that incandescent lightbulbs are only ~2% efficient at turning power into light.
That one final number is all one needs as a reply for "but they help a little".
> Real plants do photosynthesis through a physical process
(nit) it is more accurate to call this a biological process, or chemical process
Saying "physical process" makes me think of inclined planes, free-body diagrams, and EM fields.
It's all physics at the bottom. Nature doesn't have APIs.
vitally3643
today at 7:45 PM
Yes, except parent is correct. Physcial and chemical mean very different and specific things in this context.
Calling photosynthesis a physical reaction is flatly incorrect no matter how you want to look at it. It is a physics reaction, sure, but "physical reaction" specifically means a Newtonian mechanical, reversible process at the macro scale.
A "chemical reaction" specifically means a (trivially) irreversible quantum/atomic reaction involving chemical bonds at the atomic/molecular scale.
I don't really understand this. First of all, you can just weigh the plant, and tell how much CO2 it has captured, right?
Second of all, what does it matter how much CO2 I produce? What's harmful is the additional CO2 that goes into the atmosphere for burning fossil fuels. All other CO2 is just in the same cycle that's been happening for ever.
EDIT: My child comment is dead and vouching doesn't resurrect it, but now the post makes sense, thanks for the clarification.
advisedwang
today at 8:14 PM
> what does it matter how much CO2 I produce
Because the author of the piece is worried about the CO2 levels in their home, not about global warming. (well maybe they are worried about global warming too, but that's not what this is about)
no, we are useing solar PV to eliminate the excess carbon bieng added to the atmosphere, and plants, rocks, and many other natural processes will return CO² levels to a more moderate level.
Article is not about global atmospheric or climate phenomena, nor civilization scale industrial processes. It's about the CO^2 levels in your room due to your breathing.
oh no!
realy?
but since I live in a drafty farmhouse up on a windy hill beside the ocean, my room air and the atmosphere as whole have very similar compositions, and I will continue to
treat conversations about both, the same as well.
toasty228
today at 9:04 PM
> plants, rocks, and many other natural processes will return CO² levels to a more moderate level.
No... How can you be this delusional? This is cult like behavior: something will fix it somehow, eventually, don't ask about details
Getting CO2 back to preindustrial levels by natural processes may take 100,000 years, IIRC. There will be some drawdown, but the ocean surface waters will become more saturated with carbon and that will stall. Over a longer time scale, CO2 will be pumped down into the deeper ocean. The true drawdown will require mineralization and precipitation as calcium carbonate, a slow process. The fossil fuel CO2 emitted each year corresponds to the calcium added to the ocean by erosion over about 100 years.
JungleGymSam
today at 7:53 PM
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This seems trivial: if you could add enough plants to your room to reduce CO2, we could easily do the same thing at planet-scale and global warming wouldn't be an issue.
Sadly I am a bit hopeless about climate change. Even if every person on earth dropped everything and started making biochar to be buried it would not sequester enough carbon to make a difference.
Hi! I work a lot with carbon dioxide removal systems. If every person on Earth dropped everything and started making biochar, it would definitely make a huge difference. Yes, we add a lot of carbon dioxide to the air of a year, but it’s doable to remove it. Humanity has taken on much bigger challenges before and succeeded. Now that’s not to say that it’s likely. I think it’s entirely unlikely that we avert the worst impacts of climate change unless something big changes. Thankfully, we get to choose what to work on every day, and I get to choose to work on that alongside inspiring people.
(and yes, this isn’t what the article is about, but it seems like it’s what everyone is responding to)
toasty228
today at 9:05 PM
> Humanity has taken on much bigger challenges before and succeeded.
Feel free to list them, we're basically reverse terra forming ourselves out of existence at that point, I don't think we've done anything even remotely close to that scale in such time frame
During World War II, the United States spent 40% of its GDP on the war. So we can spend big on things when we decide to.
That would be the equivalent of $12 trillion per year today, and we would clean up the climate in a jiffy with that. It would be a huge opportunity for job creation, manufacturing, innovation. It’s wild as a society we’ve convinced ourselves that stabilizing the climate is a cost instead of a massive opportunity.
SoftTalker
today at 7:43 PM
This article isn't about climate change. It's about using houseplants to absorb the CO2 you exhale in your house.
JungleGymSam
today at 7:56 PM
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