I saw a youtube video about how Japan burns materials that can’t easily be recycled to produce energy and captures the CO2 produced from the process. The CO2 is then sold to some local factories to produce various things like fire extinguishers, and some algae farms (I googled this and algae is used to produce food and oil).
I googled that at sea level, CO2 in the atmosphere is at 350 PPM, but certain plants thrive at 1500 PPM.
It got me thinking – why can’t we pump CO2 into indoor farms, plantations or forests to sequester more carbon?
Would that even work? Is the carbon just released into the air again once the plants are eaten or broken down?
In: Biology
So, most carbon emissions are not in a setting that allows for easy scrubbing. But, putting that aside, this approach does work in theory. Even though carbon does get re-emitted once a plant dies, creating a larger pool of organic carbon will reduce the steady-state concentration of CO2 in the atmosphere.
The issue is that you have to plant a truly massive number of plants to make a difference. Just to be clear, this isn’t because the biosphere isn’t good at handling carbon; human CO2 emissions are small relative to the flux of carbon due to photosynthesis and respiration. But increasing that capacity even further to counteract something that we’re very, very good at doing, burning fossil fuels, turns out to be pretty tough.
To get more bang for our buck, many researchers in plant biology and biotechnology are trying to make plants that invest more heavily in recalcitrant organic matter like lignin. If we couple this with enhanced investment, by the plant, in below-ground biomass, we could leave behind large quantities of carbon after every harvest, making this a more attractive strategy.
Once the plants break down its back out again, yeah.
If you can add a bunch of standing biomass, like a forest where there wasn’t one before, then yes you can capture a bunch of carbon. Plants will die, break down and release it yes but there will also be new ones growing taking carbon back up and the cycle is much slower than farmed crops.
Thing is that just about worldwide any bit of land that would easily grow and forest is also in demand for other uses.
The other problem is we’re releasing a bunch of carbon that WAS in long term storage for lack of a better term. Things like coal. Coal…can’t form anymore. The only reason it could was that in the carboniferous period organisms that xould break down that kind of plant matter hadn’t evolved yet. So we’re letting that all out AND cutting down living stores like forests/jungles.
> Is the carbon just released into the air again once the plants are eaten or broken down?
Yes, that’s the problem. You breathe out almost all the carbon you eat as CO2. And when trees die and decompose, their carbon becomes CO2 in the air as well.
You can do this. You grow lots of trees, then you turn the trees into charcoal (using some of the trees as fuel), then the charcoal is nearly pure carbon removed from the air which you can then stack and/or bury. Then you grow more trees where the old ones were.
It takes an awful lot of trees to do this though, meaning a lot of land, nutrients, water, time, labour and infrastructure.
It can totally be done. If it is practical and scalable is another question. The temptation to use the charcoal would also be pretty high as it would be a great source of energy.
I work in carbon capture. Basically, we took a bunch of carbon that was stored underground and not going anywhere, especially not to the atmosphere, and took it out and put it in the “cycle”. Now that CO2 can go to plants, sea, forests, etc, but all of those have different carbon storage timelines (i.e. plants will degrade back into CO2 in a relatively short timeline). So our options are currently: Send it back underground, this time as CO2 instead of as massive hydrocarbon chains, or make the CO2 into something more stable than plants, forests, etc. Funnily enough, plastic is a great carbon sink. Methanol is currently the best thought of “future” usage of CO2, though it’s not cheap to make.
We can and do, and actually, downramping animal agriculture would free up a lot of land for this very purpose. The sequestration from going globally plant-based would be enough to offset more than a decade of carbon emissions.
Reforestation also helps. There are large reforestation projects on-going, that have a tangible – if a minor – impact on the net increase of carbon in the atmosphere.
Alone these methods are not enough to offset carbon emissions though, and eventually these methods would reach a point of saturation, after which no more carbon can be tied to trees or the ground.
Ideally we’d decrease fossil fuel use while increasing sequestration of atmospheric carbon to biomass and the soil. The technology and knowledge is there as it is. The problem is more political.
Yes, but they need to continue to exist in their solid form fo basicaly eternity. Fosil fuels are basically organic matter that was burried underground.
Thanks everyone for your responses. I learned a lot here about the carbon cycle and carbon capture tech, and its challenges. I thought if I could pump CO2 into my raised garden beds and seal them up for a few hours a day, I could help (minutely) to take up more carbon from the environment. I guess that would’ve been pointless anyway – I’d have to produce or purchase CO2 which is probably more harmful than helpful.
So in short, there isn’t any real way for individuals to reduce CO2 emissions, other than the usual – minimising power and goods wastage.
For millions of years trees fell and didn’t rot (nothing could digest the Lignin that makes up wood) this removed large amounts of Carbon from the atmosphere creating Coal. Also for millions of years animals that died and fell into the deep ocean removed large amounts of carbon from the world forming oil. Both of these sources of carbon have been brought out sequestration in more or less the last 200 years. The problem is… scale.
We absolutely can do that, and there are people trying to replant forests for that very reason.
However, there’s a LOT of CO2 out there, and only so many forests we can plant. And for the other things like food or algae, those aren’t carbon sinks, because they only hold carbon until they are ‘used’ in whatever fashion they get used. For example, a ton of corn is grown for ethanol (fuel.) That takes carbon from the air to grow corn… which is then put right back in the air when the fuel is burned. And a net negative, due to all the other carbon produced to grow, process, transport that fuel.
We need some kind of massive scale increase to make it have a significant effect, and that’s hard to do. Forest entire deserts perhaps. Or grow massive amount of quickly growing trees and dump them to the bottom of the ocean and plant more. (Wood takes many centuries to decay underwater.)
Latest Answers