The best long-term carbon sequestration medium we have is wood.
It is the slow and unsexy algorithm of:
Plant trees, and then build things with them. Be careful not to burn them. Repeat
It is the slow and unsexy algorithm of:
Plant trees, and then build things with them. Be careful not to burn them. Repeat
> Be careful not to burn them. Repeat
So what do you do with the wood? A billion years ago, your plan would have worked out brilliantly. Some say it's where our oil came from. But now we have fungus among us that evolved to rapidly turn your wood right back into CO2.
Unless you sterilize the wood and bury it deep in the ground where it will never be exposed to air or spores, you're right back to square one. Also there's the logistics and carbon footprint of burying and sterilizing the wood.
You're not the first person to think of this:
It requires massive timber though. And to get that on a larger scale, you need good long term forest management policies. Plan for something else than paper or chipboard or glulam.
So, not a technical problem, but a political one.
But if executed correctly (Drones sowing and harvesting millions of tons of fast-growing wood / switchgrass per year) and then correcty getting rid of it so it can't decompose (i.e. probably drying and/or sterilizing it), it might solve carbon capture.
That being said, it all involves lots of space, mineral fertilizer and moving parts — on top it might be disastrous to any animal ecosystem trying to get hold in those woods. I'm not sure we wouldn't be better off with stationary carbon capture stations eventually.
Anyway, you can also store a lot of the carbon just as forest, though it's more of a "one time" use of the land. Trees can also live for hundreds of years. And the soil can also store carbon. At least over here, large trees can often survive forest fires too.
But it requires changed policy, it's not a technological problem.
Cost is a consideration. But plastic over the long term has a cost, that isn't factored into the manufacturing+sales cost.
I'm not suggesting this would solve the problem. That single magic bullet doesn't exist. But it can't hurt either.
https://www.epa.gov/ingredients-used-pesticide-products/chro...
humungous fungus among us
and I just had to point it out :)
I'm not immediately finding a comparison of various ecosystems, though there's this on Indonesian swamps:
https://www.sciencedirect.com/science/article/pii/0045653593...
And:
"Peatlands only cover about 3 percent of the Earth but they accumulate more carbon than tropical rainforests," says biogeochemist Nancy Dise of Manchester Metropolitan University in England. "In terms of sitting there kind of quietly year after year packing away massive amounts of carbon, nothing tops these peatlands."
https://www.scientificamerican.com/article/peat-and-repeat-r...
I don't think this pencils out. We use quite a lot of machinery and trucks and electricity to build with and it's not obvious that the carbon sequestered by the wood in a structure is larger than the amount of carbon expended in all aspects of the building of it.
In fact, I suspect it might be quite a bit off ... a dry 2x4 weighs very little and there is a lot of driving and idling and generating and power usage involved in building.
The more important aspect is that something else would have been used instead. Each building that is of wood construction is one that wasn't built primarily with steel or concrete.
Also, effects of scale can be significant. As a simple example, there is about 200 billion kg of carbon sequestered in the contiguous US just in wooden telephone poles. If you can find a widescale use that makes economic sense, you make more immediate sinks. If you can also find ways of long-term sequestering the waste as it enters end of life, you can make ongoing gains in the CO2 balance.
[1] - http://articles.extension.org/sites/default/files/CIWP%20pub...
Also wood buildings can look cool https://www.google.co.uk/search?q=wood+buildings&num=30&tbm=...
and maybe our future AI robots can build them.
However, we do not know how long biochar lasts when used as a soil amendment [eg. 1]. Also, it's only useful in this way when loaded and applied to poor soil in the tropics [2].
For long term storage of CO2, it might be better to just bury the main products of pyrolysis (biochar and pyrolysis oil) where hard coal and the oil once used to be - deep in the earth. Burying both products should also make it cheaper (from a carbon mitigation point of view), since it's hard to make useful products from the pyrolysis oil. The biochar also doesn't need to be as clean as when used for soil. One can even pyrolyse old tires (and possibly plastic).
The problem is, of course, that there are no long-term studies about the stability of biochar (and the bio-oil) in deep layers.
[1] https://onlinelibrary.wiley.com/doi/abs/10.1111/gcbb.12266 [2] http://iopscience.iop.org/article/10.1088/1748-9326/aa67bd/m...
The best way to implement this is by slash-and-char of the tropical forests. I have done the calculations and using less than 30% of te tropical forests we can pull out all the CO2 being addded from human activity. It would also create a viable industry in some of the most poor regions in the world.
All Power Labs (allpowerlabs.com) produces small scale reactors that can do just that.
In contrast, the carbonate minerals from the reaction of CO2 with these silicates ARE thermodynamically stable. Even if left exposed on the surface of the Earth they will not release CO2 back into the atmosphere.