Use irrigation canals covered in solar power panels for pumps etc.
Plant vegetation and build up forests slowly. Slowly expand across the desert and connect both ends the block off grids and repeat irrigation and planting until the desert is gone.
We can, and we certainly should, but that does not solve the problem because those trees will eventually die and that carbon will cycle back through the biosphere. Mankind extracted a ton of carbon from the ground, where it was locked away, and we put it back into the air. People are trying to find ways of putting all that extra carbon back somewhere where it won't affect the cycles in nature. Trees just temporarily lock up carbon.
Stopping deforestation and massively boosting reforestation is one of the most effective things we can already do at scale. At this point we also need active carbon capture and significant reduction in emissions too, though - a multi-pronged approach.
Trees in forests are self-replicating. When one dies another grows in its place.
Yes, this isn't the only solution, but it's certainly part of the solution.
You've accomplished everything other sequestration technology promises, but you've done so in a way that is environmentally friendly.
This paper has some interesting ideas: https://cbmjournal.biomedcentral.com/articles/10.1186/1750-0...
My approach would be to find the best CO2/$ types of trees, buy them straight from the lumber industry, and sequester them in no-longer-used quarries. Just need to figure out a scalable way to ensure anaerobic conditions to help prevent CO2 release on breakdown.
For example an old coal mine and then seal it.
Old coal mines are too dangerous for humans to enter so you need some kind of robotics to load them up with trees and other biomatter to bury.
I would think that a proper solution would require figuring out how to get all that carbon into a chemical form that is chemically stable and won't biodegrade. The ideal looks a whole lot like coal, I'd guess?
AFAIK coal is composed mostly of trees that fell back before microbes evolved that could eat through their cellulose walls, and have had millennia of underground compression to further increase their stability - basically that process isn't available naturally to trees that fall today.
Western USA has had a "fire season" for every year for the last like 4 years. Last year, other places like Brazil and Africa join in on the fun.
So planting trees without a robust animal/insect ecosystem to decompose them before they combust is an incomplete solution.
Trees aren't the complete solution and the reason why has nothing to do with the tree dying and releasing the carbon.
What's going on here is that plants are converting CO2 into mass. A tree that isn't growing isn't creating new mass and therefore isn't lowering carbon in the atmosphere.
One aspect is that the required land area - https://climate.nasa.gov/news/2927/examining-the-viability-o... mentions 900 million hectares (2.2 billion acres), which would roughly cover the 10Gt/year asked by the x-prize - is enormous, and it's not an accident or negligence that this land isn't forested now, it's generally because we turned it into farmland or pastures.
Are we willing to take away 900 million hectares of land that produces food for the world and money for the locals away from that productive use and turn all of it into unproductive forest that won't get used for logging? Perhaps we are, but if there are other options for carbon removal that don't require as much land resources, that would be preferable.
I wrote a short piece about it (with sources)[0]
[0] https://carbonremoved.com/blog/trees-are-not-the-answer-to-c...
The problem is the space issue and that it takes a decade or two for there to be meaningful carbon uptake.
Most land is private so you can't go around planting willy nilly. What's worse is that you are technically not allowed to plant on most public land either, although for small amounts of native species, you can sneak by.
It seems insane that we aren't looking at trees more seriously. Here we have a self-reproducing, exponential, solar powered, organic, low-tech, carbon capture system. We don't even have to plant them, we can simply allocate land and let them do their thing on their own if we're patient for natural succession. Or we can accelerate the process by planting select species, thinning etc.
We should also be setting aside more of the remaining old-growth forests to protect them from being logged, as these forests represent a standing carbon sink (aside all of the other ecological benefits of protecting old-growth forest).
I know it's not the complete solution and that we need all the cards on the table, but I fear that in our appetite for high tech fixes, we're overlooking this simple biological solution.
As others have said, trees are only temporary as they eventually die and need to be replanted. They're also slow to start, and need to be maintained (which costs carbon as well).
That’s pretty much how we got here, except instead of planting we mined, cut and burnt.
The pathway back is rather harder.
If everyone stopped mowing their lawns for 20 years and let trees run wild instead, would that make a dent?
What about that plus turn half of our roads into parks?
Anyone got a link to a good open source interactive simulator?
That's one country, for one year. The world has been burning coal for more than a century. To get back to preindustrial CO2 levels, all that coal needs to be unburned and buried again. That's the scale of the problem.
I mean, in Canada when they raze a patch of forest they already immediately replant it.
The areas that aren't forested are so because they're being used for agriculture.