Comment by anon1253 | Hacker News Reader

Comment by anon1253 | Hacker News Reader

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It's not the only option either. Combine that solution on a massive scale with re-forestation and (even though eventually it's CO2 neutral) it might actually make a dent. My go-to model was always:

- Plant heliostat molten salt reactors in desert coastal areas [1]

- Use generated heat to desalinate water

- Use desalinated water to provide irrigation

- Plant (potentially GMO'ed) bootstrapping organisms to create a soil (greening)

- Plant trees

- Rinse repeat.

However, your idea makes more sense if the only goal is CO2 scrubbing. But adding the heliostat molten salt reactors in a desert might be quite feasible, they generate tons of heat, which can be translated into energy or simply mechanical force (water pressure)…and there is no shortage of silicates in the desert.

[1] http://www.solarreserve.com/en/technology/molten-salt-energy...

Yes, re-forestation or afforestation is another scheme worth considering. It can't scale up to the extent of accelerated silicate weathering but it could reach a scale of gigatons of CO2 per year. And it could produce food, wood products, and desirable living space for humans where once there were deserts with little biomass of any kind. You need to harvest-and-bury wood (as biochar, preferably) pretty regularly if the primary goal is CO2 sequestration; otherwise the steady state is approximately equal to current mature forested areas (which store plenty of carbon in soils but aren't great at continuing to remove more from the air).

Accelerated silicate weathering and "greening the deserts" are concepts that work well together, too. Mature fertile soil contains weathered minerals and organic matter. Crushing basalt can speed up the weathering part of producing soil, and provide micronutrients for plants plus a couple of important macros (phosphorus and potassium).

Only tangentially related, but here[0] is a video of the great reforestation program that South Korea undertook after the Korean War. They effectively transformed vast arid landscapes into healthy forests. Shows the power of a nation/people coming together with careful planning, forethought, unity, and grit can literally shape the earth.

[0] https://www.youtube.com/watch?v=_3KkN8hvUCI

Would YC incubate something like this? If we sold excess water to California farms and sold energy to the grid and sold fiber/logs to paper or saw mills I think we could see positive ROIC and do some real good for the environment at the same time.

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