Which requires digging. Which requires machinery at an industrial scale. Which requires large amounts of energy. Which makes it really hard for this to not be in the perpetual motion set of solutions.

You’d have to be extracting more carbon than your diggers consume (since even today I don’t think this has electrified and capable of running on solar). Your diggers are consuming concentrated carbon compressed from plant and animal biomass under high pressure and energy over millions of years. It seems highly unlikely just growing and burying biomass is sufficient. Additionally, I’m pretty sure the CO2 is just going to leak out in large quantities since, unlike the naturally sequestered CO2 we extract from the ground, you have bacteria that can break down the biomass and let the CO2 escape as a gas. Which means we have serious additional efficiency losses.

The only solution that could work for sequestration as far as I can tell seems like an industrial process powered by nuclear because it breaks the energy cycle completely to accomplish the task. Solar is popular but I’m skeptical that renewables are up to the task that’s required to undo several hundred years of fossil fuels being the engine of the world’s industrial progress.

I can't speak to any of the details, but this is definitely an interesting approach: https://www.cnn.com/2021/05/03/business/running-tide-kelp-ca...

The majority of carbon in the soil doesnt come from plant matter. It comes from plant root exudates. Plants pump sugars and carbohydrates into the soil to feed bacteria and fungi. As long as we dont poison or till the soil, the ecosystem keeps the carbon in the soil. Some of it will cycle. That is the way it is supposed to be.

Greater than 80% of farm land soil is dead. What little carbon that is built up in a season is released in the spring when the field is tilled.

No till, diverse cover crops, and animals (a complete ecosystem) stores immense amounts of carbon in the soil.

I like the idea of sort of (but not really) making coal again in a fight against climate change.

In WV we have tons of old strip mine - we should fill them up with plants and bury it.

If we did something like that I imagine the biomass under the earth would compress over time and the land above would end up shifting and causing issues for anyone that wants to use it.

Edit - Daydreaming about this scenario and I am imagining trying to sell the idea of refilling the old coal mines with biomass to folks living in coal country. An interesting and funny situation.