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> A plant is basically a self-healing, self-replicating CO2-capturing machine running off solar power and some chemicals. Not in itself. When the plant dies,

> A plant is basically a self-healing, self-replicating CO2-capturing machine running off solar power and some chemicals. Not in itself. When the plant dies, it rots and all the carbon goes back to the atmosphere by the action of fungi and bacteria. Plants can function as the zeroth step in a carbon capture pipeline. The actual capture happens when the plant dies and you bury (or otherwise process) its tissue somewhere so that the carbon cannot go back to the biosphere. Just growing plants and letting them die is purely carbon neutral.

corty 6y ago
> Just growing plants and letting them die is purely carbon neutral. Actually, no. Depending on the plants and circumstances, it can be carbon-(equivalent)-positive because rotting plant material exudes methane, which has a far higher global warming potential than CO₂. So even with simple plant agriculture you can harm the climate, e.g. wet rice production.
mikro2nd 6y ago
OTOH, growing plants, turning them into charcoal and sequestering that can be carbon-negative.
- Beltiras 6y ago
  It's carbon-negative even if you don't count the buried carbon due to it being a powerful fertilizing agent.
  - enriquto 6y ago
    I don't understand your remark. The plants that you are going to fertilize are part of a carbon neutral cycle anyway. It doesn't really matter if there is a big or small amount of them. The buried stuff is going to rot after a few years and release the carbon back. I think the idea is to bury it to "geological" depths, forever isolated to the biosphere. In the last century, we have burned millions of years worth of plant-based carbon sequestration. This was carbon that had been out of the biosphere for millions of years. Now our goal is to remove this carbon out of the biosphere again. I'm skeptical that this can be at all achieved by purely biological means. But burying dead plants a few meters deep, readily accessible to rot, is not likely to make any difference. Otherwise, we are going back to pre-cambrian CO2 levels, which were much higher than today.
    - Beltiras 6y ago
      Read up on black soil.

corty 6y ago

> Just growing plants and letting them die is purely carbon neutral. Actually, no. Depending on the plants and circumstances, it can be carbon-(equivalent)-positive because rotting plant material exudes methane, which has a far higher global warming potential than CO₂. So even with simple plant agriculture you can harm the climate, e.g. wet rice production.

mikro2nd 6y ago

OTOH, growing plants, turning them into charcoal and sequestering that can be carbon-negative.

Beltiras 6y ago
It's carbon-negative even if you don't count the buried carbon due to it being a powerful fertilizing agent.
- enriquto 6y ago
  I don't understand your remark. The plants that you are going to fertilize are part of a carbon neutral cycle anyway. It doesn't really matter if there is a big or small amount of them. The buried stuff is going to rot after a few years and release the carbon back. I think the idea is to bury it to "geological" depths, forever isolated to the biosphere. In the last century, we have burned millions of years worth of plant-based carbon sequestration. This was carbon that had been out of the biosphere for millions of years. Now our goal is to remove this carbon out of the biosphere again. I'm skeptical that this can be at all achieved by purely biological means. But burying dead plants a few meters deep, readily accessible to rot, is not likely to make any difference. Otherwise, we are going back to pre-cambrian CO2 levels, which were much higher than today.
  - Beltiras 6y ago
    Read up on black soil.