Why can’t we just sequester CO2 into plants we eat or forests?

Question

I saw a youtube video about how Japan burns materials that can’t easily be recycled to produce energy and captures the CO2 produced from the process. The CO2 is then sold to some local factories to produce various things like fire extinguishers, and some algae farms (I googled this and algae is used to produce food and oil).

I googled that at sea level, CO2 in the atmosphere is at 350 PPM, but certain plants thrive at 1500 PPM.

It got me thinking – why can’t we pump CO2 into indoor farms, plantations or forests to sequester more carbon?

Would that even work? Is the carbon just released into the air again once the plants are eaten or broken down?

In: Biology

Answer 1

This is a very common thing in greenhouses. Burning things creates CO2, water and heat, all of which improves the growth of plants. Usually what is being burned is natural gas though as this burns cleanly. You can also burn other things but it tends to create sot and toxins which needs to be filtered out.

The issue we come back to all the time is how to capture carbon. This is relatively easy in a chemical plant which already produce almost pure CO2 in a part of their process. Currently almost all CO2 sold in the world comes from ammonia production. There are projects working on CO2 extraction from cement plants, another chemical process which produce very clean CO2. But so far none are commercially viable.

Capturing CO2 from dirty sources like the exhaust gasses of incinerators and power plants is a much harder problem. The project you are talking about in Japan is very innovative but is costing the government a lot of money. There are other projects working on capturing CO2 from the atmosphere. This is also tricky because the atmosphere does not have much CO2 so you need to process a lot of air to get just a bit of CO2. But this does actually have some merits when connected to a greenhouse as the short transportation distance gives them an economic advantage. So we might see CO2 scrubbers connected to greenhouses in the not so distant future to replace their natural gas burners.