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I recently looked up the difference in CO2 emissions between burning 1kg wood vs 1kg petrol. Surprisingly, the values are relatively close: Burning 1kg wood re

I recently looked up the difference in CO2 emissions between burning 1kg wood vs 1kg petrol. Surprisingly, the values are relatively close: Burning 1kg wood releases 1.65 - 1.8 kg of CO2. [0] Burning 1kg of crude oil releases 3.16 kg of CO2. [1][2] I would have expected the carbon density of oil to be much higher! To me, this suggests that a very naïve approach of growing trees and storing them in the places where we obtained the oil would be a hypothetically feasible way of significantly reducing the CO2 content in the air. And that is before the wood has been turned into charcoal etc. What am I missing? [0] https://www.kaltimber.com/blog/2017/6/19/how-much-co2-is-stored-in-1-kg-of-wood https://www.kaltimber.com/blog/2017/6/19/how-much-co2-is-sto... [1] https://www.epa.gov/energy/greenhouse-gases-equivalencies-calculator-calculations-and-references https://www.epa.gov/energy/greenhouse-gases-equivalencies-ca... [2] https://energyeducation.ca/encyclopedia/Barrels_of_oil_equivalent https://energyeducation.ca/encyclopedia/Barrels_of_oil_equiv...

tlb 4y ago
Oil doesn’t come from huge caverns that we could drop trees into. Oil is often deep underground, soaked into porous rock. So wood would have to be liquified before attempting to pump it into oil wells, and it ruins the well for future use. Wood is valuable and other plant material is similar carbon/kg, so the low-hanging fruit is to take agricultural waste (currently burned or left to rot) and bury it. Hauling all that straw around burns a lot of fuel, so it’s not clear how well it scales compared to other approaches.
- vkou 4y ago
  > so the low-hanging fruit is to take agricultural waste (currently burned or left to rot) and bury it. Which would, as in the case with 'cut and bury trees' deplete the soil of non-carbon nutrients. There's a reason farmers leave that waste 'to rot'.
  - quixoticelixer- 4y ago
    You can pretty easily replace those nutrients though.
po 4y ago
>I would have expected the carbon density of oil to be much higher! You're comparing by weight, so density (which is mass/volume) isn't a part of it. 1kg of wood will take up more space than 1kg of oil. So the density is higher but equal weights of 'mostly hydro-carbon' will release equal amounts of CO2.
- oliwary 4y ago
  That’s a very good point. It seems like the densities are relatively similar as well though [0][1]. Not saying they’re the same, but even the fact that they’re in the same order of magnitude was surprising to me. Seems like filling a 1km^3 with wood could offset all CO2 emitted for over 20 years! [0] https://www.engineeringtoolbox.com/wood-density-d_40.html https://www.engineeringtoolbox.com/wood-density-d_40.html [1] https://www.transmountain.com/about-petroleum-liquids https://www.transmountain.com/about-petroleum-liquids
  - boltzmann-brain 4y ago
    which is precisely why I've spent the last 15 years petitioning the government for an all-wood generational ship to take us to the nearest extrasolar goldilocks planet

tlb 4y ago

Oil doesn’t come from huge caverns that we could drop trees into. Oil is often deep underground, soaked into porous rock. So wood would have to be liquified before attempting to pump it into oil wells, and it ruins the well for future use. Wood is valuable and other plant material is similar carbon/kg, so the low-hanging fruit is to take agricultural waste (currently burned or left to rot) and bury it. Hauling all that straw around burns a lot of fuel, so it’s not clear how well it scales compared to other approaches.

vkou 4y ago
> so the low-hanging fruit is to take agricultural waste (currently burned or left to rot) and bury it. Which would, as in the case with 'cut and bury trees' deplete the soil of non-carbon nutrients. There's a reason farmers leave that waste 'to rot'.
- quixoticelixer- 4y ago
  You can pretty easily replace those nutrients though.

po 4y ago

>I would have expected the carbon density of oil to be much higher! You're comparing by weight, so density (which is mass/volume) isn't a part of it. 1kg of wood will take up more space than 1kg of oil. So the density is higher but equal weights of 'mostly hydro-carbon' will release equal amounts of CO2.

oliwary 4y ago
That’s a very good point. It seems like the densities are relatively similar as well though [0][1]. Not saying they’re the same, but even the fact that they’re in the same order of magnitude was surprising to me. Seems like filling a 1km^3 with wood could offset all CO2 emitted for over 20 years! [0] https://www.engineeringtoolbox.com/wood-density-d_40.html https://www.engineeringtoolbox.com/wood-density-d_40.html [1] https://www.transmountain.com/about-petroleum-liquids https://www.transmountain.com/about-petroleum-liquids
- boltzmann-brain 4y ago
  which is precisely why I've spent the last 15 years petitioning the government for an all-wood generational ship to take us to the nearest extrasolar goldilocks planet