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Things are so dire that even if we use all "guns" in our disposal it will be difficult. There is no single solutions that can help, amount of CO2 is so huge tha

Things are so dire that even if we use all "guns" in our disposal it will be difficult. There is no single solutions that can help, amount of CO2 is so huge that if we would turn CO2 we need to sequester into graphite bricks we could build a wall 10 meters high and 5 meters wide encircling the Earth around Equator 32 times. So, we need all we can think at same time, now. :/ Simply, current amount of carbon in the atmosphere has been released from sources that were not there, and we are still cutting trees more than we plant. Some calculation say we need between 1-2 trillion trees. But even then trees need a quite some time to grow and become effective.

hedora 6y ago
Also, the carbon those trees sequester needs to be somehow captured permanently. I imagine a solution where people grow stands of fast growing trees, clear cut every $optimal years, use (magic?) chemistry to separate the harvest into carbon and not carbon, then dump the not carbon back onto the soil, and replant. Even with that, I’m not convinced there are enough acres of land on earth. I haven’t seen anyone do the math, and suspect direct carbon capture plants and olivine reactions will scale better.
- Panino 6y ago
  You'll be happy to know that what you describe exists and it has a name: pyrolysis. Pyrolysis is the thermal anaerobic decomposition of biomass. Basically, you heat up organic material without oxygen at temperatures attainable from a relatively small fire. During this process, volatiles such as hydrogen and oxygen separate from the carbon in the biomass feedstock (dry untreated wood, bones, old cotton tshirts, whatever) and get released as syngas, leaving more or less pure fixed carbon that is very stable, safely sequestered in soil for thousands of years. The resulting carbon, called biochar, can be co-composted to prepare it for use in soil, where it protects the soil from drought and flood alike. Plants grown in soil with higher carbon content are bigger and healthier, and these soils can produce more of whatever you're growing. I make biochar at home but there are companies that do it on an industrial scale. Humanity has been pumping CO2 into the atmosphere at an epic scale for decades. In addition to going carbon neutral with more wind, solar and nuclear, we need to draw CO2 back out of the atmosphere on an epic scale. And biochar resulting from pyrolysis is one of the major tools since it has synergistic effects with other tools, like mass tree plantings. Biochar production can also offset other energy uses, for example by either directly burning the syngas on-site for heating purposes, or for capturing it and using it later as a fuel in an application that would otherwise use fossil fuel.
  - gambiting 6y ago
    Isn't this basically how charcoal is made?
    - Panino 6y ago
      Sort of but not really. Grill charcoal is made at a lower temperature, preserving more volatiles, and then an accelerant is often added (basically lighter fluid) to help it ignite and burn. It's similar at a glance but the differences are important.
  - zamalek 6y ago
    I wonder if dumping the biochar into a subduction zone/trench would permanently remove the carbon from the system at any reasonable rate. Or possibly back-fill mines with it. Either way, I completely agree. Planting trees doesn't solve the problem if those trees are allowed to naturally decompose. Trees are just really efficient carbon fixing machinery, we need to store the solid carbon somewhere.
  - hedora 6y ago
    That doesn’t solve the “dump the non-carbon back into the soil” part. Presumably repeated clear cutting would strip the top soil of nutrients in a few generations of trees. At that point, you need to reintroduce those nutrients (especially nitrogen) somehow.
- developer92 6y ago
  you'll be glad to know that leaving wood to rot on the ground only releases about 30% of the carbon, and allows for further biodiversity to live that might absorb further carbon. The fact is the natural world has mechanisms for this, we just need to let them work: stop clearing dead wood for example.
- developer92 6y ago
  Clear cutting is a bad idea, if you think about circumference = 2piR you can see that the older the tree is the more CO2 it takes up. You need to let trees get as big as possible if you want to be efficient. Additionally big trees support more biodiversity, which afaik is also important in carbon capture.
BurningFrog 6y ago
Note that cutting trees is not a problem, as long as the wood isn't allowed to convert back to CO₂. So how do we sequester large amounts of wood for a century at least?
- developer92 6y ago
  rotting wood does not release much CO2, I think about 30%. Most of it ends up in the soil.

hedora 6y ago

Also, the carbon those trees sequester needs to be somehow captured permanently. I imagine a solution where people grow stands of fast growing trees, clear cut every $optimal years, use (magic?) chemistry to separate the harvest into carbon and not carbon, then dump the not carbon back onto the soil, and replant. Even with that, I’m not convinced there are enough acres of land on earth. I haven’t seen anyone do the math, and suspect direct carbon capture plants and olivine reactions will scale better.

Panino 6y ago
You'll be happy to know that what you describe exists and it has a name: pyrolysis. Pyrolysis is the thermal anaerobic decomposition of biomass. Basically, you heat up organic material without oxygen at temperatures attainable from a relatively small fire. During this process, volatiles such as hydrogen and oxygen separate from the carbon in the biomass feedstock (dry untreated wood, bones, old cotton tshirts, whatever) and get released as syngas, leaving more or less pure fixed carbon that is very stable, safely sequestered in soil for thousands of years. The resulting carbon, called biochar, can be co-composted to prepare it for use in soil, where it protects the soil from drought and flood alike. Plants grown in soil with higher carbon content are bigger and healthier, and these soils can produce more of whatever you're growing. I make biochar at home but there are companies that do it on an industrial scale. Humanity has been pumping CO2 into the atmosphere at an epic scale for decades. In addition to going carbon neutral with more wind, solar and nuclear, we need to draw CO2 back out of the atmosphere on an epic scale. And biochar resulting from pyrolysis is one of the major tools since it has synergistic effects with other tools, like mass tree plantings. Biochar production can also offset other energy uses, for example by either directly burning the syngas on-site for heating purposes, or for capturing it and using it later as a fuel in an application that would otherwise use fossil fuel.
- gambiting 6y ago
  Isn't this basically how charcoal is made?
  - Panino 6y ago
    Sort of but not really. Grill charcoal is made at a lower temperature, preserving more volatiles, and then an accelerant is often added (basically lighter fluid) to help it ignite and burn. It's similar at a glance but the differences are important.
- zamalek 6y ago
  I wonder if dumping the biochar into a subduction zone/trench would permanently remove the carbon from the system at any reasonable rate. Or possibly back-fill mines with it. Either way, I completely agree. Planting trees doesn't solve the problem if those trees are allowed to naturally decompose. Trees are just really efficient carbon fixing machinery, we need to store the solid carbon somewhere.
- hedora 6y ago
  That doesn’t solve the “dump the non-carbon back into the soil” part. Presumably repeated clear cutting would strip the top soil of nutrients in a few generations of trees. At that point, you need to reintroduce those nutrients (especially nitrogen) somehow.
developer92 6y ago
you'll be glad to know that leaving wood to rot on the ground only releases about 30% of the carbon, and allows for further biodiversity to live that might absorb further carbon. The fact is the natural world has mechanisms for this, we just need to let them work: stop clearing dead wood for example.
developer92 6y ago
Clear cutting is a bad idea, if you think about circumference = 2piR you can see that the older the tree is the more CO2 it takes up. You need to let trees get as big as possible if you want to be efficient. Additionally big trees support more biodiversity, which afaik is also important in carbon capture.

BurningFrog 6y ago

Note that cutting trees is not a problem, as long as the wood isn't allowed to convert back to CO₂. So how do we sequester large amounts of wood for a century at least?

developer92 6y ago
rotting wood does not release much CO2, I think about 30%. Most of it ends up in the soil.