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There is one way of storing carbon in the soil for the long term: biochar[0]. Biochar is organic matter heated anaerobically (pyrolysis) until it turns into so

by jbotz 5y ago

There is one way of storing carbon in the soil for the long term: biochar[0]. Biochar is organic matter heated anaerobically (pyrolysis) until it turns into something like charcoal. Biochar is stable for a long time. You can then bury that in the soil... it seems to improve the soil by providing surface area for soil micro-organisms and to store nutrients. This could be done on a very large scale, and pyrolysis can actually be energy positive because you can burn the hydrogen that's released to perform the pyrolysis and still have energy left over. This may be one of our best options, and we should accelerate more research in that area. [0] https://en.wikipedia.org/wiki/Biochar https://en.wikipedia.org/wiki/Biochar

chris_va 5y ago
> still have energy left over ... if it's dry biomass. Too much humidity might tip that the other way, unless I am doing the math wrong. Looking at CA's forests right now, that might not be a problem :/
- greggyb 5y ago
  Once bootstrapped, the excess energy can go into kiln drying the input for the next batch.
steve_adams_86 5y ago
It doesn't automatically improve all soil, does it? As I recall it increases the pH level, which may or may not benefit the soil in that biome, or for the given use of the soil if you're growing food there.
- jasonlaramburu 5y ago
  The southern US traditionally has moderately acidic soils. Low soil pH is increasingly a problem in the Midwest as well due to poor agricultural practices.
- navi0 5y ago
  This is an important point to consider. The agricultural studies I’ve seen typically apply 80% compost and 20% biochar to degraded soils because biochar is alkaline. It can also be made less alkaline with better, more sophisticated production technologies (i.e., reactors) that minimize ash.
mleonhard 5y ago
Why do you believe that micro-organisms will not break down biochar? From the article: > Yes, soil is enormously varied. And it contains a lot of carbon. But there’s no carbon in soil that can’t, in principle, be broken down by microorganisms and released into the atmosphere.
- nolroz 5y ago
  Biochar is interesting. It seems to be dependent on the temperature your pyrolysis occurs at and likely many other variables. It also encourages microbial growth that can help sustain and even add to the carbon content. There are studies that show it can sequester carbon from dozens to hundreds of years potentially, and patches of "terra preta" found in the Amazon are found to be self regenerating (growing at 1cm/yr) and were originally set down between 450-950BCE. Fascinating stuff.
- jasonlaramburu 5y ago
  If biochar is made with 80% or higher fixed carbon it has half life of >500 years in active agricultural soils.
- joe_the_user 5y ago
  If you have to, you can store it in underground mines. The result effectively reverse coal mining.
  - lamontcg 5y ago
    we could skip out the middleman and just leave the carbon in the ground to begin with.
    - CrazyStat 5y ago
      Probably too late for that.
    - techbio 5y ago
      If by "we" you mean everyone, no we can't. Edit: assuming you know it's too late not to start, propose something other than magic wand obvious solutions.
brandmeyer 5y ago
The science does not meet the hype. > Our review shows there are not enough data to draw conclusions about how biochar production and application affect whole-system GHG budgets. Wide-ranging estimates of a key variable, biochar stability in situ, likely result from diverse environmental conditions, feedstocks, and study designs. There are even fewer data about the extent to which biochar stimulates decomposition of soil organic matter or affects non-CO2 GHG emissions. Identifying conditions where biochar amendments yield favorable GHG budgets requires a systematic field research program. Finally, evaluating biochar's suitability as a climate mitigation strategy requires comparing its effects with alternative uses of biomass and considering GHG budgets over both long and short time scales. From https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0075932 https://journals.plos.org/plosone/article?id=10.1371/journal...
- jasonlaramburu 5y ago
  That paper is from 2013. The science has advanced substantially since then.
- mr_overalls 5y ago
  Several university laboratories are still actively researching biochar and provide snapshots of the current thinking regarding its usefulness: https://whitmanlab.soils.wisc.edu/faqs/ https://whitmanlab.soils.wisc.edu/faqs/ http://www.css.cornell.edu/faculty/lehmann/research/biochar/biocharmain.html http://www.css.cornell.edu/faculty/lehmann/research/biochar/...
ashtonkem 5y ago
Honestly not too far from the glib “just bury the coal again” solution.

by jbotz 5y ago

chris_va 5y ago

> still have energy left over ... if it's dry biomass. Too much humidity might tip that the other way, unless I am doing the math wrong. Looking at CA's forests right now, that might not be a problem :/

greggyb 5y ago
Once bootstrapped, the excess energy can go into kiln drying the input for the next batch.

steve_adams_86 5y ago

It doesn't automatically improve all soil, does it? As I recall it increases the pH level, which may or may not benefit the soil in that biome, or for the given use of the soil if you're growing food there.

jasonlaramburu 5y ago
The southern US traditionally has moderately acidic soils. Low soil pH is increasingly a problem in the Midwest as well due to poor agricultural practices.
navi0 5y ago
This is an important point to consider. The agricultural studies I’ve seen typically apply 80% compost and 20% biochar to degraded soils because biochar is alkaline. It can also be made less alkaline with better, more sophisticated production technologies (i.e., reactors) that minimize ash.

mleonhard 5y ago

Why do you believe that micro-organisms will not break down biochar? From the article: > Yes, soil is enormously varied. And it contains a lot of carbon. But there’s no carbon in soil that can’t, in principle, be broken down by microorganisms and released into the atmosphere.

nolroz 5y ago
Biochar is interesting. It seems to be dependent on the temperature your pyrolysis occurs at and likely many other variables. It also encourages microbial growth that can help sustain and even add to the carbon content. There are studies that show it can sequester carbon from dozens to hundreds of years potentially, and patches of "terra preta" found in the Amazon are found to be self regenerating (growing at 1cm/yr) and were originally set down between 450-950BCE. Fascinating stuff.
jasonlaramburu 5y ago
If biochar is made with 80% or higher fixed carbon it has half life of >500 years in active agricultural soils.
joe_the_user 5y ago
If you have to, you can store it in underground mines. The result effectively reverse coal mining.
- lamontcg 5y ago
  we could skip out the middleman and just leave the carbon in the ground to begin with.
  - CrazyStat 5y ago
    Probably too late for that.
  - techbio 5y ago
    If by "we" you mean everyone, no we can't. Edit: assuming you know it's too late not to start, propose something other than magic wand obvious solutions.

brandmeyer 5y ago

The science does not meet the hype. > Our review shows there are not enough data to draw conclusions about how biochar production and application affect whole-system GHG budgets. Wide-ranging estimates of a key variable, biochar stability in situ, likely result from diverse environmental conditions, feedstocks, and study designs. There are even fewer data about the extent to which biochar stimulates decomposition of soil organic matter or affects non-CO2 GHG emissions. Identifying conditions where biochar amendments yield favorable GHG budgets requires a systematic field research program. Finally, evaluating biochar's suitability as a climate mitigation strategy requires comparing its effects with alternative uses of biomass and considering GHG budgets over both long and short time scales. From https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0075932 https://journals.plos.org/plosone/article?id=10.1371/journal...

jasonlaramburu 5y ago
That paper is from 2013. The science has advanced substantially since then.
mr_overalls 5y ago
Several university laboratories are still actively researching biochar and provide snapshots of the current thinking regarding its usefulness: https://whitmanlab.soils.wisc.edu/faqs/ https://whitmanlab.soils.wisc.edu/faqs/ http://www.css.cornell.edu/faculty/lehmann/research/biochar/biocharmain.html http://www.css.cornell.edu/faculty/lehmann/research/biochar/...

ashtonkem 5y ago

Honestly not too far from the glib “just bury the coal again” solution.