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Most of the coal and oil we mine comes from a time before microorganisms could efficiently break down lignin and cellulose. Now that such organisms exist, trees

by wahern 6y ago

Most of the coal and oil we mine comes from a time before microorganisms could efficiently break down lignin and cellulose. Now that such organisms exist, trees alone can only temporarily sequester carbon. I guess planting more trees gives us some small buffer, but even were it significant it's not really a long-term solution.

mc32 6y ago
If you expand forests that’s ongoing sequestration. One doesn’t count rainforests or boreal forests as “zero carbon” capture. They have an ongoing capturing capacity.
- wahern 6y ago
  > If you expand forests that’s ongoing sequestration. If you expand forests it's a one-time sequestration. That's my point. > One doesn’t count rainforests or boreal forests as “zero carbon” capture. They have an ongoing capturing capacity. Each ecosystem has a turnover time. For rainforests it's like 20 years. For tundra it's as long as 65+ years. But in a stable state these carbon "sinks" are net zero carbon capture. For every ton of carbon they capture, a ton of carbon is released through decomposition. A recent study published in 2019 said that if total emissions, agricultural land use, and other factors remained steady, planting trees might buy us 20 years: https://climate.nasa.gov/news/2927/examining-the-viability-of-planting-trees-to-help-mitigate-climate-change/ https://climate.nasa.gov/news/2927/examining-the-viability-o... The problem is that we're pumping out alot of carbon: about 10GtC/year. The entire Amazon rainforest sequesters only about 100-200GtC. Actually, the biggest problem as I said is that we're pumping out carbon from a resource (Carboniferous period deposits[1]) that can never again be recreated, at least not without significant geoengineering. [1] Carboniferous deposits occurred at a golden period, immediately after woody trees first emerged, but before microorganisms evolved that could decompose them; trees could be buried long enough to fossilize before microorganisms could release all the carbon back into the atmosphere. That can't happen today naturally, at least not at any scale that could help us.
  - vnorilo 6y ago
    Thank you for the well-argued and rational post. To me, buying 20 years for decarbonization sounds kind of great. So, it's a fallacy to think we could just plant trees and otherwise go on as usual. We just need to be careful about language that might feed into defeatism: planting a lot of trees is not a wasted effort, it's a great thing to do. Yes, we need to do a lot more, but every year of extra time helps a lot.
WalterBright 6y ago
That's why we sequester the wood by building houses, etc., with it.
- wahern 6y ago
  The more wood you use, the more inefficient your building methodology given the amount of energy needed for transport, construction, etc, as well as air conditioning, etc. The less wood you use, the less space you create for regrowth. (Indeed, the space taken for building a house is often space where trees could grow, so there's a very simple space trade-off at play.) And none of this factors in the huge amount of wood from demolition that we scrap every year, requiring energy to tear down, and much of which will decompose even in landfills. Plus, a place like the United States has 0 population growth absent immigration. Are we supposed to start tearing down houses just to build new ones? That's the kind of math that begat corn ethanol. The dynamics here are just horrible. Can we slow emissions growth this way? Sure. Can we stop growth this way? Eh... okay, maybe, since we're pretending. Can we reverse global warming, removing carbon from the atmosphere? Not a chance. The only way to turn the dynamic from zero sum to positive sum is with other, major technological advances, at which point playing games with trees and home construction would very likely be the least meaningful use of such new technology. EDIT: Here's a study that looks at various different models for wood processing and disposal. TL;DR: See figures #2 and #3. 100 years post harvest there's at best 5% net carbon sequestration, while most models show 0% net carbon sequestered. https://www.sierraforestlegacy.org/Resources/Conservation/FireForestEcology/ThreatsForestHealth/Climate/CI-Ingerson-TWS2009.pdf https://www.sierraforestlegacy.org/Resources/Conservation/Fi...
  - WalterBright 6y ago
    You're arguing it must be a 100% solution or nothing. I doubt there are any 100% solutions. But we only need 10 10% solutions, so I wouldn't be in any hurry to reject even a 1% solution. Oh, and also, there's always going to be a need for new construction even with 0 population growth. Better to use wood than concrete, as concrete is a large source of carbon emissions.
    - 6y ago
epistasis 6y ago
You are very right. We need to use every tool at our disposal over the next few decades if we are going to avoid a climate disaster, and afforestation plays a role in nearly all routes to avoiding that disaster [1]. But that leaves it in the biosphere, and new forest is vulnerable to rapid deforestation and conversion to CO2 (fires, cultural change, etc.). We would ideally shift some of that highly mobile bio-sphere sequestration to far less mobile geologic sequestration. Most likely with technology that we haven't yet invented. [1] chapter 2, afforestation is part of AFOLU carbon dioxide removal (CDR) https://www.ipcc.ch/sr15/ https://www.ipcc.ch/sr15/

by wahern 6y ago

mc32 6y ago

If you expand forests that’s ongoing sequestration. One doesn’t count rainforests or boreal forests as “zero carbon” capture. They have an ongoing capturing capacity.

wahern 6y ago
> If you expand forests that’s ongoing sequestration. If you expand forests it's a one-time sequestration. That's my point. > One doesn’t count rainforests or boreal forests as “zero carbon” capture. They have an ongoing capturing capacity. Each ecosystem has a turnover time. For rainforests it's like 20 years. For tundra it's as long as 65+ years. But in a stable state these carbon "sinks" are net zero carbon capture. For every ton of carbon they capture, a ton of carbon is released through decomposition. A recent study published in 2019 said that if total emissions, agricultural land use, and other factors remained steady, planting trees might buy us 20 years: https://climate.nasa.gov/news/2927/examining-the-viability-of-planting-trees-to-help-mitigate-climate-change/ https://climate.nasa.gov/news/2927/examining-the-viability-o... The problem is that we're pumping out alot of carbon: about 10GtC/year. The entire Amazon rainforest sequesters only about 100-200GtC. Actually, the biggest problem as I said is that we're pumping out carbon from a resource (Carboniferous period deposits[1]) that can never again be recreated, at least not without significant geoengineering. [1] Carboniferous deposits occurred at a golden period, immediately after woody trees first emerged, but before microorganisms evolved that could decompose them; trees could be buried long enough to fossilize before microorganisms could release all the carbon back into the atmosphere. That can't happen today naturally, at least not at any scale that could help us.
- vnorilo 6y ago
  Thank you for the well-argued and rational post. To me, buying 20 years for decarbonization sounds kind of great. So, it's a fallacy to think we could just plant trees and otherwise go on as usual. We just need to be careful about language that might feed into defeatism: planting a lot of trees is not a wasted effort, it's a great thing to do. Yes, we need to do a lot more, but every year of extra time helps a lot.

WalterBright 6y ago

That's why we sequester the wood by building houses, etc., with it.

wahern 6y ago
The more wood you use, the more inefficient your building methodology given the amount of energy needed for transport, construction, etc, as well as air conditioning, etc. The less wood you use, the less space you create for regrowth. (Indeed, the space taken for building a house is often space where trees could grow, so there's a very simple space trade-off at play.) And none of this factors in the huge amount of wood from demolition that we scrap every year, requiring energy to tear down, and much of which will decompose even in landfills. Plus, a place like the United States has 0 population growth absent immigration. Are we supposed to start tearing down houses just to build new ones? That's the kind of math that begat corn ethanol. The dynamics here are just horrible. Can we slow emissions growth this way? Sure. Can we stop growth this way? Eh... okay, maybe, since we're pretending. Can we reverse global warming, removing carbon from the atmosphere? Not a chance. The only way to turn the dynamic from zero sum to positive sum is with other, major technological advances, at which point playing games with trees and home construction would very likely be the least meaningful use of such new technology. EDIT: Here's a study that looks at various different models for wood processing and disposal. TL;DR: See figures #2 and #3. 100 years post harvest there's at best 5% net carbon sequestration, while most models show 0% net carbon sequestered. https://www.sierraforestlegacy.org/Resources/Conservation/FireForestEcology/ThreatsForestHealth/Climate/CI-Ingerson-TWS2009.pdf https://www.sierraforestlegacy.org/Resources/Conservation/Fi...
- WalterBright 6y ago
  You're arguing it must be a 100% solution or nothing. I doubt there are any 100% solutions. But we only need 10 10% solutions, so I wouldn't be in any hurry to reject even a 1% solution. Oh, and also, there's always going to be a need for new construction even with 0 population growth. Better to use wood than concrete, as concrete is a large source of carbon emissions.
  - 6y ago

epistasis 6y ago

You are very right. We need to use every tool at our disposal over the next few decades if we are going to avoid a climate disaster, and afforestation plays a role in nearly all routes to avoiding that disaster [1]. But that leaves it in the biosphere, and new forest is vulnerable to rapid deforestation and conversion to CO2 (fires, cultural change, etc.). We would ideally shift some of that highly mobile bio-sphere sequestration to far less mobile geologic sequestration. Most likely with technology that we haven't yet invented. [1] chapter 2, afforestation is part of AFOLU carbon dioxide removal (CDR) https://www.ipcc.ch/sr15/ https://www.ipcc.ch/sr15/