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> So, perennial rice may end up reduce GHG emissions substantially. Not really. These GHG emissions from rice are in steady state with the amount of CO2 and me

by xyzzyz 4y ago

> So, perennial rice may end up reduce GHG emissions substantially. Not really. These GHG emissions from rice are in steady state with the amount of CO2 and methane in the atmosphere. They do not add additional GHG to the atmosphere the way burning fossil fuel do. When you burn fossil fuels, the carbon atoms released into atmosphere have been captured from the atmosphere millions years ago. When weeds and other organic matter in flooded fields decompose, released carbon atoms have been captured only a couple of months or years earlier.

squokko 4y ago
Not true between CO2 and methane. The total amount of carbon is the same but in methane form is worse for greenhouse effect.
- xyzzyz 4y ago
  Methane is worse, but it again doesn’t matter here, because the fields are in steady state not only with CO2, but with methane as well. Methane doesn’t linger in atmosphere forever, it decomposes into CO2 in a decade or so. This means atoms of methane emitted from the fields are pretty much exactly paired with atoms of methane in atmosphere decaying into CO2. This means that methane emitted from the fields doesn’t increase the total amount of methane in the atmosphere, the way burning fossil fuels does with CO2.
  - littlestymaar 4y ago
    This reasoning is completely wrong: there's an input and an progressive decay as output, the amount of methane in the atmosphere at any given point is directly related to the input.
    - xyzzyz 4y ago
      Yes, this is exactly what I say in my comment. The amount of methane in the atmosphere is directly proportional to the input rate. That’s why, as I said, in steady state, when the we keep steady the amount of rice under cultivation, the amount of methane in atmosphere is not changing over time. Can you point to which part exactly is “completely wrong”?
      - littlestymaar 4y ago
        > Can you point to which part exactly is “completely wrong”? First you said: > Not really. These GHG emissions from rice are in steady state with the amount of CO2 and methane in the atmosphere. And then now > That’s why, as I said, in steady state, when the we keep steady the amount of rice under cultivation, the amount of methane in atmosphere is not changing over time. These two statements are contradictory. If we assume steady state, then yeah the amount of methane is stable, but changing the way we cultivate rice is the opposite of steady state: if we reduce the methane emissions, then the amount of methane in the atmosphere will decrease that's it.
        xyzzyz 4y ago
        There is no contradiction between these two statements. They both say the exact same thing: if rice cultivation is in steady state, the amount of CO2 and CH4 in atmosphere due to it is constant. You next say if we change the steady state, the amount of methane in atmosphere will change, but that again is not a contradiction with what I said.
        littlestymaar 4y ago
        So you eventually agree with the statement you disagreed before, that is: > perennial rice may end up reduce GHG emissions substantially. (because that's the starting point of this conversation, and it's the opposite of steady state)
  - crazygringo 4y ago
    That doesn't make sense mathematically. Because you could start with zero methane in the atmosphere, just lots of CO2, but the rice would introduce methane. Eventually yes you can get to a steady state of methane, but the point is that the more rice there is, the higher that steady state becomes. Which is bad. So the total amount of methane would absolutely increase. (And if you stopped planting rice at all it would eventually decrease over the subsequent decades.)
    - xyzzyz 4y ago
      Yes, I discuss this in my comment here https://news.ycombinator.com/item?id=35483780 https://news.ycombinator.com/item?id=35483780 The point is, though, that the amount of methane that currently have in atmosphere, is only barely relevant when it comes to how it affects climate from human perspective. If all methane disappeared tomorrow, our climate would be back to 2010, which is hardy a significant change. Nobody would even notice other than climate scientists. Similarly, if we increase the rice cultivation, the amount of methane will increase in the steady state, but the increase will be wholly immaterial, so that it does not affect us in any real way. This is not really “bad”.
      - billiam 4y ago
        >our climate would be back to 2010, which is hardy a significant change. Uh, no. It is quite significant, and a mountain of evidence says that the climate changes from concentrations in the last decade are very significant. You appear to be a denier of anthropogenic climate change who is willing to make silly straw men arguments.
        xyzzyz 4y ago
        I do happen to remember what the climate looked like in 2010, and I very much do not believe that enormous social and economic projects are warranted to revert the state of climate by 10 years. > You appear to be a denier of anthropogenic climate change who is willing to make silly straw men arguments. You appear to be unable to discuss the issue on merits, but this doesn’t necessitate resorting to ad hominem. You can do better than that.
  - twic 4y ago
    Your assumption of steady state is incorrect. The carbon that is being released as methane would otherwise be accumulated in the soil.
    - codethief 4y ago
      Not the OP but: Sure, rice does cause some non-zero amount of CO2/methane in the atmosphere that would otherwise remain stored inside some other plants (or the soil) but, unless we increase rice plantations around the world, this amount will remain constant. Hence, it's a steady state.
  - hinkley 4y ago
    Methane is 20x worse, so if you capture 95% of the carbon and emit the rest as methane, you've broken even on GHG. But nothing I'm aware of captures 95% of carbon. Terra Preta might lock up the captured carbon for 100's of years, but producing charcoal is 50% efficient if you optimize for emissions, which most people do not.
crazygringo 4y ago
Can you elaborate on this? Do you mean that rice plants are actually absorbing methane earlier on, so they're just releasing the same amount? Or are they actually producing methane from other molecules, like water and carbon dioxide? Because yes, methane breaks down in the atmosphere into H2O and CO2 so you could view it as a cycle, but the more rice there is the higher the steady state methane in the atmosphere is, so it's still a problem.
- xyzzyz 4y ago
  Yes, the whole point is that it is a cycle. The fields don’t affect by much the total number of carbon atoms in the atmosphere. Without the fields, other plants would grow there, then die, decay, and release carbon into atmosphere. At best, growing rice and flooding fields might affect the balance between the amount of methane and amount of CO2 in the steady state, but this is of no practical consequence, because the methane will not accumulate year over year, like the emissions from fossil fuels do. Suppose we grow twice as much rice as we do now. This means that the steady state will have twice as much methane coming from the fields as it has now. Hell, let’s actually assume that all existing methane in atmosphere is from rice fields, and actually increase amount of methane in atmosphere by a factor of 2. What is the impact to the climate, according to our current models? Well, this is equivalent to less than 10% increase in total CO2 in the atmosphere. That’s like a difference between 2000 and 2020, which is to say, almost unobservable — and remember I assumed we increase total methane by factor of 2, not just methane from the fields.
  - crazygringo 4y ago
    > but this is of no practical consequence, because the methane will not accumulate year over year, like the emissions from fossil fuels do. Methane still takes 12 years to break down in the atmosphere, and it's more than 25 times as potent of a greenhouse gas than CO2. CO2 concentrations are currently ~420 ppm, while methane is ~1866 ppb, or 1.9 ppm. If we assume methane is 25 times worse than CO2, that 1.9 ppm is the equivalent of 48 ppm CO2. Which is gigantic. Doubling steady-state methane levels in the atmosphere would be a major problem. It would be like CO2 levels going from 468 to 516, yes a 10% increase. I don't know how you can call that "almost unobservable" when we're doing our absolute best to stop any increases. The fact that it's steady state doesn't really matter if it's still a major contributor, and/or if that steady state is increasing.
matthewdgreen 4y ago
Methane and CO2 are very different things. The former has a massively greater warming effect than the latter, and takes long enough to degrade in the atmosphere that it can significantly affect warming times. If you aren’t paying attention to the rising methane levels in our atmosphere (and possible evidence of a feedback loop) with serious trepidation, you’re a lucky person who probably sleeps well at night.
- nh23423fefe 4y ago
  > Serious people panic when I do. But you didn't address why you panic.
  - cyrusatjam 4y ago
    wrong thread?
    - drak0n1c 4y ago
      Comment was edited.
- lettergram 4y ago
  I want a warmer atmosphere. All the UN data points to a warmer atmosphere equating to more food and higher quality of life. I concede some concern about potential feedback loops, but the reality is that earth was and still is in an ice age. Ice ages are not the norm on earth, I think it’s okay if we exit an ice age. Yes things will change, but it’ll be over decades to millennia. We’re working on carbon capture right now — 150 years after the start of the Industrial Revolution. By even the most imo insane estimates we are 50-70 years from even minor discomfort. I’m fairly confident we can fix the problem when it becomes a problem
  - lm28469 4y ago
    > I want a warmer atmosphere. > All the UN data points to a warmer atmosphere equating to more food and higher quality of life. Globally and to a point, maybe. But that's not taking into account local effects and the millions (billion?) who'll be displaced and what comes with it Then you have ocean acidification, postivie and negative feedback that we won't be able to stop, &c. > I’m fairly confident we can fix the problem when it becomes a problem I’m fairly confident that the same UN data points, and basically the entire corpus of text about climate science, will show you that it's absolutely not how it works because the inertia is way too strong to only care about it when it's in front of you
dangjc 4y ago
That’s reassuring we are in steady state. If perennial rice takes over, we will gradually drop atmospheric methane to a lower steady state.

by xyzzyz 4y ago

squokko 4y ago

Not true between CO2 and methane. The total amount of carbon is the same but in methane form is worse for greenhouse effect.

xyzzyz 4y ago
Methane is worse, but it again doesn’t matter here, because the fields are in steady state not only with CO2, but with methane as well. Methane doesn’t linger in atmosphere forever, it decomposes into CO2 in a decade or so. This means atoms of methane emitted from the fields are pretty much exactly paired with atoms of methane in atmosphere decaying into CO2. This means that methane emitted from the fields doesn’t increase the total amount of methane in the atmosphere, the way burning fossil fuels does with CO2.
- littlestymaar 4y ago
  This reasoning is completely wrong: there's an input and an progressive decay as output, the amount of methane in the atmosphere at any given point is directly related to the input.
  - xyzzyz 4y ago
    Yes, this is exactly what I say in my comment. The amount of methane in the atmosphere is directly proportional to the input rate. That’s why, as I said, in steady state, when the we keep steady the amount of rice under cultivation, the amount of methane in atmosphere is not changing over time. Can you point to which part exactly is “completely wrong”?
    - littlestymaar 4y ago
      > Can you point to which part exactly is “completely wrong”? First you said: > Not really. These GHG emissions from rice are in steady state with the amount of CO2 and methane in the atmosphere. And then now > That’s why, as I said, in steady state, when the we keep steady the amount of rice under cultivation, the amount of methane in atmosphere is not changing over time. These two statements are contradictory. If we assume steady state, then yeah the amount of methane is stable, but changing the way we cultivate rice is the opposite of steady state: if we reduce the methane emissions, then the amount of methane in the atmosphere will decrease that's it.
      - xyzzyz 4y ago
        There is no contradiction between these two statements. They both say the exact same thing: if rice cultivation is in steady state, the amount of CO2 and CH4 in atmosphere due to it is constant. You next say if we change the steady state, the amount of methane in atmosphere will change, but that again is not a contradiction with what I said.
        littlestymaar 4y ago
        So you eventually agree with the statement you disagreed before, that is: > perennial rice may end up reduce GHG emissions substantially. (because that's the starting point of this conversation, and it's the opposite of steady state)
- crazygringo 4y ago
  That doesn't make sense mathematically. Because you could start with zero methane in the atmosphere, just lots of CO2, but the rice would introduce methane. Eventually yes you can get to a steady state of methane, but the point is that the more rice there is, the higher that steady state becomes. Which is bad. So the total amount of methane would absolutely increase. (And if you stopped planting rice at all it would eventually decrease over the subsequent decades.)
  - xyzzyz 4y ago
    Yes, I discuss this in my comment here https://news.ycombinator.com/item?id=35483780 https://news.ycombinator.com/item?id=35483780 The point is, though, that the amount of methane that currently have in atmosphere, is only barely relevant when it comes to how it affects climate from human perspective. If all methane disappeared tomorrow, our climate would be back to 2010, which is hardy a significant change. Nobody would even notice other than climate scientists. Similarly, if we increase the rice cultivation, the amount of methane will increase in the steady state, but the increase will be wholly immaterial, so that it does not affect us in any real way. This is not really “bad”.
    - billiam 4y ago
      >our climate would be back to 2010, which is hardy a significant change. Uh, no. It is quite significant, and a mountain of evidence says that the climate changes from concentrations in the last decade are very significant. You appear to be a denier of anthropogenic climate change who is willing to make silly straw men arguments.
      - xyzzyz 4y ago
        I do happen to remember what the climate looked like in 2010, and I very much do not believe that enormous social and economic projects are warranted to revert the state of climate by 10 years. > You appear to be a denier of anthropogenic climate change who is willing to make silly straw men arguments. You appear to be unable to discuss the issue on merits, but this doesn’t necessitate resorting to ad hominem. You can do better than that.
- twic 4y ago
  Your assumption of steady state is incorrect. The carbon that is being released as methane would otherwise be accumulated in the soil.
  - codethief 4y ago
    Not the OP but: Sure, rice does cause some non-zero amount of CO2/methane in the atmosphere that would otherwise remain stored inside some other plants (or the soil) but, unless we increase rice plantations around the world, this amount will remain constant. Hence, it's a steady state.
- hinkley 4y ago
  Methane is 20x worse, so if you capture 95% of the carbon and emit the rest as methane, you've broken even on GHG. But nothing I'm aware of captures 95% of carbon. Terra Preta might lock up the captured carbon for 100's of years, but producing charcoal is 50% efficient if you optimize for emissions, which most people do not.

crazygringo 4y ago

Can you elaborate on this? Do you mean that rice plants are actually absorbing methane earlier on, so they're just releasing the same amount? Or are they actually producing methane from other molecules, like water and carbon dioxide? Because yes, methane breaks down in the atmosphere into H2O and CO2 so you could view it as a cycle, but the more rice there is the higher the steady state methane in the atmosphere is, so it's still a problem.

xyzzyz 4y ago
Yes, the whole point is that it is a cycle. The fields don’t affect by much the total number of carbon atoms in the atmosphere. Without the fields, other plants would grow there, then die, decay, and release carbon into atmosphere. At best, growing rice and flooding fields might affect the balance between the amount of methane and amount of CO2 in the steady state, but this is of no practical consequence, because the methane will not accumulate year over year, like the emissions from fossil fuels do. Suppose we grow twice as much rice as we do now. This means that the steady state will have twice as much methane coming from the fields as it has now. Hell, let’s actually assume that all existing methane in atmosphere is from rice fields, and actually increase amount of methane in atmosphere by a factor of 2. What is the impact to the climate, according to our current models? Well, this is equivalent to less than 10% increase in total CO2 in the atmosphere. That’s like a difference between 2000 and 2020, which is to say, almost unobservable — and remember I assumed we increase total methane by factor of 2, not just methane from the fields.
- crazygringo 4y ago
  > but this is of no practical consequence, because the methane will not accumulate year over year, like the emissions from fossil fuels do. Methane still takes 12 years to break down in the atmosphere, and it's more than 25 times as potent of a greenhouse gas than CO2. CO2 concentrations are currently ~420 ppm, while methane is ~1866 ppb, or 1.9 ppm. If we assume methane is 25 times worse than CO2, that 1.9 ppm is the equivalent of 48 ppm CO2. Which is gigantic. Doubling steady-state methane levels in the atmosphere would be a major problem. It would be like CO2 levels going from 468 to 516, yes a 10% increase. I don't know how you can call that "almost unobservable" when we're doing our absolute best to stop any increases. The fact that it's steady state doesn't really matter if it's still a major contributor, and/or if that steady state is increasing.

matthewdgreen 4y ago

Methane and CO2 are very different things. The former has a massively greater warming effect than the latter, and takes long enough to degrade in the atmosphere that it can significantly affect warming times. If you aren’t paying attention to the rising methane levels in our atmosphere (and possible evidence of a feedback loop) with serious trepidation, you’re a lucky person who probably sleeps well at night.

nh23423fefe 4y ago
> Serious people panic when I do. But you didn't address why you panic.
- cyrusatjam 4y ago
  wrong thread?
  - drak0n1c 4y ago
    Comment was edited.
lettergram 4y ago
I want a warmer atmosphere. All the UN data points to a warmer atmosphere equating to more food and higher quality of life. I concede some concern about potential feedback loops, but the reality is that earth was and still is in an ice age. Ice ages are not the norm on earth, I think it’s okay if we exit an ice age. Yes things will change, but it’ll be over decades to millennia. We’re working on carbon capture right now — 150 years after the start of the Industrial Revolution. By even the most imo insane estimates we are 50-70 years from even minor discomfort. I’m fairly confident we can fix the problem when it becomes a problem
- lm28469 4y ago
  > I want a warmer atmosphere. > All the UN data points to a warmer atmosphere equating to more food and higher quality of life. Globally and to a point, maybe. But that's not taking into account local effects and the millions (billion?) who'll be displaced and what comes with it Then you have ocean acidification, postivie and negative feedback that we won't be able to stop, &c. > I’m fairly confident we can fix the problem when it becomes a problem I’m fairly confident that the same UN data points, and basically the entire corpus of text about climate science, will show you that it's absolutely not how it works because the inertia is way too strong to only care about it when it's in front of you

dangjc 4y ago

That’s reassuring we are in steady state. If perennial rice takes over, we will gradually drop atmospheric methane to a lower steady state.