5 ms·

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

by 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.
- xyzzyz 4y ago
  Thank you for redoing the math I did, and confirming I was exactly correct with figures. The increase in concentration is observable, but the impact on climate is not. Again: this increase is similar to increase between 2000 and 2020. Without extremely careful and precise measurements, nobody would really be able to perceive any difference in climate between these two dates. This matters, because it is the perceived effect of climate change that is worrying, not the measured one. Modern science can measure many things with very high accuracy, but these changes only matter if they affect our lives in a way we can perceive. If the change is only seen on accurate scientific instrument, why should the society care much about it?
  - JumpCrisscross 4y ago
    > If the change is only seen on accurate scientific instrument, why should the society care much about it? It’s difficult to perceive this as anything but elaborate climate denial, given it works for any incremental progress towards lower emissions.
    - xyzzyz 4y ago
      No, you missed the point: there is an enormous difference between methane emissions from fresh organic matter, and emission from fossil fuels. The latter accumulate, while the former do not. That’s why as we continue incrementally burning fossil fuels, the effects accumulate and affect climate over decades or centuries, but decaying weeds or (fashionable to discuss a couple of years back) cattle burps and farts do not. The point is that even if it continues over the centuries, the effect of cattle farts and weeds decaying on rice fields will only ever be observable using precise scientific instruments, whereas effect of burning fossil fuels for centuries will be very readily perceivable with very crude techniques.
      - JumpCrisscross 4y ago
        > the effect of cattle farts and weeds decaying on rice fields will only ever be observable using precise scientific instruments, whereas effect of burning fossil fuels for centuries will be very readily perceivable with very crude techniques It’s a fine distinction, and I’m glad you made it, but the arguments for why it doesn’t matter don’t stick. Gross imperceptibility does work for any small amount of any emission—there is no way to feel the effect of that emission per se. There is also the case that raising the planet’s steady-state temperature is exactly what existing fossil fuel emissions have done. They’re a problem even if they’re already there.
        codethief 4y ago
        > but the arguments for why it doesn’t matter don’t stick I'm not so sure. GP's argument was that when people say rice/cattle release so-and-so much methane into the atmosphere per year, the fact that it's a cycle and the amount of methane & CO2 in the atmosphere due to rice/cattle remains constant is usually ignored. Meanwhile, burning fossil fuel, increasing air traffic (-> water in the atmosphere), etc. actually increase the total amount of green house gases in the atmosphere, year by year. Sure, we could think about reducing the constant amount of methane in the atmosphere due to cattle/rice by reducing cattle/rice but, in light of emissions due to fossil fuel accumulating year by year, this doesn't seem to be the most pressing issue by a large margin.

by xyzzyz 4y ago

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.

xyzzyz 4y ago
Thank you for redoing the math I did, and confirming I was exactly correct with figures. The increase in concentration is observable, but the impact on climate is not. Again: this increase is similar to increase between 2000 and 2020. Without extremely careful and precise measurements, nobody would really be able to perceive any difference in climate between these two dates. This matters, because it is the perceived effect of climate change that is worrying, not the measured one. Modern science can measure many things with very high accuracy, but these changes only matter if they affect our lives in a way we can perceive. If the change is only seen on accurate scientific instrument, why should the society care much about it?
- JumpCrisscross 4y ago
  > If the change is only seen on accurate scientific instrument, why should the society care much about it? It’s difficult to perceive this as anything but elaborate climate denial, given it works for any incremental progress towards lower emissions.
  - xyzzyz 4y ago
    No, you missed the point: there is an enormous difference between methane emissions from fresh organic matter, and emission from fossil fuels. The latter accumulate, while the former do not. That’s why as we continue incrementally burning fossil fuels, the effects accumulate and affect climate over decades or centuries, but decaying weeds or (fashionable to discuss a couple of years back) cattle burps and farts do not. The point is that even if it continues over the centuries, the effect of cattle farts and weeds decaying on rice fields will only ever be observable using precise scientific instruments, whereas effect of burning fossil fuels for centuries will be very readily perceivable with very crude techniques.
    - JumpCrisscross 4y ago
      > the effect of cattle farts and weeds decaying on rice fields will only ever be observable using precise scientific instruments, whereas effect of burning fossil fuels for centuries will be very readily perceivable with very crude techniques It’s a fine distinction, and I’m glad you made it, but the arguments for why it doesn’t matter don’t stick. Gross imperceptibility does work for any small amount of any emission—there is no way to feel the effect of that emission per se. There is also the case that raising the planet’s steady-state temperature is exactly what existing fossil fuel emissions have done. They’re a problem even if they’re already there.
      - codethief 4y ago
        > but the arguments for why it doesn’t matter don’t stick I'm not so sure. GP's argument was that when people say rice/cattle release so-and-so much methane into the atmosphere per year, the fact that it's a cycle and the amount of methane & CO2 in the atmosphere due to rice/cattle remains constant is usually ignored. Meanwhile, burning fossil fuel, increasing air traffic (-> water in the atmosphere), etc. actually increase the total amount of green house gases in the atmosphere, year by year. Sure, we could think about reducing the constant amount of methane in the atmosphere due to cattle/rice by reducing cattle/rice but, in light of emissions due to fossil fuel accumulating year by year, this doesn't seem to be the most pressing issue by a large margin.