6 ms·

Rice cultivation hasn't been a factor in climate for all time, only relatively recently. The increase in methane can have an accumulating warming effect. Think

by Timon3 4y ago

Rice cultivation hasn't been a factor in climate for all time, only relatively recently. The increase in methane can have an accumulating warming effect. Think about it like this - the amount of rice fields is the derivative of climate change. If you increase the amount of rice fields once and don't decrease it, climate change will slowly but surely rise, even if rice fields don't increase.

xyzzyz 4y ago
No, that’s not the case, because the methane doesn’t accumulate. If you increase the amount of rice under cultivation, the methane content in atmosphere will stabilize after around 20 years, and after that there will be no more climate change resulting from the rice fields.
- NotYourLawyer 4y ago
  Yeah, but it will stabilize at a higher level than it would otherwise have been.
- Timon3 4y ago
  I'm not saying the methane accumulates, but the additional energy in the whole earth system does. Every year with additional methane has an effect. If you have no rice fields, then rice fields for a couple of years, and then again no rice fields, you'll have increased methane levels for those years. If you compared that earth to another one without those years of increased levels, the one without would be less warm. Remember: climate change is not a derivative, it's an integral.
  - xyzzyz 4y ago
    No, the energy doesn’t accumulate in Earth over time. Disregarding the energy of radioactive decay within Earth, the Earth is in steady state with respect to energy. All energy it receives from the Sun is radiated away promptly. The greenhouse effect works by delaying this radiation. The more the radiation is delayed by, the more energy is buffered in steady state. Make no mistake though: all of the energy from the Sun is radiated away rather quickly. > If you compared that earth to another one without those years of increased levels, the one without would be less warm. No, after the methane from the fields decays to CO2, both would be the same.
    - Timon3 4y ago
      > All energy it receives from the Sun is radiated away promptly. The greenhouse effect works by delaying this radiation. The more the radiation is delayed by, the more energy is buffered in steady state. Make no mistake though: all of the energy from the Sun is radiated away rather quickly. This is easily disproven. The Earth does trap heat - we can measure this, it's called the Earth Energy Imbalance. This imbalance has been rising since more greenhouse gases were introduced: https://www.nasa.gov/feature/langley/joint-nasa-noaa-study-finds-earths-energy-imbalance-has-doubled https://www.nasa.gov/feature/langley/joint-nasa-noaa-study-f... The amount trapped is rising because we retain the same input longer. A fraction of the total heat is radiated away (not all of it, and not "rather quickly"). If that fraction drops more heat will be trapped. Now you have a system with additional energy due to additional greenhouse gases. Over time the gases will reduce, but the radiation is still only a fraction of the total heat! Of course over time this will very slowly trend back towards the same temperature, but even when the gases themselves have returned to previous levels, the additional heat will take a number of years to be radiated away.
      - Retric 4y ago
        That’s true, but we’ve been cultivating rice for thousands of years. When people talk about returning the earth to pre industrial levels that’s a world with significant rice cultivation going back long enough to account for such differences. The global energy imbalance is simply lag before temperature’s equilibrium, when you turn up the heat in your house it takes longer to heat your fireplace than a wood door. That same effect takes longer on the scale of the earth but it’s an exponential decay. Compared to the history of rice cultivation you very quickly get to millions of a degree difference in surface temperatures. We just keep adding ever more greenhouse gasses.
        Timon3 4y ago
        > That’s true, but we’ve been cultivating rice for thousands of years. How much rice did we previously cultivate, and how many of those fields were flooded? Around 1900 the world population was around 2 billion, so I feel confident in assuming that we've since strongly increased the amount of farms. As such I don't see how this matters. Cultivation is not a boolean state. > The global energy imbalance is simply lag before temperature’s equilibrium, when you turn up the heat in your house it takes longer to heat your fireplace than a wood door. That same effect takes longer on the scale of the earth but it’s an exponential decay. Yes, this is what I've been saying. Increasing the amount of methane in the atmosphere by increasing rice production will lead to an increased temperature even after you stop.
Retric 4y ago
10,000 years isn’t relatively recently on the scales of human civilization nor how quickly the climate feedback loops operate.
- Timon3 4y ago
  Okay? I don't see how this is relevant? All I was saying was that there was a point in time without rice cultivation, and another one with rice cultivation. The point with cultivation has higher levels of methane. Even if you were to return to the point without cultivation, the period with cultivation will have lead to an increased temperature.
  - Retric 4y ago
    It’s relevant because you said relatively recently then chose a completely arbitrary yet undefined point. Once you start talking about periods before written or oral records we have little basis for comparison to say if it was good or not. Why not chose the last ice age, or even periods with higher than current global temperature as the baseline?
    - Timon3 4y ago
      I stay by that. On a climate scale, scaled-up rice production has started a short time ago - which is why I wrote my initial comment: looking at the climate right now and extrapolating that current rice farming has no impact on climate change is illogical.
      - Retric 4y ago
        There is no “long term climate scale.” Climate responds relatively quickly to changes.
        Timon3 4y ago
        Sorry, but what exactly are you arguing for? Of course you can view the climate at different time scales, and of course you can refer to those time scales by colloquial terms. Climate shows cyclic behavior at the time scales I was referring to: https://www.fs.usda.gov/ccrc/education/climate-primer/natural-climate-cycles https://www.fs.usda.gov/ccrc/education/climate-primer/natura... You could have asked for what I was referring to, but instead you chose to jump in with your definitions. Have you had conversational success with this approach?

by Timon3 4y ago

xyzzyz 4y ago

No, that’s not the case, because the methane doesn’t accumulate. If you increase the amount of rice under cultivation, the methane content in atmosphere will stabilize after around 20 years, and after that there will be no more climate change resulting from the rice fields.

NotYourLawyer 4y ago
Yeah, but it will stabilize at a higher level than it would otherwise have been.
Timon3 4y ago
I'm not saying the methane accumulates, but the additional energy in the whole earth system does. Every year with additional methane has an effect. If you have no rice fields, then rice fields for a couple of years, and then again no rice fields, you'll have increased methane levels for those years. If you compared that earth to another one without those years of increased levels, the one without would be less warm. Remember: climate change is not a derivative, it's an integral.
- xyzzyz 4y ago
  No, the energy doesn’t accumulate in Earth over time. Disregarding the energy of radioactive decay within Earth, the Earth is in steady state with respect to energy. All energy it receives from the Sun is radiated away promptly. The greenhouse effect works by delaying this radiation. The more the radiation is delayed by, the more energy is buffered in steady state. Make no mistake though: all of the energy from the Sun is radiated away rather quickly. > If you compared that earth to another one without those years of increased levels, the one without would be less warm. No, after the methane from the fields decays to CO2, both would be the same.
  - Timon3 4y ago
    > All energy it receives from the Sun is radiated away promptly. The greenhouse effect works by delaying this radiation. The more the radiation is delayed by, the more energy is buffered in steady state. Make no mistake though: all of the energy from the Sun is radiated away rather quickly. This is easily disproven. The Earth does trap heat - we can measure this, it's called the Earth Energy Imbalance. This imbalance has been rising since more greenhouse gases were introduced: https://www.nasa.gov/feature/langley/joint-nasa-noaa-study-finds-earths-energy-imbalance-has-doubled https://www.nasa.gov/feature/langley/joint-nasa-noaa-study-f... The amount trapped is rising because we retain the same input longer. A fraction of the total heat is radiated away (not all of it, and not "rather quickly"). If that fraction drops more heat will be trapped. Now you have a system with additional energy due to additional greenhouse gases. Over time the gases will reduce, but the radiation is still only a fraction of the total heat! Of course over time this will very slowly trend back towards the same temperature, but even when the gases themselves have returned to previous levels, the additional heat will take a number of years to be radiated away.
    - Retric 4y ago
      That’s true, but we’ve been cultivating rice for thousands of years. When people talk about returning the earth to pre industrial levels that’s a world with significant rice cultivation going back long enough to account for such differences. The global energy imbalance is simply lag before temperature’s equilibrium, when you turn up the heat in your house it takes longer to heat your fireplace than a wood door. That same effect takes longer on the scale of the earth but it’s an exponential decay. Compared to the history of rice cultivation you very quickly get to millions of a degree difference in surface temperatures. We just keep adding ever more greenhouse gasses.
      - Timon3 4y ago
        > That’s true, but we’ve been cultivating rice for thousands of years. How much rice did we previously cultivate, and how many of those fields were flooded? Around 1900 the world population was around 2 billion, so I feel confident in assuming that we've since strongly increased the amount of farms. As such I don't see how this matters. Cultivation is not a boolean state. > The global energy imbalance is simply lag before temperature’s equilibrium, when you turn up the heat in your house it takes longer to heat your fireplace than a wood door. That same effect takes longer on the scale of the earth but it’s an exponential decay. Yes, this is what I've been saying. Increasing the amount of methane in the atmosphere by increasing rice production will lead to an increased temperature even after you stop.

Retric 4y ago

10,000 years isn’t relatively recently on the scales of human civilization nor how quickly the climate feedback loops operate.

Timon3 4y ago
Okay? I don't see how this is relevant? All I was saying was that there was a point in time without rice cultivation, and another one with rice cultivation. The point with cultivation has higher levels of methane. Even if you were to return to the point without cultivation, the period with cultivation will have lead to an increased temperature.
- Retric 4y ago
  It’s relevant because you said relatively recently then chose a completely arbitrary yet undefined point. Once you start talking about periods before written or oral records we have little basis for comparison to say if it was good or not. Why not chose the last ice age, or even periods with higher than current global temperature as the baseline?
  - Timon3 4y ago
    I stay by that. On a climate scale, scaled-up rice production has started a short time ago - which is why I wrote my initial comment: looking at the climate right now and extrapolating that current rice farming has no impact on climate change is illogical.
    - Retric 4y ago
      There is no “long term climate scale.” Climate responds relatively quickly to changes.
      - Timon3 4y ago
        Sorry, but what exactly are you arguing for? Of course you can view the climate at different time scales, and of course you can refer to those time scales by colloquial terms. Climate shows cyclic behavior at the time scales I was referring to: https://www.fs.usda.gov/ccrc/education/climate-primer/natural-climate-cycles https://www.fs.usda.gov/ccrc/education/climate-primer/natura... You could have asked for what I was referring to, but instead you chose to jump in with your definitions. Have you had conversational success with this approach?