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Perennial rice: Plant once, harvest again and again

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Re: Perennial rice: Plant once, harvest again and again

#81

Post by mataug »

twawaaay wrote: post #33

I know Chinese harvest their rice up to three times a year. I don't see how perennial rice could compete. Harvesting normal rice is just grabbing entire plants, as many as you can grab at a time. I may know nothing about how harvesting perennial rice is supposed to work, but I grew up as a farmer and I have imagination. You have to leave some part of the plant for it to keep growing crop which means you can't just gr…

In many parts of the world, planting rice is as labor intensive as harvesting it.

If planting rice is no longer labor intensive, wouldn't harvesting be able to attract the labor needed ?

Re: Perennial rice: Plant once, harvest again and again

#84

Post by xyzzyz »

crazygringo wrote: post #74
xyzzyz wrote: post #65

Earlier quoted context omitted.

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…

> 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 th…

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?

Re: Perennial rice: Plant once, harvest again and again

#87

Post by twic »

xyzzyz wrote: post #53
squokko wrote: post #48

Earlier quoted context omitted.

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

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 in…

Your assumption of steady state is incorrect. The carbon that is being released as methane would otherwise be accumulated in the soil.

Re: Perennial rice: Plant once, harvest again and again

#90

Post by xyzzyz »

crazygringo wrote: post #59
xyzzyz wrote: post #53

Earlier quoted context omitted.

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 in…

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…

Yes, I discuss this in my comment here

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”.

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