Perennial rice: Plant once, harvest again and again

Post by xyzzyz » Fri, Apr 07, 2023, 5:56 PM UTC

billiam wrote: post #107

xyzzyz wrote: post #90

Earlier quoted context omitted.

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…

>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.

Post by philipkglass » Fri, Apr 07, 2023, 6:10 PM UTC

yunohn wrote: post #105

chris_va wrote: post #18

(disclaimer that I manage a climate group, but not a rice expert) They touch on, but don't get into the details on one of the more interesting aspects of perennial rice. Rice fields are actually a huge emitter of methane. Depending on the accounting, they contribute as much to global warming as the aviation sector. The fields emit methane when flooded, the stagnant water gets oxygen depleted, and the biomass in the s…

Just for context, rice is nearly on the bottom of the list of methane polluters - orders of magnitude lower than meat and even things like coffee. https://ourworldindata.org/carbon-footprint-food-methane

Post by lettergram » Fri, Apr 07, 2023, 6:12 PM UTC

Aromasin wrote: post #106

ericpauley wrote: post #100

Earlier quoted context omitted.

To be fair, rice also provides ~20% of global caloric needs, so this isn’t necessarily an outsized contribution.

To put this into context, animal agriculture is responsible for 18% of the worlds CO2 emissions, uses 83% of the world's farmland, but only produces 18% of our calories and 37% of our protein.

Post by lettergram » Fri, Apr 07, 2023, 6:17 PM UTC

matthewdgreen wrote: post #55

xyzzyz wrote: post #45

Earlier quoted context omitted.

> 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 organ…

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.

Post by yunohn » Fri, Apr 07, 2023, 6:20 PM UTC

philipkglass wrote: post #113

yunohn wrote: post #105

Earlier quoted context omitted.

Just for context, rice is nearly on the bottom of the list of methane polluters - orders of magnitude lower than meat and even things like coffee. https://ourworldindata.org/carbon-footprint-food-methane

That chart shows emissions per kilogram of food product. The absolute numbers are higher for rice because the world produces much more rice than coffee - about 10 million tons for coffee and 500 million tons for rice. That would put the absolute emissions from rice about 8 times higher than coffee (225 vs. 29 including methane emissions).