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I hadn't heard about rice fields emitting methane before. I was able to quickly find an article, "Methane emissions from global rice fields: Magnitude, spatiote

I hadn't heard about rice fields emitting methane before. I was able to quickly find an article, "Methane emissions from global rice fields: Magnitude, spatiotemporal patterns, and environmental controls"[0], which states: > Our study estimated that CH4 emissions from global rice fields varied from 18.3 ± 0.1 Tg CH4/yr (Avg. ±1 SD) under intermittent irrigation to 38.8 ± 1.0 Tg CH4/yr under continuous flooding in the 2000s, indicating that the magnitude of CH4 emissions from global rice fields is largely dependent on different water schemes. At 18.3-38.8 Tg CH4/yr, this estimate comes out to about 500-1500 million tons of CO2-equivalent per year according to an EPA GHG-equivalence calculator[1]. Global emissions are estimated at north of 34 billion tons of CO2-equivalent per year[2], putting the total CO2-equivalent from rice fields throughout the world at 1-3% of total global emissions. Wow. [0] https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016GB005381 https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/201... [1] https://www.epa.gov/energy/greenhouse-gas-equivalencies-calculator https://www.epa.gov/energy/greenhouse-gas-equivalencies-calc... [2] https://ourworldindata.org/co2-emissions https://ourworldindata.org/co2-emissions

ericpauley 4y ago
To be fair, rice also provides ~20% of global caloric needs, so this isn’t necessarily an outsized contribution.
- Aromasin 4y ago
  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.
  - lettergram 4y ago
    “Our protein” isn’t exactly fair. Depending on the culture meat can account for as much as 90%+ of protein.
    - slily 4y ago
      Failing to control for nutritional quality also makes those numbers very misleading. For example that 37% of protein would translate to more than double that number based on bioavailability for humans, and meat is far more nutritious than grains (and many vegetables).
    - _dark_matter_ 4y ago
      or as little as 0%. The point stands.
    - lostlogin 4y ago
      Or near zero percent. Why isn’t this stat fair?
    - ericpauley 4y ago
      I imagine they're using "our" in the global sense. Virtually no one is truly dependent on meat for protein; the food the livestock eat are probably mostly human-edible and offer sufficient protein on their own. There's minimal nutritional value added by the meat production process.
  - lm28469 4y ago
    > responsible for 18% of the worlds CO2 emissions, uses 83% of the world's farmland And ~40% of methane emissions as far as I can tell
  - mardifoufs 4y ago
    What % of farmland used for meat production is actually usable for something else? I don't think cattle grazes on prime land, or even mildly productive land.
    - tfourb 4y ago
      It really depends on what you define as "usable". I am currently looking out of a window in the Bavarian Forest and see nice lush green meadows which would be perfectly productive under many different types of crops, but which are mostly used as pasture and meadow for hay production, because the landscape is hilly, which isn't well suited to be farmed with the heavy equipment that has become standard in i.e. corn and wheat production. This type of heavy, industrialized equipment in turn has been a type of farming heavily supported and subsidized by current agricultural policies. You could change the incentives and bring a lot of the farmland currently considered "marginal" into crop production again.
      - hcurtiss 4y ago
        Yes, with humans working hoes. I do not call that progress.
        tfourb 4y ago
        Currently less than 1% of the population in many industrialized countries are working in agriculture. That is laughably few people and there is no reason why it couldn't be a greater share of the population. Guess what: many people are actually enjoying this kind of work when it isn't presented in a context of total exploitation. And no, while agriculture certainly tends to be physically demanding, it is not unreasonably so, even when done at small scale and with smaller machines. Small scale agriculture has been mechanized to a large degree and mechanized solutions have even been developed for very sustainable approaches to agriculture like agroforestry and syntropic agriculture.
        imtringued 4y ago
        I would have expected comments about AI and robotics instead. If you can build terraces and farm them robotically, then you can reuse the technology on Mars.
  - gregwebs 4y ago
    A lot of grazing is done on marginal farming land. For example land that is very dry or land that is very steep. So generally a statistic like 83% of the world's farmland doesn't make any sense. Not sure if it is possible to count factory farming properly- that takes really good farmland and sends the production to animals.
    - aaronblohowiak 4y ago
      a lot of rainforest deforestation is for cattle
    - robocat 4y ago
      > A lot of grazing is done on marginal farming land. For example, New Zealand: ~55% is being used for sheep and cattle, and only ~2% of NZ is arable (see https://youtu.be/F_g6-4swJ_s https://youtu.be/F_g6-4swJ_s at 14:45) with a major part of the reason why explained near the 10:00 mark (weather in South Island).
      - girvo 4y ago
        Although NZ is particular unique/pronounced in this way.
    - scns 4y ago
      By goat and sheep, not cattle.
  - wolfgangK 4y ago
    I really wish there was a name (that I knew of) for this logical fallacy of using precise quantities of meaninglessly confused categories. What do you think "farmland" is ? Our ancestors who knew how to raise cattle and farm cereals for millennia were surviving on the verge of starvation : why do you think that was ? Were they so dumb they'd rather die of hunger than convert some of their grazing pastures to cereal agriculture ? Or some "farmland" can be used for grazing but not for agriculture, maybe ? Same for proteins : all amino acids are not equal, a a pound of soy protein won't have the same effect on your body as a pound of meat proteins. And don't get me started on nutrients and their bio availability (e.g. iron and B12). As far as CO₂ emissions from cattle, where do your think the C comes from ? The grass/food that cattle eat, what would happen to it if let to decompose ?
    - arghwhat 4y ago
      Yes, some land is not suitable for agriculture. No, this does mean that having cattle is a neutral usage as each cattle requires agriculture to feed for 3-4 years before they are slaughtered. Yes, cattle emissions are largely from the food. No, this is not just grass that was already there and would decompose anyway - the majority of agricultural production is to feed cattle and would not be necessary without (the efficiency of raising an animal for years to get a few steaks is horrible), and even if fed naturally it significantly increases the rate of plant turnover. Yes, meat protein is a great source of nutrition. No, it is not magically better than equivalent vegetarian nutrition. Both have diets ranging from super healthy to obesity inducing. Being carnivorous or vegetarian is itself not a significant health factor - chips and crisps are often vegan, and Big Macs contain meat.
      - AmericanChopper 4y ago
        > Yes, meat protein is a great source of nutrition. No, it is not magically better than equivalent vegetarian nutrition. It’s not magic, but the protein from animal sources is just scientifically better than protein from plant sources. If you want to compare the nutritional benefits of different protein sources you need to account for how bioavailable they are. Some plant sources aren’t bad, but none are as good as animal sources, and some of the them aren’t very good at all. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3905294/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3905294/
  - DuckFeathers 4y ago
    The whole "plant based" thing is based on the simplified Wall Street model of food based on misunderstanding of nutrition. For their purposes, protein and fat are just protein and fat whether they come from meat, milk, eggs or dairy... or if they come from grass seeds. If that was the case, it would make sense that we replace ALL animal agriculture with grain farming. Grains can practically be transported and stored for years very cheaply. Unfortunately, plant foods do not provide us the necessary nutrients. ALL human civilizations and tribes had animal foods as a part of their diet. There is not a single tribe that survived on plants alone. So, even if 99.99% of "farm land" was required for animal agriculture, we'd have to keep it that way.
    - pcrh 4y ago
      >ALL human civilizations and tribes had animal foods as a part of their diet. There is not a single tribe that survived on plants alone. FYI, India contains about 280 million vegetarians.
      - BenjiWiebe 4y ago
        Don't the Indian vegetarians use milk/egg products?
        DuckFeathers 3y ago
        They do, famously so for recognising cows as holy animals which make vegetarianism possible.
  - jws 4y ago
    That “farmland” number is next to meaningless. The vast majority of animal land is useless for other agriculture. If you are visualizing a green grassy field full of cows, that is nice and they might even support one cow per acre (2/hectare). Those area numbers are completely swamped by the huge areas you don’t see where someone is grazing one skinny cow per 200 acres (100 hectares) of high desert. A more useful number might discount the grazing/fodder lands which are not useful for other agriculture.
- TurkishPoptart 4y ago
  I couldn't give a damn about carbon emissions, provided people have food.
  - tfourb 4y ago
    Why not have both low carbon emissions and enough food for everyone? We have the technology.
hinkley 4y ago
It's a similar problem with hydroelectric dams. If you drown a biosphere, then methane is a product of anaerobic decay. So it's a question of how much material is there to decay, and what fraction of that decay is oxygen deprived, so that it can't fully oxidize the C-C, C=C, and C-H bonds to water and carbon dioxide.

ericpauley 4y ago

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

Aromasin 4y ago
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.
- lettergram 4y ago
  “Our protein” isn’t exactly fair. Depending on the culture meat can account for as much as 90%+ of protein.
  - slily 4y ago
    Failing to control for nutritional quality also makes those numbers very misleading. For example that 37% of protein would translate to more than double that number based on bioavailability for humans, and meat is far more nutritious than grains (and many vegetables).
  - _dark_matter_ 4y ago
    or as little as 0%. The point stands.
  - lostlogin 4y ago
    Or near zero percent. Why isn’t this stat fair?
  - ericpauley 4y ago
    I imagine they're using "our" in the global sense. Virtually no one is truly dependent on meat for protein; the food the livestock eat are probably mostly human-edible and offer sufficient protein on their own. There's minimal nutritional value added by the meat production process.
- lm28469 4y ago
  > responsible for 18% of the worlds CO2 emissions, uses 83% of the world's farmland And ~40% of methane emissions as far as I can tell
- mardifoufs 4y ago
  What % of farmland used for meat production is actually usable for something else? I don't think cattle grazes on prime land, or even mildly productive land.
  - tfourb 4y ago
    It really depends on what you define as "usable". I am currently looking out of a window in the Bavarian Forest and see nice lush green meadows which would be perfectly productive under many different types of crops, but which are mostly used as pasture and meadow for hay production, because the landscape is hilly, which isn't well suited to be farmed with the heavy equipment that has become standard in i.e. corn and wheat production. This type of heavy, industrialized equipment in turn has been a type of farming heavily supported and subsidized by current agricultural policies. You could change the incentives and bring a lot of the farmland currently considered "marginal" into crop production again.
    - hcurtiss 4y ago
      Yes, with humans working hoes. I do not call that progress.
      - tfourb 4y ago
        Currently less than 1% of the population in many industrialized countries are working in agriculture. That is laughably few people and there is no reason why it couldn't be a greater share of the population. Guess what: many people are actually enjoying this kind of work when it isn't presented in a context of total exploitation. And no, while agriculture certainly tends to be physically demanding, it is not unreasonably so, even when done at small scale and with smaller machines. Small scale agriculture has been mechanized to a large degree and mechanized solutions have even been developed for very sustainable approaches to agriculture like agroforestry and syntropic agriculture.
      - imtringued 4y ago
        I would have expected comments about AI and robotics instead. If you can build terraces and farm them robotically, then you can reuse the technology on Mars.
- gregwebs 4y ago
  A lot of grazing is done on marginal farming land. For example land that is very dry or land that is very steep. So generally a statistic like 83% of the world's farmland doesn't make any sense. Not sure if it is possible to count factory farming properly- that takes really good farmland and sends the production to animals.
  - aaronblohowiak 4y ago
    a lot of rainforest deforestation is for cattle
  - robocat 4y ago
    > A lot of grazing is done on marginal farming land. For example, New Zealand: ~55% is being used for sheep and cattle, and only ~2% of NZ is arable (see https://youtu.be/F_g6-4swJ_s https://youtu.be/F_g6-4swJ_s at 14:45) with a major part of the reason why explained near the 10:00 mark (weather in South Island).
    - girvo 4y ago
      Although NZ is particular unique/pronounced in this way.
  - scns 4y ago
    By goat and sheep, not cattle.
- wolfgangK 4y ago
  I really wish there was a name (that I knew of) for this logical fallacy of using precise quantities of meaninglessly confused categories. What do you think "farmland" is ? Our ancestors who knew how to raise cattle and farm cereals for millennia were surviving on the verge of starvation : why do you think that was ? Were they so dumb they'd rather die of hunger than convert some of their grazing pastures to cereal agriculture ? Or some "farmland" can be used for grazing but not for agriculture, maybe ? Same for proteins : all amino acids are not equal, a a pound of soy protein won't have the same effect on your body as a pound of meat proteins. And don't get me started on nutrients and their bio availability (e.g. iron and B12). As far as CO₂ emissions from cattle, where do your think the C comes from ? The grass/food that cattle eat, what would happen to it if let to decompose ?
  - arghwhat 4y ago
    Yes, some land is not suitable for agriculture. No, this does mean that having cattle is a neutral usage as each cattle requires agriculture to feed for 3-4 years before they are slaughtered. Yes, cattle emissions are largely from the food. No, this is not just grass that was already there and would decompose anyway - the majority of agricultural production is to feed cattle and would not be necessary without (the efficiency of raising an animal for years to get a few steaks is horrible), and even if fed naturally it significantly increases the rate of plant turnover. Yes, meat protein is a great source of nutrition. No, it is not magically better than equivalent vegetarian nutrition. Both have diets ranging from super healthy to obesity inducing. Being carnivorous or vegetarian is itself not a significant health factor - chips and crisps are often vegan, and Big Macs contain meat.
    - AmericanChopper 4y ago
      > Yes, meat protein is a great source of nutrition. No, it is not magically better than equivalent vegetarian nutrition. It’s not magic, but the protein from animal sources is just scientifically better than protein from plant sources. If you want to compare the nutritional benefits of different protein sources you need to account for how bioavailable they are. Some plant sources aren’t bad, but none are as good as animal sources, and some of the them aren’t very good at all. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3905294/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3905294/
- DuckFeathers 4y ago
  The whole "plant based" thing is based on the simplified Wall Street model of food based on misunderstanding of nutrition. For their purposes, protein and fat are just protein and fat whether they come from meat, milk, eggs or dairy... or if they come from grass seeds. If that was the case, it would make sense that we replace ALL animal agriculture with grain farming. Grains can practically be transported and stored for years very cheaply. Unfortunately, plant foods do not provide us the necessary nutrients. ALL human civilizations and tribes had animal foods as a part of their diet. There is not a single tribe that survived on plants alone. So, even if 99.99% of "farm land" was required for animal agriculture, we'd have to keep it that way.
  - pcrh 4y ago
    >ALL human civilizations and tribes had animal foods as a part of their diet. There is not a single tribe that survived on plants alone. FYI, India contains about 280 million vegetarians.
    - BenjiWiebe 4y ago
      Don't the Indian vegetarians use milk/egg products?
      - DuckFeathers 3y ago
        They do, famously so for recognising cows as holy animals which make vegetarianism possible.
- jws 4y ago
  That “farmland” number is next to meaningless. The vast majority of animal land is useless for other agriculture. If you are visualizing a green grassy field full of cows, that is nice and they might even support one cow per acre (2/hectare). Those area numbers are completely swamped by the huge areas you don’t see where someone is grazing one skinny cow per 200 acres (100 hectares) of high desert. A more useful number might discount the grazing/fodder lands which are not useful for other agriculture.
TurkishPoptart 4y ago
I couldn't give a damn about carbon emissions, provided people have food.
- tfourb 4y ago
  Why not have both low carbon emissions and enough food for everyone? We have the technology.

hinkley 4y ago

It's a similar problem with hydroelectric dams. If you drown a biosphere, then methane is a product of anaerobic decay. So it's a question of how much material is there to decay, and what fraction of that decay is oxygen deprived, so that it can't fully oxidize the C-C, C=C, and C-H bonds to water and carbon dioxide.