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How does animal agriculture affect this? Are there any authorities on the subject on HN? Everything I've heard suggests the greenhouse gas emissions in support

How does animal agriculture affect this? Are there any authorities on the subject on HN? Everything I've heard suggests the greenhouse gas emissions in support of animal agriculture far outstrip those of pretty much anything else, but nobody seems to really talk about it. Pre-empting a couple of replies here - I already don't eat meat, and yes I've seen "Cowspiracy". :)

morganwilde 10y ago
As far as I know, this issue is not comparable to our carbon economy, I.e. Natural gas extraction, coal mining, oil, etc. Key difference is that agriculture is a closed cycle, animals produce a lot of green house gas, but it's gas that's already a part of our ecosystem. When we did stuff from the ground we add new carbon to the ecosystem, and this feat is what's destabilizing the environment. I heard this argument from an interview Elon Musk did about agriculture after someone posted a tweet at him about the documentary "Cowspiracy".
- retrac98 10y ago
  > Key difference is that agriculture is a closed cycle, animals produce a lot of green house gas, but it's gas that's already a part of our ecosystem. How is it a closed cycle? They require a lot of food and water to be grown, all of which has its own greenhouse gas cost to produce, and then they fart methane while they're alive and require more fuel to process/transport. All the while the world demand for meat is increasing pretty quickly, right?
- tgjsrkghruksd 10y ago
  But we do dig stuff from the ground for agriculture. Massive amounts of forestland are cleared, plowed, and massive amounts of inorganic NPK inputs are added. This releases enormous amounts of previously entrapped CO2 to the atmosphere.
- ctolsen 10y ago
  It is comparable, and thinking about agriculture as a closed system is not even close to correct. We're mowing down natural carbon sinks to an insane degree to grow crops to feed animals, one of the major reasons of deforestation and land use change in South America, for instance. And not only that, we grow slow-acting carbon and turn it into fast-acting methane. I strongly doubt Musk would have such a simplistic view of agricultural emissions, they're a big concern for a reason.
- marchenko 10y ago
  Modern agriculture is part of the carbon economy, especially since the Green Revolution. Inorganic fertilizers are produced using coal and natural gas, and nitrogen-enriched fertilizers emit nitrous oxide, a greenhouse gas. These inputs were previously mostly sequestered.
jessriedel 10y ago
This UN site says 5% of actual CO2 and 14% of CO2-equivalent emissions. Cow and pig production emit mostly methane and nitrogen oxide. http://www.fao.org/news/story/en/item/197623/icode/ http://www.fao.org/news/story/en/item/197623/icode/
- retrac98 10y ago
  Doesn't methane have a much more powerful greenhouse effect than CO2 though?
  - amatix 10y ago
    Yeah, that's how the 5% becomes 14% equivalent in @jessriedel's numbers.
  - yrro 10y ago
    Yes but it breaks down into CO2 very quickly.
- flukus 10y ago
  Pigs are actually a lot better than cows because they are monogastric. So we can cut CO2 emissions by eating more pork and less beef. https://en.wikipedia.org/wiki/Ruminant#Ruminants_and_climate_change https://en.wikipedia.org/wiki/Ruminant#Ruminants_and_climate...
  - spangry 10y ago
    Even better, kangaroos (I know, I know, poor skippy...). Their digestive systems don't produce methane: https://en.wikipedia.org/wiki/Kangaroo#Absence_of_digestive_methane_release https://en.wikipedia.org/wiki/Kangaroo#Absence_of_digestive_... And I'm less sure of this, but I've heard that they cause far less soil erosion compared to cows, as their weight is spread out over a much larger area (i.e. they have big feet). Their populations in some parts of Australia have also reached unsustainable starvation levels, to the point where some State-level governments have initiated culling (i.e. licensed shooting of kangaroos, in a country with very tight gun-control laws).
dandelion_lover 10y ago
https://en.wikipedia.org/wiki/Environmental_impact_of_meat_production https://en.wikipedia.org/wiki/Environmental_impact_of_meat_p...
Detect 10y ago
Animal ag can both be a carbon sink and a carbon source depending on management. Ruminant animals play an important role in grassland ecosystems for nutrient cycling, which can affect the carbon cycle and potentially sequester carbon in soil. Whether we eat the animals is another question. Check out Carbon Farming or Holistic Management for more details.
- doofus3 10y ago
  Complete nonsense. Animal farming contributed 51% of ghg emissions, to portray that as helpful is dishonest or stupid.

morganwilde 10y ago

As far as I know, this issue is not comparable to our carbon economy, I.e. Natural gas extraction, coal mining, oil, etc. Key difference is that agriculture is a closed cycle, animals produce a lot of green house gas, but it's gas that's already a part of our ecosystem. When we did stuff from the ground we add new carbon to the ecosystem, and this feat is what's destabilizing the environment. I heard this argument from an interview Elon Musk did about agriculture after someone posted a tweet at him about the documentary "Cowspiracy".

retrac98 10y ago
> Key difference is that agriculture is a closed cycle, animals produce a lot of green house gas, but it's gas that's already a part of our ecosystem. How is it a closed cycle? They require a lot of food and water to be grown, all of which has its own greenhouse gas cost to produce, and then they fart methane while they're alive and require more fuel to process/transport. All the while the world demand for meat is increasing pretty quickly, right?
tgjsrkghruksd 10y ago
But we do dig stuff from the ground for agriculture. Massive amounts of forestland are cleared, plowed, and massive amounts of inorganic NPK inputs are added. This releases enormous amounts of previously entrapped CO2 to the atmosphere.
ctolsen 10y ago
It is comparable, and thinking about agriculture as a closed system is not even close to correct. We're mowing down natural carbon sinks to an insane degree to grow crops to feed animals, one of the major reasons of deforestation and land use change in South America, for instance. And not only that, we grow slow-acting carbon and turn it into fast-acting methane. I strongly doubt Musk would have such a simplistic view of agricultural emissions, they're a big concern for a reason.
marchenko 10y ago
Modern agriculture is part of the carbon economy, especially since the Green Revolution. Inorganic fertilizers are produced using coal and natural gas, and nitrogen-enriched fertilizers emit nitrous oxide, a greenhouse gas. These inputs were previously mostly sequestered.

jessriedel 10y ago

This UN site says 5% of actual CO2 and 14% of CO2-equivalent emissions. Cow and pig production emit mostly methane and nitrogen oxide. http://www.fao.org/news/story/en/item/197623/icode/ http://www.fao.org/news/story/en/item/197623/icode/

retrac98 10y ago
Doesn't methane have a much more powerful greenhouse effect than CO2 though?
- amatix 10y ago
  Yeah, that's how the 5% becomes 14% equivalent in @jessriedel's numbers.
- yrro 10y ago
  Yes but it breaks down into CO2 very quickly.
flukus 10y ago
Pigs are actually a lot better than cows because they are monogastric. So we can cut CO2 emissions by eating more pork and less beef. https://en.wikipedia.org/wiki/Ruminant#Ruminants_and_climate_change https://en.wikipedia.org/wiki/Ruminant#Ruminants_and_climate...
- spangry 10y ago
  Even better, kangaroos (I know, I know, poor skippy...). Their digestive systems don't produce methane: https://en.wikipedia.org/wiki/Kangaroo#Absence_of_digestive_methane_release https://en.wikipedia.org/wiki/Kangaroo#Absence_of_digestive_... And I'm less sure of this, but I've heard that they cause far less soil erosion compared to cows, as their weight is spread out over a much larger area (i.e. they have big feet). Their populations in some parts of Australia have also reached unsustainable starvation levels, to the point where some State-level governments have initiated culling (i.e. licensed shooting of kangaroos, in a country with very tight gun-control laws).

dandelion_lover 10y ago

https://en.wikipedia.org/wiki/Environmental_impact_of_meat_production https://en.wikipedia.org/wiki/Environmental_impact_of_meat_p...

Detect 10y ago

Animal ag can both be a carbon sink and a carbon source depending on management. Ruminant animals play an important role in grassland ecosystems for nutrient cycling, which can affect the carbon cycle and potentially sequester carbon in soil. Whether we eat the animals is another question. Check out Carbon Farming or Holistic Management for more details.

doofus3 10y ago
Complete nonsense. Animal farming contributed 51% of ghg emissions, to portray that as helpful is dishonest or stupid.