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> My understanding is that around half of the world's greenhouse gas comes from livestock That's not right. The highest number I've been able to find for the w

> My understanding is that around half of the world's greenhouse gas comes from livestock That's not right. The highest number I've been able to find for the whole of agriculture is 24% of world greenhouse gas emissions. https://www.epa.gov/ghgemissions/global-greenhouse-gas-emissions-data https://www.epa.gov/ghgemissions/global-greenhouse-gas-emiss... About 25% of that is methane from livestock (http://old.grida.no/graphicslib/detail/greenhouse-gas-emissions-from-agriculture-and-land-use_12b0# http://old.grida.no/graphicslib/detail/greenhouse-gas-emissi...) So livestock is about 6% of total greenhouse gas emissions.

nothrabannosir 8y ago
As far as I can see, those references do not mention whether they have corrected for the fact that methane is a ~20x more potent greenhouse gas than CO2. Are they counting per volume or per potency? That is an incredibly important distinction. Which, to be honest, they should have made, one way or the other.
- Chris_Jay 8y ago
  Potency is typically assumed in the industry, the volume of methane is trivial compared to volume of CO2.
- rbkillea 8y ago
  They are in the units "greenhouse gas emissions" which corrects for the extra potency. The sad thing is that people often double-correct for such things.
sdenton4 8y ago
Random Gaurdian story puts methane : "Methane accounted for about 16% of global greenhouse gas emissions in 2015, according to the IPCC." (https://www.theguardian.com/environment/2017/sep/29/methane-emissions-cattle-11-percent-higher-than-estimated https://www.theguardian.com/environment/2017/sep/29/methane-...) Wikipedia puts (with some question about the citation) methan at 4-9% of total greenhouse effect contribution, and CO2 at 9-26%. (And then water vapor way above that, at 36-72%.) https://en.wikipedia.org/wiki/Greenhouse_gas#Greenhouse_gases https://en.wikipedia.org/wiki/Greenhouse_gas#Greenhouse_gase...
- samstave 8y ago
  How are we producing water vapor more than say clouds?
  - sdenton4 8y ago
    I think the table is attributing greenhouse to gases generally, not to man-made gases; as a result, water vapor wins. (OTOH, turning clouds into drinking water at scale would be a cool way to fight global warming and deal with drought at the same time. My understanding is that storm seeding has a pretty seedy history, though.)
konschubert 8y ago
One also has to consider that the methane decays over a matter of decades. Other than CO2, which stays in the atmosphere until it is taken out. So, even if methane takes a big share in current greenhouse emissions, its share in the accumulated greenhouse gases in the atmosphere will be lower. The climate change it causes is temporary. (Disregarding runaway effects.) https://en.wikipedia.org/wiki/Atmospheric_methane https://en.wikipedia.org/wiki/Atmospheric_methane
- Retric 8y ago
  Methane contains carbon so it's not 100% temporary just mostly.
  - deleted 8y ago
    [deleted]
- skosch 8y ago
  Decades – we don't have decades to fix this. Also, it decays into CO2, so to claim that its effects are temporary is misleading. On top of that, as long as the carbon is in a CH4 bond, it traps at least 20× as much radiation. Please don't dismiss the significance of methane emissions.
  - samstave 8y ago
    We should he focusing on plastics rather than methane.
  - Jach 8y ago
    How many years do we have to fix this then? Alternatively, at what point will activists start saying we passed the point of no fix and give up their activism?
    - marssaxman 8y ago
      I got to that point 3-4 years ago, personally. Even if it were economically and technically possible to get our act together, it has become entirely clear that the political system is incapable of acting quickly enough.

nothrabannosir 8y ago

As far as I can see, those references do not mention whether they have corrected for the fact that methane is a ~20x more potent greenhouse gas than CO2. Are they counting per volume or per potency? That is an incredibly important distinction. Which, to be honest, they should have made, one way or the other.

Chris_Jay 8y ago
Potency is typically assumed in the industry, the volume of methane is trivial compared to volume of CO2.
rbkillea 8y ago
They are in the units "greenhouse gas emissions" which corrects for the extra potency. The sad thing is that people often double-correct for such things.

sdenton4 8y ago

Random Gaurdian story puts methane : "Methane accounted for about 16% of global greenhouse gas emissions in 2015, according to the IPCC." (https://www.theguardian.com/environment/2017/sep/29/methane-emissions-cattle-11-percent-higher-than-estimated https://www.theguardian.com/environment/2017/sep/29/methane-...) Wikipedia puts (with some question about the citation) methan at 4-9% of total greenhouse effect contribution, and CO2 at 9-26%. (And then water vapor way above that, at 36-72%.) https://en.wikipedia.org/wiki/Greenhouse_gas#Greenhouse_gases https://en.wikipedia.org/wiki/Greenhouse_gas#Greenhouse_gase...

samstave 8y ago
How are we producing water vapor more than say clouds?
- sdenton4 8y ago
  I think the table is attributing greenhouse to gases generally, not to man-made gases; as a result, water vapor wins. (OTOH, turning clouds into drinking water at scale would be a cool way to fight global warming and deal with drought at the same time. My understanding is that storm seeding has a pretty seedy history, though.)

konschubert 8y ago

One also has to consider that the methane decays over a matter of decades. Other than CO2, which stays in the atmosphere until it is taken out. So, even if methane takes a big share in current greenhouse emissions, its share in the accumulated greenhouse gases in the atmosphere will be lower. The climate change it causes is temporary. (Disregarding runaway effects.) https://en.wikipedia.org/wiki/Atmospheric_methane https://en.wikipedia.org/wiki/Atmospheric_methane

Retric 8y ago
Methane contains carbon so it's not 100% temporary just mostly.
- deleted 8y ago
  [deleted]
skosch 8y ago
Decades – we don't have decades to fix this. Also, it decays into CO2, so to claim that its effects are temporary is misleading. On top of that, as long as the carbon is in a CH4 bond, it traps at least 20× as much radiation. Please don't dismiss the significance of methane emissions.
- samstave 8y ago
  We should he focusing on plastics rather than methane.
- Jach 8y ago
  How many years do we have to fix this then? Alternatively, at what point will activists start saying we passed the point of no fix and give up their activism?
  - marssaxman 8y ago
    I got to that point 3-4 years ago, personally. Even if it were economically and technically possible to get our act together, it has become entirely clear that the political system is incapable of acting quickly enough.