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> your comment suggests a misunderstanding. Cows convert inert carbon from feed into methane, a much more potent greenhouse gas. Not all carbon is created equal

by sampo 4y ago

> your comment suggests a misunderstanding. Cows convert inert carbon from feed into methane, a much more potent greenhouse gas. Not all carbon is created equal from the perspective of climate. Your comment also suggests a misunderstanding. Methane has an atmospheric lifetime of only ca. 10 years. A constant source of methane will not lead to increasing atmospheric methane levels, nor to continuous warming. Whereas a constant source of CO2 will.

blueflow 4y ago
> Whereas a constant source of CO2 will. Which Methane is. It decomposes into CO2 and Water.
- sampo 4y ago
  Yeah, but that is mostly beside the point. In pure carbon, anthropogenic CO2 emissions are about 12 GtC/year, and CH4 emissions (from fossil fuel, agriculture, waste) about 0.27 GtC/year. So CO2 from methane emissions is only 2% of all CO2 emissions.
  - giantrobot 4y ago
    Methane is like 80x worse than CO2 in terms of greenhouse effect. So that 0.27Gt of CH4 has the GHG effect of 22Gt of CO2. When it decomposes to CO2 it then still has the greenhouse effect of gigs tons of CO2.
  - virgildotcodes 4y ago
    Assuming these numbers are correct - given that CH4 traps 80x more heat than CO2 over the first 20 years[1], it would be the equivalent of adding another 21.6 GtC per year for those first 20 years. Over the span of 100 years, that CH4 degrades into CO2 but still ends up trapping 25x more heat than the same amount of CO2 emitted at the outset, resulting in the same impact as releasing another 6.75 GtC/year over the next century. Nothing to dismiss, especially because that extra boost to heating in those first 20 years could be the difference between us hitting various tipping points, like melting permafrost and releasing yet another 185 GtC[2] into the atmosphere, and not. [1]https://climate.mit.edu/ask-mit/why-do-we-compare-methane-carbon-dioxide-over-100-year-timeframe-are-we-underrating https://climate.mit.edu/ask-mit/why-do-we-compare-methane-ca... [2]https://www.carbonbrief.org/imminent-tipping-point-threatening-europes-permafrost-peatlands/ https://www.carbonbrief.org/imminent-tipping-point-threateni...
virgildotcodes 4y ago
Methane traps about 80 times more heat than CO2 over the first 20 years, before it degrades into CO2 and then overall ends up trapping about 25 times more over the first 100 years. https://climate.mit.edu/ask-mit/why-do-we-compare-methane-carbon-dioxide-over-100-year-timeframe-are-we-underrating https://climate.mit.edu/ask-mit/why-do-we-compare-methane-ca...
- tomp 4y ago
  Sure, but that methane + CO2 has been in a steady cycle (cow -> air -> grass -> cow) and fairly constant quantity (before mass agriculture there were e.g. numerous bisons in the US), so they’re not contributing to “global warming” (i.e. a rise in temperature). All of that warming is caused by fossil fuels.
  - virgildotcodes 4y ago
    - tomp 4y ago
      My final thoughts are, what my original comment (2-3 comments up the chain) was. Your “solution” doesn’t solve anything, but merely delays the inevitable. There is only one solution to global warming, which is stopping fossil fuels. Deleting all cows is not a solution, therefore it is promoted simply as a distraction, and a way to let people hate each other, via “sin taxes” (very similar to “paper straws” drive a few years back, which also had a zero-to-negative effect on pollution and global warming)
      - rafaelero 4y ago
      - virgildotcodes 4y ago
        I agree that we need to eliminate fossil fuels. I also didn't state that eliminating animal agriculture was the singular solution to climate change. All I was pointing out was that it doesn't seem correct to say that cattle do not contribute to climate change, as you seemed to be saying.
deleted 4y ago
[deleted]

by sampo 4y ago

blueflow 4y ago

> Whereas a constant source of CO2 will. Which Methane is. It decomposes into CO2 and Water.

sampo 4y ago
Yeah, but that is mostly beside the point. In pure carbon, anthropogenic CO2 emissions are about 12 GtC/year, and CH4 emissions (from fossil fuel, agriculture, waste) about 0.27 GtC/year. So CO2 from methane emissions is only 2% of all CO2 emissions.
- giantrobot 4y ago
  Methane is like 80x worse than CO2 in terms of greenhouse effect. So that 0.27Gt of CH4 has the GHG effect of 22Gt of CO2. When it decomposes to CO2 it then still has the greenhouse effect of gigs tons of CO2.
- virgildotcodes 4y ago
  Assuming these numbers are correct - given that CH4 traps 80x more heat than CO2 over the first 20 years[1], it would be the equivalent of adding another 21.6 GtC per year for those first 20 years. Over the span of 100 years, that CH4 degrades into CO2 but still ends up trapping 25x more heat than the same amount of CO2 emitted at the outset, resulting in the same impact as releasing another 6.75 GtC/year over the next century. Nothing to dismiss, especially because that extra boost to heating in those first 20 years could be the difference between us hitting various tipping points, like melting permafrost and releasing yet another 185 GtC[2] into the atmosphere, and not. [1]https://climate.mit.edu/ask-mit/why-do-we-compare-methane-carbon-dioxide-over-100-year-timeframe-are-we-underrating https://climate.mit.edu/ask-mit/why-do-we-compare-methane-ca... [2]https://www.carbonbrief.org/imminent-tipping-point-threatening-europes-permafrost-peatlands/ https://www.carbonbrief.org/imminent-tipping-point-threateni...

virgildotcodes 4y ago

Methane traps about 80 times more heat than CO2 over the first 20 years, before it degrades into CO2 and then overall ends up trapping about 25 times more over the first 100 years. https://climate.mit.edu/ask-mit/why-do-we-compare-methane-carbon-dioxide-over-100-year-timeframe-are-we-underrating https://climate.mit.edu/ask-mit/why-do-we-compare-methane-ca...

tomp 4y ago
Sure, but that methane + CO2 has been in a steady cycle (cow -> air -> grass -> cow) and fairly constant quantity (before mass agriculture there were e.g. numerous bisons in the US), so they’re not contributing to “global warming” (i.e. a rise in temperature). All of that warming is caused by fossil fuels.
- virgildotcodes 4y ago
  - tomp 4y ago
    My final thoughts are, what my original comment (2-3 comments up the chain) was. Your “solution” doesn’t solve anything, but merely delays the inevitable. There is only one solution to global warming, which is stopping fossil fuels. Deleting all cows is not a solution, therefore it is promoted simply as a distraction, and a way to let people hate each other, via “sin taxes” (very similar to “paper straws” drive a few years back, which also had a zero-to-negative effect on pollution and global warming)
    - rafaelero 4y ago
    - virgildotcodes 4y ago
      I agree that we need to eliminate fossil fuels. I also didn't state that eliminating animal agriculture was the singular solution to climate change. All I was pointing out was that it doesn't seem correct to say that cattle do not contribute to climate change, as you seemed to be saying.

deleted 4y ago

[deleted]