Why do cow burps and farts harm the planet?

Question

It is often said that meat is among the most damaging foods from a climate change perspective. However, I don't quite understand why that is true, in the long run.

Disclaimer: I am a vegan for animal rights reasons, however I still want to understand those who make the environmental case against beef.

If I understand correctly, the primary contribution of beef production to climate change is the burping and farting the cows do when they digest their food.

Now, all carbon dioxide emitted by human and animal bodies should be carbon neutral. This is because we get our carbon from the food we eat and that food was just recently grown, the plants having built themselves out of carbon from the atmosphere. Thus, so long as we don't eat coal, we are all solar powered with a delay of a few months (or slightly longer, for non-vegans). The same must be true for farts, except that because methane is far more potent (maybe 20-30 times) as a greenhouse gas, it does more damage, once emitted, than the CO2 (captured a few months prior) that it is replacing. However, methane in the atmosphere is short lived: It breaks down to carbon dioxide after only about 12 years. So shouldn't this mean any environmental damage from cow burps and farts is temporary, lasting only 12 years? And shouldn't this mean that if meat consumption remains constant the planet would only warm a little for that amount of meat consumption and not continue warming?

Answer 1

If I understand correctly, the primary contribution of beef production to climate change is the burping and farting the cows do when they digest their food.

There are other important factors, such as deforestation for growing animal fodder. However, burping is a real issue as well.

As you've already pointed out, cows burp methane, not carbon dioxide. Methane is a much stronger greenhouse gas than carbon dioxide. Therefore, any process that turns carbon dioxide into methane and then releases it into the atmosphere contributes to climate change in the short-to-medium term.

However, methane in the atmosphere is short lived: It breaks down to carbon dioxide after only about 12 years. So shouldn't this mean any environmental damage from cow burps and farts is temporary, lasting only 12 years? And shouldn't this mean that if meat consumption remains constant the planet would only warm a little for that amount of meat consumption and not continue warming?

I think 12 years is the half-life, not the total lifetime. But even with constant meat consumption, that means there's constantly a higher level of methane in the atmosphere. If we're unlucky, this triggers a climate threshold.

Answer 2

In addition to all the valid points given in gerrit's answer, a critical part of the methane emissions from livestock is emmitted from their manure. Once solid and liquid manure (their poop and their pee-pee) are stored together like in a typical stable in industrial agriculture anaerobic microbes process the nitrogen present in both mainly into methane. This is in contrast to letting livestock graze on pasture, where they naturally do not poop in the same place they pee and carefully till the soil with their hoof - both of which lead to nitrogen fixation into the soil such that far less nitrogen (in the form of methane) is emitted to the air.

In fact, pasture feeding (especially in locations where crop-based agriculture is not possible) has a considerably better ecological and climate impact than industrial, stable-based holding of livestock.