One cow* produces as much greenhouse gas emissions as driving a car for 50,000km. So we should get rid of all the cows and plant trees. But wait! When a grown tree** dies and decomposes, it will produce as much CO2 emissions as driving a car 200,000km. So we should not plant any more trees?
Here is the flaw in the logic: Where does the carbon come from that the cows breathes out or the tree loses when it decomposes? It comes from the air. Plants breathe in the CO2 and store the carbon until they die and release it back to the atmosphere. Its part of a cycle.
You may say: but plants assimilate CO2 and cows breathe out methane (CH4) and CH4 is much more potent than CO2! And here is where it gets a little technical. New research is showing that there are a lot of bacteria in the soil that live off the methane in the air. According to Wikipedia "methanotrophs (methane metabolising bacteria) occur mostly in soils, and are especially common near environments where methane is produced" - where cows live and shit. Wikipedia goes on to explain that "the amount of methane emitted by one cow is equivalent to the amount of methane that around 3.4 hectare of methanotrophic bacteria can consume." So the amount of methane produced by an average cow living on rangeland is roughly in balance with the amount of methane being metabolised by methanothrophs.
Another crucial point is that methane in the atmosphere naturally breaks down very quickly. According to Wikipedia methane has a "net lifetime of 8.4 years" in the atmosphere. This means that methane emissions are not cumulative. If the number of animals remains stable, so does the amount of methane in the atmosphere (which can be attributed to them). This point is quite critical, because all herbivores produce methane in their digestion process, even cute little beavers or great bison. Wildlife (bison and beavers) produce the same methane as domesticated animals (cattle). Nobody would however suggest that we should get rid of wildlife because they produce methane.
When European settlers first came to North America it was home to an incredible amount of wildlife - 25-100 million bison, 100-200 million beavers and many more. All of them producing methane. Sadly, we did end up exterminating most of them and replacing them with 110 million domesticated cattle. It is crucial to keep in mind here that the net amount of methane emissions has remained more or less unchanged. And if we were to get rid of all the cows and let the wildlife reclaim the American Great Plains, this would not help to reduce methane emissions.
To keep things in context, it is important to note that methane only accounts for only 20% of the greenhouse effect. And all ruminants combined only account for less than 20% of all methane emissions. 20% of 20% = 4%. To be clear: cows with all their burps and farts are accountable for 4% of the greenhouse gas emissions, not some 50% which fake documentaries (propaganda pieces) like Cowspiracy would like us to believe.
Something is often ignored in these debates is animal husbandry "largely based on grasslands – provides livelihoods for about 1 billion of the world’s poorest people and one third of global protein intake." - Food and Agricultural Organisation (FAO) of the UN. Those cows are not having any negative environmental impact because only as much cattle is being held there as the natural holding capacity of the land would allow (this is sometimes referred to as "default livestock system").
If however we let our appetite for beef dictate how many cows we raise and we start locking them up in concentrated feedlots (CAFOS) to feed them with corn and soybeans, then cows really do have en extremely detrimental effect on the environment.
In conclusion, it is not cows who are bad for the environment, but humans who decide to do crazy things with them. And I am not letting anyone off the hook here. If you do want consume beef, you should make sure that it has been grass-fed. And you should probably eat less of it.
For more information, I suggest you check out my TEDx: This bullshit might save the world: Composting cow manure with biochar
For further reading, please check out:
The Ecologically Optimal Amount of Animal Products is not Zero. Far from it.
1 kg of Beef takes 100'000 Liters of Water! - no it does not!!
Going one year without beef saves 3,432 trees - no it does not!
Red meat does not cause heart disease, diabetes, cancer, cardiovascular disease or obesity - says Harvard
The meat of one cow is worth $2,000. You will not believe what the true cost of production is...
The moral case for eating meat
Cattle vs. the Climate
A Vegan couple eats Meat again for the first time in 40 years after operating their own farm. Here is why:
Eating Meat - The ecological and Moral Arguments: My conversation with two Vegans
The Greatest Ecological Cock-up of recent History
Your organic vegetables are all meat eaters!