A few words on the subject of Methane as it relates to global warming... Many a treatise has been written expounding the near imminent cataclysmic consequence of excess Methane in the atmosphere so I thought I'd throw in my 5 cents worth
Much of the blame for the ( not so ) gradual creation of this excess has been attributed to herds of farm animals. There even seems to be some disagreement as to which end of the said farm animals the Methane comes out of.
Loss of the world's permafrost has the potential to release LARGE quantities of methane thereby accelerating global warming which would in turn accelerate the thawing of permafrost ...
Even properly controlled oil extraction vents known as gas flares, (the flame tops you see on extended pipes next to drilling rigs) burn non-commercially viable Methane producing CO2 and H2O. Land based flares also kill a lot of insects and birds but don't get me started ...<rant ends> All of this has led to (what I would call) anecdotal hysteria on a global scale. The Intergovernmental Panel on Climate Change (IPCC) suggests that Methane has a Global Warming Potential (GWP) around 25 times greater than Carbon Dioxide (V/V) (cue pre-emptive hysterical sound effects).
Carbon, remember Carbon? well in the form of Carbon Dioxide it has a much greater total effect on global warming than atmospheric Methane by virtue of sheer volume and persistence.
The volume of Carbon Dioxide in the atmosphere is over 100 times that of Methane plus the effective persistence of Carbon Dioxide is around 100 years compared to atmospheric Methane at around 10 years.
Atmospheric Methane in the troposphere is reduced (most commonly) by reacting with hydroxyl (OH) radicals mimicking combustion forming water vapour and (more) Carbon Dioxide. Methane is further reduced through halogenation by radical substitution reaction (again most commonly) with naturally occuring Bromine or Chlorine. Carbon Dioxide reduction pretty much comes down to photosynthesis. Whilst large scale deforestation and burning (think Indonesia) must inherently have a marked, compound negative effect, non-forest areas should also be factored in - the large scale loss of any Green plant biomass is going to have a negative impact.
Globally, peatlands cover about 3 percent of the Earth but they store something in the order of twice as much carbon as all the trees in all the world's forests !
Some 65 million hectares of peatlands have been dried by intentional draining leading to the emission of nearly three billion tons per year of carbon dioxide. 1
Active ( ie: damp ) peatlands do emit Methane but this is far outweighed ( in atmospheric greenhouse terms ) by the Carbon Dioxide they would release if dried and allowed to smoulder.
Note 1: To put this into perspective, 3bn tonnes equates to about 8.3% of global ( energy related ) CO2 emissions
If the vegetarians / vegans got their way the entire population of the planet would be vegies and there'd be no
large herds of (domesticated) cows, sheep, goats, pigs, etc. Atmospheric Methane would be dramatically reduced in a very short time.
This would not save the world from global warming but a lot of people would feel better about it.
Currently a HUGE amount of Methane is produced by farm animals so if no-one was allowed to eat meat (no, not even bacon) the farm animals could be eliminated and the Methane they produce would disappear, this of course totally ignores the fact that certain carnivorous domestic pets might not be too impressed.
Unfortunately the necessary production of sufficient organic produce to feed the worlds 7 odd billion (now) vegetarians / vegans plus all the (now) dead set dangerous / cannibalistic domestic pets is likely to require vast tracks of land be converted from livestock grazing, meadows, parklands, etc to irrigated orchards, vineyards and grain growing fields.
Soy beans being harvested in Brazil
Image © 2016 Copyright The New York Times Company
Growing all this produce is going to require irrigation and fertilisation on a biblical scale leading to major changes in river flow dynamics and creating enormous quantities of nutrient rich run-off.
Harvesting all the fruit, vegetables and grain produced by said vast tracks of land is going to require armadas of harvesting machinery not to mention transportation !
Processing LOTS of this produce in to things like tofu (ugh) and meat substitutes made (unimaginably) from for example some mushroom concoction is going to consume enormous amounts of energy. Add to this 1000's of smallgoods manufacturers and delicatessens will go out of business. Fertiliser manufacturers would have to go chemical free. Pesticide / herbicide manufacturers like Monsanto would go broke.
Try to imagine ordering a deluxe McTofu and nutmeat burger then being asked "would you like carrot sticks with that?" Of course 7 odd billion
vegetarians would likely produce an equally HUGE amount of Methane as all the existing farm animals anyway, this is ignoring the less than likeable problem associated with lots of (now)
flatulent people in confined spaces like offices, public and private transport, etc. When the meat (especially bacon) lovers finally revolt the ensuing global civil war would result in a
nuclear Winter lasting decades wiping out all life on Earth anyway.
... hmmm Monsanto going broke sounds pretty good to me, lets do it :-)