Convert carnivores to vegans by michaelbheaney

There is a damaging TED talk which claims (falsely) that cattle (beef) is the answer to climate change: https://en.wikipedia.org/wiki/Allan_Savory#Criticism

It is very difficult to stick an "inconvenient truth" when plausible deniability allows convenient peace of mind...

Here is both a mitigation and education strategy:

"The ‘fartpacks’ extract 300 litres of methane a day from a tube inserted into the cow's digestive tract and convert it into enough energy to run a car for 24 hours.
Read more: http://www.dailymail.co.uk/sciencetech/article-2606956/Now-THATS-wind-power-Cows-wear-BACKPACKS-capture-emissions-miniature-power-stations.html#ixzz3pJMoHgT0
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So cows are many times (convert 300 l to CO2e, compared to CO2 released by burning 300 l) worse than a car!

Hmmm, did some math and something is wrong...

300 l of methane is 300 liter*0.656 g/liter = 196.8 grams

CO2 emissions factor 2.8:

http://www.engineeringtoolbox.com/co2-emission-fuels-d_1085.html

196.8 grams * 2.8 = 551.04 grams CO2

average car produces 12,000 miles/365 days * .364 kg CO2e/mile = 12 kg co2 per day

Maybe the energy content per emission is better for methane?

One GGE of natural gas is 126.67 cubic feet (3.587 m3)

https://en.wikipedia.org/wiki/Gasoline_gallon_equivalent#Compressed_natural_gas

So 300 l is energy equivalent to = 0.0836353499 of one gallon or this fraction of a mpg, so given 25 mpg for example, we get 2 miles of travel on 300 l of methane, far from the average 33 miles per day.

So it would take over 16 cows to power 1 car's worth of driving.

http://bigthink.com/design-for-good/this-is-how-you-turn-cow-fart-gas-into-energy

Are the methane emissions as damaging as a car's?

196.8 grams * 25 GWP = 4920 grams CO2e

18.95 pounds (8.60 kg) of CO2 are produced when a gallon of E10 is combusted.

http://www.eia.gov/tools/faqs/faq.cfm?id=307&t=11

So, ~25 mpg in 2013

http://www.csmonitor.com/Business/In-Gear/2013/0406/Average-fuel-economy-of-US-cars-reaches-an-all-time-high

25/8.6* 4.920*365/12,000 = 0.44, so ~2 cows emit the same CO2e as 1 car.

If methane from cows were collected, emissions would reduce to 551.04 grams /4920 grams = 11.2% CO2e plus the reduction in emissions from the “free” energy of combustion. 

Does this look right?

You forgot to factor in the fact that we could feed more than the world population with what we feed to farm animals....Maybe their math is a little overzealous but farming animals to eat is certainly unsustainable and the future of it doesn't look promising. Vegan is the future like it or not.