Just saying for comparison, not for some "don't eat cows" agenda.
Cow fart source: http://www.fastcoexist.com/3054212/collecting-cow-farts-the-...
(208l of methane farts = 135g/day. 120 days = 16.2kg. 97 x 10^6/16.2 = roughly 6 x 10^6.)
Just smell that dairy air...
Imagine all that methane coming from ~1.5 billion cows on a yearly basis. I don't have to, it's happening already :D
Methane is 80 times more potent (long-term) than CO2 for global warming.
I personally can't wait for the economic prosperity of India and Africa. The beef and dairy business will top the oil one as the biggest pollutant, if it isn't topping already.
Why are there no regulations and taxes for them?
It isn't.
Agriculture accounted for an estimated emission of 5.1 to 6.1 GtCO2-eq/yr in 2005 (10-12% of total global anthropogenic emissions of greenhouse gases (GHGs)). (IPCC AR4[0], slightly revised to 5.0 to 5.8 GtCO2eq/y in AR5)
That's all agriculture, including livestock, this (IPCC AR5[1]) is just "cow farts":
Enteric Fermentation. Global emissions of this important category grew from 1.4 to 2.1 GtCO2eq/yr between 1961 and 2010, with average annual growth rates of 0.70% (FAOSTAT, 2013).
[0] https://www.ipcc.ch/pdf/assessment-report/ar4/wg3/ar4-wg3-ch...
[1] https://www.ipcc.ch/pdf/assessment-report/ar5/wg3/ipcc_wg3_a...
Here's an 18% estimate while transportation is 13%.
Here's a 51% estimate, trumping everything else.
http://www.worldwatch.org/node/6294
No one can say with certainty.
Although, raising 100 billion animals yearly, most of them having over 250lbs, I'd say it's pretty close for CO2.
When it comes to methane, cow farts are 65% of our methane emissions.