[botexpert]

51% of CO2 emissions is just a number that was repeated.

there's also dead oceans by 2048 which is the most pessimistic estimate.

but some numbers are fine.

the amount of land that is used for livestock is incomparable. water pollution, dead ocean zones, all caused by animal agriculture.

the amount of environmental destruction and pollution is incomparable. more than 90% of destroyed Amazon rainforest was for the sole reason of raising more livestock.

yeah, CO2 equivalent footprint might not be 51% but the oil industry does less environmental damage than animal agriculture. highest CO2 footprint isn't even cars and transport but heating and cooling.

[alex_duf]

I believe it's 51% of the greenhouse effect, that include 20ish percent of co2 emission resulting from cattle + the effect of methane which is a much more powerfull green house gas than co2.

(now whether this number is 51% or something else is another debate)

[mklarmann]

51% includes also respiration of cows, which should be net zero, because it is exactly the CO₂ that was captured by the plants before. (which is not okay to do)

Also 51% because equivalent calculations are not done over the span of 100 years, but shorter (methane becomes more dominant) and deforestation is also accounted for - (which is both fine).

So it is somewhere in between the results of renovated studies that say it is around 31% (e.g. Tukker et al) and the 51% worldwatch report.