https://quillette.com/2018/04/05/case-sustainable-meat/ Here (in Section II: Cows as Eco Vandals) they provide a pretty good counter-argument to this 18% figure. > [the 2006 UN report entitled “Livestock’s Long Shadow.”] made the shocking claim that livestock accounts for 18 percent of all greenhouse gas emissions globally, placing it ahead of the transport sector. [...] > For the last decade, “Livestock’s Long Shadow” has contributed to the near-religious dogma that to tackle global warming we all need to eat less meat. However, there are important caveats behind the UN figures that take much of the darkness out of the ‘long shadow.’ > Firstly, this is a global figure. It masks the fact that the preponderance of greenhouse gas (GHG) come from deforestation to create new beef pasture or animal feed crops. That is, most of the carbon emissions attributed to the beef are actually from the destruction of the carbon sinks (forests) that preceded them, rather than the ranching itself. Furthermore, this activity is chiefly happening in developing countries. Most developed countries, by contrast, have seen increasing forest cover for many decades. Consequently, when the US did its own analysis of carbon emissions, researchers found that the American livestock industry contributes only 2.8 percent to US GHG emissions. So, even if everyone in the US gave up meat entirely, it would barely put a dent in the country’s emission figures. >Secondly, in many cases it is the value of the extracted timber which drives such deforestation, not the beef production that might follow in its wake. Even if beef production ceased tomorrow, the logging would still take place. >Thirdly, the UN report didn’t consider alternative land use after the loggers had gone. Indeed, researchers have since identified that changing to grassland actually provides the most effective sink and store of soil carbon – far superior to farmland and, surprisingly, even better than replanting forest. Indeed, the Irish Government has identified restoration of grasslands and pasture around the world as a priority with significant potential to mitigate Global Warming. In their analysis, they found that for UK and Irish livestock farms, the greenhouse emissions were negligible. This is in large part because our animals feed primarily on grass for much of the year. edit: and sorry for the long ass quote. It's not just that I'm lazy, but also this article was written much better than my paraphrase would've been