TL;DR: Including land use and crops production, livestock and fisheries account for ~15% of GHG emmissions.
You might want to read this https://ourworldindata.org/environmental-impacts-of-food#whe...
and maybe this too https://ourworldindata.org/emissions-by-sector#food-producti...
Highlights:
> there are massive differences in the GHG emissions of different foods: producing a kilogram of beef emits 60 kilograms of greenhouse gases (CO2-equivalents). While peas emits just 1 kilogram per kg.
> For most foods – and particularly the largest emitters – most GHG emissions result from land use change (shown in green), and from processes at the farm stage (brown). Farm-stage emissions include processes such as the application of fertilizers – both organic (“manure management”) and synthetic; and enteric fermentation (the production of methane in the stomachs of cattle). Combined, land use and farm-stage emissions account for more than 80% of the footprint for most foods.
> Food is responsible for approximately 26% of global GHG emissions.
> Livestock & fisheries account for 31% of food emissions ... This 31% of emissions relates to on-farm ‘production’ emissions only: it does not include land use change or supply chain emissions from the production of crops for animal feed: these figures are included separately in the other categories.
> 21% of food’s emissions comes from crop production for direct human consumption, and 6% comes from the production of animal feed.
> Land use accounts for 24% of food emissions.
Twice as many emissions result from land use for livestock (16%) as for crops for human consumption (8%).
So including land use and crops production, livestock and fisheries account for ~15% of GHG emmissions