Carbon Footprint of Beef Production

C. Alan Rotz et al. Environmental footprints of beef cattle production in the United States, Agricultural Systems (2018). DOI: 10.1016/j.agsy.2018.11.005

see also: https://phys.org/news/2019-03-beef-resource-greenhouse-gas-emissions.html

'The seven regions' combined beef cattle production accounted for 3.3 percent of all U.S. GHG emissions (By comparison, transportation and electricity generation together made up 56 percent of the total in 2016 and agriculture in general 9 percent).'

Globally this translates to .47% of GHG emissions!

Data from the EPA seems in line with this, finding total agriculture emissions at 9% of total U.S. GHG emissions.

see: https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions

HERE is a nice susmmary fo the Rotz article:

• Greenhouse gas emissions: Beef production, including the production of animal feed, is responsible for only 3.3 percent of greenhouse gas emissions in the U.S. This is dramatically lower than the often-misapplied global livestock figure of 14.5 percent2. Furthermore, through continuous improvements in production practices, U.S. beef farmers and ranchers have avoided 2.3 gigatons of carbon emissions since 19753.
• Grain feed consumption: Per pound of beef carcass weight, cattle only consume 2.6 pounds of grain. This is comparable to feed conversion efficiencies of pork and poultry. Additionally, nearly 90 percent of grain-finished cattle feed is inedible to humans, meaning these plants can only provide value to humans when they're upcycled by cattle into high-quality protein.
• Corn feed consumption: Corn used to feed beef cattle only represents approximately 9 percent of harvested corn grain in the U.S., or 8 million acres. By comparison, 37.5 percent of corn acreage in the U.S. is used for producing fuel ethanol4.
• Water use: On average, it takes 308 gallons of water to produce a pound of boneless beef. Previous reports have estimated upwards of 24,000 gallons5. Additionally, water use by beef is only around 5 percent of U.S. water withdrawals, and this water is recycled.  
• Fossil fuel inputs. Total fossil energy input to U.S. beef cattle production is equivalent to 0.7% of total national consumption of fossil fuels.