Impact of Farm Subsidies on Food Prices and Consumption

Julian M. Alston, Daniel A. Sumner, Stephen A. Vosti,
Farm subsidies and obesity in the United States: National evidence and international comparisons,
Food Policy,
Volume 33, Issue 6,
2008

Even if eliminating farm subsidies were to increase corn prices by as much as 10% (which is in the high end of the highest estimates) the resulting impact on food prices is minimal. Food price reductions as a result of corn subsidies are around 2% which would imply an increase in consumption as a response to price near .5%. The resulting increase in beef consumption would be .10%.

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.

Environmental and Water Use Economies of Scope in Beef and Cotton Production

According to CGIAR and the FAO there is a lot of variation globally in when it comes to livestock production. This variation explains differences in GHG emissions due to differences in resources, technology, management, nutrition, environment, political economy and economic development. While this implies the environmental impact of livestock presents a serious challenge globally, it also implies there is a lot of opportunity to mitigate these effects. 

Research by Allen et al integrating cotton and beef production is a proof of concept that managing food and fiber production differently can make a significant difference:

"Per hectare, the integrated system used 23% less (P < 0.001) irrigation water, 40% less N fertilizer, and fewer other chemical inputs than the cotton monoculture. Profitability was about 90% greater for the integrated system at described conditions. Integrated production systems that are less dependent on irrigation and chemical inputs appear possible while improving profitability."

In other words in irrigated environments like those in this study there can be economies of scope in beef and cotton production related to water use efficiency and other inputs.

These kinds of synergies also speak to the variation we might see when it comes to attempts to estimate the water footprint of livestock production. Depending on genetics, nutrition, technology, environment, and management there is a lot of variation.  Three different estimates we find in the literature related to beef production include:

Capper, J.L. 2011. The environmental impact of beef production in the
United States: 1977 compared with 2007. J. Anim. Sci. 89:4249-4261.

~ 317 gallons per pound

Beckett, J.L. and J.W. Oltjen. 1993. Estimation of the water
requirement for beef production in the United States. J. Anim. Sci.
71:818-826

~ 441 gallons per pound of beef

Rotz, C.A., B.J. Isenberg, K.R. Stackhouse-Lawson, and E.J. Pollak.
2013. A simulation-based approach for evaluating and comparing
the environmental footprints of beef production systems. J. Anim. Sci.
91(11):5427-5437

~ 808 

Reference: 

Allen, V. G., C. P. Brown, R. Kellison, E. Segarra, T. Wheeler, P. A. Dotray, J. C. Conkwright, C. J. Green, and V. Acosta-Martinez. 2005. Integrating cotton and beef production to reduce water withdrawal from the Ogallala aquifer in the Southern High Plains. J. Agron. 97: 556-567