In just 30 years (1982 to 2012) global meat consumption has increased from 125 to 300 million metric tons.
Massive increases in sewage wastewaters discharged to coastal ecosystems have caused (and still cause) massive ecosystem changes, destruction of coastal fisheries, and prevent the growth of sustainable aquaculture because of destroyed water qualities.
Along with this have been increases in the concentrations of nitrogen in wastewater.
Almaraz et al. (2022) assessed the nitrogen content in wastewaters in the US and found that it was due to an increased and excessive amount of human protein consumption. A similar situation is occurring in Europe and China due to the skyrocketing amount of terrestrial meats being consumed (Lassaletta et al 2014; Sans and Combris 2015; Wang et al. 2019).
Changes in Annual Protein Consumption in the USA in 50 Years (kg/capita)
Years Seafood Meat
1965 10.9 44.4
2005 15.0 64.0
2015 14.0 105.6
The US Centers for Disease Control and Prevention (CDC) recommends an average daily protein consumption rate of 46 grams for women and 56 grams for men (CDC 2010). A 2005-2006 US National Health and Nutrition Examination Survey measured the amount of protein consumed by US men and women ages 20 and over and found that men were consuming almost twice the daily recommended amount of protein (101.9 grams). Women consumed a daily average of 70.1 grams (USDA ARS 2008)
Almaraz et al. (2022) attributed 67–100% of wastewater nitrogen resulted from protein consumption. They made a calculation that if the average daily protein consumption could be reduced to the CDC recommended values, that nitrogen discharges could be almost halved from 1.33 TgN/year to 0.78 TgN/year. (NOTE: 1Tg=1 million metric tons). Such a reduction of 0.55 Tg N/year would “be comparable to nitrogen inputs attributed to septic tank leakage (0.4 TgN/year) or efforts to improve human waste treatment practices and reduce nitrogen exports using existing technology (0.5–0.8 TgN/year, EPA 2015).”
References
Almaraz, M., Caitlin D Kuempel, Andrew M Salter , and Benjamin S Halpern. 2022. The impact of excessive protein consumption on human wastewater nitrogen loading of US waters. Front Ecol Environ 2022; 20(8): 452–458, doi:10.1002/fee.2531
CDC (Centers for Disease Control and Prevention). 2010. Nutrition for everyone – protein. Atlanta, GA: CDC.
EPA (US EnvironmentalProtection Agency). 2015. Reactive nitro- gen in the United States: an analysis of inputs, flows, conse- quences,and managementoptions. Washington, DC: EPA.
Lassaletta L, Billen G, Grizzetti B, Garnier J, Leach AM, Galloway JN. Food and feed trade as a driver in the global nitrogen cycle: 50-year trends. Biogeochemistry. 2014; 118: 225–241.
Sans, P. and P. Combris. 2015. World meat consumption patterns: An overview of the last fifty years (1961–2011). Meat Sci. 2015; 109: 106–111. https://doi.org/10.1016/j.meatsci.2015.05.012 PMID: 26117396
USDA ARS (United States Department of Agriculture, Agriculture Research Service). 2008. Nutrient intake from foods: mean amounts and percentages of calories from protein, carbohydrates, fat, and alcohol, on e day, 2005-2006. https://www.ars.usda.gov/ba/bhnrc/fsrg
Wang, X, Daigger G, de Vries W, Kroeze C, Yang M, Ren N-Q, et al. 2019. Impact hotspots of reduced nutrient discharge shift across the globe with population and dietary changes. Nat Commun. 2019; 10: 2627. https://doi.org/10.1038/s41467-019-10445-0 PMID: 31201305
