Comparative analysis of environmental impacts of agricultural production systems, agricultural input efficiency, and food choice

Abstract

Global agricultural feeds over 7 billion people, but is also a leading cause of environmental degradation. Understanding how alternative agricultural production systems, agricultural input efficiency, and food choice drive environmental degradation is necessary for reducing agriculture's environmental impacts. A meta-analysis of life cycle assessments that includes 742 agricultural systems and over 90 unique foods produced primarily in high-input systems shows that, per unit of food, organic systems require more land, cause more eutrophication, use less energy, but emit similar greenhouse gas emissions (GHGs) as conventional systems; that grass-fed beef requires more land and emits similar GHG emissions as grain-feed beef; and that low-input aquaculture and non-trawling fisheries have much lower GHG emissions than trawling fisheries. In addition, our analyses show that increasing agricultural input efficiency (the amount of food produced per input of fertilizer or feed) would have environmental benefits for both crop and livestock systems. Further, for all environmental indicators and nutritional units examined, plant-based foods have the lowest environmental impacts; eggs, dairy, pork, poultry, non-trawling fisheries, and non-recirculating aquaculture have intermediate impacts; and ruminant meat has impacts ∼100 times those of plant-based foods. Our analyses show that dietary shifts towards low-impact foods and increases in agricultural input use efficiency would offer larger environmental benefits than would switches from conventional agricultural systems to alternatives such as organic agriculture or grass-fed beef.

A fresh look at inland fisheries and their role in food security and livelihoods

“…For example, Bogard, Farook, et al (2017) found that wild-caught species in Bangladesh had higher micronutrient density than commonly farmed aquatic species. Studies in Zambia and Malawi have demon- In light of recent studies suggesting food production systems have already reached planetary boundaries in terms of land use (Acevedo, Harvey, & Palis, 2018) and rising concern regarding the climate impacts of agriculture (Clark & Tilman, 2017;Foley et al, 2005), it is import- Incorporating such analyses into development decision-making is necessary to drive policy processes to look beyond simplistic economic valuation of lost production, to consider the full economic and environmental costs of replacing lost protein and other micronutrients (Ainsworth et al, 2018). Nonetheless, this is a potential, partial explanation of a different study finding that micronutrient provision from fish The small fish species Mola (Amblypharyngodon mola, Cyprinidae), among others, has been researched extensively for its potential to alleviate vitamin A deficiency (Roos, 2016;Roos, Mazharul Islam, & Thilsted, 2003).…”

Asymmetries of cattle and crop productivity and efficiency during Brazil’s agricultural expansion from 1975 to 2006

“…This meta-analysis also showed that increasing agricultural input efficiency (the amount of food produced per input of fertilizer or feed) would have environmental benefits for both crop and livestock systems; and, that for all environmental indicators and nutritional units examined, plant-based foods have the lowest environmental impacts while ruminant meat had impacts 100 times those of plant-based food (Clark and Tilman, 2017). Clark and Tilman (2017) added that dietary shifts towards low-impact foods and increases in agricultural input use efficiency would offer larger environmental benefits. Intensification for sustainability outcomes requires increases in production and higher yields but it also demands radical rethinking of food production to achieve major reductions in environmental impact.…”

“…Another comprehensive study made a meta-analysis of life cycle assessments that included 742 agricultural systems and over 90 foods and concluded that grass-fed beef requires more land and emits similar GHG emissions as grain-feed beef (Clark and Tilman, 2017). This meta-analysis also showed that increasing agricultural input efficiency (the amount of food produced per input of fertilizer or feed) would have environmental benefits for both crop and livestock systems; and, that for all environmental indicators and nutritional units examined, plant-based foods have the lowest environmental impacts while ruminant meat had impacts 100 times those of plant-based food (Clark and Tilman, 2017). Clark and Tilman (2017) added that dietary shifts towards low-impact foods and increases in agricultural input use efficiency would offer larger environmental benefits.…”

Mapping and linking supply- and demand-side measures in climate-smart agriculture. A review

“…Agricultural input efficiency is a key to reduce environmental impacts (Clark and Tilman 2017). Globally, less than half of the nitrogen applied as fertilizers to agricultural fields is taken up by crops (West et al 2014).…”

“…With the possible exception of vegetables grown in heated greenhouses, plant-based products emit less than animal-based products (González et al 2011;Clark and Tilman 2017), including wild-caught and farmed fish (Cao et al 2013). The greenhouse gas emissions of beef are exceptionally high due to enteric fermentation (González et al 2011;Clark and Tilman 2017).…”