Virtue PostMortem

Diets compared

You want to reduce the carbon footprint of your food? Focus on what you eat, not whether your food is local

Title: "Food: greenhouse gas emissions across the supply chain." Graphic shows that beef emits the most GHG, followed by lamb & mutton (1/3 of the beef emissions), cheese, beef from dairy herds, then chocolate & coffee, and to a much lesser degree other animal products, and other plant products on the bottom.

Title: "Global land use for food production." The earth's surface is 29% land. 71% of that is habitat land, and 46% of that land is used for agriculture. Of that agricultural land, 77% are used for livestock while producing 18% of global calories and 23% is crop land while producing 82% of global calories.

The earth's surface is 29% land. 71% of that is habitat land, and 46% of that land is used for agriculture. Of that agricultural land, 77% are used for livestock while producing 18% of global calories and 23% is crop land while producing 82% of global calories.

If the world adopted a plant-based diet, we would reduce global agricultural land use from 4 to 1 billion hectares

Paper of the Day: Poore & Nemecek (2018): Reducing food’s environmental impacts... - EnvironMath!

GHG per energy and per protein

Food production is responsible for one-quarter of the world’s greenhouse gas emissions

Inefficiency

Disrupting MeatMeat makes for curious math: about 25 calories is required to create just 1 calorie of beef. The ratio for pork is nearer 15-to-1. Even the most efficient meat, chicken, requires 9 calories of input to produce just 1 calorie of food.

Beans produce 300 times less GHG CO2 Eq

www.ox.ac.uk/news/2018-06-01-new-estimates-environmental-cost-food?s=03

Researchers at Oxford University and the Swiss agricultural research institute, Agroscope, have created the most comprehensive database yet on the environmental impacts of nearly 40,000 farms, and 1,600 processors, packaging types, and retailers. This allows them to assess how different production practices and geographies lead to different environmental impacts for 40 major foods. They found large differences in environmental impact between producers of the same product. High-impact beef producers create 105kg of CO2 equivalents and use 370m2 of land per 100 grams of protein, a huge 12 and 50 times greater than low-impact beef producers. Low-impact beans, peas, and other plant-based proteins can create just 0.3kg of CO2 equivalents (including all processing, packaging, and transport), and use just 1m2 of land per 100 grams of protein.

Environmental impact of diets in the UK

Vegans, vegetarians, fish-eaters and meat-eaters in the UK show discrepant environmental impacts

https://www.mdpi.com/1660-4601/20/5/3797

Sustainability benefits of transitioning from current diets to plant-based alternatives or whole-food diets in Sweden - Nature Communications

Grass-fed CO2

US grass-fed beef is as carbon intensive as industrial beef and ≈10-fold more intensive than common protein-dense alternatives | PNAS

The high resource intensity of industrial beef in high-income economies has prompted growing interest in alternative, potentially lower environmental impact beef production pathways. Of those, grass feeding is promoted by some as one such alternative, but rigorous quantification of this claim is required. Motivated to bridge this knowledge gap, we integrate empirical evidence with a model based on authoritative equations governing beef cattle performance to quantify the greenhouse gas emissions of producing grass-fed beef. Because geographical specificity and dependence on agricultural intensity are key, we model widely varied herds, from extensive operations on semiarid, marginal rangelands to partially industrial, intensive ones in lusher, more accommodating settings. We find that emissions per kg protein of even the most efficient grass-fed beef are 10 to 25% higher than those of industrial US beef and 3- to over 40-fold higher than a wide range of plant and animal alternatives. Soil sequestration enhancement by rangeland grazing reduces these emissions from 280–390 to 180–290 kg CO2eq (kg protein)−1, still somewhat above industrial beef’s 180 to 220 kg CO2eq (kg protein)−1, and well above nonbeef alternatives’ 10 to 70 kg CO2eq (kg protein)−1. These differences prove robust across a broad set of combinations of grass-fed beef operation types, management practices, and ration qualities. Consequently, even with maximal credit for putative sequestration enhancement, grass-fed beef is still no less carbon intensive than industrial beef, and severalfold more intensive than nonbeef alternatives.

A global meta-analysis of livestock grazing impacts on soil properties

Abstract Grazing effects on soil properties under different soil and environmental conditions across the globe are often controversial. Therefore, it is essential to evaluate the overall magnitude and direction of the grazing effects on soils. This global meta-analysis was conducted using the mixed model method to address the overall effects of grazing intensities (heavy, moderate, and light) on 15 soil properties based on 287 papers published globally from 2007 to 2019. Our findings showed that heavy grazing significantly increased the soil BD (11.3% relative un-grazing) and PR (52.5%) and reduced SOC (-10.8%), WC (-10.8%), NO3- (-23.5%), and MBC (-27.9%) at 0–10 cm depth, and reduced SOC (-22.5%) and TN (-19.9%) at 10–30 cm depth. Moderate grazing significantly increased the BD (7.5%), PR (46.0%), and P (18.9%) (0–10 cm), and increased pH (4.1%) and decreased SOC (-16.4%), TN (-10.6%), and P (-23.9%) (10–30 cm). Light grazing significantly increased the SOC (10.8%) and NH4+ (28.7%) (0–10 cm). Heavy grazing showed much higher mean probability (0.70) leading to overgrazing than the moderate (0.14) and light (0.10) grazing. These findings indicate that, globally, compared to un-grazing, heavy grazing significantly increased soil compaction and reduced SOC, NO3-, and soil moisture. Moderate grazing significantly increased soil compaction and alkalinity and reduced SOC and TN. Light grazing significantly increased SOC and NH4+. Cattle grazing impacts on soil compaction, SOC, TN, and available K were higher than sheep grazing, but lower for PR. Climate significantly impacted grazing effects on SOM, TN, available P, NH4+, EC, CEC, and PR. Heavy grazing can be more detrimental to soil quality based on BD, SOC, TN, C: N, WC, and K than moderate and light grazing. However, global grazing intensities did not significantly impact most of the 15 soil properties, and the grazing effects on them had insignificant changes over the years.

Cattle industry walks away from net-zero target by 2030 pledge

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