The impacts of livestock agriculture on environmental degradation and GHG emissions

Question 1

How much GHG emission does the animal agriculture industry produce?

Answer 1

In 2013, the Food and Agriculture Organization of the United Nations estimated that livestock production accounted for 14.5% of global greenhouse gas emissions. More recent data and science indicate that livestock may contribute a wider range of emissions, potentially more, potentially less. For its part, the Food and Agriculture Organization of the United Nations has released a new, lower estimate that livestock produce 11.1% of global greenhouse gas emissions. Peer-reviewed studies have put the figure higher, at up to 19.6% of emissions.

Answer 2

There is scientific consensus that anthropogenic greenhouse gas (GHG) emissions influence global warming and climate change [1]. To limit the negative consequences of climate change, 196 parties have committed to keep the increase in global average temperature below 2 °C above pre-industrial levels and try to limit warming to 1.5 °C [2].

Answer 3

For example, the government of the United Kingdom (UK) has laid out a ten-point plan for a green industrial revolution in which they commit to transforming the energy sector, ending the sale of petrol and diesel cars, decarbonising public transport, developing greener buildings, investing in carbon capture and storage, and protecting the natural environment [4]. Worryingly, they failed to address agriculture in their plans.

Answer 4

Revolutionizing agricultural systems should arguably be a top priority considering food production is the single largest cause of global environmental change [5]. Current agricultural practices constitute up to 21% to 37% of global total emissions [6] and 70% of freshwater use [7], whilst occupying approximately 40% of Earth’s land

Answer 5

Per-capita emissions from food consumption are 39% and 41% higher in very high human development index (HDI) countries than in high HDI countries and low HDI countries, respectively [14].

Answer 6

These differences in emissions are despite the use of high emission-intensity beef farming in low HDI countries. In very high HDI countries, cattle products are responsible for 68% of total consumption-based agricultural GHG emissions [14]. Reducing red meat consumption is a major key to meeting emission targets for very high HDI countries and it would deliver substantial health co-benefits.

Answer 7

Around 43% of the planet’s ice-free terrestrial landmass is occupied by farmland (including croplands and pasturelands). Approximately 77- 83% of this farmland is used to produce meat, eggs, farmed fish, and dairy, yet they only provide 18% and 37% of our calories and protein, respectively

Answer 8

According to a 2021 FAO study, livestock grazing is responsible for nearly 40% of deforestation

Answer 9

According to grazingfacts.com, beef cattle use around 60% of the world’s agricultural land. However, according to fefac.eu, 2.5 billion hectares of agricultural land is used globally for livestock farming, which is about 50% of the world’s agricultural area.

Answer 10

If we combine pastures used for grazing with land used to grow crops for animal feed, livestock accounts for 77% of global farming land.

Answer 11

Brown and Eisen used publicly available data on livestock production, livestock-linked emissions and biomass recovery potential on land currently used to support livestock to predict how the phaseout of all or parts of global animal agriculture production would alter net anthropogenic, or human-caused, emissions from 2019 levels. They then used a simple climate model to project how these changes would impact the evolution of atmospheric greenhouse gas levels and warming for the rest of the century.

They examined four dietary scenarios: an immediate replacement of all animal agriculture with a plant-only diet; a more gradual and, the authors say, more realistic, 15-year transition to a global plant-only diet; and versions of each where only beef was replaced with plant-only products.

For each hypothetical scenario, the scientists assumed that non-agricultural emissions would remain constant and that the land formerly used for livestock production would be converted to grasslands, prairies, forests and the like that will absorb atmospheric carbon dioxide.

Answer 12

While the complete phase out of animal-based agriculture was projected to have the largest impact, 90 percent of the emission reductions could be achieved by only replacing ruminants such as cattle and sheep, according to the model.

Answer 13

Consumption of a high-resource diet based on animal products without a reciprocal nutritional value while degrading the environment and animal and human health is unethical and no longer sustainable. Without a major and urgent transformation in global meat consumption, and even if zero GHGE in all other sectors are achieved, agriculture alone will consume the entire world’s carbon budget needed to keep global temperature rise under 2 °C by 2050

Answer 14

The Holocene, the current geological epoch, is notable for climate stability, with temperature oscillating within a range of 2–3 °C. Human population growth and development coupled with centuries of atmospheric colonization by the world’s richest regions have now made evident a potentially irreversible disruption in the restoration capacity of the planet’s ecosystems.

Answer 15

The current rate of warming on Earth is unprecedented in the last 50 million years, with no 200-year interval during the past 12,000 years exceeding the warming of the most recent decade [2,3].

Answer 16

The production, utilization, and consumption of animal products has been closely intertwined to human biologic and social evolution [4], [5], [6]. This relationship is now threatening human health and the equilibrium of the planet’s ecosystem. Global food production is responsible for 35% of all greenhouse gas emissions (GHGE) with the use of animals as a source for food, as well as livestock feed, responsible for almost 60% of all food production emissions [7].

Answer 17

Industrial animal farming (i.e., concentrated animal feeding operations [CAFOs]) has direct effects on global land and freshwater use, ocean acidification, GHGE, biodiversity loss, antibiotic resistance, and increased risk of emerging infectious and non-communicable diseases such as cancer and cardiometabolic conditions [8,9].

Answer 18

According to National Geographic, only 55% of food-crop calories directly nourish people. The remaining 4% comes from meat, dairy, and eggs from animals raised on feed. The rest of crop calories go toward biofuels or animal feed.

Answer 19

In South America, approximately 85% of rainforest degradation has been done for animal grazing or croplands for animal feed [15]. Increased food production has been possible in part by the synthetic production of nitrogen and phosphorus fertilizers. The levels of these biologically active elements in the environment have dramatically increased as a result and have led to decreased plant diversity, ocean acidification, algal blooms, and eutrophication [16]. In just the last 50 years, there has been a 68% population decrease in monitored vertebrate species; with the largest declines in the tropical regions of the world [17]. The current rate of species extinction is unprecedented – being 100–1000 times that of historic values of 0.1 extinction per million species per year [15,18].

Answer 19

The degree of water utilization for cattle-feed irrigation and ultimate beef consumption is substantial. Nearly one-third of the planet’s water used in agriculture is related to the production of animal products. In the United States, beef consumption accounts for 22% of the total water utilization and for 55% of water consumption in the Colorado River basin; with cattle-feed irrigation being the leading driver of water depletion of the rivers in western states [19]

Answer 19

The loss of biodiversity in our oceans due to large-scale commercial fishing for both direct human consumption and animal feed is threatening fish survival. From 1950 to 2010, 27% of global fish (∼20 million tons annually) were destined towards feeding farmed fish, pigs, chickens, and cattle [20]. This level and rate of exploitation is not sustainable with global collapse of all oceanic taxa predicted to occur by the mid-21st century

Answer 19

For example, in the U.S., reducing daily protein consumption by 25% while reducing the percentage of animal derived protein will lead to a 4% savings in freshwater use and to a climate change mitigation equivalent in GHGE of about 8% [23].

Answer 19

Manure from concentrated animal feeding operations (CAFOs) is a leading contaminant of both underground and surface water, often leading to accumulation of nitrates, ammonia, and phosphorus with a deleterious effect on the flora and fauna of lakes, rivers, and other water reservoirs 1. The production of manure by some facilities each year can surpass the waste produced by some major U.S. cities 1. Livestock manure management strategies include pumping liquefied manure onto spray fields, trucking it off-site, or storing it in deep pits, treatment lagoons, and holding pools 1.

Answer 20

CAFOs also contribute to poor air quality, especially in communities living in proximity to the industrial farms. The frequently identified air pollutants include ammonia, hydrogen sulfide, methane, and particulate matter 2. Studies have found higher rates of asthma (especially in children), chronic bronchitis, and interstitial lung disease in animal farm workers and surrounding communities 2. Although carbon is often considered the main greenhouse gas of concern, the methane and nitrous oxide emitted by manure are 23 and 300 times more potent than carbon in trapping heat in the atmosphere 2. Livestock is the main source of methane; derived from the anaerobic breakdown of manure in lagoons and pits and from the digestive tract of ruminants.