F4 agriculture

What share of global GHG emissions comes from the food system, and what share from agriculture alone (2015)?

The food system accounts for 34% of total global GHG emissions; agriculture alone is responsible for 24% of global GHGs.

Where does most of the environmental impact of food occur along the supply chain?

The vast majority of environmental impacts occur at the agricultural production stage — not during processing, transport, or retail. Agriculture dominates the climate, land use, water, and biodiversity footprints of food products.

Why must the environmental impacts of agriculture be considered from both a local and a global perspective?

Agricultural land use is a local process that generates social and economic benefits locally, but also causes ecosystem damage at local, regional, and global scales. Because agricultural production is integrated into global markets, local demand drives global land prices and land use changes elsewhere.

What is the Anthropocene?

The Anthropocene is the current geological epoch characterized by dominant human influence on the Earth system. Since 1750, accelerating socio-economic and earth system trends (industrialization, population growth, resource use) have pushed the planet into a new state.

What is the Planetary Boundaries framework?

Developed by the Stockholm Resilience Centre, it defines nine Earth-system processes that regulate the stability of the planet. Each has a "safe operating space." As of 2025, 13 control variables across these 9 boundaries are measured. Exceeding a boundary increases the risk of large-scale, potentially irreversible change.

Which planetary boundaries are most directly transgressed by agriculture?

Agriculture most directly transgresses: Land-System Change, Biogeochemical Flows (nitrogen & phosphorus cycles), Freshwater Change, Biosphere Integrity (biodiversity loss), and Novel Entities (pesticides). The slides illustrate each of these being highlighted when discussing agricultural intensification.

What does the EAT-Lancet Commission (2019) state about natural resource boundaries and food production?

The commission defines boundaries of natural resources necessary for sustainable food production. Current agricultural practices are pushing against or beyond several of these planetary boundaries, requiring a fundamental transformation of both production systems and diets.

How has total agricultural land use evolved since 1780?

Total land used for agriculture (croplands + pastures/rangelands) grew massively from about 800 million ha in 1780 to approximately 4–5 billion ha by 2010, with the steepest increase occurring in the 20th century.

How has agricultural land use per person changed over time?

Agricultural land per person peaked around 1200 CE (roughly 1.6 ha/person) and has declined sharply since the mid-20th century, falling to around 0.6 ha/person by 2023. This decline reflects both population growth and productivity gains through intensification.

What proportion of Earth's terrestrial surface is currently used for agriculture?

Croplands cover approximately 11% of the terrestrial surface, while grasslands and rangelands cover approximately 26%, totalling roughly 37% of the terrestrial surface used for agriculture.

What are the key drivers of agricultural land use expansion

(1) animal source food consumption (meat demand),

(2) biofuels production, and

(3) bioplastics demand. These pressures push agricultural land use beyond what is needed for direct human food consumption

What does the trend in "arable land needed to produce a fixed quantity of crops" show from 1961 to 2021?

The arable land needed to produce a fixed quantity of crops has declined dramatically — from 1.0 (index) in 1961 to roughly 0.3 by 2021. This means about 70% less land is now required to produce the same amount of crops, reflecting major productivity gains through intensification.

How have cereal production, yield, land use and population changed since 1961?

Since 1961 (indexed to 0%): cereal production increased by ~+250%, cereal yield by ~+200%, and population by ~+150%. Meanwhile, land used for cereals remained nearly flat (+10–15%). This demonstrates that intensification (higher yields per hectare), not land expansion, drove increased production.

How has global fertilizer use changed since 1961, and which planetary boundary does this relate to?

Fertilizer use grew massively from 1961 to 2021. Nitrogen fertilizer use reached ~100 million tonnes, phosphorus ~40 million tonnes, and potassium ~40 million tonnes. This directly drives the transgression of the Biogeochemical Flows planetary boundary (nitrogen and phosphorus cycles).

How has global pesticide use evolved since 1990?

Total pesticide use grew from approximately 1.5 million tonnes of active ingredient in 1990 to over 3 million tonnes by 2021. The largest category is herbicides, followed by fungicides/bactericides and insecticides. This is linked to the transgression of the Novel Entities planetary boundary.

How has global meat production changed from 1961 to 2022?

Total meat production grew from roughly 70 million tonnes in 1961 to approximately 350 million tonnes by 2022. Poultry and pigmeat showed the fastest growth. Beef/buffalo production also grew but more slowly. This rise is linked to climate change (via livestock GHG emissions) and land-system change.

What are the main environmental impacts of intensified agriculture?

(1) Fertilizer and pesticide use → water pollution and biodiversity loss;

(2) Increased irrigation → soil salinization, causing annual losses of ~1.5 million ha of cropland;

(3) ~40% of global cropland is prone to erosion and declining soil fertility;

(4) Loss of natural habitats → loss of ecosystem services (pollination, natural pest control).

What is the key long-term contradiction of modern agriculture?

Modern agriculture is trading short-term increases in food production for long-term losses in ecosystem services — including the very ecosystem services (pollination, soil fertility, water regulation) that agriculture itself depends on.

Why do the environmental impacts of agriculture need to be assessed from a global perspective?

Because agricultural markets are globally integrated: local demand drives global product and land prices, which in turn causes land use changes in other regions. A consumer in one country may be indirectly driving deforestation in another.

What is the core dilemma facing sustainable agriculture?

(1) produce enough food to feed a growing, increasingly meat-eating world population;

(2) meet growing demand for biofuels and bioplastics;

(3) dramatically reducing its negative environmental impacts.

What yield increase is predicted to be needed by 2050, and why is this difficult?

Agricultural yields would need to roughly double by 2050 to meet projected food, biofuel, and bioplastics demands. However, this will be difficult: current yield growth rates (e.g. for cereals like wheat and rice) have been stagnating in many regions.

What concept describes the trade-off between maximizing agricultural production and preserving ecosystem services?

The trade-off between land use and ecosystem functioning. Maximizing food production degrades ecosystems, while conserving ecosystems limits food production. Sustainable agriculture must find ways to optimize both simultaneously.

What is agroecology (FAO definition)?

According to the FAO (2018), agroecology integrates ecological and social concepts into the design and management of agricultural production and food systems, optimizing the interactions between plants, animals, humans, and the environment.

What are the 10 elements of agroecology according to the FAO

The 10 FAO elements are: (1) Diversity, (2) Synergies, (3) Efficiency, (4) Recycling, (5) Resilience, (6) Co-creation and sharing of knowledge, (7) Human and social values, (8) Culture and food traditions, (9) Responsible governance, (10) Circular and solidarity economy.

How does food system transformation go beyond the supply chain?

(1) regenerative use of natural resources (production side), and (2) eco-efficient diets (consumption side). Supply chain improvements alone are insufficient.

What does van Berkum et al. (2018) mean by "food supply chains are embedded in the food system"?

Food supply chains do not operate in isolation — they are part of a broader food system that includes natural resources, social structures, governance frameworks, cultural practices, and economic incentives. Sustainability interventions must address this entire system, not just isolated steps in the chain.

What are the key elements of organic farming?

(1) Establishment of nearly closed nutrient loops; (2) No mineral (readily soluble nitrogen) fertilizers; (3) No synthetic pesticides; (4) No GMOs; (5) Reducing input flows while maintaining ecosystem services; (6) Active enhancement of soil quality as the basis for production.

What is the main goal of organic farming?

To produce food with minimal negative impacts on ecosystems, animals, and humans.

How widespread is organic agriculture globally (2024)?

Only 2.1% of the global agricultural area is cultivated using (certified) organic agriculture, totalling 98.9 million hectares in 2024.

What is the yield gap between organic and conventional farming according to meta-analyses?

Meta-analyses show an average organic yield gap of: -25%, -20% , and -18.4% , with very high variation (standard deviation >20%). The main limiting factor is nitrogen availability. Organic yields depend more on knowledge and good management practices.

What is the main criticism of organic farming in terms of land use?

Because organic yields are lower, organic farming requires more land to produce the same amount of food. Critics argue this could contribute to further land use expansion and biodiversity loss — the so-called "land sparing" argument.

How does the unit of assessment change the conclusions of organic vs. conventional LCA comparisons?

This is the central tension in organic LCA debates:

• Per product unit (e.g. per kg milk): organic often appears worse or equal in some categories because lower yields mean more resources per unit of output → organic is termed "inefficient."

• Per area unit (e.g. per hectare/year): organic usually shows environmental benefits — lower impacts per unit of agricultural land.

What does the organic vs. conventional milk LCA (Meier et al., 2015) show?

• Energy demand: -70 to -39%

• Global warming potential (GWP): -67 to -13%

• Eutrophication potential: -76 to -2%

• Acidification potential: -51 to -2%

• Ecotoxicity (terrestrial): -73%

• Pesticide use: -100 to -94%

What do the organic vs. conventional cereal data (Meier et al., 2015) show regarding eutrophication potential?

For winter wheat: organic uses 122 kg N/ha vs. conventional 143 kg N/ha. Per product unit, organic wheat has ~22% higher eutrophication potential (EP) than conventional. Per area unit, organic has ~22% lower EP. For potato: similar pattern — organic uses 83 kg N vs. conventional 123 kg N, giving lower EP per area but higher EP per product unit.

What conclusion does Hashemi et al. (2024) reach regarding organic vs. conventional carbon footprints

The carbon footprint of conventional and organic products is often comparable overall. However, organic products generally use natural resources more responsibly (lower pesticide use, better soil health, biodiversity) and are therefore more environmentally friendly when assessed beyond just carbon.

What is the key overall conclusion about organic farming and the food system dilemma?

The lower productivity of organic farming is itself evidence of agriculture's fundamental dilemma: producing enough food while substantially reducing environmental impacts cannot be achieved through production changes alone. It requires changes in consumption patterns — especially reducing overall food demand and shifting to less resource-intensive diets.

How do agroecology principles relate to the four organic principles (Ecology, Health, Fairness, Care)?

• Agroecology principles like recycling, soil health, biodiversity, synergy, efficiency align with the Ecology and Healthorganic principles.

• Agroecology's human and social values, co-creation of knowledge, and social values/diets align with Fairness and Care.

• Organic principles include economic diversity, fairness, connectivity, and participation which go beyond purely ecological agroecology elements.

• Agroecology is broader in scope (socio-technical system change); organic is a certified production standard. (FiBL, 2024)

What are the two main beef production systems compared in the exercises, and what are their approximate GHG emissions

(1) Pasture-based beef: ~8 kg CO₂-eq. per kg live weight; animals slaughtered at ~23 months. (2) Concentrate feed-based beef: ~6 kg CO₂-eq. per kg live weight; animals slaughtered at ~13 months. Concentrate-fed beef has a lower carbon footprint per kg because of faster growth and shorter life cycle — but uses more feed grain and less permanent grassland.

What are the main trade-offs between pasture-based and concentrate-fed beef systems?

Pasture-based: higher GHG per kg, longer life cycle, but uses grasslands (often non-arable land), can support biodiversity and carbon sequestration in soils, lower grain demand. Concentrate-fed: lower GHG per kg, faster production, but uses arable crops (feed competition with humans), intensive production, less biodiversity value. Which is more sustainable depends on the context: grassland type, feed origin, and the metric used.

What are the edible protein yields (g protein per kg dry matter feed) for ruminants vs. monogastrics vs. poultry?

• Ruminants (beef): 8–19 g edible protein / kg DM feed

• Pigs (monogastric): 16–37 g edible protein / kg DM feed

• Poultry: 55–91 g edible protein / kg DM feed

What are the climate impacts (kg CO₂-eq. per kg ready-to-eat meat) for ruminants vs. monogastrics vs. poultry?

• Ruminants (beef): average ~33 kg CO₂-eq./kg (range: 18–51)

• Pigs: average ~12 kg CO₂-eq./kg (range: 7–22)

• Poultry: average ~10 kg CO₂-eq./kg (range: 4–20)

Why do ruminants have a higher climate impact per kg despite being able to use non-arable land?

Ruminants produce methane (CH₄) through enteric fermentation, which is a potent GHG. They also have lower feed conversion efficiency. However, ruminants can graze permanent grasslands unsuitable for crop production, so their land use footprint is not always comparable to monogastrics that consume arable crops.

How do ruminants and monogastric animals fit differently into a sustainable food system?

Ruminants have a role in utilizing permanent grasslands and marginal land that cannot produce human food crops — this is their ecological niche in a sustainable system. Monogastrics (pigs, poultry) are more efficient converters of feed but compete directly with humans for arable crop land. A sustainable food system uses both strategically: ruminants on non-arable land, monogastrics when feed is available as by-products or surplus crops.

How can the general global trend of decreasing arable land requirements per person be explained?

The decline in arable land required per person is primarily explained by agricultural intensification — higher yields per hectare through improved seeds, fertilizers, pesticides, mechanization, and irrigation. More food is produced on similar or slightly expanded land areas while feeding a much larger population.

How can differences in arable land requirements per person across world regions be explained?

(1) Diet composition — higher meat consumption requires more land (animal feed);

(2) Agricultural productivity — regions with less intensive farming require more land per unit of output;

(3) crop types grown;

(4) climate and soil quality. High-income countries with meat-heavy diets and high productivity can show paradoxically lower or higher land footprints depending on the metric used.