En-en adult card 8 agriculture
Card #8: Agriculture
Agriculture does not emit much CO2 but does emit large quantities of methane (from cattle and rice paddies) and nitrous oxide (from fertilizers). In all, agriculture accounts for 25% of GHGs if we include the induced deforestation.
Agriculture uses very little fossil fuel compared to the emissions of other GHGs for which it is responsible. It is responsible for 80% of deforestation because of the large areas needed to grow crops, especially to feed farm animals. Agriculture is a human activity that began as soon as the climate stabilised, at the beginning of the Neolithic period 10,000 years ago, after the last deglaciation, which itself lasted 10,000 years.
Since then, the impact of human activity on its environment has been growing. Plant species have been domesticated (today, domesticated rice is no longer able to reproduce without human intervention), forests have been cleared to expand cultivated areas, depriving animal species of their natural habitat, and since the Green Revolution (green for agricultural, not for ecological), we have been using pesticides and inputs that are harmful to the environment and to our health.
- Fossil fuels Agriculture does not use much fossil fuel, just enough to keep tractors running. Its carbon emissions are high, bu mainly because of methane and nitrous oxide.
- CO2 emissions Agriculture does not emit much CO2 except from deforestation. Its carbon emissions mainly come from othe GHGs.
- Aerosols Spraying crops does result in aerosols and air pollution, but not to the same extent as incomplete combustion from power plants.
- Carbon Sinks It doesn't matter if this link is not made, but it is true that agriculture can improve storage capacity through photosynthesis. This is the 0.4% principle (if we increased the soil's capacity to sequester carbon by even 0,4%, we would have a significant impact on CO2).
- Terrestrial Biodiversity Here, we are thinking mainly of pesticides (especially Roundup or neonicotinoids). No link with the climate, but an interesting relation to make.
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Footprint of animal husbandry
Much of the impact of agriculture is due to animal husbandry. However, it is very difficult to agree on a percentage of greenhouse gases due to livestock.
- Which Global warming potential (GWP) to choose: methane is the main warming gas due to livestock farming. If we look at a 20-year horizon, it has a GWP of 84, but of 28 only over a 100-year horizon: difference of a factor three.
- Partnerships with various private institutions  who have a vested interest in this number, such as:
- The European Feed Manufacturers' Federation (FEFAC)
- the European Vegetable Oil and Proteinmeal Industry (FEDIOL)
- the International Dairy Federation, (IDF)
- the International Meat Secretariat (IMS)
- the International Egg Commission (IEC)
- the International Poultry Council (IPC)
- the International Federation for Animal Health (IFAH)
- the World Wildlife Fund (WWF).
However, the two figures most often found are:
- 18% of total emissions according to the 2007 report 
- 14.5% of total emissions according to the 2012 report 
- The IPCC distribution key logically assigns to industry the agro-industry (fertilisers, crop treatment products, herbicides, agricultural machinery) and the agro-food industry. But this does not help to estimate the positive effects that a system based on agroforestry, shorter distribution channels and a sharp drop in the consumption of industrially processed food products could have.
- The massive use of chemical fertilisers and pesticides gradually destroys the micro-flora and micro-fauna of the soil.
- Earthworms are disappearing, whereas they act as small ploughmen working for root penetration and improving the permeability of the soil and the renewal of water tables. They also feed on the residues of previous crops and transform them into humus, a stable form of organic matter capable of storing a large quantity of water and releasing it in times of drought. Moreover, humus stores the mineral elements that can be used by the plant.
- Fungi are also disappearing under the effect of fertilisers and chemical treatment products, although they are intermediaries living in symbiosis with the plants. They act as an extension of the roots, fetching water and mineral salts and exchanging them for organic molecules produced by the plant.
Storing carbon through agroforestry
The disappearance of earthworms and fungi, as well as deep and frequent ploughing and leaving land naked for many months between two crops, accelerate the decomposition of organic matter. Agricultural soils in chemical-input agriculture are net producers of carbon and deplete organic matter, while agroforestry provides an annual increase of 4‰ in the level of organic matter in the soil. The soil thus becomes a carbon sink.
Widespread use of these techniques would make agriculture the safest and cheapest carbon sink at very low or no cost. It would provide a much healthier diet and would maintain and even develop a population that could live decently from agriculture, the basis of food autonomy in many countries. Biodiversity would be greatly enhanced as a result. The shortening of circuits would reduce energy consumption. The same applies to a decline in the agri-food industry, which would also improve the health of our fellow citizens. A major source of pollution would disappear.
The jobs lost in agribusiness and agro-industry would be largely offset by those generated by agroforestry, which is much more labour-intensive than chemical-input agriculture.
At the same time, a significant reduction in meat consumption would sharply reduce the areas devoted to the production of cereals for animal feed (mainly cattle, pigs and poultry). This would compensate for the lower crop yields in the absence of chemical inputs.
In total, we would have :
- much healthier food produced by farmers who are proud of their work
- a healthier population (reduction in particular of cardiovascular diseases and cancers) as a result of eating less meat and food that does not contain chemical residues,
- soils becoming an important carbon sink by increasing the level of organic matter in the soil (4‰/year)
- a shift from industrial jobs (agrochemicals, agricultural machinery, agri-foodstuffs) to agricultural jobs
- a reduction in food packaging
- a strong decrease in energy consumption by the whole sector
- a decrease in methane production by reducing the number of ruminants
- the disappearance of nitrous oxide production linked to nitrogen fertilizers
- a boost to Terrestrial and Marine Biodiversity (disappearance of green algae and the ecological imbalance of which they are a symptom).
- Page 714 of IPCC fifth assessment report, working group #1
- FAO, New effort to harmonize measurement of livestock’s environmental impacts
- FAO, Livestock's long shadow, page xxi, 2007
- FAO, Tackling climate change through Livestock, page xii, 2012
- Official web Site "4 pour 1000" initiative
- Mathilde Gérard et Pascale Santi Comment l’alimentation ultratransformée affecte notre santé, Le Monde, 30 mai 2019