We sometimes joke about the idea of flatulent cows contributing to global warming, but the subject is more serious than it may appear, on two counts. Agriculture is the world’s second largest producer of CO2 emissions, only just behind transport, and the principal source of non-CO2 greenhouse gas emissions: 50% of all methane emissions and 60% of all nitrous oxide emissions.
There are several reasons for this. The first is deforestation. Most deforestation occurs when land is cleared and converted to agricultural use. Deforestation contributes massively to the release of greenhouse gases into the atmosphere. The second is the spread of rice plantations. Rice farming is responsible for significant emissions of methane, a greenhouse gas 21 times more potent than CO2. The third reason relates to the use of fertilizers, the principal source of emissions of nitrous oxide, a greenhouse gas 310 times stronger than CO2.
Farming could also provide part of the solution in our fight against global warming. Some methods of farming—often inspired by age-old techniques—are more effective in protecting biodiversity and storing CO2. Conservation agriculture, as it is known, does not as a rule require complex technology: rather it involves better use of traditional materials such as compost and pig manure, as well as techniques such as hedge-planting. It is also tillage-free agriculture, which prevents soil erosion, absorbs more carbon dioxide thanks to year-round vegetation cover and reduces the need for nitrate fertilizers, so preventing the release of nitrous oxide into the atmosphere.
By adapting our farming methods we could reduce our production of CO2 equivalents by several billion tons annually, mainly in developing countries. If a global market for greenhouse gas emissions could be developed, with a price for each non-emitted ton of gas, this could provide a significant source of income for farmers in developing countries: the fight against global warming could thus also become a means of fighting poverty.