This is my 14th article in the Mercury Food and Wine supplement.
Durban is about to host the COP17 climate conference. Climate change and global warming are real and 98% of the scientific consensus is that it has been caused by human activity. Agriculture is one of the most significant human activities on earth. According to a recent Greenpeace report, conventional agriculture is responsible for up to 37% of all greenhouse gas emissions. How can we change this?
Organic farming offers a considerably more climate friendly approach to food production than the current mainstream conventional model. The emphasis of Organic farming is on building the soil. As a result carbon is added into the soil as opposed to conventional farming which depletes the soil and releases carbon into the atmosphere.
Organic farming seeks to protect natural ecosystems. It is forbidden under organic regulations to destroy forests and grasslands for farming. These ecosystems are essential as they scrub CO2 from the atmosphere.
Organic farming does not use energy intensive synthetic fertilisers. Soil fertility is instead built up using methods such as composting and green manuring. Bacteria, fungi and worms do most of the work in producing compost. No biocides are used to control pests and weeds, instead beneficial animals and plants are used.
Synthetic nitrogen fertiliser is the most energy intensive fertiliser to produce requiring a significant quantity of fossil fuel input. However the most damaging effect of nitrogen fertiliser on the climate is the release of nitrous oxide gas into the atmosphere as the fertiliser breaks down in the soil. This gas is 300 times more potent than CO2 as a greenhouse gas. Organic farming does not use fertiliser and instead relies on compost and nitrogen fixing bacteria to supply crops with necessary nitrogen.
The essential nutrient phosphorus is obtained by conventional agriculture by mining phosphate rock. There are only a few places globally where this is mined. A significant carbon footprint is produced by the mining process and the long transport network necessary to deliver it to the farm. Organic farming relies more on phosphorus from animal manures and that concentrated in plants such as comfrey, that send deep roots into the subsoil.
Industrial animal farming is responsible for most of the human induced methane output and a proportion of the nitrous oxide output. Most of the feed is grain and this is farmed with conventional, fertiliser intensive methods. The fermentation of this grain in the gut of cattle is responsible for a large portion of the methane emitted. The vast quantities of manure produced are left to rot anaerobically, which results in more methane. Organic farming does not permit factory farming and animals are fed on grass based pastures. Manure is composted and returned to the soil .
Most organic farmers believe in growing crops according to the seasons. we also prefer to supply locally. This is in contrast to conventional agriculture which aims to supply produce all year round. This is achieved by growing in artificial systems, such as hydroponics or freighting produce around the world. Both methods are energy intensive and have a high carbon footprint.
If a household wants to play their part in protecting our environment and reducing human induced global warming, the most significant act will be choosing food that has been produced organically. Your food choice has a long chain of consequences. The right choices will help determine the world your children and grandchildren will live in.