Industrial Agriculture and Energy
"Since most of the energy used in the industrial food system comes from fossil fuel consumption, the amount of energy it uses translates directly into the emission of GHGs. The US food system alone is calculated to account for a formidable 20 per cent of the country’s fossil fuel consumption. This figure includes the energy used on the farm to grow the food, and the post-agricultural processes of transporting, packaging, processing, and storing food. The US Environmental Protection Agency reported that US farmers emitted as much carbon dioxide in 2005 as 141 million cars in the same year! This hopelessly inefficient food system uses 10 non-renewable fossil-fuel calories to produce one single food calorie. 
The difference in energy use between industrial and traditional agricultural systems could not be starker. There is much talk of how efficient and productive industrial agriculture is compared with traditional farming in the global South but, if one takes into consideration energy efficiency, nothing could be further from the truth. The FAO calculates that, on average, farmers in industrialised countries spend five times as much commercial energy to produce one kilo of cereal as do farmers in Africa. Looking at specific crops, the differences are even more spectacular: to produce one kilo of maize, a farmer in the US uses 33 times as much commercial energy as his or her traditional neighbour in Mexico. And to produce one kilo of rice, a farmer in the US uses 80 times the commercial energy used by a traditional farmer in the Philippines!  This “commercial energy” that FAO speaks of is, of course, mostly the fossil-fuel oil and gas needed for the production of fertilisers and agrochemicals, and that used by farm machinery, all of which emit substantial amounts of GHGs. 
But then, agriculture itself is responsible for only about a quarter of the energy used to get food to our tables. The real waste of energy and the pollution happen in the broader international food system: the processing, packaging, freezing, cooking, and moving of food. Crops for animal feed may be grown in Thailand, processed in Rotterdam, fed to cattle somewhere else, which are then eaten in a McDonalds in Kentucky.
Transporting food consumes huge amounts of energy. Looking at the USA again, it is calculated that 20 per cent of all the commodity transport within the country is to move food, resulting in 120 million tonnes of CO2 emissions. The US import and export of food accounts for another 120 million tonnes of CO2. Add to that moving supplies and inputs (fertilisers, pesticides, etc.) to industrial farms, transporting plastic and paper to the packaging industries, and moving consumers to increasingly faraway supermarkets, and we get a picture of the tremendous amount of GHGs produced by the industrial food system’s transport requirements alone. Other big GHG producers are the food processing, freezing, and packaging industries, which account for 23 per cent of the energy consumed in the US food system.  It all adds up to an incredible waste of energy. And on the subject of waste, the industrial food system discards up to half of all the food that it produces, in its journey from farms to traders, to food processors, to stores and supermarkets! This is enough to feed the world’s hungry six times over.  Nobody has begun to calculate how much GHG is produced by the rotting of all this thrown-away food.
Much of this tremendous global waste and destruction could be avoided if the food system were decentralised and agriculture oriented more towards local and regional markets. Small farmers and consumers would get closer together again, and large agribusiness would be cut out of the food system. Healthier food, happier producers and consumers, and a sustainable planet would be the result." (http://www.grain.org/seedling/?id=642)
17 FAO, “The energy and agriculture nexus”, Rome 2000, Tables 2.2 and 2.3, http://tinyurl.com/2ubntj
18 GRAIN, “Stop the agrofuel craze!”, Seedling, July 2007, http://www.grain/seedling/?id=477
19 Data in this paragraph is from Food & Water Watch, “Fuels and Emissions from Industrial Agriculture”, Washington , November 2007, http://tinyurl.com/mdgypy
20 Tristram Stuart, “Waste: Uncovering the Global Food Scandal”, Penguin, 2009, http://tinyurl.com/m3dxc9