Currently for every 1 calorie of food, some 10 calories of energy are used to make it. As George Monbiot said in the Guardian last week, it is increasingly unclear where future supplies of water and phosphates will come from. After world war two the world population was around 3 Billion. Using newer techniques and fertilisers we have increased the amount of food an acre produces. The population has risen to match. Fertilisers are almost entirely all oil-based on large scale, however. With biofuels taking away land and oil prices rising as well as increased transportation costs, the current system of food from around the world is becoming a danger to supply. If the recent survey of 155 oil experts saying peak oil will come before 2010 turns out to be true, we will have to downscale very quickly indeed.
Two ways to combat this would also reverse many of the social changes of the last thirty or so years. Firstly, the reduction of food miles by producing stuff closer to home will bring down fuel needed to transport the food, often a massive contribution to the energy cost. The second involves fertilisers and other fuel-intensive techniques. As the amount of machinery and fertiliser brought into farms decreases due to prices, manual labour becomes increasingly important again. Eating less meat, particularly red meat, will reduce the amount of calories an acre of land can produce, as well as boosting our health. Large farms currently operating with few employees will need to split into smaller units and introduce nitrogen fixing vegetables between grain crops. On a social level this could increase the number of people making a small living for themselves off a plot of land, selling most of their produce locally. Using more varied crops, utilising the seasons and even vertical farming mean we could have good food even without shipping it in from abroad.
Note: edited to attribute the photo to Chris Jacobs, who says: ‘For all of you out there…this illustration is NOT how a real vertical farm would be…it would be 100% hydroponic. This was just created to “show” growing food.’ – thanks for keeping us informed Chris!