The numbers suggest that home food production should be a central strategy of the global environment movement.

The global food system is almost certainly the most environmentally destructive force on the planet. Vast industrial monocultures extend into what were once forests, plains and wetlands; our rivers flow grey with our precious inherited topsoil; aquifers are sucked dry; ocean 'dead zones' develop wherever fertilisers leach; and the greenhouse gases nitrous oxide, methane and carbon dioxide escape from the tortured soils and machinery.

Plant and animal products are processed, irradiated, chemically preserved, sterilised, frozen, packaged and moved around the world where they produce oceans of waste, and nations of undernourished and overfed (sometimes both) consumers disconnected from nature and their food sources.

Our source of basic life-giving sustenance is mediated by advertising, packaging, and the process of earning money at a meaningless job to buy food at an impersonal supermarket where we are forced through the subtly humiliating rituals of programmed greetings, long queues and bag searches. None of it is good for our health, our morale or the planet. Certainly it's not sustainable, which as Michael Pollan points out, means that it will inevitably collapse.

With this in mind I wondered if we could quantify just how much greenhouse gas, how much fossil fuel energy, how much water and landfill waste could be saved in Australia through home food production.

Home food production is possible even on the scale of the balcony. A small family can be self-sufficient in fresh vegetables on a quarter acre block, and produce about a third of their fruit too. Choosing an aspirational situation for a benchmark, I considered a block where both of the above food targets are being met, as well as having a 10,000 litre rain tank installed. All the organic matter is also composted on site where it improves the soil rather than going to landfill.

Broadacre industrial agriculture uses 65% of Australia's water, and more is used in processing. Modern food production is hugely energy intensive. In the US, two studies have estimated that 10 times as many calories are consumed as are contained in the food we eat. The Australian situation is likely very similar. If so, we put almost twice as much fossil fuel into our food as we do into our cars. We are literally eating oil. These are not comforting statistics in light of the peak in global oil production.

Meanwhile, due to soil carbon loss, methane and nitrous oxide emissions, the greenhouse impacts of the food system are disproportionately large, particularly given its already large energy usage. The ACF-funded Consuming Australia report suggested that food production counts for 28% of Australian's greenhouse gas emissions, excluding home refrigeration, cooking and preparation. According to the most recently available figures, most of Victoria's household wastes – about 64% – are compostable organic materials.

Furthermore, the type of food which it makes most sense to grow at home are the foods which taste best and are healthiest eaten fresh, in particular fruit and vegetables. These happen to be the same foods that take more energy and water resources to grow, and require refrigerated storage and energy intensive transport. At an estimate, producing about one third of our diet by weight at home (according to what best suits home gardening) should allow us to decrease the energy and water footprints of the food we eat by about one half. Artificial fertiliser inputs are unnecessary if food and garden wastes are composted.

With a 10,000 litre tank, grey water systems and water saving gardening techniques, home food production should require no town water in an average year. That works out to a saving of 100,000 litre or 35% of average Australian household use. Of course one should consider water embodied in the infrastructure, so the true savings maybe somewhat lower. However the real savings are 'upstream'. Around 410,000 litres might be saved by home food production. In total that's over 500,000 litres of water saved per household.

If our food system is responsible for 28% of our greenhouse emissions, and uses energy the equivalent of about eight barrels of oil, we might drop about 14% off our annual emissions, and save the equivalent of four barrels of oil per year per person. By comparison the average Australian's car use amounts to five barrels of oil per year.

Based on 1999 data, the average Victorian household has the potential to reduce landfill waste by around 1.5 tonnes per year by composting, or 64% of the total – although green-waste programs may have already begun reducing this.

Whatever margins for error there are in these estimates, the overall picture is clear – home and other local small-scale intensive food production are essential environmental strategies. What makes the approach even more appealing is that while most environmental strategies ask us to give something up, home gardening offers to give us something: fresh food full of flavour, a new sense of connection to our food supply, and the health which comes from fresh food and exercise. The communities that grow around urban food production cross boundaries of age and culture, and as the global food system enters uncertain times, they help us develop friendships and social bonds equally as important as the food security they entail.

References at: <www.eatthesuburbs.org/2007/10/grow-your-own>.

Adam Grubb is founder of the peak oil news clearinghouse Energy Bulletin <www.EnergyBulletin.net>, and a member of the permablitz network <www.permablitz.net>.