Sydney: Everyday an average person gobbles up 4.1 litres of diesel fuel, 29 kg of soil and 2.2 tonnes of fresh water, according to an Australian study, which describes `eating` as taking a big toll on the Earth`s health.
"That`s what it takes to feed the typical human being - and when you multiply it by seven billion people, our food system is devouring a huge amount of resources that are increasingly hard to replace," science-writer Julian Cribb told the Australian Academy of Science in Canberra.
Cribb, who has authored "The Coming Famine: the global food crisis and how we can avoid it," says that an average person`s "eating" probably leaves their largest personal impact on the planet - but most people are unaware how great it is.
In his paper to the Second Australian Earth System Outlook Conference, Cribb warns of a series of `tipping points` - points of no-return - that will be reached by the global food system in the coming half century, unless there is radical change to farming systems, cities and the world diet.
"Take soil. According to the UN Food and Agriculture Organisation, half the planet is already degraded, and we`re losing around 75-100 billion tonnes of topsoil a year, mostly into the oceans. Soil takes thousands of years to form, so it is not going to be replaced any time soon," according to Sciencealert.
"Despite progress in places like Australia, soil degradation is getting worse, not better. Some scientists say we could run short of good farming soils within 50-70 years. This is what`s driving today`s global land-grab - which has so far swallowed an area as large as western Europe," it said.
Cribb says the picture is similar for water, with more than 4,000 cubic kilometres of groundwater being extracted - most of it unsustainably - every year. Places such as north China, the Indo-Gangetic region, the Middle East and midwest US face critical scarcity by the 2030s.
At the same time, there is a huge worldwide grab by megacities and gas companies of farmers` water - making the task of feeding the world much harder.
"Regardless of when you think peak oil is or was, world car production is growing 8-10 times faster than oil production - so a major oil shock is increasingly likely. Since food accounts for 30 percent of global energy use, there could be a very large impact on world food prices and supply," Cribb says.
However, Cribb says, what most governments and commentators on food security have failed to recognise is that scarcities of water, land, oil, nutrients, technology, fish and finance are now acting in synergy - and being amplified by climate shocks.
"Because these scarcities are operating in sync, we are likely to reach tipping points in the food system much more quickly and unpredictably than many people realise," he said.
"There is still time to act - but the action must be fast and it must be universal, as globalisation means everybody is now affected by food prices, supply and the conflicts and migratory floods that arise when the food chain fails," Cribb added.
Cribb also says there are opportunities for major new developments in food production, including a 300 percent growth in world aquaculture, a massive new industry in algae farming to produce food, feed, fuel and plastics, a spectacular rise of urban agriculture and totally new ways to produce low-cost food sustainably with bio-cultures.