By 2075, the United Nations’ mid-range projection for global population growth predicts that human numbers will peak at about 9.5 billion people. This means that there could be an extra 3 billion mouths to feed by the end of the century, a period in which substantial changes are anticipated in the wealth, calorific intake and dietary preferences of people in developing countries across the world. Such a projection presents mankind with wide-ranging social, economic, environmental and political issues that need to be addressed today to ensure a sustainable future for all. One key issue is how to produce more food in a world of finite resources.
Today, we produce about 4 billion metric tonnes of food per annum. Yet due to poor practices in harvesting, storage and transportation, as well as market and consumer wastage, it is estimated that 30 to 50 percent (or 1.2 to 2 billion tonnes) of all food produced never reaches a human stomach. Furthermore, this figure does not reflect the fact that large amounts of land, energy, fertilisers and water have also been lost in the production of foodstuffs that simply end up as waste. This level of wastage is a tragedy that cannot continue if we are to succeed in the challenge of sustainably meeting our future food demands.
In less-developed countries, such as those of sub Saharan Africa and Southeast Asia, wastage tends to occur primarily at the farmer-producer end of the supply chain. Inefficient harvesting, inadequate local transportation and poor infrastructure mean that produce is frequently handled inappropriately and stored under unsuitable farm site conditions. As the development level of a country increases, so the food loss problem generally moves further up the supply chain, with deficiencies in regional and national infrastructure having the largest impact. In Southeast Asian countries, for example, losses of rice can range from 37 percent to 80 percent of total production depending on development stage, which amounts to total wastage in the region of about 180 million tonnes annually. In China, a country experiencing rapid development, the rice loss figure is about 45 percent, whereas in less developed Vietnam, rice losses between the field and the table can amount to 80 percent of production.
In mature, fully developed countries, more efficient farming practices and better transport, storage and processing facilities ensure that a larger proportion of the food produced reaches markets and consumers. However, characteristics associated with modern consumer culture mean produce is often wasted through retail and customer behaviour.
Major supermarkets, in meeting consumer expectations, will often reject entire crops of perfectly edible fruit and vegetables at the farm because they do not meet exacting marketing standards for their physical characteristics, such as size and appearance. For example, up to 30 percent of the UK’s vegetable crop is never harvested as a result of such practices. Globally, retailers generate 1.6 million tonnes of food waste annually in this way.
Over the last five decades, improved farming techniques and technologies have helped to significantly increase crop yields along with a 12 percent expansion of farmed land use. However, with global food production already utilizing about 4.9 gha [global hectares] of the 10 gha of usable land surface available, a further increase in farming area without impacting unfavourably on what remains of the world’s natural ecosystems appears unlikely.
The challenge is that an increase in animal-based production will require greater land and resource requirement, as livestock farming demands extensive land use. One hectare of land can, for example, produce rice or potatoes for 19 to 22 people per annum. The same area will produce enough lamb or beef for only 1 or 2 people. Considerable tensions are likely to emerge, as the need for food competes with demands for ecosystem preservation and biomass production as a renewable energy source.
Over the past century, fresh water abstraction for human use has increased at more than double the rate of population growth. Currently about 3.8 trillion m3 of water is used by humans per annum. About 70 percent of this is consumed by the global agriculture sector, and the level of use will continue to rise over the coming decades. Indeed, depending on how food is produced and the validity of forecasts for demographic trends, the demand for water in food production could reach 10 to 13 trillion m3 annually by mid-century. This is 2.5 to 3.5 times greater than the total human use of fresh water today.