In 2010, the population of Australia will reach 22.5 million and is estimated to be 55-62 million by 2060, a growth rate of 65 per cent per annum. World population is now 6.8 billion and is expected to reach about 10 billion by 2060, with 30 per cent of the projected total in China and the Indian sub-continent.
How are such large populations to be fed? Millions are already faced with hunger, malnourishment and only narrowly escape starvation because of international efforts. The food we all need includes the products of agriculture, livestock and fisheries. All are affected by loss of arable land, waste, inefficiency and the effects of anthropogenic global warming.
Loss of land
Land and sea which might have been used for food production is being continually and significantly degraded, reduced in area or used for other purposes, primarily because of population demands, movement and growth. Major causes for this loss are:
- Urban sprawl: increasing numbers of people are moving from farms and villages to towns and cities, increasing demand for housing, roads, shops, businesses, schools, hospitals etc., taking up vast areas of land which might otherwise have been used for food production.
- Setting aside land for recreation and national parks for public enjoyment (urban parks, gardens, sporting facilities and other reserves) and for protection of wildlife in national parks, including protection of fish stocks in marine parks. These aims are commendable but do limit food production.
- Soil salinity is primarily caused by clearing trees and other plants with deep roots, then planting shallow root vegetable and grain crops. Shallow roots absorb some of the water resulting from rainfall and irrigation but the rest sinks into the ground, causing a saline water table to rise. This brings salt to the surface, making the land unusable for agriculture. It is a major problem in grain-growing areas in many countries, particularly in Australia and Africa.
- Land degradation is caused by human activity such as over-stocking, over-cropping and other practices including inappropriate use of low fertility land for intensive agriculture. Climatic conditions cause high rainfall to wash away fertile topsoil while draught and high wind blows it away. Both result in land degradation. All cause or contribute to fertility depletion and desertification, resulting in loss of millions of hectares of arable land per annum.
- Mining activities, particularly open cast mining located on or near arable land is responsible for loss of land that might otherwise have been used for food production. Even if not located on farmland, pollution produced from mining activity, particularly of coal or iron ore, affects the ability to use a far wider land area than that occupied by the mine itself.
- Locust and rabbit plagues cause massive crop losses. In Australia rabbits have become immune to biological agents used to control their number and have increased in number by a factor of 10. Locust plagues usually follow good rains, are difficult to control and rapidly destroy crops.
- Biofuel production: land is effectively taken out of food production when crops planted are not available for consumption as food. These include oil palm, canola and other crops planted to yield vegetable oil needed for production of biodiesel. Other crops fit for human consumption (grains, sugarcane, soya etc) are grown but used for production of the petrol extender, ethanol.
- Loss of fish stocks arises from a variety of causes all associated with human activity. Overfishing of all the major commercial fisheries has seriously depleted stocks, yet fishing boats continue to make catches in these areas, risking ultimate destruction of the fishery. Trawling causes immense damage to fish habitat but remains a common method of catching fish. These problems are made worse by ocean pollution arising from discharge of untreated sewage into the sea and the dumping of other toxic waste.
At a time of ever increasing demand from rapid population growth, ability of industry to produce food is decreasing. The results include growing food shortages with over 1 billion people now undernourished or starving, rapidly escalating cost of food commodities and deteriorating food security. These outcomes are further exacerbated by:
Global warming poses more serious problems for food production and ability of humans to survive, particularly in the most densely populated parts of the world. The cause of this concern is that global warming is causing:
- melting of land based ice;
- rising sea levels;
- ocean acidification; and
- climate change.
Melting of land-based ice is occurring at an increasing rate, is caused by rising atmospheric temperatures and exacerbated by carbon aerosols. Many of the world’s most important rivers are fed by glaciers in the Himalaya, Hindu-Kush, Andes, Rockies and other mountain ranges. These rivers provide fresh water essential for agriculture and human consumption. Depleted river flows are already causing humans to pump fresh water from aquifers at unsustainable rates to meet their needs.
In northern India, this practice is sanctioned by government policy and made necessary by the rate of population growth and their demand for food and water. In California, it is made necessary by the inability of glaciers to provide sufficient river water to meet the demands for drinking water and agriculture irrigators producing food in the Central Valley.
As land-based glaciers continue to melt and contract, their ability to maintain water flows in rivers such as the Indus, Ganges, Mekong, Yangtze-Kiang and Yellow will diminish further. These rivers provide drinking water and irrigation for agriculture and are relied on by more than 2 billion people.
How this loss of fresh water from glaciers and rivers is to be supplemented and distributed has yet to be devised or explained. The threat to a vast and growing human population is increasing year by year as land-based glaciers continue to melt and do so at an increasing rate as global temperatures rise. By 2050 a critical situation will have been reached where millions will face starvation.
Sea levels are already rising largely as a result of land-based ice melting, particularly at the polar ice caps and ocean warming causing water expansion. It is variously estimated that a rise of between 1 and 2 metres will occur by 2100. By 2050 a rise of 1 metre in some coastal areas is likely and, if accompanied by extreme weather events (hurricanes or typhoons) or simply by gale force winds during “king” tides, is likely to cause coastal erosion and flooding.
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