Discuss on the impact of human population explosion on the environment and the world food problem as a biological and social issues.

The term “population explosion” refers to the situation that the human population grows so fast that it exceeds the carrying capacity of the environment such that human lives are threatened. It is evident that some areas on the Earth are already so ever populated that a single disturbance, such as a flood, drought or crop failure, will result in the deaths o thousands or even millions of people.

The world's population has doubled during the last half century. This unprecedented surge in population, combined with rising individual consumption, is pushing human claims on the planet beyond its natural limits.

The living of human beings depends upon a large variety of natural resources including food, energy, water and land. They also depend on various materials for medicinal, recreational and many other purposes. As the population continues to grow, there is an increasing rate of consumption of resources in the environment. Thus the natural resources that support human population are being exhausted at a faster and faster rate. At the same time, utilization of natural resources results in production of waste products, which continuously pollution problems are becoming more severe as the human population grows.

Population growth, the uneven distribution of food, inability to afford food, and political unrest threaten world food security for human society. And, because the world population continues to expand, more pressure than ever before is being placed on the basic resources that are essential for food production. Unfortunately, the human population is growing exponentially, whereas food production can only increase linearly. Furthermore, the degradation of land, water, energy, and biological resources that are vital to a sustainable agriculture continue unabated. The lives and livelihood of future generations depend on what the present generation is willing to do now to make agriculture sustainable and conserve the world's ecological resources.

There is surplus of food in developed countries while starvation and famine occur in some developing countries. It is estimated that one-third if the world’s population is consuming over one-half of the world’s food supply. The present problem is mainly an unbalanced food supply due to the following reasons :

~People in order to earn more money in the export market, farmers in many developing countries grow cash crops. Therefore, less land is available for growing food crops. In some countries, the pastures are over-grazed, i.e. people allow too many cattle and sheep to feed on the pastures. The vegetation is eaten away at a rate much faster than it grows. Consequently, the fertile topsoil is stripped off, resulting in the transformation of pastures into deserts. On the other hand, deforestation is another reason for turning fertile soils into deserts in some countries. As trees have been cut down, the soil can no longer retain water. Thus the exposed topsoil is subjected to soil erosion. Deforestation has been especially serious in the last several decades in the developing countries. A population-deforestation model has been developed to relate the population density with the cumulative forest loss, which is defined and computed as the total forest loss until 1990 since prior to human civilization. NOAA-AVHRR-based land cover map and the FAO forest statistics have been used for 1990 land cover. A simulated land cover map, based on climatic data, is used for computing the natural land cover before the human impacts. With the 1990 land cover map as base and using the projected population growth, predictions are then made for deforestation until 2025 and 2050 in both spatial and statistical forms.

~Large quantities of food are being wastes in developed countries due to the wasteful eating habits of the people.

~Modification of the environment by human activities has result in increased chances of having natural disasters such as droughts, floods and pests in many parts of the world. This would lead to the slow-down of food production.

~Frequent warfare in some developing countries seriously disturbs the production of food. The likelihood global war, utilizing nuclear or other weapons of mass destruction, will halt the ongoing destruction of Earth's biosphere by human overpopulation & industrial activity.

~There are still some possible solutions to the food problem posed by population explosion.

~Eating low in the food chain is an effective way of reducing energy loss during trophic transfer.

We still have some possible solutions to the food problem posed by population explosion. We can reduce energy loss and food loss, increase food production from crops, increase food production from livestock, develop technology in marine and freshwater cultures, develop technology to culture single cell proteins and have population control.

Eating low on the food chain is an effective way of reducing energy loss during trophic transfer. In other words, we should take in a large proportion of food derived from plants, algae and herbivores rather than that derived from carnivores. Further, effective shortage and transport systems can avoid spoilage of food by insects, moulds, mildews and bacteria. Crops should be handled, shipped and stored properly after harvest.

The protein content in crops can be improved by the regular use of chemical fertilizers, crop wastes, manure and other organic materials on the farmland. Crop rotation that includes leguminous plants can increase the availability of nitrogen for crops. It also provides better weed and insect control, and improves nutrients cycles, thus improving crop yields. Am alternative way is to inoculate nitrogen-fixing microorganisms into the soil. New strains of crops, which are more productive, more responsive to nitrogen fertilizers and more resistant to diseases and pest infections, can be obtained by selective breeding. Using pesticides can reduce crop diseases and control crop pests. The application of plant growth regulators and appropriate vegetative propagation methods can significantly increase crop productivity and yield.

The productivity and yield of livestock can be improve by selective breeding, the use of growth hormones and associated reproductive technology, and the use of antibiotics, drugs and immunization to control diseases and parasites. The use of alternative food sources for livestock can reduce their consumption of human food proteins.

Many aquatic organisms such as fish, crustaceans and mollusks are important sources of food proteins. The yield of these marine and freshwater organisms can be improved by manipulating their ecological requirements, controlling diseases, parasites, predators and competitors in confined culture areas.

Single cell proteins are produced from cells of some organisms such as bacteria, algae, yeasts and mushrooms. These cellular products contain not only proteins, but also fats, carbohydrates, vitamins and minerals. They are useful as animal feeds and even food for humans. If the appropriate conditions for growth of these organisms are identified, single cell proteins can be produce in large scales.

An effective way to control the rapid population growth is birth control. The birth rate can be controlled through intensive family planning and increasing access to contraceptive methods. Today a variety of contraceptive methods are widely adopted, which include rhythmic method, condom, diaphragm, intra-uterine device, contraceptive pills, vasectomy and ligature of oviduct. The status of women in the society can affect fertility levels to a certain extent. In developing countries, women should be provided with better education, health and other services. These widen their opportunities and reduce their dependence on giving birth to children for a status in the family. Furthermore, the population control programmes in some countries may restrict the total number of children in a family, for example, the “one child per family policy” in china. Late marriage may also be helpful in reducing the rate of births.