6s Elaine Leung 25

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

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. If the populations continue to grow without restriction, natural resources, such as food, water and land will become exhausted. It is evident that some areas on the Earth are already so over-populated that a single disturbance, such as a flood, drought or crop failure, will result in the deaths of thousands or even millions of people until the population density is reduced to a certain level.

One of the major problems of population explosion is food supply. Food is known as a major limiting factor for organism. The overall production of food in the world should still be enough to feed the present population. There is a surplus of food in developed countries while starvation and famine occur in some developing countries. It is estimated that one-third of the world’s population is consuming over one-half of the world’s food supply.

At the biological side, deforestation make the world suffering unbalanced the food supply. Deforestation is a 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. No trees can grow on the soil, then the animals can’t find any food to eat.

Modification of the environment by human activities has resulted in increased chances of having natural disasters such as droughts, floods and pets in many parts of the world. This will lead to the slow-down of food production. This is another biological reason that causes the unbalanced supply of food.

For the social issue, farmers in many developing countries grow cash crops (e.g. coffee, tea, cotton, and tobacco), in order to earn more money in the export market. Therefore, less land is available for growing food crops.

Frequent warfare in some developing countries seriously disturbs the production of food. This is also a social issue reason for the unbalanced supply of food.

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

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 pasture into desert. No vegetation can grow on the desert, the animals can no longer to find any food to eat.