The human population is the underlying environmental issue, because most current

environmental damage results from very high number of people on Earth and their great power

to change the environment. In 2005 hurricanes, earthquakes and tsunamis caused tremendous

human deaths along with the new emerging bird flu and other possible diseases seemed to

threaten even greater human catastrophes in the future. But the human population has been

growing rapidly and seemingly steadily for decades. The problem of human population growth

is the top priority, as there can be no long term solution to our environmental problems unless

the human population stops growing at its present rate.

Population density, its size, birth rate, death rate, growth rate and age structure are the key

aspects of population dynamics. In Less Developed Countries (LDCs), average lifetimes are

short, children care of their parents and therefore it benefits parents to have more children.

However, in More Developed Countries (MDCs), parents tend to have fewer children and invest

more in each. This makes zero population growth possible.

Throughout most of our earth history, the human population and its average growth rate were

small. This growth of human population can be divided into four major stages including hunters

and gatherers period, preindustrial agricultural period, the period of industrial revolution and

the modern era. Although population has increased in each stage, the current s ituation is

unprecedented.

As long as the growth of human population continues, the sustainability of other environmental

resources remains doubtful. Although the growth rate of human population varies from nation

to nation, the overall environmental effects of rapidly growing human population are global.

The danger that the human population poses to the environment is the result of two factors:

the number of the people and the impact of each person on the environment. When there

were few people on the earth and technology was limited, human impact was local. In that

situation, overuse of a local resource had few or no large or long-lasting effects. The

fundamental problem now is that there are so many people and our technologies are so

powerful that our effects on the environment are global and important.

One of the major patterns in the growth of human population is the increasing urbanization of

the world. Cities are not self-contained but are linked to the surrounding environment,

depending on it for resources and affecting environment elsewhere. Urban development often

leads to encroachment on highly valued natural areas, especially because cities are typically

located where water, transportation and material resources are readily available.

Malthus argued that the population growth is infinitely greater than the power of earth to

produce subsistence. He recognized the possibility of potential disease threats like the bird flu

etc. to sustain the human population on earth. His statements are quite straightforward from

the perspective of modern science, they simply point out that in a finite world nothing can grow

or expand forever. Today, earth constitutes more than 6.6 billion human population. MDCs

have experienced a demographic transition marketed by a decrease in the death rate flowed by

a decrease in birth rates, while LDCs have experienced a great decrease in their death rates but

still have very high birth rates.

The problem of human population exemplifies the connection between values and knowledge.

Scientific and technological knowledge helped us cure diseases, decrease death rates, and

thereby increase the growth of the human population. The acceptable carrying capacity is not

simply a scientific issue; it is an issue combining science and values. Science plays two roles.

First, by leading to new knowledge which in turns leads to new technology, it makes possible

both a greater impact per individual on earth’s resources and a higher density of human beings.

Second, scientific method can be used to forecast a probable carrying capacity. Standard

estimates suggest that the human population will reach 10 to 16 billion before stabilizing.

On our finite planet, human population will eventually be limited by some factors or

combination of factors. These factors consist of short-term, intermediate-term and long-term

growth limiting factors of human population. Drought, shortage of energy for transportation of

food etc. involves in the short-term growth limiting factors of human population. Dispersal of

certain pollutants such as toxic metals and fisheries etc. are considered as intermediate-term

growth limiting factors of human population. However, a decline in ground water supplies, soil

erosion, climate change etc. are considered as long term growth limiting factors of human

population.

One of the most effective ways to lower a population’s growth rate is to lower the age of first

child bearing which involves relatively few societal and value issues. Breast feeding, birth

control pills, contraceptive devices, abortion and many other traditional and modern methods

are used widely in many parts of the world. Family planning programs have been introduced

worldwide to explain the problem arising from rapid population growth. The first country to

adopt an official population policy was India in 1952.

Although most countries now have some kind of family planning program but their approaches

and effectiveness varies greatly from simply providing more information to promoting and

providing means for birth control, offering rewards and imposing penalties. Ghana, Malaysia,

Pakistan, Singapore and the Philippines have used a combination of methods including limits on

tax allowances for children to control birth rate. But still, LDCs has to work on their programs

and policies in order to control the birth rate.