I = PAT - Population

Population

See also: World Population and overpopulation

In the I=PAT equation, the variable P represents the population of an area, such as the world. Since the rise of industrial societies, human population has been increasing exponentially. This has caused Thomas Malthus and many others to postulate that this growth would continue until checked by widespread hunger and famine (see Malthusian growth model).

The United Nations and the US Census Bureau project that world population will increase from 7.0 billion today to about 9.2 billion by 2050. These projections take into consideration that population growth has slowed in recent years as women are having fewer children. This phenomenon is believed to be a result of demographic transition in developed nations. As a result, the UN believes that human population might stabilize around 9 billion by 2100. However, since the world population is set to keep rising for the next few decades, this factor of the I=PAT equation will likely keep increasing human impact on the environment for the near future.

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Famous quotes containing the word population:

    O for a man who is a man, and, as my neighbor says, has a bone in his back which you cannot pass your hand through! Our statistics are at fault: the population has been returned too large. How many men are there to a square thousand miles in this country? Hardly one.
    Henry David Thoreau (1817–1862)

    This was the Eastham famous of late years for its camp- meetings, held in a grove near by, to which thousands flock from all parts of the Bay. We conjectured that the reason for the perhaps unusual, if not unhealthful development of the religious sentiment here, was the fact that a large portion of the population are women whose husbands and sons are either abroad on the sea, or else drowned, and there is nobody but they and the ministers left behind.
    Henry David Thoreau (1817–1862)

    The most advanced nations are always those who navigate the most. The power which the sea requires in the sailor makes a man of him very fast, and the change of shores and population clears his head of much nonsense of his wigwam.
    Ralph Waldo Emerson (1803–1882)