Fact Sheet -World population

The world population is the total number of humans alive on the planet Earth at a given time. According to estimates published by the United States Census Bureau, the Earth's population hit 6.5 billion on Saturday February 25, 2006. In line with population projections, this figure continues to grow at rates that are unprecedented prior to the 20th century. Approximately one fifth of all humans that have existed in the last six thousand years are currently alive. By some estimates, there are now one billion (thousand million) young people in the world between the ages of 15 and 24.

The Day of 6 Billion

The United Nations Population Fund designated October 12, 1999 as the approximate day on which world population reached six billion.

It was officially designated The Day Of 6 Billion.

This was about 12 years after the world population reached five billion, in 1987. The child that has been proclaimed by the United Nations Population Fund and welcomed by the U.N. Secretary-General Kofi Annan as the six billionth baby, was born on the designated day two minutes after midnight, not in India or China, as might be expected, but to Fatima Nevic and her husband Jasminko in Sarajevo, Bosnia

Rate of population increase

The last 70 years of the 20th century saw the biggest increase in the world's population in human history. The following table shows when each billion milestone was met:

• 1 billion was reached in 1802.
• 2 billion was reached 125 years later in 1927.
• 3 billion was reached 34 years later in 1961.
• 4 billion was reached 13 years later in 1974.
• 5 billion was reached 13 years later in 1987.
• 6 billion was reached 12 years later in 1999.

From the figures above, the world's population has tripled in 72 years, and doubled in 38 years up to the year of 1999.

Including a few more estimates (beginning with 250 million around AD 950 and ending with 8 billion in 2027), the world population was doubled by the following years (doubling times in parentheses):

• AD 950 (650) 1600 (202) 1802 (125) 1927 (47) 1974 (50) 2027,

or (beginning with 375 million around year 1420):

• 1420 (300) 1720 (155) 1875 (86) 1961 (38) 1999.

Note how, during the 2nd millennium, each doubling has taken roughly half as long as the previous doubling.

The UN estimated in 2000 that the world's population was then growing at the rate of 1.4 percent (or 91 million people) per year. This represents a decrease in the growth rate from its level in 1990, mostly due to decreasing birth rates.

The first five years of the twenty-first century saw something of a decline in the overall volume of population growth, with the world's population increasing at a rate of about 76 million people per year as of 2005.

Forecast of world population

The future growth of population is difficult to predict. Birth rates are declining slightly on average, but vary greatly between developed countries (where birth rates are often at or below replacement levels) and developing countries. Death rates can change unexpectedly due to disease, wars and catastrophes, or advances in medicine. The UN itself has issued multiple projections of future world population, based on different assumptions. Over the last 10 years, the UN has consistently revised its world population projections downward.

Current projections by the UN's Population Division, based on the 2004 revision of the World Population Prospects database , are as follows.

other projections of population growth predict that the world's population will eventually crest, though it is uncertain exactly when or how. In some scenarios, the population will crest as early as the mid-21st century at under 10 billion, due to gradually decreasing birth rates. In less optimistic scenarios, disasters triggered by the growing population's demand for scarce resources will eventually lead to a sudden population crash, or even a Malthusian catastrophe.

Doomsayers

In 1798, Thomas Malthus predicted that population growth would eventually outrun food supply, resulting in catastrophe. In 1968 Paul R. Ehrlich reignited this argument with his book The Population Bomb, which helped give the issue significant mindshare throughout the1960s and 1970s. The dire predictions of Ehrlich and other neo-Malthusians were vigorously challenged by a number of economists, notably Julian Simon.

On the opposite end of the spectrum there are a number of doomsayers who argue that today's low fertility rates will have severe negative consequences: The Death of the West: How Dying Populations and Immigrant Invasions Imperil Our Country and Civilization (ISBN 0312302592), by Patrick Buchanan, The Empty Cradle: How Falling Birthrates Threaten World Prosperity (ISBN 0465050506), by Longman, and Fewer: How the New Demography of Depopulation Will Shape Our Future (ISBN 156663606X), by Wattenberg.

Child poverty has been linked to people having children before they have the means to care for them.

More recently, some scholars have put forward the Doomsday argument applying Bayesian probability to world population to argue that the end of humanity will come sooner than we usually think (toxic waste rather than food shortages).

References

1. ↑ United States Census Bureau
2. ↑ Leonard, David. "World Population to hit 6.5 Billion on Saturday". February 24, 2006. MSNBC
3. ↑ World population prospects: the 2004 revision population database

External links

• The Day of 6 Billion official homepage
• World Population Prospects. URL accessed on April 7, 2005. The World in Balance Transcript of two-part PBS' Nova on World Population
• BBC (1999). UN chief welcomes six billionth baby. URL accessed on March 7, 2005.
• Central Intelligence Agency (2004). CIA The World Factbook 2004. URL accessed on February 13, 2005.
• United Nations (2001). United Nations Population Information Network. URL accessed on February 13, 2005.
• United States Census Bureau (2004). Historical Estimates of World Population. URL accessed on February 13, 2005.
• PopulationData.net (2005). PopulationData.net - Information and maps about populations around the world.
• Population Reference Bureau www.prb.org - News and issues related to population.
• World Population Clock (2005). WorldPopClock.com - World population clock.
• Population Counter. Real time counter..

Based on an edited version of the Wikipedia entry on population.