Around 1800 A.D., the earth's population reached 1 billion people. That number rose to 3 billion by 1960. Since then, world population has increased by another 1 billion people every 12-14 years. This unprecedented growth rate has led to a more-than doubling of global population over the last fifty years. Today, the total global population is approximately 6.5 billion people and best projections anticipate continued rapid increases in coming decades.
[Total and projected world population: 1950-2050]
Original data comes from the United Nations Population Division Population Prospects: The 2004 Revision. Analytical report and CD-ROM are available online.
World population is currently growing by 1.1 percent annually. As shown in the chart above, nearly all of this population growth is occurring within developing countries. As a result, roughly 9 in 10 children (1.6 billion total children) under the age of 15 currently reside in developing parts of the world, up from 7 in 10 in 1950 (EarthTrends and UNPD). By 2050, total population is expected to reach 9.1 billion (medium projection) despite overall declines in population growth rates. Major growth is expected to occur in developing countries' urban populations; assuming current trends "poor countries will have to build the equivalent of a city of more than one million people each week for the next 45 years" (Cohen, 2005). Limited access to health care, contraception, and education in many of these countries has resulted in national demographic trends that exhibit stark contrasts to those of the industrialized world (e.g., fertility rates), leading to high population densities in developing regions of Africa and Asia (see map).
Global Population Density. Data are for 1995. For more information, please see the full source notes.
A continuation of these trends will create greater pressures on food, water, sanitation, and infrastructure resources, particularly in places where these are already scarce. According to the Millennium Ecosystem Assessment, 60 percent of earth's ecosystems are currently being used at a rate exceeding their capacity to provide goods and services. The rapid increase in global population will also impose significant strains on earth's natural environment.
Population growth, therefore, poses a number of socioeconomic and geopolitical challenges, including intensifying agricultural production without further contamination of the world's waterways, increasing energy use without continuing to raise greenhouse gas levels, and protecting expanding urban and coastal populations from disease and natural disasters. International cooperation to ensure specific sustainable development targets, such as those provided by the UN's Millennium Development Goals, are met, will also encourage sustainable population growth in the developing world.
Although population trends ultimately depend on several factors, population size, density, and demographics are extremely relevant to the design and implementation of government strategies, regarding, for example, health care, labor, financial allocations, and ecosystem protection. World population growth presents important challenges in these areas, as well as opportunities for innovation, to be addressed by diverse national and international communities.
RELATED LINKS
United Nations Population Division
EarthTrends Population and Demographics Indicators
Cohen, Joel E. 2005. "Human Population Grows Up". Scientific American. Volume 293, Number 3. p. 48-55.
"Mapping the Future of World Population"
The Center for Climate Systems Research at Columbia's Earth Institute, Population Action International, and Hunter College co-authored this high-resolution map of projected population change for the year 2025.
Population Action International
"An independent policy advocacy group working to strengthen political and financial support worldwide for population programs grounded in individual rights."
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