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Definition

Population density (in agriculture standing stock and standing crop) is a measurement of population per unit area or unit volume. It is frequently applied to living organisms, and particularly to humans. It is a key geographic term. [1]

History of Population Growth

Entry added with information from Wikipedia

Population Before Common Era

The human population has gone through a number of periods of growth since the dawn of civilization in the Holocene period, around 10,000 BC. The beginning of civilization coincides with the final receding of glacial ice following the end of the last glacial period.[citation needed] It is estimated that about 1,000,000 people, subsisting on hunting and foraging, inhabited the Earth in the period before the neolithic revolution, when human activity shifted away from hunter-gathering and towards very primitive farming.

Around 8000 BCE, at the dawn of agriculture, the population of the world was approximately 5 million. The next several millennia saw minimal changes in the population, with a steady growth beginning in 1000 BCE, plateauing (or alternatively, peaking) in 1 BCE, at between 200 and 300 million people. The Plague of Justinian caused Europe's population to drop by around 50% between 541 and the 8th century. Steady growth resumed in 800 CE. This growth was disrupted by frequent plagues; most notably, the Black Death during the 14th century. The effects of the Black Death are thought to have reduced the world's population, then at an estimated 450 million, to between 350 and 375 million by 1400. The population of Europe stood at over 70 million in 1340; these levels did not return until 200 years later.

Population Anno Domini

On the other side of the globe, China's population at the founding of the Ming dynasty in 1368 stood close to 60 million, approaching 150 million by the end of the dynasty in 1644.

England's population reached an estimated 5.6 million in 1650, up from an estimated 2.6 million in 1500. New crops that had come to Asia and Europe from the Americas via the Spanish colonizers in the 16th century contributed to the population growth.

Since being introduced by Portuguese traders in the 16th century, maize and manioc have replaced traditional African crops as the continent's most important staple food crops

Alfred W. Crosby speculated that increased production of maize, manioc, and other American crops "...enabled the slave traders [who] drew many, perhaps most, of their cargoes from the rain forest areas, precisely those areas where American crops enabled heavier settlement than before."

Epidemics

The population of the Americas in 1500 may have been between 50 and 100 million.Encounters between European explorers and populations in the rest of the world often introduced local epidemics of extraordinary virulence. Archaeological evidence indicates that the death of around 90% of the Native American population of the New World was caused by Old World diseases such as smallpox, measles, and influenza. Over the centuries, the Europeans had developed high degrees of immunity to these diseases, while the indigenous peoples had no such immunity.

After the effects of the plagues had subsided during the 17th century, shortly before the Industrial Revolution, the world population began to grow once again. After the start of the Industrial Revolution, during the 18th century, the rate of population growth began to increase. By the end of the century, the world's population was estimated at just under 1 billion. At the turn of the 20th century, the world's population was roughly 1.6 billion. By 1940, this figure had increased to 2.3 billion.

Baby Boomers

Dramatic growth beginning in 1950 (above 1.8% per year) coincided with greatly increased food production as a result of the industrialisation of agriculture brought about by the Green Revolution. The rate of growth peaked in 1964, at about 2.2% per year. The world population was at some point in 2010 estimated to be 6,915,100,000, with unreported variability.

1900

Africa                       133 million
Asia                         946 million
Europe                       408 million
Latin America and Caribbean   74 million
North America                 82 million

Many of the world's countries, including many in Africa and South East Asia, have seen a sharp rise in population since the end of the Cold War. The fear is that high population numbers are putting further strain on natural resources, food supplies, fuel supplies, employment, housing, etc. in some the less fortunate countries. The population of Chad has, for example, ultimately grown from 6,279,921 in 1993 to 10,329,208 in 2009,further straining its resources. Nigeria, Egypt and Ethiopia are witnessing a similar growth in population, strained resources and a possible over-population problem in the near future.

Largest Population by Country

   COUNTRY                         POPULATION                  % OF WORLD POPULATION
 1. China                         1,343,740,000                        19.4%
 2. India                         1,210,193,422                          17% 
 3. United States                   311,265,000                         4.5%
 4. Indonesia                       238,400,000                        3.39%
 5. Brazil                          194,586,000                        2.81%
 6. Pakistan                        175,907,000                        2.54%
 7. Bangladesh                      164,425,000                        2.38%
 8. Nigeria                         158,259,000                        2.29%
 9. Russia                          141,927,297                        2.05%
10. Japan                           127,380,000                        1.84%

An Increase In Population Density

The scientific consensus is that the current population expansion and accompanying increase in usage of resources is linked to threats to the ecosystem. The InterAcademy Panel Statement on Population Growth, which was ratified by 58 member national academies in 1994, called the growth in human numbers "unprecedented", and stated that many environmental problems, such as rising levels of atmospheric carbon dioxide, global warming, and pollution, were aggravated by the population expansion. At the time, the world population stood at 5.5 billion, and lower-bound scenarios predicted a peak of 7.8 billion by 2050, a number that current estimates show will be reached around 2030. [2]

Population Grown Projections

Entry added with information from Wikipedia

According to projections, the world population will continue to grow until at least 2050, with the population reaching 9 billion in 2040, and some predictions putting the population in 2050 as high as 11 billion.

According to the United Nations' World Population Prospects report:

  • The world population is currently growing by approximately 74 million people per year. Current United Nations predictions estimate that the world population will reach 9.0 billion around 2050, assuming a decrease in average fertility rate from 2.5 down to 2.0.
  • Almost all growth will take place in the less developed regions, where today's 5.3 billion population of underdeveloped countries is expected to increase to 7.8 billion in 2050. By contrast, the population of the more developed regions will remain mostly unchanged, at 1.2 billion. An exception is the United States population, which is expected to increase 44% from 305 million in 2008 to 439 million in 2050.[77]
  • In 2000-2005, the average world fertility was 2.65 children per woman, about half the level in 1950-1955 (5 children per woman). In the medium variant, global fertility is projected to decline further to 2.05 children per woman.
  • During 2005-2050, nine countries are expected to account for half of the world's projected population increase: India, Pakistan, Nigeria, Democratic Republic of the Congo, Bangladesh, Uganda, United States, Ethiopia, and China, listed according to the size of their contribution to population growth. China would be higher still in this list were it not for its One Child Policy.
  • Global life expectancy at birth, which is estimated to have risen from 46 years in 1950-1955 to 65 years in 2000-2005, is expected to keep rising to reach 75 years in 2045-2050. In the more developed regions, the projected increase is from 75 years today to 82 years by mid-century. Among the least developed countries, where life expectancy today is just under 50 years, it is expected to be 66 years in 2045-2050.
  • The population of 51 countries or areas, including Germany, Italy, Japan and most of the successor States of the former Soviet Union, is expected to be lower in 2050 than in 2005.
  • During 2005-2050, the net number of international migrants to more developed regions is projected to be 98 million. Because deaths are projected to exceed births in the more developed regions by 73 million during 2005-2050, population growth in those regions will largely be due to international migration.
  • In 2000-2005, net migration in 28 countries either prevented population decline or doubled at least the contribution of natural increase (births minus deaths) to population growth. These countries include Austria, Canada, Croatia, Denmark, Germany, Italy, Portugal, Qatar, Singapore, Spain, Sweden, United Arab Emirates and United Kingdom.[78]
  • Birth rates are now falling in a small percentage of developing countries, while the actual populations in many developed countries would fall without immigration. By 2050 (Medium variant), India will have 1.6 billion people, China 1.4 billion, United States 439 million, Pakistan 309 million, Indonesia 280 million, Nigeria 259 million, Bangladesh 258 million, Brazil 245 million, Democratic Republic of the Congo 189 million, Ethiopia 185 million, Philippines 141 million, Mexico 132 million, Egypt 125 million, Vietnam 120 million, Russia 109 million, Japan 103 million, Iran 100 million, Turkey 99 million, Uganda 93 million, Tanzania 85 million, Kenya 85 million and United Kingdom 80 million.

2050

Africa                        1.9 billion
Asia                          5.2 billion
Europe                        674 million
Latin America and Caribbean   765 million
North America                 448 million

Summary of the World

If we could shrink the Earth's population to a village of precisely 100 people, with all existing human ratios remaining the same, it would look like this:

81 would be from less developed countries with a gross income per capita and year of US$ 3,580, 19 would be from developed countries with a gross income per capita and year of US$ 22,060.

There would be 61 Asians, 12 Europeans, 13 Africans, 9 would be from South America and the Caribbean, and 5 from North America including Canada.

75 would be non-white, while 25 would be white.

60 would mistrust their own government. No wonder, that the governments mistrust their people.

60 would live within 62 miles of a coastline.

50 would be female, and 50 would be male.

50 would rely in some manner on coastal and marine habitats for food, building sites, transportation, recreation, and waste disposal.

48 would live on less than US $2 a day.

48 would lack access to basic sanitation.

47 would be urban dwellers. The world's urban areas are expected to surpass rural areas in population around the year 2005

29 would believe in witchcraft.

25 would live in substandard housing or have no home at all.

20 would live on less than US $1 a day.

17 would be under 18 years old.

16 would lack access to safe drinking water.

16 would be unable to read and write.

14 would suffer from malnutrition.

10 would live in least developed countries.

8 would have Internet access from home.

4.5 would be citizens of the United States

1 would be infected with HIV/AIDS.

1 would be near death, and 1 would be near birth.

Only 1 would have a college education.

Half of the entire village's wealth would be in the hands of only 6 people, and most of them would be citizens of the United States.

When one considers our world from such an incredibly compressed perspective, the need for cooperation, tolerance and understanding becomes glaringly apparent.

Sources

[1] Population Density http://en.wikipedia.org/wiki/Population_density

[2] Over Population http://en.wikipedia.org/wiki/Overpopulation

[3] Summary of the World http://www.nationsonline.org/oneworld/world_population.htm