"Unlike the plagues of the dark ages or contemporary diseases (which) we do not yet understand, the modern plague of overpopulation is soluble by means we have discovered and with resources we possess. What is lacking is not sufficient knowledge of the solution, but universal consciousness of the gravity of the problem and the education of the billions who are its victims."

 – Dr. Martin Luther King, Jr.

In the six seconds it takes you to read this sentence, 15 people will be added to the Earth's population. Within an hour, California's population will grow by 60 people – that's one person a minute. California's population in 2016 was 39, 524,000 million, growing by 335,000 versus the prior year, according to the California Department of Finance, whose projections indicate a state population of 51 million people by 2060. 

Causes of Overpopulation

Fertility: The U.S. total fertility rate is currently 1.87 births per woman. (For comparison, the United Kingdom's fertility rate is 1.89, Canada's is 1.60, and Germany's is 1.44.) Source: World Factbook, CIA

Immigration: Legal immigration contributes to more than one million people to the U.S. population annually. Although much more difficult to count, an estimated 2.2 to 4 million illegal aliens enter annually, although many of these leave voluntarily or are deported, for a net annual increase in the number of illegal immigrants ranging from several hundred thousand to a million or more annually. An estimated 12 to perhaps 20 million or more immigrants in the U.S. are here illegally.


California Population Facts

U.S. American Community Survey - Quick Facts about California's Population  (Census)

U.S. Population Facts

  • The United States is the third most populous country on Earth. The United States had a larger population in 2016 than all other countries except for China and India. (United Nations Statistics Division)
  • By 2100 the United States, along with seven other countries (Nigeria, India, the United Republic of Tanzania, the Democratic Republic of Congo, Niger, Uganda, and Ethiopia), are expected to account for half of the world's projected population increase. (United Nations Population Division)
  • According to the U.S. Census Bureau’s population clock, our national population was 325 million in March 2017

World Population Facts

  • The acceleration of human expansion can be seen dramatically in the time it took for each milestone of a billion to be reached. Our first billion, passed around 1800, took perhaps 200,000 years to reach. The second billion took only 120 years and the third, reached in 1960, a mere 30 years. Since then we have been in overdrive, adding a billion every 12 to 14 years. We passed the 7 billion mark late in 2012.
  • Global population, now 7.5 billion (May, 2017), still is growing rapidly – currently by more than 80 million persons (net) per year. By 2050, the world may add some 2.5 billion people, an amount equal to the world’s total population in 1950. This growth will continue to add tremendous pressure on the environment, according to the United Nations Population Fund (UNFPA) State of the World Population 2016 Report.
  • Globally, every second on average 4.5 persons are born and 1.8 persons die, for a net gain of 2.7 people. At the end of every day, on average, there are 226,000 more people on Earth than when the day began. 

Population Terms and Definitions

Age-sex structure: The composition of a population as determined by the number or proportion of males and females in each age category. The age-sex structure of a population is the cumulative result of past trends in fertility, mortality and migration. Information on age-sex composition is essential for the description and analysis of many other types of demographic data. 

Birth Rate (or crude birth rate): The number of live births per 1,000 population in a given year. Not to be confused with the growth rate. 

Carrying Capacity: The maximum sustainable size of a resident population in a given ecosystem. 

Crude birth rate: The number of births in a given year divided by the total population in that year. 

Demographic Transition: (1) The historical shift of birth and death rates from high to low levels in a population. The decline of mortality usually precedes the decline in fertility, thus resulting in rapid population growth during the transition period. (2) The transition from a traditional demographic regime in which fertility and mortality are high to a modern regime in which fertility and mortality are much lower. The transition from a so-called regime of "natural" fertility (not controlled by couples) towards a regime of "controlled" fertility may be referred to as a fertility transition. The period during which mortality decreases is referred to as an epidemiological transition or a health transition. It is accompanied by improved health, nutrition and organization of health services and a change in the causes of death, infectious diseases disappearing progressively in favor of chronic and degenerative diseases and accidents. 

Doubling time: The number of years required for the population of an area to double its present size, given the current rate of population growth. Population doubling time is useful to demonstrate the long-term effect of a growth rate, but should not be used to project population size. Many more developed countries have very low growth rates and, as a result, the equation shows doubling times of hundreds or thousands of years. But these countries are not expected to ever double again. Most, in fact, likely have population declines in their future. Many less developed countries have high growth rates that are associated with short doubling times, but are expected to grow more slowly as birth rates are expected to continue to decline. (Note that the U.S. is projected to double. Also see explanation and examples.)

Fecundity: The physiological capacity of a woman to produce a child. 

Fertility: (1) The actual reproductive performance of an individual, a couple, a group, or a population. See general fertility rate. (2) The term "fertility" is used instead of natality when births are put in relation with the number of women of fertile age. The fertility of a generation can be summarized by completed fertility and mean age at childbirth; whereas, the total period fertility rate measures the fertility rate for the year. 

General Fertility Rate: The number of live births per 1,000 women ages 15-44 or 15-49 years in a given year. 

Growth Rate: The number of persons added to (or subtracted from) a population in a year due to natural increase and net migration expressed as a percentage of the population at the beginning of the time period. (Also see World Bank Population Growth Rate information.)

Immigration Rate: The number of immigrants arriving at a destination per 1,000 population at that destination in a given year. 

Life Expectancy at Birth: The average number of years a newborn infant would be expected to live if health and living conditions at the time of its birth remained the same throughout its life. (Also see World Bank Life Expectancy information.)

Less developed countries: Less developed countries include all countries in Africa, Asia (excluding Japan), and Latin America and the Caribbean, and the regions of Melanesia, Micronesia and Polynesia. A number of less developed countries, such as China, Brazil, Mexico, South Korean, South Africa and certain Middle Eastern and Asian countries, are developing very quickly and are, in fact, joining the ranks of the more developed countries. Other less developed countries are stagnant or even slipping backwards, in which case they may join the ranks of the “failing” or “failed” states.

More developed countries:  More developed countries include all countries in Europe, North America, Australia, New Zealand and Japan. As noted above under “less developed countries,” a number of countries around the world are rapidly becoming more developed. 

Life expectancy: The average number of additional years a person of a given age could expect to live if current mortality trends were to continue for the rest of that person's life. Most commonly cited as life expectancy at birth. 

Mortality: Deaths as a component of population change. 

Natural Increase (or Decrease): The surplus (or deficit) of births over deaths in a population in a year or given time period. 

Net Migration Rate: The net effect of immigration and emigration on an area's population, expressed as an increase or decrease per 1,000 population of the area in a given year. 

Population Increase: The total population increase resulting from the interaction of births, deaths and migration in a population in a given period of time. 

Population Momentum: The tendency for population growth to continue beyond the time that replacement-level fertility has been achieved because of the relatively high concentration of people in the childbearing years. (Also see momentum factors and decreasing population momentum.) 

Population Policy: Explicit or implicit measures instituted by a government to influence population size, growth, distribution or composition. 

Population Projection: Computation of future changes in population numbers, given certain assumptions about future trends in the rates of fertility, mortality and migration. Demographers often issue low, medium and high projections of the same population, based on different assumptions of how these rates will change in the future. 

Population Pyramid: A bar chart, arranged vertically, that shows the distribution of a population by age and sex. By convention, the younger ages are at the bottom, with males on the left and females on the right. 

Rate: A ratio between events having occurred in a population during a year and the number of persons in a population in the middle of the year. When the events are observed over a period shorter or longer than a year their number is multiplied or divided by the appropriate factor so as to preserve the rate's annual dimension. A rate may refer to all of the population (mortality rate, birth rate, etc.), or to an age or age group (age-specific mortality rate, or age-specific fertility rate). 

Rate of Natural Increase (or Decrease): The rate at which a population is increasing (or decreasing) in a given year due to a surplus (or deficit) of births over deaths, expressed as a percentage of the base population. 

Replacement-Level Fertility: The level of fertility at which a couple has only enough children to replace themselves, or about two children per couple (2.1 children per woman in the U.S.).

Total Fertility Rate (TFR): (1) The average number of children that would be born alive to a woman (or group of women) during her lifetime if she were to pass through her childbearing years conforming to the age-specific fertility rates of a given year. This rate is sometimes stated as the number of children women are having today. See also gross reproduction rate and net reproduction rate. (2) An estimate of the average number of children that would be born to each woman if the current age-specific birth rates remained constant. (2) A hypothetical estimate of completed fertility. It indicates how many births a woman would have by the end of her reproductive life, if, for all of her childbearing years, she was to experience the age-specific birth rates for that given year. (From U.S. Census Bureau Fertility of American Women: June 2000). 

Zero population growth: A population in equilibrium, with a growth rate of zero, achieved when births plus immigration equal deaths plus emigration.

(Source: www.ecofuture.org)

Additional Resources