Haritima : The Environmental Society Of Hansraj College


How has the population grown?

  • Population growth was stable and slow till 1900, but a dramatic exponential growth occurred after 30’s following technological growth.
  • In 1800, the population was about one billion.
  • It took about 39000 years of human history to reach 1billion.
  • Afterwards, population increased to 2billion within 130 years and in 45 years to 4 billion.
  • We have already crossed the 7billion mark and may reach 11.21 billion by 2100.
  • In agricultural based societies children were considered as economic assets who could help parents in work, resulting in massive hike in population at rate of 3-4% per year, accounting for about 90-95% population growth of the world in the last 50 years.

What are the factors influencing population size?

Population size is influenced by growth rate, fertility rate, and mortality rate and age structure of the population.

  1. Growth Rate: The Annual average rate of change of population size, for a given country or territory or for a geographical area, during a specific time period is known as growth rate.
  2. Total Fertility Rate: It is defined as the average of children that would be born to a woman in her lifetime if the age specific birth rates remain constant.
    • It varies from 9 in developed nations to 4.7 in developing nations.
  1. Infant Mortality Rate: It is calculated by dividing the number of deaths of children under age of one by the number of live births in the same year and multiplying by 1000, and is inferred as probability of a child born in a specific year or period, dying before reaching the age of one.
  2. Age Structure: Age Structure of population of a nation can be represented by age pyramids, based upon belonging to different age classes like pre-reproductive (0-14 years), reproductive (15-44 years) and post reproductive (45 years and above).
  • Pyramid shaped: More young, less old population thus, making a broad base.
    • Examples are India, Bangladesh, and Nigeria.
    • Individuals in large numbers at a very young age will soon enter into reproductive age, thus causing an increase in population.
    • And less number of people in old age indicates less population due to death.
  • Bell Shaped: Occurs in countries like France, USA and Canada.
    • Decline in birth rates in past one or two decades resulting in people of almost equal age group 0-35.
    • In next 10 years people entering into reproductive age group is not going to change much
    • Such pyramids indicate stable populations.
  • Urn Shaped: No. of individuals in very young class is smaller than the middle reproductive age class.
    • In next 10 years, no. in reproductive age class will become less resulting in a decline of population growth.
    • Examples are Germany, Italy, Hungary, Sweden and Japan.

The TFR, age structure, mortality rate are all important parameters determining population growth. But population will not stop increasing even when all couples have only 2 children.

Zero Population Growth: When birth plus immigration in a population =  death plus emigration, this is called zero population growth.

Population Explosion

  • The unparalleled growth of human population at an alarming rate is referred to as population Explosion
  • In the year 2000, the world population was 6.3 billion and it is predicted to grow 4x in the next hundred years.

The Population Growth

Every second on an average 4.3 children are born and 2 people die, thus resulting in net gain of nearly 2.3 persons every second. This means that every hour we are growing by 8684 and everyday by 2,08,400 persons.

Can Population Growth be slowed down?

Population Growth can be slowed down and stabilized by adopting family planning measures and awareness programs.

  • Family Welfare Programs
    • Population must be kept much below the carrying capacity and stabilized.
    • We are getting warning signals that if not controlled, all the resources will deplete.
    • A catastrophic doomsday warns us that the earth cannot sustain more than two doublings i.e. 25 billion.
  • Family Planning
    • Allowed couples to decide their family size
    • Modern science has provided several birth control techniques.
    • WHO estimates 50% of married couples adopt family planning measures compared to just 10% about 30 years back.

Stabilization ratio of developing and developed nations


  • Environmental health, as defined by WHO, comprises those aspects of human health, including quality of life, that are determined by physical, chemical, biological, social, and psychosocial factors in the environment. It also refers to the theory and practice of assessing, correcting, controlling, and preventing those factors in the environment that adversely affect the health of present and future generations.
  • A huge and large population would mean a lot of consumption of resources. Natural resources are renewable but take millions of years and with the speed of consumption of resources, they may get exhausted before time.
  • Agricultural is the main source to feed population but as human population increases, the infrastructure increases leading to great amount of pressure on  Agricultural lands
  • Education and health are vital for human beings. As population increases, the human health index as well as education decrease.

For example: The current Pandemic has affected countries with majority of population like China, India, United States, etc.

  • The sex ratio imbalances result in economic as well as communal disparity.
  • Coastal population will affect sea as increasing sea food consumption results in decreasing aquatic population.
  • Peoples living in dry areas specifically deserts are a victim of famine and poverty.
  • The increasing deforestation for infrastructure development is resulting in Global warming, Greenhouse effect and unpredictable earthquakes and Tsunamis.
  • Even after implementing family planning policy in few countries, the population is increasing simultaneously decrease in economical benefits.

For example: population of China and India is increasing rapidly.

There is an urgent need to adopt a sustainable approach to tackle the rapidly increasing population.

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