Does Earth Have a Human Carrying Capacity?

Malthusian theory (what Malthus theorized):

• Earth has a human carrying capacity, probably based on food production

• Human population growth is happening faster than growth of food production

• Humans will reach a carrying capacity limited by food

Technological Advancement

• Humans can alter earth’s carrying capacity with tech. Innovation

  • Ex: synthetic fixation of Nitrogen in 1918 leads to synthetic fertilizer, dramatically increasing food supply

Birth Rate, Death Rate, and Growth

• Growth Rate (r) = % increase in a population (usually per year)

  • Ex: a growth rate of 5% for a population of 100 means they grow to 105

• Crude Birth Rate & Crude Death Rate (CBR & CDR)

  • Births & deaths per 1,000 people in a pop.

    • Ex: Global CBR = 20 & CDR = 8

Doubling Time (Rule of 70)

• Rule of 70: The time it takes (in years) for a population to double is equal to 70 divided by the growth rate

  • Ex: Global growth rate = 1.2%

    • 70/1.2 = 58.3 years

    • Global pop. will double in 58.3 years

Calculating Population Change

Practice Problem: A country has a CDR of 9 and a CBR of 18.

• Calculate the annual growth rate, and the doubling time

• Solution: (18-9)/10 = 9/10 = 0.9% growth rate

• 70/0.9% = 77.77 years to double

Factors Affecting Human Pop. Growth

• Factors that increase pop. growth

  • Higher TFR  → higher birth rate

  • High infant mortality rate can drive up TFR (replacement children)

  • High immigration level

  • Increased access to clean water & healthcare (decrease death rate)

• Factors that decrease population growth rate

  • High death rate

  • High infant mortality rate

  • Increased development (education & affluence)

  • Increased education for women

  • Delayed age of first child

  • Postponement of marriage age

Standard of Living Indicators

• Standard of Living

  • What the quality of life is like for people of a country based

• Gross Domestic Product (GDP) = key economic indicator of standard of living

  • Total value of the goods & services produced

  • Per capita GDP is total GDP/total population

• Life expectancy = key health indicator of standard of living

  • Average age a person will live to in a given country

  • Increases with access to clean water, health care, stable food sources

    

    Stages & Development 1 = pre-industrial 2 = developing 3= Developed 4 = Highly developed