ENVS 1000 Lecture Notes - Lecture 3: Total Fertility Rate, Rate Equation, Dependency Ratio
ENVS Chapter 12 Notes: Human Population
What determines how fast populations grow?
● Rate of increase=birth rate + immigration rate - death rate - emigration rate
● Expressed as per unit population
○ 2 births per 1000 people
● Growth rate equation:
○ Population (t)= Population (t-1)(1+ growth rate)^t
■ t= time, t=1 (1 year)
● Birth rates:
○ The number of births per thousand people per year
○ Birth rates change mostly due to cultural and societal change
● Death rates:
○ The number of deaths per thousand people per year
○ Death rates change mostly due to economic and infrastructure development
● Modern growth rate is due largely to the decrease in death rates
● The role of women in society is a major factor in population growth
● The most important statistic in population growth is the total fertility rate
Population Momentum
● Even if fertility rates drop, the population structure can lead to continued, rapid growth
How does population growth affect the environment?
● More people= more impact
● Food production
● Water use
● Energy use
● Land use change
Energy Use
● Energy is the foundation of economic development
○ Economic growth requires increased energy consumption
● Impacts:
● Depends on the type of energy
● Fossil sources larger impact than renewable sources
Greenhouse Gas Emissions
● Emissions from fossil fuel combustion
● All economies are largely fossil based at present
● Impacts:
○ Right now, impacts rise with affluence but many technologies available to break
this link
○ Examples: wind, solar, etc
Water Use
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Document Summary
Rate of increase=birth rate + immigration rate - death rate - emigration rate. Birth rates: t= time, t=1 (1 year) The number of births per thousand people per year. Birth rates change mostly due to cultural and societal change. The number of deaths per thousand people per year. Death rates change mostly due to economic and infrastructure development. Modern growth rate is due largely to the decrease in death rates. The role of women in society is a major factor in population growth. The most important statistic in population growth is the total fertility rate. Even if fertility rates drop, the population structure can lead to continued, rapid growth. Energy is the foundation of economic development. Fossil sources larger impact than renewable sources. All economies are largely fossil based at present. Right now, impacts rise with affluence but many technologies available to break this link. Heavily depends on the amount of agricultural activity.