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1500f: Lecture 3: Monday September 19th 2016: What is IPAT?
Impact = Population x Affluence x Technology
Impact: Land and resource use, pollution
Population: Number of people
Affluence: Consumption per person (Income or GDP)
Technology: Resource intensity of production
What caused the global population to grow so quickly after being slow for so
Death rates fell because:
o Advances in agriculture and transport made food supplies more reliable
Why is the population growth rate now slowing?
Birth rates are falling because of:
o Widely accessible birth control
o Empowerment of women in society (including education, engagement in
o Increased incomes
o Better health services on general
o In some cases, state policies
Thomas Malthus (Late 1700s)
Population size is limited by available resources
If population overshoots carrying capacity, a crisis will cause it to fall (famine,
Ester Boserup (1970s)
As population grows, innovation increases
New agricultural methods will increase production to meet demand