Questions to ponder:Does the world have a carrying

capacity for the human population? If so, what is it?

How long until we reach it? Or have we already overshot it?

What will be our “limiting factor”?

Billions 1 2 3 4 5 6 7

Year 1805 1927 1960 1974 1987 1999 2011

# of years

250,000 123 33 14 13 12 12

The amount of time to reach each “billion” milestone has been decreasing, but now appears to be leveling off

What main factors affected human population growth in early

civilization?

What were some major events that allowed the human growth rate to

increase so dramatically?

Are all countries growing at the same rate?

How does the birthrate of a developed country differ from that of a developing country?

• Developed countries =

• Ex:

•Developing countries =

• Ex:

• India and China are both undergoing intense population control efforts

• Population control greatly dependson the countries’ religion/culture

Population Control- China

• Countries with overall low birth and death rates have stable populations

• Countries that have high birth/death rates are in:

EXAMPLE Demographic Transition

Age structure diagramsHow is growth different in US vs. Nigeria?

How does the age structure of a population affect its growth rate?

• In the US- age structure more rectangular

• Developing countries are pyramidal

• Population is dominated by young people

• What happens as females at the bottom of the pyramid move up to reproductive age?

Why is the exponential growth of the human population considered a

“success”?

How is this rapid growth dangerous?

Americans make up 5% of the global population (300 million), yet we use 25% of the world’s energy

• Scientists have identified 9 “planetary boundaries” – limits that humans must not cross, otherwise the natural systems of the planet may be in jeopardy– Climate change – Arable land (farmland)– Biodiversity loss– Chemical pollution– Nitrogen and phosphorus cycles– Ocean acidification– Freshwater use

Exponential? Or going into logistic?

Questions to Consider…

• Is the human growth rate speeding up or slowing down?

• Is Earth at it’s carrying capacity?

• How long until we reach carrying capacity?

• What limiting factors will affect us the most? What will we run out of first?

• What problems will an out of control human population create with regards to the environment continuing to provide effective natural functions?

• Why is there a great concern over the environmental impact and effects of developing countries that have very large populations?

• Will there come a time when you would agree to population control in the US? Why/Why not?

• If you were in control of the world, how would you solve our current and looming population crisis?