Presentation 5: Carrying Capacity How Many People Can Earth Support

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Presentation 5Carrying CapacityHow Many People
Can Earth Support?

• Organized by Tim Culbertson
• Adapted from presentations by Diana Nichols

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Carrying Capacity

• What might limit the number of people the earth
  is capable of holding?

• Amount of livable or arable land
• Supply of natural resources
• drinkable water
• fuel
• Ability to absorb wastes

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Approaching Capacity

• When the population doubles, we will

• Double the number of houses
• Double the number of cars
• Double the number of streets
• Double the pollution
• Double the need for food
• Double the waste
• Double the number of teachers
• Double the number of doctors

In next 50 years!
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Exceeding Capacity

• And then doubling everything again in another 50
  years (or less)

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Consumption of Finite Resources

• More people and more goods means

• Cutting more trees for lumber
• Burning more fuel for energy
• Causing more pollution

And, as an effect, we impact the resources for
other species.
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Impact on Wildlife

• Like humans, wildlife requires

• clean air
• clean water
• space
• food

With limited amount of space on Earth, more
humans means taking the living space of other
species.
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Sharing the Planet

• Do we have the right to take all of the land for
  humans?

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We Live In An Interconnected World

• Everything on earth is interdependent.
• If we damage one part of the web, other parts are
  damaged as well.

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Destroying Ourselves

• Species are becoming extinct at a rate one
  thousand times faster than they were two hundred
  years ago.

Species becomes extinct ?
Gene pool disappears ?
Ecosystem breaks down ?
?
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Growth Strategies K-Selected
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Growth StrategiesK-Selected

• Fast growth followed by crash
• Typically large number of offspring
• Little parental care
• Strategy to maximize resource use

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Growth Strategies R-Selected
Carrying Capacity
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Growth StrategiesR-Selected

• Fast growth approaching a carrying capacity
• Oscillation around carrying capacity
• Few offspring requiring much care
• Many limiting resources

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Growth Strategies R-Selected
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Your Choices Have Impact

• 6.5 billion people share Earths natural
  resources.
• Consumption choice of each person impacts the
  natural world.

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Ecological Footprint of One US Citizen

• 52 tons of garbage
• 10 million gallons of water
• 20,000 gallons of gasoline
• 500 trees

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Population, Resource Consumption, and Waste
Production
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What Can We Do?

• What happens to animal populations when exceeding
  the carrying capacity of the land?
• Death rate solution
• Humans are the first species to have a choice.
• Birth rate or death rate solution?

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What Can We Do?

• Birth rate solution

Death rate solution

• Overcrowding
• Housing shortages
• Poverty
• Starvation
• Poor medical care
• Increased disease
• Lack of education
• Outbreaks of violence

• Limit the number of births to replacement levels

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Will People Recognize the Problem?

• A stimulus is any change in ones environment.
• A response is an organisms reaction to that
  change.
• The rate at which the change occurs has a
  profound effect on an organisms response to a
  stimulus.

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Will People Recognize the Problem?

• Frog Experiment 1

A frog was dropped in abeaker of boiling water.
It reacted to the stimulusby jumping out.
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Will People Recognize the Problem?

• Frog Experiment 2

• This time a frog was placed in a beaker of
  luke warm water.
• The temperature was raised very slowly.
• It stayed in the beaker and boiled to death.

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Will People Recognize the Problem?
This?
or
This?
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Our Earth as an Apple

• 3/4 of the Earth is ocean.
• 1/8 is land that is inhospitable to people.
• 3/32 is land that is livable but not arable.
• 1/32 is land that is arable.
• The skin of 1/32 is the topsoil of the arable
  land.
• How can we make the most of the topsoil we have?
• Do not live on arable land
• Reduce pollution
• Eat lower on the food chain