ARTH 3002 Lecture Notes - Lecture 5: Exponential Growth, Smart People, Doubling Time
19 Dec 2016
School
Department
Course
Professor
I = PxAxT
(Our environmental impact = I)
(Population = P)
(Affluence = A)
(Technology = T)
Human population (global)
8000BCE = 5 million
1 AD = 200 million
1650 AD = 500 million
1850 AD = 1 Billion
1945 AD = 2.3 Billion
1980 AD = 4.4 Billion
2015 AD = 7.3 Billion
________________________
1804 = 1b
1927 = 2b
1960 = 3b
1974 = 4b
1987 = 5b
1999 = 6b
2011 = 7b
_______________________
At 2015 we should have been at 8.8 Billion, but it slowed. But it will double soon.
What does this mean?
Well, it could mean that for everyone to have the same quality of life; then to double the
population means to double the amount of resources.
People are concerned about population. In 2015 the current population growth rate in the world
was 1.14%.
That means that the doubling time would be about 61.4 years.
Which is right, why? Because if biology… doubling time is approximately equal to:
70/ Growth rate (in percent) = DT
That just goes to say, what do we do about population?
Several people in the book project looked at the Bet (by Paul)
— had a bet about prices of resources in 10 years. Erik saw population growth as an issue,
stripping us of sources. (Vs. Technology)
— Simon on the other hand (debating vs Paul) argued that increased population gives you more
smart people to solve your problems. As long as you have more smart people than problems
then it is a good thing. (For technology)
Well, how do people grow in general?
For all organisms with “infinite” resources, the way that population grows is…
Population on the Y
Time on the X
They demonstrate an exponential growth. There are two kinds of growths. A linear growth,
adding a specific amount every certain time. (example: 100 a year)
Or, exponential growth. Where the amount increases by a multiplication.
What happens in reality is that most things do not grow like that. If you have one housefly
couple, assuming all eggs survive, you’ll have 37 trillion babies in your house, they will
reproduce etc. Something stops them from reproducing so much…
In nature:
Population on Y
Time on X
Population goes up, then levels off, for example.
Something has happened to stop their growth; this is called logistic growth.
The population maximum that can be sustained is called ‘K’.
K = the carrying capacity of an environment
And, what often happens in real life is not so much logistic growth alone, but something that
goes up above the K (carrying capacity). When this happens a correction happens to lower the
population to the correct amount.
In the case of humans, this may happen. It can only be done by death. What would be nice, is if
we do not suffer from this and follow nature’s ‘K’.
Kabob Plateau (Grand Canyon Area)
People noticed there were cougars coyotes and wolves there, and they were eating their
animals. They wanted to get rid of them… So they tried to; what happened is the following:
# Removed:
Cougars — 600
Wolves — 11
Coyotes — 3000
Approx 30-40 years later
# Removed:
Cougars — 815
Wolves — 30
Coyotes — 7388
One of the things they ate, other than the farmers’ animals, were deer.
The deer population went up.
Document Summary
I = pxaxt (our environmental impact = i) (population = p) (af uence = a) (technology = t) At 2015 we should have been at 8. 8 billion, but it slowed. Well, it could mean that for everyone to have the same quality of life; then to double the population means to double the amount of resources. In 2015 the current population growth rate in the world was 1. 14%. That means that the doubling time would be about 61. 4 years. Because if biology doubling time is approximately equal to: Several people in the book project looked at the bet (by paul) Had a bet about prices of resources in 10 years. Erik saw population growth as an issue, stripping us of sources. (vs. technology) Simon on the other hand (debating vs paul) argued that increased population gives you more smart people to solve your problems.
