Human populations have grown exponentially
* 1700s, changes in technology gave humans more control over their food supply.
* The human population has grown explosively over the last 300 years.
* Birth rate has remained unchanged at about
30 per 1000 per year over this period.
* Death rate has fallen dramatically, from 20 per 1000 per year to its present level of 13 per
1000 per year.
* A 1.2% annual growth rate may not see large, but it has produced a current human population of
nearly 7 billion people.
Population pyramids show birth and death trends
*Population Pyramid – it is when the rate at which population can be expected to grow in the future
that can be assessed graphically.
* It displays the age composition by sex.
* The number of older females is disproportionately large compared with the number of older males.
Humanity’s future growth is uncertain
* Humanity is adding 78 million people a year to its population---- over a million every five days, 150
* A key element in the world’s population growth is its uneven distribution among countries.
In the future, the world’s population growth will be centered in the parts of the worlds least
equipped to deal with the pressures of rapid growth.
The population growth rate has declined
*Declined from a high of 2% in 1965-1970 to 1.2% in 2008
*78 million per year to 53 million per year
Ecological footprints of individuals in different countries
2.1 1.9 5.3
75 65 29
6.5 30 95
78 72 49
$40,100 $8100 $800
15 years old
21 26 44