Trend in the human
population growth up to 1650
and from 1650 to the present
moment
It is evident from the graph that :1. the human population is increasing rapidly and shows a geometric (J-shaped)
growth form
2. the population is doubling in shorter periods
3. the next doubling period (8 000 million) has been calculated to be in the year 2010
– a doubling period of 35 years
4. this increase in population CANNOT go on indefinitely – as environmental resistance
(shortage of food, O2 and living space) increases – something has to give – unless we
are able to stabilise the population at the carrying capacity of the world
Worldwide
human
population
growth
from 1750
to 2000
Human population growth according to History
Human population growth in SA from
1947 to 2011
Human population age and gender
distribution in:
1. an increasing population
A population pyramid with a small number of old people
indicates a population with a high birth rate, a high death
rate and a short life expectancy. This pattern is typical of
less economically developed countries (LDC) like South
Africa, South America and Asia (excluding Japan)
2. a stable population
There is approximately the same number of young people
and old people. About the same number of children is born
each year compared to the number of people who die
each year. Economical developed countries like Ireland
have this kind of pyramid
3. a decreasing population
There are more old people than young people. Each year
more people die than are born. Developed countries like
Germany have this kind of pyramid. Some southern African
countries, like Botswana (experiencing the effects of
HIV/AIDS) are also starting to show this kind of age-gender
pyramid.
Population sizes in different parts of the world
The graph is divided into 2 groups:
1. The less developed countries (LDC) like Latin America, Africa and Asia (excluding
Japan). Population growth is expanding rapidly and the majority of people live in
poverty. Medical care and technological advances are not readily available, food is
scarce and levels of education are low. A high social value is placed on large families.
2. The more developed countries (MDC) like North America, Australia and Europe.
Population growth is low and people enjoy a good standard of living. Medical care and
technology is readily available. Food and technology are available, level of education is
high.
A comparison of
less developed
countries with
more developed
countries
Discuss the differences
between the gender-age
pyramids for Japan &
Zimbabwe.
Use these graphs to discuss the changing trends in
the SA population. Indicate the working group (20
– 60 years), mention how their economical
contributions will support the non-economical
groups (children and old people). Take the % of
jobless people into consideration and the fact that
only 5.6% of the population pays tax
The effect of high population growth on the environment
The effect of high population growth on the environment
(depletion of resources and increased pollution)
The effect of a growing population on resources,
pollution, industrial output and the availability of food
Ecological footprint: the impact of a person, city, or
country on the ecology of a local area or the whole planet.
It is a measure of how much land and water a person, city
or country needs and the wastes that are produced.
We do not know what the carrying capacity of
the world is. The United Nations has predicted a
global human population of over 10 billion
people by 2050 – therefore an estimated 4
billion people will be added to the population in
the next 40 years.
One approach to estimate the carrying capacity
of the earth is to look at the ecological footprint
of different groups of humans.
• According to the Global Footprint Network, humanity uses
the equivalent of 1.3 planets to provide the amount of
resources we consume and absorb the waste we produce.
This means it now takes the Earth one year and four
months to regenerate what we deplete in a year.
To calculate the ecological footprint of a population all
their needs need to be taken into account, e.g. food,
water, fuel, building materials, clothing and medical
care. The impact, to produce the needs, on the
environment is then calculated. An ecological
footprint represents the area of land and water
utilised by a particular nation. It takes into account
the resources used by wastes produced by that
country. It measures how much land an water a
human population requires to produce what it
consumes, and to absorb its wastes using current
technology. It compares human demand with the
earth’s capacity to regenerate
In 2006, the global ecological footprint outpaced the Earth’s biological capacity by 30
percent. This trend is increasing. In fact, on September 23rd of this year, we passed
“Overshoot Day,” the day the human ecological footprint exceeded the Earth’s
biocapacity and began living beyond its ecological means. Since then, we have been
engaged in the ecological equivalent of deficit spending: our rate of resource
consumption is exceeding the rate at which those resources can be naturally
replenished.
What are we doing?
Activity 3:Use the next two slide to complete the
table:
Greater ecological
footprint than South
Africa
Similar ecological footprint Smaller ecological
to South Africa
footprint than South Africa
Australia
Ethiopia
India
The effect of high population growth on the environment. The
darker the colour, the greater the ecological footprints.
Reckless consumption is depleting the world’s natural capital to a
point where we are endangering our future prosperity. The Living
Planet Index shows that over the past 35 years along the Earth’s
wildlife populations have declined by a third.
Yet our demands to continue to escalate, driven by the relentless
growth in human population and in individual consumption. Our
global footprint now exceeds the world’s capacity to regenerate by
about 30%. If our demands on the planet continue at the same rate,
by the mid-2030s we will need the equivalent of two planets to
maintain our lifestyles.
The ecological credit crunch is a global challenge. The Living Planet
Report 2008 tells us that more than three quarters of the world’s
people live in nations that are ecological debtors—their national
consumption has outstripped their country’s biocapacity. Thus, most
of us are propping up our current lifestyles, and our economic
growth, by drawing (and increasingly overdrawing) upon the
ecological capital of other parts of the world.
The following categories affect your ecological footprint:
Ecological “footprint" for different countries
It is likely that the countries
and regions with surplus
ecological reserves, and not
the ones relying on continued
ecological deficit spending,
will emerge as the robust and
sustainable economies and
societies of the future.
•To support my lifestyle, it takes 15.4 acres of the Earth's productive area.
What will happen if this trend continue?
What can you do to save the
world?
Sustainable: careful use of natural and human
resources so that they will also be
available to future generations
Conservation: the management of the Earth’s
resources so that it yields the
greatest sustainable benefit to future
generations while maintaining its
potential to meet the needs of future
generations