Human Population Explosion
Homo sapiens, the humans are relatively recent
arrivals in Earth’s history.
But their influence on the environment is very great.
The explosive growth in the human population has
had dramatic consequences for the environment and
for other organisms
How quick is the population growing???
Rate of increase = births - deaths
Though birth rate remains constant or
has a slightly drop, but the death rate
The population has grown at an
It’s just like a explosion!!!!!
The Human Snowball
-Human population grows so fast
->>exceeds the carrying capacity of the More and more people live
environment on the Earth,
As a result , a large number
of human may die.
>> human lives are threatened.
Cause Of Overpopulation
1. Change in methods of food production?
2. Agricultural Revolution?
3. Industrial Revolution?
4. Progress in medicine?
The significant rise in
population growth rate
1st increase in population growth rate:
Age of colonization begins
(More space for living)
2nd increase in population growth rate:
Agricultural + Industrial Revolution
(Food production increased)
3rd increase in population growth rate:
(Mortality Rate decreased)
The Domino Effect of the development of humans
The other Domino Effect
•Control of harmful bacteria made water safer to drink
•Sewage disposal systems
•Things for daily use are made which could be easily washed
•The new medicine was introduced
•Living Standard improves
Problem posed by overpopulation
Ⅰ Social Problems
Ⅰ World Food Problem
Ⅰ Impact to Environment
1. The Social problem of the overpopulating
Conflict --> war
“Aging” problem in developed countries
Other moral problems
Those would not be discussed deeply, just be mentioned only.
2. The World Food Problem
Which is the most serious social problem of the overpopulating
1. Political instability
2. Unfair trading policy
3. Uneven distributed food supply
Famine in less-
4. Unbalanced population distribution
5. So much food is wasted
6. Deforestation inhibits food production
7. Natural disasters
The cause of world food problem
1. Political instability:
- Hinder the export and import of food in the less-developed countries
- War destroy the agriculture less food produced
2. Unfair trading policy:
the government and businessman from well developed countries ( such as USA)
deprive the less-development countries by selling the low cost food to destroy
the agriculture of those countries.
3. Uneven distributed food supply:
Though food production is increasing faster than the population.
-- 1/3 world population (well developed countries)
consume ½ world food supply
4. Unbalanced population distribution:
population of less-developed countries >>> population of well developed countries
consumption(well developed countries)>>>consumption(less-developed countries)
5. So much food is wasted:
Wasteful eating habits of the people
6. Deforestation inhibits food production:
Soil erosion -> soil no longer fertile
7. Natural disasters:
Droughts, floods, pests
Slow-down of food production
Country Population at
Africa Food Crisis
If the population still keep on increasing,
the food problem will be worsen Burundi 2 million
Ethiopia > 10 million
Kenya 3.5 million
Source: USAID. Executive Overview of Food Security in Sub-Saharan Africa, 15 Feb 2006;
for Burundi figure, News from Africa
How to solve this problem?
•The food aids
•Teaching the agriculture technology to the people in those countries
•GM food !!!
•New policies to the agriculture and trading system.
•Reduction of energy loss and food loss
-reduce the energy loss during TROPHIC TRANSFER , such as eat plants
-reduce the waste of food
Genetic engineering, genetic modification
(GM, 基因改造) and gene splicing are
terms for the process of manipulating
genes, usually outside the organism's
normal reproductive process.
Genetic Modified food can benefit the food
in the following categories:
- Nutrition value
III. Impact to the environment
The environment has largely destroyed by
us. There are a lot of environmental
problems. Air pollution, land pollution and
As the human population increase, the
demand of natural resources increase as
Air Pollution Land Pollution Water Pollution
-Carbon monoxide -Waste disposal Toxic chemical
-Sulphur dioxide -pesticides Oil
A large area of forest was pulled down by
Lots of organisms lost their habitat.
The community of Hong Kong disposes about
17,900 tons of solid wastes every day. Of this,
7,500 tons are domestic waste, 1,800 tons are
commercial and industrial waste and 7,500 tons
come from construction activities. The municipal
waste production amount of each person is
about 1.4 kilograms per day.
Hong Kong only got a population of 7 million,
can you imagine the amount of waste produce
each day in the World, which got a population of
Green House Effect
In 2006, the average temperature or Hong
is 23.6 , which is the highest record.
Increasing concentration of greenhouse
Lead to Global warming
Exploitation of resources
Renewable Resources – resources that can be
regenerate fairly rapidly through natural
processes. E.g. Oxygen, Minerals in soil.
Non renewable resources – resources that
limited in availability. They are fixed in total
quantity in the Earth’s Crust and are not
replenished by natural processes in short time.
E.g. Fossil fuels
Are you noticed our resources are
Resources like coal and oil are non
renewable. Once they had depleted, we
will lost the access of almost all our
Why should have population control?
The critical question is: In the present of such a
huge human population, can the natural
environment be maintained in a condition that
will supply all living things with the required food,
water, and space?
An immediate task must be to reduce the birth
The Earth has its capacity, its resource will
be used up one day. if the population keep
on increasing, the problem of food and the
problem of pollution will be worsen
Controlling the population is critical to savi
ng the environment from hazards of polluti
Population Control Policy
China : one family one child
Hong Kong (past): 2 children is
-in the mid 1970s
-concentrated on male sterilisation.
-strong resistance developed to the
concept family planning.
Tunisia and Jamaica:
-improved the provision of freely
available family planning advice and
-introduction of education skills and a
general raising of the economic
-improved the health of mother and
the child by preventive medicine.
Population control is fundamental and
essential as to avoid long term damage to
the environment as a consequence of acid
rain, green house effect and possible
Global Warming, and the threat to the