3.2.4 Population and the environment
3.2.4.1 Introduction
Human population growth is the driver of many environmental, socio-economic and political
challenges of the modern world. The ability of a place to support the population depends upon
whether it can provide an adequate food supply. This could be from local food sources and/or trade
with other areas. This in turn depends upon the climate, soils and other aspects of the environment.
Population change is often associated with economic development.
- Population distribution = how people are spread out.
- Population density = how crowded a place is, people/km2.
What is the pattern of population change?
Population is growing in most countries of the world. There are only a few countries, mainly in
Eastern Europe, as well as Russia, where the population is decreasing. The highest population
percentage growth is mostly concentrated in Africa, Libya and South Sudan. In the northern
hemisphere, Greenland, Scandinavia and Siberia are experiencing low growth rates. The population
of much of Africa is growing rapidly (over 2% per year). Notably, growth is fastest in LICs. Zimbabwe
is an anomaly – it has an unusually high growth rate compared to surrounding countries in Southern
Africa. China is an anomaly also – it has a low growth rate compared to other Asian countries.
Elsewhere, population is increasing between 0.5 and 1.5% per year. In high-income countries,
growth rates are lower as they are more developed. In low-income countries, growth rates are
higher because heath services and education on contraception isn’t as good, so women have more
children.
There is a shortage of arable land in the world. We can preserve farmland by:
- Not building on farmland (housing, shops, services, industry (business parks, hi-tech etc),
roads and railways).
- Changing our diet; vegetarianism/ vegan and eat lower down the food chain.
- Reducing pollution – from waste/ heavy metals etc, and clean up pollution.
- Stabilising or reducing population growth.
Elements in the physical environment
- Climate:
This is arguably the most important. Rainfall, temperature, wind velocity and levels of solar
insolation all determine food productivity, the type of farming system adopted and which
species are selected for cultivation. For example, many crops need temperatures of at least
5ºC to grow and pasture-fed livestock need to be supplemented with fodder crops at
temperatures below 5ºC. High concentrations of population are determined by adequate
rainfall and temperatures that are suitable for growth of crops and rearing of livestock, with
sufficient sunlight for photosynthesis. Characteristics of climate can also drive the level and
nature of diseases. For example, tropical diseases such as malaria, yellow fever and Ebola
will directly affect death rates and life expectancy in the human population. High infant
mortality rates in tropical and subtropical areas can also influence fertility rates as families
seek to compensate for their loss.
- Soils:
The most important feature of soil is its fertility. This depends upon soil structure, texture,
acidity (pH), organic matter and nutrients. These will determine agricultural output and the
3.2.4.1 Introduction
Human population growth is the driver of many environmental, socio-economic and political
challenges of the modern world. The ability of a place to support the population depends upon
whether it can provide an adequate food supply. This could be from local food sources and/or trade
with other areas. This in turn depends upon the climate, soils and other aspects of the environment.
Population change is often associated with economic development.
- Population distribution = how people are spread out.
- Population density = how crowded a place is, people/km2.
What is the pattern of population change?
Population is growing in most countries of the world. There are only a few countries, mainly in
Eastern Europe, as well as Russia, where the population is decreasing. The highest population
percentage growth is mostly concentrated in Africa, Libya and South Sudan. In the northern
hemisphere, Greenland, Scandinavia and Siberia are experiencing low growth rates. The population
of much of Africa is growing rapidly (over 2% per year). Notably, growth is fastest in LICs. Zimbabwe
is an anomaly – it has an unusually high growth rate compared to surrounding countries in Southern
Africa. China is an anomaly also – it has a low growth rate compared to other Asian countries.
Elsewhere, population is increasing between 0.5 and 1.5% per year. In high-income countries,
growth rates are lower as they are more developed. In low-income countries, growth rates are
higher because heath services and education on contraception isn’t as good, so women have more
children.
There is a shortage of arable land in the world. We can preserve farmland by:
- Not building on farmland (housing, shops, services, industry (business parks, hi-tech etc),
roads and railways).
- Changing our diet; vegetarianism/ vegan and eat lower down the food chain.
- Reducing pollution – from waste/ heavy metals etc, and clean up pollution.
- Stabilising or reducing population growth.
Elements in the physical environment
- Climate:
This is arguably the most important. Rainfall, temperature, wind velocity and levels of solar
insolation all determine food productivity, the type of farming system adopted and which
species are selected for cultivation. For example, many crops need temperatures of at least
5ºC to grow and pasture-fed livestock need to be supplemented with fodder crops at
temperatures below 5ºC. High concentrations of population are determined by adequate
rainfall and temperatures that are suitable for growth of crops and rearing of livestock, with
sufficient sunlight for photosynthesis. Characteristics of climate can also drive the level and
nature of diseases. For example, tropical diseases such as malaria, yellow fever and Ebola
will directly affect death rates and life expectancy in the human population. High infant
mortality rates in tropical and subtropical areas can also influence fertility rates as families
seek to compensate for their loss.
- Soils:
The most important feature of soil is its fertility. This depends upon soil structure, texture,
acidity (pH), organic matter and nutrients. These will determine agricultural output and the
