| Factors
influencing population growth
By
Marjorie Henry, Contributor
 |
| Students
from Bridgeport High School sing a Christmas carol. - Photo by Anthony Minott |
I ended
the last lesson with reference to the factors that influence population growth.
I gave you an exercise to do, that of calculating the population growth of an
imaginary town named George. If you had followed the steps given in the lesson,
you should have had no difficulty in arriving at the correct answer. Let me restate
the question and then work it through. 'At
the beginning of the year, town George has a total population of 10,000,000. There
is no migration. The birth rate is 20 per 1000 and the death rate is 15 per 1000.
What will be the increase in total population in town George by the end of the
year?' Birth
rate (20) - Death rate (15) = 5 per 1000 5/1000
X 10,000,000 = 50,000 The
population of George increased by 50,000. So, at the end of the year, the population
is 10,000,000 + 50,000 = 10,050,000. In
today's lesson, I will share with you the general factors that influence population
distribution and population density. These can be categorised as physical, economic,
social, political, transportation and communication. In the text, Population
Geography, written by Hazel R. Barrett, it is stated that - 'The overriding
factor affecting population distribution is the ability of a population to make
a satisfactory living. This in turn may be dependent on ecological factors, as
well as socio-economic and political considerations.' These factors vary both
in space and time. Where they are positive, they encourage many persons to live
there, resulting in a dense population. The reverse is true, that is, where these
factors are negative, few persons are there-hence a sparse settlement is present.
The
information on the factors affecting population distribution and population density
globally is presented in the table. My source of reference is the text, The Wider
World written by David Waugh. Although the syllabus requires you to be aware
of these factors in a named Caribbean country, the information is being given
to offer a broader perspective on the subject. Afterwards, we will select those
that are applicable to the Caribbean country. | FACTORS | SPARSELY
POPULATED AREAS | DENSELY
POPULATED AREAS | | Relief | Rugged
mountains where temperature and pressure decrease with height; active volcanoes
(the Ades); high plateaus (Tibet) and worn down shield lands. | Flat,
lowland plains are attractive to settlement (the Netherlands) as are areas surrounding
some volcanoes (Mt. Etna). | | Climate | Areas
receiving very low annual rainfall (the Sahara Desert); areas having a long seasonal
drought or unreliable, irregular rainfall (the Sahel countries); areas suffering
high humidity (the Amazon basin); very cold areas, with a short growing season. | Areas
where the rainfall is reliable and evenly distrubuted throughout the year, with
no temperature extremes and lengthy growing season (north-est Europe); where sunshine
(the Costa del Sol) or snow (the Alps) is sufficient to attact tourists; and areas
with a monsoon climate (south-east Asia). | | Vegetation | Areas
such as the coniferous forests of nothern Eurasia and nothern Canada, and the
rainforests of the tropics. | Areas
of grassland tend to have higher population densities than places with dense forest
or desert. | | Soils | The
frozen soils of the Artic (the permafrost in Siberia); the thin soils of mountains
(Nepal); the leached soils of the tropical rainforest (the Amazon basin); also,
increasingly large areas are experiencing severe soil erosion resulting from deforestation
and overgrazing (the Sahel). | Deep,
humus-filled soils (the Paris Basin) and, especially river-deposited silt (the
Ganges and Nile deltas) both favour farming. | | Water
Supply | Many
areas lack a permanent supply of clean fresh water, mainly due to insufficient,
irregular rainfall or to a lack of money and technology to build reservoirs and
wells or lay pipelines (Ethiopia) | Population
is more likely to increase in areas with a reliable water supply. This may result
from either a reliable, evenly distributed rainfall (nothern England) or where
there is the wealth and technology to build reservoirs and to provide clean water
(California). Places with heavy seasonal rainfall (the monsoon lands of south-east
Asia) also support many people. | | Resources | Areas
devoid of minerals and easily obtainable sources of energy rarely attract people
or industry (Paraguay) | Areas
having or formerly having large mineral deposits and/or energy supplies (the Ruhr)
often have major concentrations of population, these resources ofen led to the
development of largescale industry (the Pittsburgh region, U.S.A). | | Communications | Areas
where it is difficult to construct and maintain transport systems tend to be sparsely
populated, e.g. mountains (Bolivia), deserts (the Sahara) and forests (the Amazon
basin and nothern Canada). | Areas
where it is easier to construct canals, railways, roads and airports have attracted
settlements (the North European Plain), as have large natural ports which have
developed for trade (Sigapore). | | Economic | Areas
with less developed, subsistence economics usually need large areas of land to
support relatively few people (although this is not applicable to south-east Asia).
Such areas tend to fall into three belts: tundra (the Lapps), desert fringes (the
Rendille) and tropical rainforests (shifting cultivators). | Regions
with intensive farming or industry can support large numbers of people on a small
area of land (as in the Netherlands). | | Political | Areas
where the state fails to invest sufficient money or to encourage development -
either economically or socially (the interior of Brazil) | Decisions
may affect population distribution - e.g. creating new cities, such as Brasilia;
by opening up pioneer' lands for development, as in Israel. |
Can
you think of other factors? How many of these factors are applicable to the Caribbean
and, more specifically, to Jamaica? List them in preparation for the next lesson. Marjorie
Henry is a vice-principal at Glenmuir High School and is head of the Geography
Department. She teaches the subject at the CSEC Level. |
