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Bangladesh: Population Pyramids and the Demographic Transition Model
By Luke Juran, University of Iowa
Population pyramids, or age-sex pyramids, graphically depict the distribution of a country’s population based on age and gender. A top-heavy pyramid represents a country with an aging population that is failing to replace itself. Contrarily, a bottom-heavy pyramid represents a country with a rapid growth rate. Furthermore, indentations and spikes represent natural, environmental, and human phenomena that have affected population growth over time. Causes of these reductions and booms in population are natural disasters, famine, wars, postwar eras, increase in level of healthcare, and baby boom eras.
Bangladesh’s current population pyramid
Bangladesh’s population pyramid projected for year 2025
Bangladesh’s population pyramid projected for year 2050
As countries industrialize they go through what geographers and demographers call a ‘demographic transition.’ In the demographic transition countries go through four stages:
- High crude birth rate (CBR) and high crude death rate (CDR)- little or no population growth
- High CBR and decreasing/low CDR- high population growth or ‘population explosion’
- Decreasing CBR and low CDR- population growth begins to steady
- Low CBR and low CDR- little, no, or even negative population growth
The duration countries take to make the transition varies from country to country. Factors that affect the transition include mitigation of preventable diseases (through basic healthcare, sanitation, hygiene, and immunizations); maternal, antenatal, and postnatal healthcare; agricultural revolutions, increase in food supply, and better nutrition; and cultural and social change regarding education and literacy, women’s employment, contraception and suppression of fertility, and raising the level of human (women’s) rights.
A graphic depiction of the Demographic Transition Model (Bennett, 2006)
Bangladesh’s population has gone through the second stage of the demographic transition. Bangladesh is now in the third stage of the transition- CBR is decreasing and beginning to converge with CDR. Projections predict that Bangladesh’s population will reach its replacement rate (CBR = CDR) around year 2050. However, when this occurs the population will still be increasing due to the large amount of its population at reproductive age.
A significantly large population, combined with a small land area and high population density (2,365 people per sq. mi.), means that Bangladesh faces numerous population issues in both the present and future. Among the most pressing problems are scarcity of land, insufficient tax base, issues of sustainability broadly defined, and inadequate infrastructure, education, healthcare, and public services for the swelling population. Furthermore, the situation becomes more complex when governmental issues, corruption, natural disasters, global warming, and a rising sea level are accounted for.
Sources:
Bennett, Anthony. Internet Geography: Population. 2006. Accessed 08/01/07. http://www.geography.learnontheinternet.co.uk/topics/popn1.html
Population Pyramids. International Data Base. U.S. Census Bureau. Updated 07/16/07. Accessed 07/31/07. http://www.census.gov/ipc/www/idb/
