Bangladesh may not be very important in the global arena, but it has a large population making it world's seventh largest country ahead of Russia which has 143 million people only. A review in retrospect reveals that the area now comprising Bangladesh had only 18.2 million people in 1872. The rate of population increase was then very trivial -- number of births was close to the number of deaths and resultant increase of population was less than one percent. Even in 1901, population census could report only 21.2 million people. Malaria, plague, typhoid, small pox and other deadly diseases took some 40/42 lives per 1000 population per annum. Thus in the next four decades, i.e. until 1941, population could grow up to 3.4 million. Up to 1960, the population growth rate sharply increased to 2.1 percent and the human number was estimated to be 54 million. Over the following next decade and a half, growth rate was hovering around 2.5 to 3.0 percent. In 1991, this population became more than double. Such a phenomenal increase in a span of 30 years was unprecedented. Analysts attributed to this growth two factors, namely high birth rate and declining death rate with resultant increase in high growth rate. This growth trend continued until 1980 and then started slowly falling down to the present level of 1.6 percent.

Death matters no less than birth -- indeed more, to demographers. As public health measures are likely to further improve, deaths decline particularly among the infants and thus, more babies will live to grow up. So a country's population becomes more youthful as in the case now in Bangladesh where 40 percent people are under 15 years of age. More young adults mean more births. Birth rate may decline further through programmatic means reinforced by non-family planning measures like female education, micro credit facilities for women, skill training, use of media etc. All these measures will eventually help create a conducive environment to reduce birth and death rates leading to population stabilisation. But when? In seeking answer to this question, this writer offers a range of projections, hereinafter, called variants. Variant i assumes replacement level fertility (i.e. just over 2 children) in 2012 variant ii and variant iii assume the same fertility level in 2016 and 2021 respectively. Discussion that follows will mainly concentrate on medium variant projection to illustrate the future population prospects, timing of population stabilisation and changes in various demographic parameters in the next 100 years.

Demographic prospects
A country's growth potentials is built in the age structure of its population. Already stated that in Bangladesh, population below 15 years is about 40 percent and that women in reproductive age (15-49) are about 41 percent of total female population -- both are indications of future population growth potentials. Notwithstanding an elaborate and modestly persuasive family planning programme, fertility reduction to replacement level may be difficult to achieve by 2012 unless far more vigorous efforts are made at the grassroots level by the health and family planning workforce; and also, dysfunctionality that currently prevails in large chunk of underserved areas is removed. Assuming that public and private sectors efforts in this respect shall continue and that public health measures will augment considerably to thwart the menace of deadly deceases, Bangladesh is quite likely to achieve its demographic goal of NRR=1 by 2016. If the current pace of progress continues, life expectancy at birth is likely to increase anywhere between 68-70 years. As a result, age structural shift will occur in favour of higher age groups.

The medium variant projection that assumes NRR=1 by 2016 and life expectancy at birth of 70 years by then, shows Bangladesh's population will increase up to 175.2 million in 2021 and 233.4 million in 2051 which means 63.0 percent increase of present population. Population growth rate will be reduced to 0.56 percent in 2051. The implications of this projection are: the size of the population below 15 years shall be 49 million against 52.4 in 2001. The size of the school age population in absolute number shall decrease up to 32.4 million against 34.2 million in 2001; while the working age population (15-64 years) will increase up to 155 million (as against 85 million now), aggravating further the strained labour market; and number of elderly population (i.e. 65 year+) shall be 29.8 million (as against 5.8 million now requiring old age supports and medical care from which no responsible government can get away. The other obvious implications include: population density of 4157 persons per square mile as against the present density of 2591 persons. The existing man-land ratio of 1:14 decimals shall be reduced to a half. Because per capita availability of arable land will be reduced, per person food production will be reduced too. Thus, one may go on relating this growing population to any social and economic objects, but that will give simply a bleak scenario which will make one instantly feel bad about having too many people in too little space. Analysts have already estimated that Bangladesh is the world's seventh populous country comprising only 3000th part of its land space!

Momentum and stabilisation
Population growth momentum has already started; and a wave of various kinds of pressures has already been generated and the people have started feeling the pinch of it. So, population will go on rising even if Bangladesh achieves the replacement level fertility. The timing of population stabilisation depends on the time when replacement level fertility is achieved. In our present case, if Bangladesh can achieve NRR=1 by 2016, population will stabilise by 2070, followed by a stationary population in next 12-15 years (i.e. number of births will be equal to number of deaths and resultant growth rate is zero). In medium variant projection, status of stationary population in Bangladesh is likely to be achieved around 2086 and thereafter, number of deaths will exceed number of births i.e. minus growth rate will begin which will eventually decelerate the country's population as is the case with Russia, Japan and some of the European countries now. The deceleration process (i.e. minus-growth rate) in Bangladesh shall start according variant-ii by 2097, and by this time, population shall have grown up to 250 million.

A great deal of population momentum is coming from the low income families, such as poor, ultra poor and other lower income groups who together comprise 50 percent of the society. These are the people among whom infant mortality and maternal mortality rates are the highest. Total fertility rate is twice as much of the upper middle and high income groups. They are the ones who have very little access to education beyond primary, health care services and other benefits which government and society usually offer to the individuals. So if the goal of replacement level fertility is to be achieved any time in the next decade, our policies, programmes and resources should be directed towards them.

There are, however, some grounds for optimism. A large number of women want children fewer than ever and the younger the women, the fewer they want. The recent surveys of married women reveal that there is a considerable unmet demand. Meeting this demand is not restricted to modern methods of contraception; even traditional methods help plan family size as in some countries. But for this to happen, education, use of media, arousing people's consciousness and democratisation of social and political institutions at all levels to allow the hitherto neglected people to participate and involve themselves in all kinds of state sponsored development works are essential. If we can create an enabling environment through such processes and other civilized means, demographic momentum effect can be significantly reduced and the timing for population stabilisation may be advanced a few years earlier.

Dr M A Mabud, a social scientist and demographer is professor of Public Health at North South University, Dhaka.