|There was an estimated 1bn on the planet when Thomas Malthus penned his famous essay in 1798 - - up from 310m in 1000 AD and 300m in 0 AD. In the period to 1924, when the population grew to 2bn, there was a remarkable advance in technology and fall in the death rate through improved hygiene. American historian David Christian says that in the last two centuries, humans have learned to tap the huge stores of energy buried millions of years ago in the fossilized bodies of ancient plants and microorganisms, and available today in coal, oil, and natural gas. These statistics indicate the astonishing ecological power acquired by our species in the course of its history. Finfacts article, 2008: Global Food Crisis: Malthus, Food Price Surge, Climate Change and a 42% rise in World Population by 2050
The global population, which was expected to stabilize at about 9bn by
2050, is now forecast to rise to 10.1bn by the year 2100, the United
Nations said in
a report published on Tuesday. The world's population is expected to hit
the 7bn level this October, just 12 years after reaching the 6bn milestone.
The UN said growth in Africa will result in a tripling of the population
from the current level of 1bn to 3.6bn. In Nigeria, the most
populous country in the continent, the report forecasts that the population will
rise from today’s 162m to 730m by 2100. Malawi, which has a
population of 15m today, could grow to 129m by 2100, the
The report says small variations in
fertility can produce major differences in the size of populations over the
long run. The high projection variant, whose fertility is just half a child above that
in the medium variant, produces a world population of 10.6bn in 2050
and 15.8bn in 2100. The low variant, whose fertility remains half a
child below that of the medium, produces a population that reaches 8.1bn in 2050 and declines towards the second half of this century to
reach 6.2bn in 2100. For long-term trends the medium variant is taken
The medium-variant projection for 2050 is more certain than for 2100
because people who will be 40 years and older in 2050 are already born.
According to the medium variant, it will take 13 years to add the 8bn, 18 years to add the
9bn and 40 years to reach the 10bn. According to the high variant, an additional
billion would be added
every 10 or 11 years for the rest of this century.
Today, 42% of the world’s population
lives in low-fertility countries, that is, countries where women are not
having enough children to ensure that, on average, each woman is replaced by
a daughter who survives to the age of procreation. Another 40% lives
in intermediate-fertility countries where each woman is having, on average,
between 1 and 1.5 daughters, and the remaining 18% lives in
high-fertility countries where the average woman has more than 1.5 daughters
High-fertility countries are mostly concentrated in Africa (39 out of the
55 countries in the continent have high fertility), but there are also nine
in Asia, six in Oceania and four in Latin America. Low-fertility
countries include all countries in Europe except Iceland and Ireland, 19
out of the 51 in Asia, 14 out of the 39 in the Americas, two in Africa
(Mauritius and Tunisia) and one in Oceania (Australia).
The report says because declining fertility and increasing
longevity lead to population ageing, population ageing is fastest in the
Today, 11% of the population of low-fertility countries is aged 65
years or over and just 34% is under age 25. By 2050, according to
the medium variant, 26% of their population will be aged 65 or over
and just 24% will be below age 25. However, because fertility is
projected to increase over the projection period, by 2100 the proportion
under 25 increases to 27% and that of those aged 65 or over rises
minimally to 28%.
Population ageing is slower among the intermediate-fertility
but results in a 2100 population similar in age structure as that of the
low-fertility countries. The proportion of the population under age 25
passes from 47% in 2010 to 26% in 2100 and that aged 65 or
over rises from 6% in 2010 to 26% in 2100.
Population ageing is slowest among the high-fertility countries,
which have still a very young population. In 2010, 62% of their
population was under age 25 and that proportion is projected to decline
markedly to 48% in 2050 and 35% in 2100. At the same time,
the proportion aged 65 or over is projected to rise from just over 3% in 2010 to 6% in 2050 and to 16% in 2100.
The report says that China, which has a one-child policy could see its
population peaking at 1.4bn in the next couple of decades, then
declining to 941m by 2100.
Meanwhile the United States, which today has a population of 311m,
is growing faster than many rich countries, because of high immigration
and higher fertility among Hispanic immigrants will see the population
rising to 478m by 2100.
In recent times, the funding of family planning programs have been
under attack from the Catholic Church and conservatives in the United
An example of the
challenges is the experience of Yemen, a country in an arid region
at the bottom of the Arabian Peninsula, which is currently in political
The population has quintupled since
1950, to 25m and may rise to 100m by the end of the century; it has to import
most of its food and if it had an abundant supply of oil, it could desalinate
water but it does not have that flexibility.
Finally, the rising food demand
will coincide with global warming, the impact of which will be felt in
particular in tropical regions.