Post 2015: Global Action for an Inclusive and Sustainable Future

CHApTER SIx
The world’s
median age
is expected to
increase from
29.2 years in
2010 to 37.9 in
2050, a change
that will be felt
most strongly
in developing
countries. While
the proportion of
people aged 60 or
above rose from
8.1% in 1950 to
11% in 2010, it is
expected to reach
21.8% in 2050.
82
policy changes. under a ‘high variant’ scenario,
the world population would reach 10.6 billion by
2050, while the ‘low variant’ alternative projects 8.1
billion by 2050 (unDESa, 2011a). 59 the ‘constant
fertility’ assumption generates huge population
growth, but this is unlikely to materialise given
historical trends and patterns of demographic
transition. nonetheless, fairly small changes in the
underlying assumptions – especially with regard to
fertility rates – can generate large differences in the
forecasts (see Figure 6.1).
broad population trends mask regional variations
(see Figure 6.2). at the regional level, SSa is
expected to experience the highest nominal and
relative population increases, as its population is
likely to more than double by 2050 (to about 2.2
billion). asia will remain the world’s most populated
region, although its share of world population
will decline as SSa’s grows. the population of the
remaining regions will grow only marginally, if
at all. collectively, africa and asia will represent
nearly 80% of the world population by 2050, while
Europe will account for 8%, down from the 22%
registered in 1950 (unDESa, 2011a).
Despite the decline in the rate of growth, the
world population will continue to grow in the
medium term, mainly because of predicted growth
in developing countries, which will be equivalent
to the entire (mostly stagnant) population of more
developed countries (about 1.2 billion people).
6.1.2 Ageing societies
the broad demographic dynamics described
above will also affect the age structure of the world
population. For instance, while a country’s population
size usually booms in the early stages of demographic
transition, its growth tends to decelerate as birth rates
EuropEan rEport on DEvElopmEnt 2013
and mortality rates converge. 60 barring significant
migration, this usually leads to an increase in the
median age of the population. population ageing
is an inevitable outcome of lower fertility rates and
greater life expectancy.
as more countries undergo this demographic
transition, the world’s median age is expected to
increase from 29.2 years in 2010 to 37.9 in 2050, a
change that will be felt most strongly in developing
countries. In addition, while the proportion of
people aged 60 or above rose from 8.1% in 1950 to
11% in 2010, it is expected to reach 21.8% in 2050.
In more developed countries, the proportion of the
population aged 60 years and above is projected to
increase from 21.7% in 2010 to 31.9% in 2050, and
of over-80s from 4.3% to 9.3% (unDESa, 2011a).
these trends will mean a substantial increase in
old-age dependency ratios. 61 between 1950 and 2010,
the world ratio rose from 0.09 to 0.12 dependants and
is projected to reach 0.26 by 2050. In other words, in
1950 there were 11 people of working age per elderly
person, whereas by 2010 there were eight and the
ratio is expected to drop to four by 2040. In china,
for example, the old-age dependency ratio of 0.11 in
2010 is projected to increase to 0.42 by 2050, while the
ratio in Europe will increase from 0.24 in 2010 to 0.47
in 2050 (unDESa, 2011a). these trends are likely to
have significant impacts on the demand for health
services and pensions, as well as on tax revenues,
and may affect intergenerational solidarity and
dynamics. International migration, especially from
africa, could potentially play a role in rejuvenating
ageing populations and reversing these trends.
While there are concerns about population
ageing, youth has also become a major issue in
national and international policy agendas, notably
59 the medium variant assumes that global fertility will fall from 2.52 children per woman between 2005 and 2010 to 2.17 by 2045–2050, while
the low [high] variant assumes that fertility rates are 0.5 children below [above] that of the medium variant.
60 Initially, mortality rates decline sharply due to better health (reduced child survival and increased life expectancy) while fertility rates remain
comparatively high.
61 this is the ratio of the population aged 65 years or over to the population aged between 15 and 64 years.