Visualizing Environmental Science

(^)
Year
Population size Population density(number/sq km)
(million)
0
10
20
30
40
50
60
70
80
90
100
0.0
0.8
1.6
2.4
3.2
4.0
4.8
5.6
6.4
7.2
8.0
1950 1960 1970 1980 1990 2000 2010 2020 2030 2040 2050
Less developed regions
More developed regions
As population is projected into the future, some countries are
predicted to grow substantially, while others are forecasted to
experience population decline. Europe shows a pattern of
general decline, as fertility rates are low and life expec-
tancies high. Many countries
in sub-Saharan Africa are projected to grow because of
high fertility rates. One excep-tion in the region is Namibia,
where high mortality rates due to the HIV/AIDS epidemic are
projected to cause the popula-tion to shrink. Population size (solid lines) and population density (broken lines) are growing at a much faster pace in the world’s developing regions than in its more developed regions.
Life on a Crowded Planet
One billion, five billion, fifty billion ... how many
people is too many? Few issues are more im-
portant to human well-being than population,
and few have been fought over as bitterly or
misunderstood as often.
Some facts are not in dispute. First, we
live on an Earth of finite size, and we rely
on resources that are limited either by their
total amounts or by the rates at which they
are replenished. Second, our numbers have
increased dramatically over the past two cen-
turies. And population is still growing, fast. In
the past 100 years, the number of human be-
ings has quadrupled, from 1.75 billion in 1910
to 7 billion in 2011. We are not spread evenly
across the face of the planet, and how and
where we cluster matters. The quality of hu-
man life is affected more by population density
and access to resources, such as clean water
and arable land, than numbers alone.
It is where poverty and population inter-
sect that the challenges of booming human
numbers are most apparent. And almost all of
the increase in population expected by 2050—
another two billion people or more—will come
in those most distressed places.
PROJECTING FUTURE POPULATION
COMPARING POPULATION GROWTH IN DEVELOPED AND DEVELOPING REGIONS
Projected growth
REGIONAL POPULATION GROWTH
Earth’s population has burgeoned since 1800, from approximately 1 billion to today’s 7 billion. Africa is
sustaining high fertility rates (average number of children per woman) and is projected to contain 21
percent of the world’s population by 2050.
Asia Africa
Latin AmericaEurope
North AmericaAustralia & Oceania
U.N. Population Division 2010
Human Population Patterns 169