How did migration lead to the population of the world?

The developed regions as a whole will experience a

shrinking of population after 2040. According to the

medium-variant projection of the United Nations, the

world’s population is likely to increase from 7.6 billion in

2017 to 8.6 billion by 2030, the target year of the

Sustainable Development Goals, and to 9.8 billion in

2050.1 Most of this increase will take place in the

developing regions, while the developed regions will, for

the first time in recorded history, start to experience

negative population growth by around 2040 or 2050.

Under a scenario that assumes a net migration of zero,

the projected population of the developed regions would

be nine per cent smaller in 2050 than if current migration

trends continued. With no migration, or with equivalent

levels of immigration and emigration, the population of

the developing regions would be about one per cent

larger in 2050 than if current migration trends continued.

With fertility falling, the contribution of migration to

population change is likely to increase. Total fertility,

which stands at 2.5 births per woman at the world level

today, is projected to fall to 2.2 in 2050. Fertility in the

developed regions, which fell below the replacement

level of 2.1 births per woman shortly before 1980,

stands currently at 1.7 births per woman. Birth rates in

many developing countries, while declining, remain

relatively high. In the long run, the trend towards lower

fertility rates could result in an eventual stabilization of

the world’s population at around 11 billion people.

Migration already makes an important contribution

to population growth. Since the 1950s, the developed

regions continuously gained population due to positive

net migration. From 1950-1970 to 2000-2010, the level

of net migration to the developed regions increased

from 0.3 million to 3.1 million migrants per year.

However, the net inflow of migrants fell to about 2.2

million persons annually between 2010 and 2015.

Since the 1990s, migration has been the primary

source of population growth in the developed

regions. Migration is projected to be the only driver of

population growth in the developed regions starting after

2020. By 2050, it is expected that the population of the

developed regions will start to decline in size, as the net

inflow of migrants will no longer be sufficient to

compensate for the excess of deaths over births. The

impact of outmigration on population growth in the

developing regions is expected to remain minimal.

Indeed, for the next several decades, it is expected that

elevated levels of fertility in the developing regions will

continue to dwarf the role of net migration, which is

negative but relatively small (figure 1).

Migration and population change - drivers and impacts

Net migration refers to the difference between

numbers of immigrants and emigrants, who arrive in

or depart from a particular country or area in a given

time period, irrespective of country of birth or

citizenship. The “medium variant” of the United

Nations population projections assumes a

continuation of recent levels of net migration in future

years, whereas the “zero-net-migration scenario”

assumes that numbers of immigrants and emigrants

will be equal, starting in the period from 2015 to 2020.

Comparing these two scenarios provides useful

insights into the contribution of international

migration to population change

Explanation:

1960: wilma rudolph was the first woman to win three olympic gold medals in track and field at one olympic games. she was an american sprinter from tennessee, she was acclaimed the fastest woman in the world. she was among the most visible black women in america and abroad. she became a role model for black and female athletes. she was also known as a civil rights and women right's pioneer.

1973: billy jean king is an american former number one tennis player. she represented the united states in the federal cup and the wightman cup. for three years she was the usa's captain in the federation cup. she defends gender equality and has been a pioneer for equal and social justice. at the age of 29, she won "the battle of sexes" tennis match against the 55 year old bobby riggs. she was also the founder of women's tennis association and the women's sports foundation.  

1983: tamara mckinney becomes the first american female skier to win the alpine world cup overall championship top. she was the only american to hold that title for a quarter century until 2008.

1992: manon rhéaume, from canada,   becomes the only woman to start in a national hockey league game in an exhibition game for the tampa bay lightning . she played on the canada women's national ice hockey team winning gold medals in 1992 and 1994. and silver medals in 1998. manon marked the first time a woman appeared in a regular season professional game with her first appearance against the salt lake golden eagles.

2013: serena williams won 78 of 82 matches at the age of 31. she is an american professional tennis player. she reached the number 1 ranking for the first time on july, 8, 2002. at the age of 16, she played against karsten braasch the battle of sexes. she was the highest paid female athlete in 2016. she is a unicef ambassador .