Demographic History
and Forecast
Before the demographic transition, life was short, births were frequent, growth was slow, and the population skewed young. The transition brought declining mortality, followed by falling fertility, leading to initially accelerated and then slowed population growth rates. This trend, starting around 1800 in Europe, has now gone global and is expected to conclude by 2100. This shift has reshaped economies, life cycles, and populations. Since 1800, the global population has grown sixfold, set to be tenfold by 2100. The elderly will increase by 50 times, and children by fivefold, causing the elderly-to-children ratio to surge tenfold. Life expectancy doubled, set to triple; births per woman dropped from six to two. In 1800, women spent 70% of adulthood on child-rearing, now about 14% due to lower fertility and longer lifespans.
Malthus said slow
population growth connects to growing economies. When the population grows
quickly, wages drop, and more people die – that's the "positive"
check. Lower wages also make people marry later and use less birth control –
the "preventive" check. In the past, like before 1800 in Europe,
these ideas made sense. Things stayed balanced when more babies were born, and
the economy worked together.
In Europe, people
married late because they needed many resources, so they had fewer kids. Babies
had a harder time surviving, so the population grew slowly, with some faster
times. But outside Europe, changes in birth and death happened later. Before
World War II, India had many babies but shorter lives, and Taiwan was similar.
After World War II, many poor countries still had lots of babies, but China was
different.
Around the world, the number of people grew slowly, with changes because of trading, exploring, diseases, and the weather. Malthus' ideas and history show how population and money connect in different places and times.
The Current
Population
The world’s
population is more than three times larger than it was in the mid-twentieth
century. The global human population reached 8.0 billion in mid-November 2022
from an estimated 2.5 billion people in 1950, adding 1 billion people since
2010 and 2 billion since 1998. The world’s population is expected to increase
by nearly 2 billion persons in the next 30 years, from the current 8 billion to
9.7 billion in 2050 and could peak at nearly 10.4 billion in the mid-2080s.
This dramatic growth
has been driven largely by increasing numbers of people surviving to
reproductive age, the gradual increase in human lifespan, increasing
urbanization, and accelerating migration. Major changes in the fertility rate
have accompanied this growth. These trends will have far-reaching implications
for generations to come.
China (1.4 billion) and India (1.4 billion) remain the two most populous countries of the world, both with more than 1 billion people, each representing nearly 18 percent of the world’s population, respectively. Around 2023, India is projected to overtake China as the world’s most populous country, while China’s population is projected to decrease by 48 million, or around 2.7 percent, between 2019 and 2050.
Factors influencing
the population growth
1.
Fertility:
Future growth depends on fertility rates, predicted to drop from 2.3 to 2.1
children per woman by 2050.
2.
Longevity:
Global life expectancy is rising from 72.8 to 77.2 years by 2050. Disparities
persist, especially in least-developed countries.
3. Migration: While less impactful, migration affects the population. Over a decade, around 17 places will have over a million migrants arriving, and 10 will see a similar number leaving.
Overpopulation Issues
Overpopulation arises
when the number of individuals surpasses what the planet can sustain, causing need
to outpace Earth's carrying capacity.
In ecology, carrying
capacity denotes the maximum number of individuals an area can support without
resource scarcity leading to loss of life or irreversible natural resource
degradation. Overpopulation strains resources, depleting them faster than they
can regenerate, ultimately limiting the number of sustainable lives.
This can also stem
from overconsumption, often linked with overpopulation, signifying resource
usage at an unsustainable pace. Even smaller populations can deplete resources
rapidly if usage isn't sustainable.
Overpopulation
emerges from excessive births and limited deaths, plus low emigration and high
immigration in specific regions. Globally, it's propelled by rapid population
growth due to medical and technological advancements reducing mortality rates,
as well as poverty, limited education, and restricted access to birth control.
Factors that lead to
overpopulation:
1.
Advances in Medicine:
Reduced deaths from diseases extended life expectancy and created a generational
overlap, accelerating population growth.
2.
Technological Progress:
Agricultural advancements, notably the "Green Revolution" in the late
1960s, enabled feeding larger populations than thought possible. Contrary to
predictions, it boosted food production significantly.
3.
Improved Childbirth Practices:
Lowered child and infant mortality rates historically contributed to slower
population growth. Despite higher birth rates in the past, survival challenges
prevented many children from reaching reproductive age.
In the last century,
global child mortality dropped from 25% to 2.9%, especially within the last 50
years. Improved healthcare and surgical safety led to fewer children in
developed nations, yet more surviving to establish their families. Lack of
education in developing regions hampers family planning, reinforcing
traditional beliefs linking numerous offspring to affluence.