Global Demography Notes

Shanghai's population decreased in 2022, marking the first decline in five years.
The decrease is attributed to COVID-19 lockdowns and the departure of migrant workers.
Shanghai's birth rate decreased to $4.4$ per $1,000$ people, while the death rate increased to $6.0$ per $1,000$ , indicating an aging population.
A survey showed that around $60$ % of Shanghai residents preferred one child or none, with over $28$ % citing high childcare costs as a deterrent.

The demographic transition involves a shift from high birth and death rates to low birth and death rates.
Initially, mortality declines, followed by fertility declines, leading to changes in population growth rates.
Began around 1800 in Europe and is projected to be completed worldwide by 2100.
Global population has increased sixfold since 1800 and is expected to increase tenfold by 2100.

The demographic transition started in northwest Europe around 1800 with a decline in mortality.
Initial mortality decline was due to reductions in contagious and infectious diseases.
Preventive medicine, such as the smallpox vaccine, and improved personal hygiene played a significant role.
Improvements in nutrition and reductions in famine mortality also contributed.
Recent mortality reductions are due to declines in chronic and degenerative diseases, such as heart disease and cancer.
Life expectancy in India rose from approximately $24$ years in 1920 to $62$ years, while in China, it rose from $41$ in 1950-1955 to $70$ in 1995-1999.

Marital fertility began to decline in most European provinces between 1890 and 1920.
Economic theories suggest couples aim for a certain number of surviving children.
Improvements in child survival influence parental decisions to invest more in fewer children.
Technological progress and increasing capital raise the value of time, making children more costly.
Rising incomes shift consumption demand toward nonagricultural goods/services, increasing the economic burden of children; educated parents have a higher opportunity cost of child rearing.

Fertility and mortality rates determine population growth.
Convergence in fertility and mortality rates has occurred globally over the past 50 years.

The world's population is expected to rise from 1 billion in 1800 to approximately $9.5$ billion in 2100.
Average life expectancy is expected to double or triple, and the median population age is projected to double from the low 20s to the low 40s.
Many developed countries are experiencing negative population growth rates.
Family structures are evolving, with fewer children and more adult years available for other activities.
Increased joint survivorship of couples and denser intergenerational kin networks