redOrbit Staff & Wire Reports – Your Universe Online
Economic factors, rather than medical or cultural influences, will have the greatest impact on global population levels over the next decade, according to a recent University of Missouri College of Arts and Science (COAS) study.
According to United Nations figures, the Earth´s population could exceed 8 billion people by the year 2023 if current trends continue.
But improvements in economic development, such as higher educational attainment, increasing employment levels and the shift away from agriculture have a powerful effect in raising standards of living, and correlate with declining fertility rates, said study leader Mary Shenk, assistant professor of anthropology at University of Missouri (MU).
Understanding these causes of declining birth rates may lead to improved policies designed to reduce competition for food, water, land and wealth, she said.
The study also found that intervention programs to reduce fertility rates had a profound effect, and achieved the best results.
“For example, although advertising campaigns encouraging lower fertility may reach a wider audience for less money, face-to-face intervention campaigns providing health services or access to contraception provide better results and are thus a better use of resources,” said Shenk in a statement.
The researchers used data collected since 1966 from approximately 250,000 people in rural Bangladesh, along with detailed interviews of nearly 800 women from the region.
Sixty-four factors related to family size were considered and organized according to three possible explanations for declines in fertility rates:
- Risk and mortality — according to this theory, parents have fewer children when they have more hope that their children will survive into adulthood.
- Economic and investment — This explanation suggests that rising costs of children and higher payoffs to investing in self and children reduce fertility with the shift to a market economy.
- Cultural transmission — This concept holds that social perceptions of the value of children, ideal family size and acceptance of contraception influence fertility rates.
Using custom-designed data collection and statistical methods, Shenk and colleagues found that “economic and investment” factors were most clearly correlated with lower fertility.
However, the three explanations were interlaced, she noted.
And while economic factors were significantly more influential, other issues such as mortality rates and health interventions also affected fertility decline in Bangladesh.
“Few studies have compared those three possible explanations for fertility declines to determine which had the strongest effect,” Shenk said. “Population growth rates have fallen globally, starting in 18th century Western Europe, but the exact cause was intensely debated because there are so many different explanations in the literature. Our study created a framework by which different explanations could be explicitly compared.”
Shenk said population data from any region could be analyzed using the methods employed in her study, which could help researchers, policymakers, health workers and others understand the key drivers of demographic change in many areas of the world.