Human Population Growth and Its Impact

Human Population Growth

• Most important issue facing conservation
• 6 billion people in 2001, 8 billion in 2024
• 83% of the world’s population lives in Asia, Africa, and Latin America
• Human overpopulation directly destroys wildlife habitat and agricultural lands
• Human populations are exceeding carrying capacity in some places
• Major warning to slow human population growth

Problems Due to Overpopulation

• Famine: Somalia, North Korea
• War: Darfur, Sudan
• Erosion and loss of farmland: Indonesia
• Water and air pollution: First and Third World
• Land conversion and habitat loss: Brazil
• Resource extraction: Nigeria

Demography

• Study of human population growth and its consequences
• Social, political, economic, and ethical factors influence population growth

Metrics to Measure Population Growth

• Population density: Number of people per unit area
• Total fertility rate (TFR): Number of children born per woman in her lifetime
• Replacement fertility: TFR of 2.1 replaces parents
• Goal: Balanced population growth where natality (births) equals mortality (deaths)
• This does not mean zero reproduction, just a balance between birth and death rates
• Age distribution: Number of people in different age classes; difficult to stabilize

Malthus Box

• Predicted exponential human population growth but only linear increase in agricultural production
• War, famine, disease, and natural disasters were limiting factors on human populations
• Two medical advances changed this: contraception and agricultural advances
• Critics argued that behavioral and technological changes would negate these effects

Social Factors

• Developed countries have low fertility and growth rates, while underdeveloped countries have the opposite.
• Factors influencing fertility rates include cultural, economic, and religious beliefs.
• Status of women in society plays a significant role.
• Higher education levels for women are directly related to lower fertility rates.
• Access to contraceptives is important.
• Attitudes towards family size are crucial.
• The number of children often exceeds desired family size.

Political Factors

• Population growth and immigration policies vary.
• Some countries offer incentives to have children (Europe and Japan).
• These incentives are misguided as they necessitate re-engineering of government services due to insufficient child labor laws.
• Most countries seek to limit population growth.

China

• Encouraged population growth in the 1950s which led to a population nearly doubling despite war, famine, and revolution (high mortality).
• Trying to reverse this trend with a population of 1.5 billion.
• Solutions include education and contraception.
• Implemented the “Later-Longer-Fewer” campaign and a one-child limit with incentives.
• Achieved stabilization over the last 10 years.
• Recent reversal of the LLF policy has had disastrous consequences.

India

• Faced historical difficulties with poverty and lack of education.
• Cultural and religious beliefs continue to impact population growth.
• Significant improvements in recent years with a TFR reaching approximately 2.1.
• Achieved success through birth control, sterilization incentives, cultural shifts, egalitarian access to healthcare, and reduced infant mortality rates.

Brazil

• Reduced TFR from over 6 to 3 over a 40-year period.