Chapter 7 The Human Population

The Environmental Implications of China’s Growing Population Human population size, affluence and resource consumption Example – China Current population estimate: 1.35 billion What has China done?  One Child Policy CONTROVERSIAL!! Successful in reducing fertility rate As China’s standard of living improves…

Human Population Exponential growth and limiting factors

Scientists Disagree on Earth’s Carrying Capacity Thomas Malthus Concluded? What is carrying capacity of humans? Graphs show theoretical models of food supply and population size

Projecting Future Populations Population clock: http://www.census.gov/popclock/ Population is increasing Growth rate (r) has started to decline Projections for 2050 Low = 7.7 billion High = 10.6 billion Most likely = 9.1 billion

Factors that Drive Human Population Growth Demography- the study of human populations and population trends Changes in Population Size Fertility Life Expectancy Age Structure Migration

Changes in Population Size Factors that increase a population: Factors that decrease a population: If inputs are greater than outputs, population goes up In human history

Changes in Population Size Let’s look at immigration and emigration first… Difference… Net migration rate – be able to calculate!! Positive net migration vs. Negative net migration Important to still look at where they are going

Changes in Population Size Crude birth rate (CBR) Crude death rate (CDR) Some important formulas: Global population growth rate = (CBR- CDR)/ 10 National population growth rate = [(CBR+ immigration) - (CDR + emigration)] / 10 Doubling time (in years) = 70/ growth rate

Fertility ~ Terminology Total fertility rate (TFR)- an estimate of the average number of children that each woman in a population will bear Replacement level fertility- the total fertility rate required to offset the average number of deaths in a population and for the current population size to remain stable

Fertility and HDC vs. LDC Developed countries- countries with relatively high levels of industrialization and income Replacement level fertility? Developing countries- countries with relatively low levels of industrialization

Fertility ~ TFR Influences Major influences on total fertility rate Cultural traditions Social & economic status of women Education of women Family planning Government Policies

Fertility ~ TFR Influences Cultural Traditions Culture influences and controls individuals’ behaviors Gender- important part of culture Marriage age Family size expectations High infant and child mortality rates Children often work in family business (gender) Religious values

Fertility ~ TFR Influences Social & Economic Status of Women Gender inequality is common worldwide  lead to higher TFR Disparities Political participation Education Social status Economic status Legal rights Employment and earnings

Fertility ~ TFR Influences Education Link between education and TFR.. Why? Control of fertility Women with more education Marry later Have fewer children Spouse as partner

Fertility ~ TFR Influences Family Planning Family planning- the regulation of the number or spacing of offspring through the use of birth control Focus on maternal and child health Difficulties - Gender inequality and cultural constraints Examples of family planning campaigns: Kenya Thailand

Fertility ~ TFR Influences Government Policies and Fertility Government involvement includes: Determine the minimum age people may marry Amount of compulsory education Budgets for family planning services, education, health care, old-age security, incentives for smaller or larger family size Tax structure- additional charges or allowances based on family size 78 developing countries have recognized they must limit population growth in recent years Most common example – CHINA India, Nigeria, Europe

Life Expectancy Life expectancy- the average number of years that an infant born in a particular year in a particular country can be expected to live Resource consumption? Reported in 3 ways: Overall population Males only Females only

Life Expectancy - Factors Infant mortality rate Child mortality rate IMR and CMR may be drastically different for a portion of a population

Life Expectancy – Factors CDR and life expectancy not directly linked When you have a higher number of elderly in a population, CDR is higher Disease helps to regulation human population In the past – TB and malaria were biggest threats Now – HIV

Age Structure Age structure diagrams- visual representations of age structure within a country for males and females Aka: population pyramids Generalized:

Age Structure Population momentum – continued population growth that does not slow in response to growth reduction measures

The Demographic Transition Theory of the demographic transition - as a country moves from a subsistence economy to industrialization and increased affluence, it undergoes a predictable shift in population growth Does not adequately describe population growth patterns Industrial activity does not link to population size

The Demographic Transition

The 12 Most Populous Countries in the World

Economic Development Population disparity between rich and poor counties has accelerated in recent decades

Ecological Footprints Affluence - having a lot of wealth such as money, goods, or property

The IPAT Equation IPAT – estimates the impact of human lifestyles on Earth Conceptual representation Formula: I = PAT I – environmental impact P – population A – affluence T – technology Some use “destructive technology” instead of technology

Local, Global and Urban Impacts Impacts can occur on multiple scales (region/city, country, global) Local impacts: Can lead to overuse or resources and environmental degradation Global impacts: Examples: reduction in atmospheric CO2 uptake

Urban Impacts Urban area – one that contains more than 1000 people per square mile More than 75% of people in developed countries Challenges to environment

The Impact of Affluence Gross domestic product (GDP) - the value of all products and services produced in a year in that country Made up of consumer spending, investments, government spending, and exports minus imports Country’s GDP and pollution levels Why is this important?  best way to save environment: Rising income = falling birth rates Can afford environmental improvements / increased efficiency of resources

Sustainable Development is a common, if elusive goal Many people believe we cannot have both economic development and environmental protection So how can sustainable development be achieved? Millennium Ecosystem Assessment project (2005) – global analysis of effects of human population on ecosystem services (clean water, forest products, natural resources) and offer a blueprint for sustainable development Conclusions…