Human Population Dynamics

US –310,241,523 (Net gain of 1 person every 11 seconds) World –6,868,672,761 Current Population

2000 years ago Historical Population Sizes

World Population Distribution

World Population Density

Historical Population Sizes

Historical Population Changes 3 surges in population –Tools and fire –Agricultural Revolution –Industrial and Medical Revolution

Rapid growth in past ~100 years due to decrease in death rate –Increased nutrition (more food, better distribution) –Improvements in medical technology –Improvements in sanitation and personal hygiene –Safer water supplies Recent Population Changes

Change = (crude birth rate + immigration) – (crude death rate + emigration) % change = (crude birth rate - crude death rate)/10 Current world growth rate = 1.1% –Increase of 76 million per year Population Change

High income, highly developed Middle income, moderately developed (upper & lower) Low income, developing Different Worlds

Putting it in Perspective

Replacement Level Fertility (RLF) –Couple has enough children to replace themselves –RLF = 2.1 required to replace each generation Total Fertility Rate (TFR) –Total number of children a woman will have in her life Fertility Rates

CountryTFRDoubling Time (years) World2.854 Developing Countries3.144 Niger7.523 Brazil2.254 Developed Countries US Germany Fertility Rates

What if TFR < 2.1? –Population decline –Population aging In US, 66% of growth by 2050 from immigrants and their descendants Fertility Rates

Growth rate has decreased However, population still increasing - rapidly Growth Rate

950 CE to years 1600 to years 1800 to years 1925 to years 1975 to years Doubling Time

If a population has a growth rate of 2.0%, what is its doubling time? If a population has a doubling time of 14 years, what is its growth rate? Calculating Doubling Time

Population Projection

Population Profiles

Demographic Transition Process occurring during last ~100 years Stabilization of population growth in highly developed nations

Factors influencing transition Demographic Transition

Phase I –Common Characteristics? –NET RESULT = Countries? –Brazilian tribes?

Demographic Transition Phase II –Common Characteristics? –NET RESULT = ex. Nepal, Afghanistan, Sub-Sahara Africa –Niger –Burundi –Tanzania

Demographic Transition Phase III –Common Characteristics? –NET RESULT = Ex. China

Demographic Transition Phase IV –Common Characteristics? –NET RESULT = Ex: US, England

Phase V? –Characteristics? –Consequences? Ex: Japan, Germany Demographic Transition