Passage 24 A #1

Fugo TAKASU, Dept. Environmental Science, Nara Women' s University
takasu@es.nara-wu.ac.jp

Aim of this course

Overview the history of the world population - how many people lived on the earth in the past? 
Learn to describe how the world population will change using simple mathematics.
This course is also an introduction to human demography.

What is demography?

Demography is a science of population. A population consists of a certain number of individuals of the same biological species (e.g., Homo sapience as human being, biological species, etc.). Population size, or the number of individuals, changes with time by birth, death, and immigration in and emigration out. Demography focuses on social, economical, cultural, and biological aspects of populations.

Why do we study demography?

Consider why?

The World Population now

The world population has reached 7.3 billion in 2015 and it is sill increasing. Now in 2019, it is over 7.6 billion.
http://www.census.gov/popclock/world

The World Population in the past

Since 2000 years ago

Data from Wikipedia “World population” (https://en.wikipedia.org/wiki/World_population). Population size is in million.

dataYearPopSize={{0,200},{1000,400},{1500,458},{1600,580},{1700,682},{1750,791},{1800,1000},{1850,1262},{1900,1650},{1950,2525},{1955,2758},{1960,3018},{1970,3682},{1975,4061},{1980,4440},{1985,4853},{1990,5310},{1995,5735},{2000,6127},{2005,6520},{2008,6764},{2010,6930},{2012,7097.5},{2015,7349}}

ListPlot[dataYearPopSize,Joined->True,PlotMarkers->Automatic,PlotRange->{0,8000},AxesLabel->{"Yesr","Pop size in million"},ImageSize->500]

The World Population in future

Since 1950 to Future projection of the world population

Estimates and projections are available at the United Nations web site:
https://www.un.org/en/development/desa/population/index.asp
https://population.un.org/wpp/

Questions

How did the worl population change in the past?
How can we estimate the world population?
What is annual growth rate (%)?
How will it change in future? How can we predict it?

Reference

How many people can the earth support? J E Cohen. 1995. W W Norton & Company, New York.
Population: An introduction to concepts and issues 8th edition. John R Weeks. 2002. Wadsworth Groups.
Lecture by Prof. J E Cohen at the Floating University: http://www.floatinguniversity.com/lectures-cohen
Youtube: https://www.youtube.com/watch?v=2vr44C_G0-o