Introduction: Class Overview + 10,000 Years of World Population. Economic Demography (econ/demog c175) Prof. Josh Goldstein Spring 2018, Lecture 1

Transcription

1 Introduction: Class Overview + 10,000 Years of World Population Economic Demography (econ/demog c175) Prof. Josh Goldstein Spring 2018, Lecture 1

2 Today s agenda 1. Some motivation: demographic surprises 2. Format of class Semester plan Work and grading Resources 3. Humanity s past and future A very brief history of humanity The exponential growth model econ 175 (Goldstein) 2

3 Demographic surprises econ 175 (Goldstein) 3

4 Longer life, beyond anyone s guess 95 Life expectancy in years Australia Iceland Japan The Netherlands New Zealand non-maori Norway Sweden Switzerland UN World Bank Olshansky et al. UN Fries, Olshansky et al. Coale Coale & Guo World Bank, UN Bourgeois-Pichat, UN Siegel Bourgeois-Pichat UN, Frejka Dublin Dublin & Lotka Dublin Year Fig. 1. Record female life expectancy from 1840 to the present [suppl. table 2 (1)]. The linear-regression trend is depicted by a bold black line (slope = 0.243) and the extrapolated trend by a dashed gray line. The horizontal black lines show asserted ceilings on life expectancy, with a short vertical line indicating the year of publication (suppl. table 1). The dashed red lines denote projections of female life expectancy in Japan published by the United Nations in 1986, 1999, and 2001 (1): It is encouraging that the U.N. altered its projection so radically between 1999 and Oeppen & Vaupel (2002) econ 175 (Goldstein) 4

5 A drop in births in high fertility USA 2.10 total fertility rate year econ 175 (Goldstein) 5

6 Very low fertility around the world Source: United Nations e-maps_tf.htm econ 175 (Goldstein) 6

7 The end of poverty? econ 175 (Goldstein) 7

8 Fights over marriage econ 175 (Goldstein) 8

9 Not just because younger generation s attitudes are changing econ 175 (Goldstein) 9

10 At same time, childbearing and marriage less tightly linked For Hispanic and White women 60-70% of unmarried births to cohabitors. econ 175 (Goldstein) 10

11 Increase in immigrant education

12 The (im)possibility of work-life balance? econ 175 (Goldstein) 12

13 Dramatic population aging Japan 2000 Japan 2050 econ 175 (Goldstein) 13

14 The end of world population growth? Source: Lutz et al. (2001) The end of world population growth Nature 412:543-5 econ 175 (Goldstein) 14

15 Format of Class Details are in syllabus on bcourses Please read the fine-print

16 Plan for semester Part 1: Macro-demography (how population matters) Grand theories (optimum population, Malthus, neo-classical growth, Boserup) Demographic Transition Population Aging Population and Environment Part 2: Micro-demography (behavior and determinants of population) Marriage and the family Fertility Migration Mortality econ 175 (Goldstein) 16

17 Course requirements Class attendance Reading Weekly labs (23%) + Piazza (2%) Exams: mid-term (30%) and final (45%) econ 175 (Goldstein) 17

18 Active classroom Dos Take part in in-class activities. Raise your hand, volunteer for demo,... Take notes (pen and pencil) Ask questions; argue, query, contradict! Tell me if too fast, unclear, too quiet,... Don'ts No cell phones ("negative externalities") No laptops* * (unless in front row) econ 175 (Goldstein) 18

19 Labs Most weeks computing labs with real data and simulations We re going to be using R and Rstudio Don t worry if you don t know R or haven t had statistics. We are going to build gradually. Goal of labs is to learn economic demography, but a nice side-effect will be to learn R. econ 175 (Goldstein) 19

20 Labs (grading) Electronic submission of graded portion (gradescope) No late submissions We will drop your lowest 2 grades (low stress). Can work together on problem sets, but you (1) must acknowledge the names of your collaborators. And (2) you must write up your answers by yourself. An optional independent lab, for you to to extend one of our labs in your own way.

21 Lab #1 Due Monday, Jan 22, 10 p.m. Is shorter than others. Main purpose is to introduce you to our computing system Everyone registered receives automatic with temporary password and instructions. Please contact Dr. Carl Mason by Friday noon with any account problems. Special help session this Friday, Jan 19, at 2232 Piedmont from 2-4.

22 Mid-term and Final Mid-term will be in class Final will be during regular exam time, covers whole semester, but emphasizes 2 nd half. econ 175 (Goldstein) 22

23 Our team (people who can help you) GSIs (I ll introduce in a minute) GSIs will lead several optional sections, hold officehours, and are an excellent first contact Dr. Ellen Langer (erlanger@berkeley.edu), my faculty assistant (Enrollment, CE, getting in touch with me, scheduling a special meeting, ) Dr. Carl Mason (cmason@berkeley.edu) (Computing for our labs) econ 175 (Goldstein) 23

24 GSIs Leslie Root (Head GSI*, bcourses and labs) (TBA) Mia Zhong (Piazza and labs) (Mon 12-2) Gabriel Borges (computing and labs) (Wed 2-4) Carla Johnston (exams and labs) (TBA, Evans Hall) Updated office hours will be on bcourses

25 Traditional Resources Human beings Optional sections (4 or 5 weeks over semester, multiple times in week) Office hours (GSIs and professor) Study Hall at 2232 Piedmont (Friday afternoon) Written word required readings ( pages a week) Available on line, via bcourses econ 175 (Goldstein) 25

26 e-resources Course website (computing & important docs) Piazza econ 175 (Goldstein) 26

27 Questions? Topics? Logistics? Anything else? econ 175 (Goldstein) 27

28 Population Growth The Exponential Model and the History of Humanity econ 175 (Goldstein) 28

29 Class activity: Generational Population Growth We ll simulate generational growth, with each row of class a generation. Everyone in front row gets out a piece of paper. Everyone in class computes generational growth implied by their own family. Let s see what happens. econ 175 (Goldstein) 29

30 Format of sheet Generation # of kids per parent cumulative product N N/2 multiply econ 175 (Goldstein) 30

31 Discussion What happened? If we shift order of generations, would it matter? Is this a good statistical estimate of your parent s generations growth rate? What might be wrong? econ 175 (Goldstein) 31

32 World Population Growth An overview of all of humanity s past and its future

33 World Population Size Year Millions Growth rate (persons per yr) (%) -8, , ,218 Source of Pop. Estimates: Weeks econ 175 (Goldstein) 33

34 World Population Size Year Millions Growth rate (persons per yr) (%) -8, k k k k ,160k ,000k ,080 75,000k ,218 econ 175 (Goldstein) 34

35 World Population Size Year Millions Growth rate (persons per yr) (%) -8, k ~ k ~ k k ,160k ,000k ,080 75,000k ,218 econ 175 (Goldstein) 35

36 Which should we model? The change in absolute numbers OR The proportional change? econ 175 (Goldstein) 36

37 Calculating exponential growth rate Exponential Model N( t ) = N(0) e Rt To rewrite in terms of R, take natural logs ("ln") and rearrange log N(t ) = log N(0) + R t R = [ log N(t ) log N(0) ] / t This is slope (rise-over-run) of graph of logarithm of population econ 175 (Goldstein) 37

38 Seeing World Population Growth Original scale Log-scale Pop (millions) log of Pop (millions) Year Year What is average exponential growth rate over last 10,000 years? Has the growth rate been constant or increasing? econ 175 (Goldstein) 38

39 Conclusions Most of human history, no population growth Then, a period of accelerating growth rate Most recently, slowing growth rate (Future of humanity depends on pace of this slowing) Understanding each of these phases is one of our goals, beginning next week with Malthus. econ 175 (Goldstein) 39

40 For Thursday 1. Log in to our 175Rstudio server and change your password 2. Read Carl Mason s Rstudio175 instructions at nstructions/rstudio175.pdf 3. Can bring your laptop for crash test 4. Do the Sauvy reading [available at bcourses]