Lecture 1: Population and Sustainability Key Questions

Transcription

1 Lecture 1: Population and Sustainability Key Questions 1. How is the population growth rate determined? 2. What is an exponential growth rate? 3. Is the population currently rising exponentially? 4. What countries have the highest population growth rate? Lowest? 5. Where are population densities with respect to natural hazards? 6. What is sustainability? 7. Is our population and life style sustainable?

2 Environmental geology is the study of the affect of geological processes on society, and how society impacts the Earth Indonesia Tsunami Global Warming change2.jpg

3 The Earth s growing population is spilling into more vulnerable landscape, and requiring more resources. %20North%20Indian%20culture/Giant%20traffic%20jam.jpg

4

5 Relative distribution of the world s population

6 Relative distribution of the largest countries

7 Population Density of the World How does the population density relate to plate boundaries?

8 Populations are concentrated in cities Mexico City

9 Population densities with respect to geologic hazards 1985 Earthquake (Mag 8.1) Mexico City

10 Population densities with respect to geologic hazards In 1990 about 8.8% (455 million people) of the world's population lived within 100 km of an historically active volcano. And 12% lived within 100 km of a volcano believed to have been active during the last 10,000 years (the Holocene Epoch). Small, C and T. Naumann. Environmental Hazards, v.3, p ,

11 Volcanoes, earthquakes, and tsunamis in Indonesia

12 Floods in Bangladesh

13 Earthqakes in Japan

14

15 Population densities with respect to coastal hazards

16 Washington Population Density (2000) State population: 6,668,200 as of April 1, million people in the Puget Sound

17 Washington Population Density (2000) Major Faults in the Puget Sound 4.1 million people in the Puget Sound

18 Washington Population Density (2000) Seismic Hazards 4.1 million people in the Puget Sound

19 World Population Growth Rate Birth Rate = number of births per 1000 per year (14 in the USA) Death Rate = number of deaths per 100 per year (8 in the USA) Natural Growth Rate = birth rate death rate 14 8 = 6/1000 = or 0.6 % in the USA Due to immigration and emigration the overall growth rate is 0.9% in the USA

20

21

22

23

24 Exponential Growth Rate P = P o e GT P = future population P o = current population G = growth rate (%) T = time in years e = base of the natural logarithm, where ln(e x ) = x

25 Doubling Time Doubling means that: Therefore: P P o = 2 P = P o e GT P P o = e GT 2 = e GT Take the natural log of both sides: ln(2) = GT

26 Doubling Time Take the natural log of 2: ln(2) = or 0.70 Since G is in %, multiply 0.70 by 100: 70 = GT Solve for time (T): T = 70 G

27 Doubling Time The textbook uses D for time, hence: D = 70 G G is the growth rate in %

28

29 Doubling Time For example, the world growth rate is currently 1.13% D = = 62 years Assuming that the world growth rate follows an exponential function, then our current population of billion will double to billion in about 62 years!

30

31 Projected World Population

32

33 Exponential Growth Rate P = P o e GT P = future population P o = current population G = growth rate (%) T = time in years e = base of the natural logarithm, where ln(e x ) = x

34 Exponential Growth Rate P = P o e GT P = 310,593,000 (current USA population) P o = 268,951,000 (Jan 6, 1998, 13 years ago) T = 13 Solve for G ln(p/p o ) G = = 1.11% 13

35 But, the current USA growth rate is about 0.97%

36

37

38

39

40 If each person on Earth is given 9 square feet to stand on, how much space on Earth would 6.87 billion people take up? 9 sq-ft 3 ft 3 ft

41

42

43

44 6,870,000,000 x 9 = 61,830,000,000 square feet

45 6,870,000,000 x 9 = 61,830,000,000 square feet 5280 x 5280 = 27,878,400 square feet = 1 square mile

46 6,870,000,000 x 9 = 61,830,000,000 square feet 5280 x 5280 = 27,878,400 square feet = 1 square mile 61,830,000,000 27,878,400 = 2218 square miles

47 6,870,000,000 x 9 = 61,830,000,000 square feet 5280 x 5280 = 27,878,400 square feet = 1 square mile 61,830,000,000 27,878,400 = 2218 square miles Whatcom County is 2120 square miles

48 The world s population would fit in Whatcom County!

49 Space isn t the limiting factor for growth.

50 .our impact on the Earth and recourse availability limits growth. ecological footprint

51 Sustainability is the balance between population, economic growth, and the carrying capacity of the Earth Carrying Capacity

52 Sustainable Development Economy Energy recourses Water supplies Cropland and food supplies Waste storage Environmental impacts

53

54

55

56

57