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?
Environmental geology is the study of the affect of geological processes on society, and how society impacts the Earth. 2004 Indonesia Tsunami Global Warming http://mendocoastcurrent.files.wordpress.com/2009/11/climate change2.jpg http://www.masternewmedia.org/images/before_after_tsunami_2004_500.jpg
The Earth s growing population is spilling into more vulnerable landscape, and requiring more resources. http://seattletimes.nwsource.com/html/localnews/2009889867_levees18m.html http://www.malaysiaairlinesblog.com/pt/uploads/october%202009/diwali%20celebrated%20the %20North%20Indian%20culture/Giant%20traffic%20jam.jpg
Relative distribution of the world s population http://www.geohive.com/earth/gen_popsize.aspx
Relative distribution of the largest countries http://www.geohive.com/charts/pop_graph1.aspx
Population Density of the World http://svs.gsfc.nasa.gov/vis/a000000/a002900/a002912/ How does the population density relate to plate boundaries?
Populations are concentrated in cities Mexico City http://farm1.static.flickr.com/24/45181212_f642cc839e.jpg
Population densities with respect to geologic hazards 1985 Earthquake (Mag 8.1) Mexico City http://farm1.static.flickr.com/24/45181212_f642cc839e.jpg
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.93-109, 2002 http://www.ldeo.columbia.edu/~small/popvol.html
Volcanoes, earthquakes, and tsunamis in Indonesia http://www.ldeo.columbia.edu/~small/popvol.html
Floods in Bangladesh http://sedac.ciesin.columbia.edu/gpw/maps/lecz/bangladesh_10m_lecz_and_population_density.jpg
Earthqakes in Japan
http://earthobservatory.nasa.gov/iotd/view.php?id=7052
Population densities with respect to coastal hazards
Washington Population Density (2000) State population: 6,668,200 as of April 1, 2009 4.1 million people in the Puget Sound http://www.ofm.wa.gov/pop/popden/colormap.asp
Washington Population Density (2000) Major Faults in the Puget Sound 4.1 million people in the Puget Sound http://www.ofm.wa.gov/pop/popden/colormap.asp http://www.geophys.washington.edu/seis/pnsn/info_general/fig.pug_flts.gif
Washington Population Density (2000) Seismic Hazards 4.1 million people in the Puget Sound http://www.ofm.wa.gov/pop/popden/colormap.asp http://kula.geol.wwu.edu/rjmitch/seattle_hazard.pdf
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 = 0.006 or 0.6 % in the USA Due to immigration and emigration the overall growth rate is 0.9% in the USA
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
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
Doubling Time Take the natural log of 2: ln(2) = 0.693 or 0.70 Since G is in %, multiply 0.70 by 100: 70 = GT Solve for time (T): T = 70 G
Doubling Time The textbook uses D for time, hence: D = 70 G G is the growth rate in %
Doubling Time For example, the world growth rate is currently 1.13% D = 70 1.13 = 62 years Assuming that the world growth rate follows an exponential function, then our current population of 6.870 billion will double to 13.74 billion in about 62 years!
Projected World Population http://www.census.gov/ipc/www/idb/worldpopgraph.php
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
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
But, the current USA growth rate is about 0.97% http://www.npg.org/assets/images/usprojgrowth.jpg
http://www.census.gov/ipc/www/idb/worldpopgraph.php
http://www.xist.org/charts/pop_graph3.aspx
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
6,870,000,000 x 9 = 61,830,000,000 square feet
6,870,000,000 x 9 = 61,830,000,000 square feet 5280 x 5280 = 27,878,400 square feet = 1 square mile
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
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
The world s population would fit in Whatcom County!
Space isn t the limiting factor for growth.
.our impact on the Earth and recourse availability limits growth. ecological footprint http://www.mfe.govt.nz/publications/about/environz/environz-mar08/images/ecological-footprint-illustration.jpg
Sustainability is the balance between population, economic growth, and the carrying capacity of the Earth Carrying Capacity
Sustainable Development Economy Energy recourses Water supplies Cropland and food supplies Waste storage Environmental impacts
http://www.mint.com/blog/wp-content/uploads/2009/06/mint-consumption-map.png