The Real Wealth of NationsPaul Sutton
The Real Wealth of Nations
Mapping and MonetizingBio-Capacity and the Human Ecological Footprint
― by Paul C. Sutton
Introduction
Problem
Following the publication of Aldo Leopold’s ‘A Sand County Almanac’ in 1949, Rachel Carson’s ‘Silent Spring’ in 1962, and Paul and Anne Ehrlich’s ‘The Population Bomb’ in 1968, the early 1970’s were a time of rapidly expanding consciousness of issues associated with environmental degradation and human responsibility for those impacts on the environment. In 1969 the Cuyahoga river in Cleveland Ohio actually caught on fire and there was a significant oil spill in the Santa Barbara Channel. These events likely contributed to precipitating the first ‘Earth Day’ celebration in 1970. Approximately one year after the first ‘Earth Day’ celebration, Paul Ehrlich and John Holdren published an important conceptual paper titled: Impact of Population Growth. This paper postulated an oft-cited equation: I=P*A*T (where ‘I’ is Impact, ‘P’ is Population, ‘A’ is Affluence, and ‘T’ is Technology.
Questions about human impact on the environment remain with us today and are perhaps even more pressing in light of global climate change, peak oil, and the rapid loss of biodiversity. These questions are often framed within the broader context of “Sustainability”. In a strictly bio-physical sense, ‘sustainability’ is perhaps a more palatable way of expressing the idea of ‘Carrying Capacity’. The Carrying Capacity of the earth is the number of human beings that can be sustained indefinitely by the Earth’s natural endowment. This laboratory exercise will explore several questionsrelated to sustainability and carrying capacity by mapping and monetizing both human ‘Impact’ on the earth; and, mapping and monetizing the earth’s ‘ecosystem services’ or ‘natural endowment’ as measured by photosynthesis (aka Net Primary Productivity or NPP). You will then use these maps to determine what countries are beyond their ‘carrying capacity’ (The ‘real debtor nations’); and, which countries are below their ‘carrying capacity’ (The ‘real surplus nations’). In addition you will calculate a dollar value of these national ‘debts’ and ‘surpluses’:
1)“How could I map and assign a dollar value to the human impact on the environment at a global scale?”
2) “How can photosynthesis (as measured by NPP) be used to assign a spatially explicit dollar value to the earth’s natural endowment?”
3) “What is the difference between human impacts and natural endowments for the countries of the world?”
Location
The geographic scope of this laboratory exercise is global.
Time to complete the lab
Completion of this laboratory exercise should take 2-3hours.
Prerequisites
An understanding of elementary GIS (preferably ArcMap), and basic statistics and mathematics.
Keywords
Topical: (Ecological Footprint; Carrying Capacity; Impervious Surface, DMSP OLS, nighttime satellite imagery, population density, Net Primary Productivity, Ecosystem Services).
GISc: Concepts / tools / techniques used (raster calculator, cell based modeling, zonal statistics, Table Joins, Field Calculations, Table Sorting) and types of data used (grids and polygons).
Data used in this lab
National boundaries of the world’s countries (ESRI)
Global Grid of Impervious Surface Area (National Geophysical Data Center of NOAA)
Global Map of Net Primary Productivity(SEDAC CIESIN at Columbia University)
Geographic coordinate system:GCS_WGS_1984
Datum: D_WGS_1984
Projection: Geographic Coordinate System
Data must have no copyright restrictions; otherwise, please provide data sources and permissions using the ESRI Press Copyright Permissions Form.
Student activity
The Brundtland Report of the World Commission on Environment and Development
The term “Sustainable Development” was first put forth in 1983 by the World Commission on Environment and Development (WCED). The chair of this commission was a woman named Gro Harlem Brundtland whose minor accomplishments include serving three-times as the Prime Minister of Norway and as Director General of the World Health Organization. The Brundtland Report coined the notionthat “Sustainable Development is development that meets the needs of the present generation without compromising the ability of future generations to meet their own needs”. Many would argue that this idea of “sustainability” is brilliantly vague while others would argue that this ambiguity makes it practically useless (answer Q1).
You will explore the idea of ‘sustainability’ using global maps of photosynthesis and impervious surface and a Geographic Information System (GIS). The earth provides many ecosystem services or 'benefits' that enable and enhance human existence. Humanity, in turn, imposes myriad environmental impacts or 'costs' on the earth. You will explore the idea of mapping these 'costs' and 'benefits' using proxy measures. You will set the total value of the world's ecosystem services to be equal to the total cost of anthropogenic environmental impacts at fifty trillion dollars (roughly the global GDP in the year 2000). A global representation of ecosystem service value is mapped at 1 km2 resolution using Net Primary Productivity (NPP) as a proxy measure of ecosystem service value. A similar global representation of environmental impact is mapped using pavement (i.e., anthropogenically created impervious surface area or ISA) as a proxy measure of 'cost'. Subtracting the 50trillion mapped onto ISA from the 50 trillion mapped onto NPP produces a1 km2 resolution map of those areas where: 1) Human imposed costs exceed naturally supplied benefits, resulting in an ecological deficit, 2) Human costs balance with environmentalbenefits, and 3) Environmental benefits exceed human costs, resulting in an ecological surplus. Mapping this ecological balance produces a spatially explicit and monetized representation ofsustainability that can be aggregated to national levels. A potential benefit of this methodology for mapping and monetizing sustainability is the idea that the national values derived from this difference mapsuggest a starting point for discussions of the dollar values and costsof both sustainable and non-sustainable behavior on the part of thenations of the world.
Mapping and Monetizing Human Impact on the Environment
Start ArcMap by either clicking on the icon on the desktop or by going to ‘Start’ > ‘All Programs’ > ‘ArcGIS’ > ‘ArcMap’. Open the mxd titled: Wealth_of_Nations.mxd (mxd is the filename extension for an ArcMap map document). If you are successful in opening the file you should get a window that looks something like the image below (Figure 1). This map document contains four raster layers and a vector layer of the world’s national boundaries. The layer called ISA_world has cell values that vary from 0-100 for all of the land area. The value in these cells represent what fraction of the land has been converted to impervious surface by human activity. Now is a great time to explore your data. The layers are displayed so that areas with zero % impervious surface are clear and you can see through to the Net Primary Productivity layer. Pan and zoom around the world to study the patterns of pavement and photosynthesis (answer Q2).Right click on the layer titled: isa_world and choose ‘Open Attribute Table’. Thisopens the ‘Value Attribute Table’ of the ISA_world layer. The ‘Value’ column is the pixel or grid cell value whereas the ‘count’ column is the number of cells with that particular ‘value’. So, upon inspection of the table you should be able to see that there are 312,916 cells that have 6% impervious surface. Now export this table using the ‘Options’ > ‘Export’ utility of ArcMap. You will choose a location on your hard drive to save a table that you can name or you can accept the default name of ‘Export_output.dbf’. Read your table into a spreadsheet or statistics package (e.g. MS Excel or JMP) and use what you know about the ‘Value Attribute Table’ to calculate an ‘Impact Conversion Factor’ that you can multiply the ISA_world grid by to have the total sum of all of it’s pixels be 50 trillion dollars (answer Q3). The monetized ‘Impact’ layer has already been created for you because this takes some time for ArcMap to do. The layer titled ISA_500B is a monetized impact layer that was created by multiplying the isa_world layer by 7,290. The total sum of all the pixels in the ISA_500Bis 500 billion.
The layer titled isa_500b is a monetized version of the impervious surface area of the world that sums globally to a total value of 500 Billion. Use the Zonal Statistics function to add up all the ‘impact’ of human activity as measured in dollars for each country of the world. Go to ‘Spatial Analyst’ > ‘Zonal Statistics’ and fill out the dialog box using World_Countries as your zone dataset, CNTRY_NAME as your zone field, and isa_500b as your Value raster (Figure 2). In a minute or two after clicking ‘OK’ you should get a table that has added up all the grid cells of isa_50b in each country of the world. A table similar to the one below should be displayed. The columns have the following meanings: Count (# of pixels in that country), Area (areal extent of country in square meters), MIN (lowest isa_50b pixel value found in that country), MAX (highest isa_50b pixel value found in that country), Range (max isa_50b pixel – min isa_50b pixel in that country), MEAN
(average isa_50b pixel value in that country), STD (standard deviation of isa_50b pixel values in that country), SUM (total sum of isa_50b pixel values in that country), Variety (# of different isa_50b pixel values in that country), Majority (most common isa_50b pixel value in that country), Minority (least common isa_50b pixel value in that country), Median (median isa_50b pixel value in that country). You are most interested in the SUM column. The value in the SUM column represents your modeled estimate of the dollar ‘cost’ of human impact on the earth produced by that nation of the world. Minimize the table that you just created (‘Attributes of zstat1’). Where did it go? At the bottom of the table of contents (TOC) click on the ‘Source’ tab. Your table should appear at the bottom of the TOC now. Open the table by right clicking on it and choosing ‘Open’. Let’s use the table manipulation functionality of ArcMap to find out what countries of the world are having the greatest impact on the earth according to our model. Right Click on the ‘SUM’ header of the table and choose ‘Sort Descending’ (answer Q4).
Mapping and Monetizing the Earth’s Natural Endowment
In a manner similar to your production of a monetized ‘Human Impact’ map you will explore a map of monetized ‘Natural Endowment’. Just as we used anthropogenic impervious surface as a proxy measure of human impact on the environment we use photosynthesis as a proxy measure of the earth’s natural endowment. The layer titled npp_world is a map of the net primary productivity of the earth’s land surface from photosynthesis. The cells were modeled at a spatial resolution of ¼ degree by ¼ degree and have units of grams of carbon converted to sugar per year per grid cell.
Photosynthesis is the amazing process by which plants convert sunlight to chemical energy in the form of sugar (CO2 + H2O + light = Sugar and Oxygen – How cool is that?). The idea of ‘Peak Oil’ and our use of fossil fuels has been described by some as ‘The last hours of ancient sunlight’ (there is a book with this very name by Thom Hartmann). There are various ideas as to how the dollar value of the Earth’s ‘Natural Endowment’ could be measured. Ecosystem services are one means by which this can be accomplished. Some examples of ecosystem services arethe earth’s hydrologic cycle purifying water, microbes decomposing waste, and bee’s pollinating crops. Studies that involve the economic valuation of ecosystem services have come up with numbers that exceed the marketed global economy. In other words, the dollar value of the services provided by nature in a given year exceeds the dollar value of all goods and services produced by human activity in that same year. For more information on ecosystem services and their valuation take look at the Daily and Costanza references (answer Q5).
The layer titled npp_500b has been created using a ‘Natural Endowment Conversion Factor’ that was a little more complicated than the ‘Impact Conversion Factor’ because it involved a change in spatial resolution and conversion to a dollar value. In any case, this layer represents the annual flow of ecosystem services across the earth’s land surfaces valued at 500 Billion dollars. Calculate the dollar value of each country’s ‘Natural Environmental Endowment’ using the same ‘zonal statistics’ function that you did for tabulating the dollar value of ‘impacts’ at a national level. You should get a table that looks like the one below (answer Q6). The ‘SUM’ column represents the adding up of all
the cell values of the npp_500b grid layer for each country of the world. Again, click on the ‘SUM’ column and use ‘Sort Descending’ to identify those nations of the world with the greatest ‘Natural Endowment’ as measured by Net Primary Productivity from photosynthesis. Minimize this table. At the bottom of your TOC there should be two tables with names like zstatN1 and zstatN2, where N1 and N2 are two different numbers. Later we will use both of these tables to identify the ‘surplus’ and ‘debtor’ nations of the world with respect to sustainability.
Conducting a National Environmental Cost-Benefit Analysis
By now you should have two tables that have different national statistics in them. Your first table has a ‘SUM’ column that represents the ‘Dollar Cost’ of that nation’s environmental impact as measured by how much of their country they have ‘paved’. Check your table to make sure you have the following values for the following countries (BTW – remember these values are 100 times too low): Brazil - 6.46 x 1010; Canada- 2.58 x 1010; New Zealand - - 6.46 x 109; Portugal - 5.71 x 108. These are dollar values of ‘Natural Endowment’. Your second table has nationally aggregated dollar values of the cost of environmental ‘impact’ as measured by impervious surface. Look at this table and verify that you have the following values for those same countries: Brazil – 13.116 x 109; Canada - 11.68 x 109; New Zealand - 4.40 x 108; Portugal - 1.48 x 109. All of these countries (with the exception of Portugal) are countries in which their ‘Natural Endowment’ is greater than the cost of their ‘Environmental Impact’. To calculate ‘The Real Wealth of Nations’ you can simply
substract the ‘Environmental Impact’ ($ Impact) from the ‘Natural Endowment’ ($ Nature). The table above provides an example for the five countries we have used to check our results for. GIS often provides more than one way to tackle a problem. Tabulating the $Nature - $Impact for all the countries of the world provides a good example of this. The following summarizes two methods by which you can accomplish this tabulation of ‘surplus’ and ‘debtor’ nations.
Method 1 - Table Join and Field Calculation: The first approach is to simply do all of the problem within the tables you have already created. Right Click on the first table you created in the table of contents and choose ‘Joins and Relates’. This should open a dialog box like the one portrayed to the right (Figure 3). When you click ‘OK’ you will have joined the second table to your first table. This new ‘joined’ table will now have two columns titled ‘SUM’, ‘STD’, ‘MAX’ etc. Use the ‘Options’ > ‘Export’ choice to write a table to your workspace. You can ‘edit’ this exported table easily (you can name it whatever you like but ArcMap defaults to names like Export_Output_#.dbf). Right click on the leftmost ‘SUM’ column which you should verify represents you ‘$Impact’ figures and choose ‘properties’. Type ‘$Impact’ in the ‘Alias’ text box. Now right click on the rightmost ‘SUM_1’ column and type ‘$Nature’ in the ‘Alias’ text box. Now choose ‘Options’ > ‘Add Field’ and type ‘Wealth’ in the ‘Name:’ text box and choose ‘Double’ for the type. Click ‘OK’. This creates a column in the table called ‘Wealth’ that you will fill with a simple subtraction calculation ($Nature - $Impact = Wealth). Right click on the column you just created and named ‘Wealth’ and choose ‘Field Calculator’. You should get a dialog box like the one on the right (Figure 4). Here you complete the equation that calculates the values of your column. In this case choose ‘SUM’ – ‘SUM_1’ by double clicking on ‘SUM’ in the ‘Fields’ Choice area above, clicking on the ‘-‘ sign, and then clicking on ‘SUM_1’ , and then clicking ‘OK’. Your ‘Wealth’ column will now contain values that represent the ‘Real Wealth of those Nations’ based on your model of ‘Natural Endowment’ and ‘Human Impact’. Use the ‘Sort Descending’ and ‘Sort Ascending’ options by clicking on the ‘Wealth’ column title. What are the top ten ‘debtor’ nations of the world? What are the top ten ‘surplus’ nations of the world? (answer Q6) Hint: Bangladesh is the 10th largest debtor nations whose adjusted debt (the 100 x fix) is: $599,570,534,400. Argentina is the 10th largest surplus nations whose adjusted surplus is: $740,075,059,200.
Method 2 – Map Algebra and a Raster Calculation: The second way of calculating the ‘Real Wealth of Nations’ is to do the math at the pixel level and then aggregate to the national level using zonal statistics again. To accomplish this go to ‘Spatial Analyst’ > ‘Raster Calculator’ and fill out the dialog box like as done to the right (Figure 5). Once you click on ‘Evaluate’ you will start creating a grid with the ‘debt’ and ‘surplus’ values at the pixel value (this will take a while). The raster calculation will create a temporary grid that is typically called ‘Calculation’. You can save this permanently by right clicking on it and exporting and naming it. For now, lets just use the temporary grid to do our zonal statistics tabulation. As you have done before, chose ‘Spatial Analyst’ > ‘Zonal Statistics’ and use World_Countries as your ‘zone’ dataset, ‘CNTRY_NAME’ as your zone field, and ‘Calculation’ as your value raster. This will produce a table very similar to the one produced in Method 1. As you did in Method 1, Use the ‘Sort Descending’ and ‘Sort Ascending’ options by clicking on the ‘SUM’ column title. What are the top ten ‘debtor’ nations of the world? What are the top ten ‘surplus’ nations of the world? (answer Q7, Q8, and Q9).