Transcription

TG 1-97FINAL.qxd8/3/20041:38 PMPage 84How Big is MyEcological Footprint?Measuring their dependence on nature on a typical day can give studentsa new understanding of the connection between personal lifestyle choicesand the health of the planetby Tim TurnerSubject areas: mathematics,science, social studiesKey concepts: ecological footprint,lifestyle, sustainabilitySkills: lifestyle analysis, criticalthinkingLocation: indoorsTime: 1 hourTim TurnerMaterials: chart paper, coloredmarkers (blue, green, brown,and black), copy of PersonalEco-Footprint Calculator foreach studentach of us consumes someof the Earth’s products andservices every day. Howmuch we take depends on the ways Students calculating their ecological footprints at the Sea to SkyOutdoor School in British Columbia.in which we satisfy our needs andwants — the many habits thatHaving students calculate their ecological footprinttogether create our lifestyle. We can ask ourselves thesegives them a concrete understanding of their own perquestions to get a better sense of what these habits are:sonal impact on the Earth’s systems and offers a meansHow much water do I use on a typical day? What do Iof assessing the sustainability of their lifestyles. Moreeat and how much do I eat? How much food do Ithan that, engaging students in an ecological footprintwaste? How do I transport myself and how far do I go?analysis elicits curiosity, enthusiasm, and genuine interestHow much clothing and footwear do I have and howin taking action to reduce the demand they place onoften do I replace it? What and how much stuff do Inature. Students like the fact that the analysis focuses onbuy? How much energy and materials are required totheir own lives, and they understand its clear message:keep me dry and warm/cool? How much garbage do Ithat their choices — and hence they, themselves — canproduce? How much land and energy is used for mymake a difference. Calculating one’s ecological footprintrecreational activities?reinforces the notion that sustainability is a journey andOur answers to these questions reflect the demandnot a destination and that it is participatory, not a specthat each of us places on nature. In the 1990s, sustaintator sport. It serves as a simple guide to living, working,ability gurus Mathis Wackernagel and Bill Rees coinedand playing in ways that don’t cost the Earth.the term “ecological footprint” to refer to the load orHow much Earth do we have?demand that we place on the Earth’s resources. An ecological footprint is a measure of how much of theOur “living” Earth has a surface area of 51 billionEarth’s biologically productive land and water is neededhectares, but less than one quarter of this — under 12to produce our food, material goods, and energy, and tobillion hectares — is biologically productive for humanabsorb our waste.use. This is the amount of land available on the planet toE84Teaching Green: The Middle Years

TG 1-97FINAL.qxd8/3/20041:38 PMPage 85provide all of the food, water, and other materials thatfertility in lakes and oceans. These include thewe need to support ourselves. To help students visualizedestruction of coral reefs, oil spills, overfishingthis, create a pie graph that shows how the Earth’s(of both marine and lake species), and shorelinesurface area is divided.development.1. Begin by drawing a large circle on chart paper.7. This leaves a pie chart featuring four segments ofExplain that the circle represents the surface areavarying sizes — an excellent picture of our “living”of the Earth.planet. Label the sections, noting the percentage ofthe Earth’s surface that each represents and listing2. Draw lines to divide the pie into land and water: 28the forces represented by the “tentacles.”percent of the Earth’s surface is land and 72 percentis water.Wrap-up: Remind students that only the green and blue3. Focusing on the 28 percent of the pie that is land:sections — about 23 percent of the Earth’s surface — color about two-thirds of the land area green toare biologically productive. This small percentage of landrepresent the 19 percent of Earth’s surface thatand water is all we have to produce all of our food,is biologically productive for human use (i.e.,materials, and energy, and to absorb our waste. Theseland that is fertileprecious slices of theenough to supportEarth’s surface are alsoThree Facts andagriculture, forests,needed by the other 10or animal life).One Inescapable Conclusion!million or more specieswith whom we share the color the other thirdFact #1: Of the 51 billion hectares of the Earth’s surface,planet.of the land areaonly 12 billion hectares are biologically productive andbrown to representtherefore capable of providing resources and treatingCalculatingthe 9 percent ofwaste. That’s 10 billion hectares of land and 2 billionEarth’s surface thathectares of water.a footprintis marginally producHave students completeFact #2: The human population is 6.3 billion and climbtive or waterthatisthe Personal Ecofor human use (e.g.,available, our average Earth share is 1.9 hectares per perFootprint Calculator toland that is paved,son (not including the needs of all other life forms). Asestimate how much ofcovered by ice, lacksour population grows, we must either reduce our averagethe Earth’s biologicallywater, or has unsuitEarth share or find more Earths to inhabit.productive land andable soil conditions).water is needed to supFact #3: The amount of biologically productive land on4. Explain that processesport their own lifestyles.Earth is in decline owing to urbanization, overgrazing bysuch as desertification,The calculator is dividedlivestock, deforestation, toxic contamination, poor agriculsoil erosion, andinto eight categories thattural practices, desertification, and global climate change.urbanization arerepresent the many waysInescapable conclusion: Less is more: we all need toconstantly reducingthat we “consume”shrink our ecological footprint.the amount of biologinature each day. Explaincally productive landto students that it is noton Earth. To showa scientific survey, but itthis, draw small brown tentacles reaching from thedoes give a good approximation of the impact of one’sborder of the brown segment into the green segment.lifestyle on a typical day. More detailed lifestyle analysesinclude other considerations that usually increase the size5. Now, focusing on the water realm:of one’s ecological footprint. Therefore, the calculation color about one-twentieth of the water sectionderived from this calculator should be seen as a simplifiblue to show that 4 percent of the Earth’scation and an underestimate of reality.surface is lakes and oceans that are biologicallyStudents may point out that some lifestyle choices,productive for human use (i.e., yield more thansuchas the size of their house or the number of family95 percent of the global fish catch).cars, are not under their direct control. Explain that the color the remaining section black to show thatcalculator is meant to provide a snapshot of their lives at68 percent of the Earth’s surface is ocean thatpresent, and that the baseline information they gather willis marginally productive or unproductive forhelp them to monitor the impact of changes they makehuman use (i.e, yields only about 5 percent ofin their lifestyles. They may, for example, make differentthe global fish catch).choices if they purchase their own house or car in the6. Draw black “tentacles” from the unproductive-water future. The connection between these lifestyle considerations and their future ecological footprints is an importantsegment to the productive-water segmentlearning outcome of using the Footprint Calculator.to represent processes that contribute to loss ofLiving Sustainably85

TG 1-97FINAL.qxd8/3/20041:38 PMPage 86Personal Eco-Footprint CalculatorProcedure: Complete each of the charts for a typical day in your home community. Add the points on each chart to obtaina subtotal for that category, and transfer it to the summary chart. Use the grand total to calculate your ecological footprint.Water UseMy Score1. My shower (or bath) on a typical day is:No shower / no bath (0)1–2 minutes long / one-fourth full tub (50)3–6 minutes long / half full tub (70)10 or more minutes long / full tub (90)2. I flush the toilet:Every time I use it (40)Sometimes (20)3. When I brush my teeth, I let the water run. (40)4. I washed the car or watered the lawn today. (80)5. We use water-saving toilets (6-9 liters/flush). (-20)6. We use low-flow showerheads (-20)7. I use a dishwasher on a typical day. (50)Subtotal:Food1. On a typical day, I eat:Beef (150/portion)Chicken (100/portion)Farmed fish (80/portion)Wild fish (40/portion)Eggs (40/portion)Milk/dairy (40/portion)Fruit (20/portion)Vegetables (20/portion)Grains: bread, cereal, rice (20/portion)My Score2. of my food is grown locally.All (0)Some (30)None (60)3. of my food is organic.All (0)Some (30)None (60)4. I compost my fruit/vegetable scraps and peels.Yes (-20)No (60)5. of my food is processed.All (100)Some (30)None (0)6. of my food has packaging.All (100)Some (30)None (0)7. On a typical day, I waste:None of my food (0)One-fourth of my food (100)One-third of my food (150)Half of my food (200)Subtotal:86TransportationMy Score1. On a typical day, I travel by:Foot (0)Bike (5 per use)Public transit (30 per use)Private vehicle (200 per use)2. Our vehicle’s fuel efficiency is liters/100 kilometers(gallons/60 miles).less than 6 liters / 2 gallons (-50)6–9 liters / 2–2½ gallons (50)10–13 liters / 3–3½ gallons (100)More than 13 liters / 3½ gallons (200)3. The time I spend in vehicles on a typical day is:No time (0)Less than half an hour (40)Half an hour to 1 hour (60)More than 1 hour (100)4. How big is the car in which I travel ona typical day?No car (-20)Small (50)Medium (100)Large (SUV) (200)5. Number of cars in our driveway?No car (-20)1 car (50)2 cars (100)More than 2 cars (200)6. On a typical day, I walk/run for:5 hours or more (-75)3 to 5 hours (-25)1 to 3 hours (0)Half an hour to 1 hour (10)Less than 10 minutes (100)Subtotal:ShelterMy Score1. Number of rooms per person (divide number ofrooms by number of people living at home)Fewer than 2 rooms per person (10)2 to 3 rooms per person (80)4 to 6 rooms per person (140)7 or more rooms per person (200)2. We share our home with nonfamily members. (-50)3. We own a second, or vacation home that isoften empty.No (0)We own/use it with others. (200)Yes (400)Subtotal:Teaching Green: The Middle Years

TG 1-97FINAL.qxd8/3/20041:38 PMPage 87Personal Eco-Footprint CalculatorEnergy UseMy Score1. In cold months, our house temperature is:Under 15ºC (59 F) (-20)15 to 18ºC (59 to 64 F) (50)19 to 22ºC (66 to 71 F) (100)22 C (71 F) or more (150)2. We dry clothes outdoors or on an indoor rack.Always (-50)Sometimes (20)Never (60)3. We use an energy-efficient refrigerator.Yes (-50)No (50)4. We use compact fluorescent light bulbs.Yes (-50)No (50)5. I turn off lights, computer, and television whenthey’re not in use.Yes (0)No (50)6. To cool off, I use:Air conditioning: car / home (30 for each)Electric fan (-10)Nothing (-50)7. Outdoors today, I spent:7 hours (0)4 to 6 hours (10)2 to 3 hours (20)2 hours or less (100)Subtotal:ClothingMy Score1. I change my outfit every day and put it inthe laundry. (80)2. I am wearing clothes that have been mendedor fixed. (-20)3. One-fourth of my clothes are handmade orsecondhand. (-20)4. Most of my clothes are purchased neweach year. (120)5. I give the local thrift store clothes thatI no longer wear.Yes (0)No (100)6. I buy hemp instead of cotton shirtswhen I can. (-10)7. I never wear % of the clothes in my cupboard.Less than 25% (25)50% (50)75% (75)More than 75% (100)8. I have pairs of shoes.2 to 3 (20)4 to 6 (60)7 or more (90)Subtotal:Living SustainablyStuffMy Score1. All my garbage from today could fit into a:Shoebox (20)Large pail (60)Garbage can (200)No garbage created today! (-50)2. I reuse items rather than throw them out. (-20)3. I repair items rather than throw them out(-20)4. I recycle all my paper, cans, glass, and plastic.(-20)5. I avoid disposable items as often as possible.Yes (-10)No (60)6. I use rechargeable batteries whenever I can. (-30)7. Add one point for each dollar you spendin a typical day.Today was a Buy Nothing Day (0)Subtotal:FunMy Score1. For typical play, the land converted into fields,rinks, pools, gyms, ski slopes, parking lots, etc.,added together occupy:Nothing (0)Less than 1 hectare / 2½ acres (20)1 to 2 hectares / 2½ to 5 acres (60)2 or more hectares / 5 or more acres (100)2. On a typical day, I use the TV or computerNot at all (0)Less than 1 hour (50)More than 1 hour (80)3. How much equipment is needed fortypical activities?None (0)Very little (20)Some (60)A lot (80)Subtotal:SummaryTransfer your subtotals from each section and add themtogether to obtain the grand total.Water useFoodTransportationShelterEnergy UseClothingStuffFunGrand Total:My ecological footprint is:Grand Total divided by 100 hectares(To convert to acres, multiply hectares by 2.47)87

TG 1-97FINAL.qxd8/3/20041:38 PMPage 88Sharing Earth fairlyOnce students have calculated their ecological footprints,they can compare their results with others and determinewhether the Earth could sustain the human population ifeveryone lived as they do.1. Have students consider how their results comparewith the following average ecological footprints:United States: 10 hectares (24 acres) per personCanada: 9 hectares (22 acres) per personItaly: 4 hectares (9 acres) per personPakistan: less than 1 hectare (2 acres) per person2. Have students calculate how much of Earth’s biologically productive land is available to each person onthe planet. To do this, they divide the total area ofbiologically productive land (12 billion hectares)by the number of people on the planet (about 6.3billion). This amount (1.9 hectares / 4.7 acres perperson) is known as th