# Limits to Human Population Growth and Ecological Footprints IB syllabus: 3.7.1-3.7.2 3.8.1-3.8.5 Calculate your ecological footprint Video – The Human.

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Limits to Human Population Growth and Ecological Footprints IB syllabus: 3.7.1-3.7.2 3.8.1-3.8.5 Calculate your ecological footprint Video – The Human Footprint

Syllabus Statements 2.7.3: Describe and evaluate the use of environmental impact assessments 3.7.1: Explain the difficulties in applying the concept of carrying capacity to local human populations 3.7.2: Explain how reuse, recycling, remanufacturing and absolute reductions and material use can affect human carrying capacity

Syllabus Statements 3.8.1: Explain the concept of an ecological footprint as a model for assessing the demands that human populations make on their environment 3.8.2: Calculate from appropriate data the ecol,ogical footprint of a given population, stating the approximations and assumptions involved 3.8.3: Describe and explain the differences between the ecological footprints of two human populations, one from an LEDC one from an MEDC 3.8.4: Discuss how national and international development policies and cultural influences can affect human population dynamics and growth 3.8.5: Describe and explain the relationship between population, resource consumption and technological development, and their influence on carrying capacity and material economic growth.

Carrying Capacity Environmental resistance = all factors which limit the growth of populations Population size depends on interaction between biotic potential and environmental resistance Carrying capacity (K) = # of individuals of a given population which can be sustained infinitely in a given area Should be able to estimate this by examining the requirements of a species and the resources available in the environment

Forms of Growth Exponential growth  starts slow and proceeds with increasing speed J curve results Occurs with few or no resource limitations Logistic growth  (1) exponential growth, (2) slower growth (3) then plateau at carrying capacity S curve results Population will fluctuate around carrying capacity

© 2004 Brooks/Cole – Thomson Learning Time (t) Population size (N) K Exponential GrowthLogistic Growth Population Growth Curves

Carrying capacity is Difficult for Humans 1.Use a wide range of resources 2.If a resource becomes limiting humans readily substitute others 3.Requirements vary according to lifestyle Differ in time, by populations, by areas 4.Technology impacts resources used and available 5.Import and export moves resources beyond local boundaries -Import and export change K for an area but have no impact on its global level

Human Carrying Capacity Human carrying capacity determined by Rate of energy and material consumption Extent of human interference in global life support systems – environmental degradation Levels of pollution created Recycling, Reuse and Remanufacturing Reduce these impacts BUT  can increase carrying capacity as well

Waste U.S.  4.6% world population & 33% of the worlds solid waste production Only 1.5% is municipal solid waste, MSW from homes & businesses (garbage) 200 million metric tons MSW produced per year Average 1700 lbs per person yearly Timeline of US waste stream http://www.tufts.edu/tuftsrecycles/usstats.html

Municipal 1.5% Sewage sludge 1% Mining and oil and gas production 75% Industry 9.5% Agriculture 13% Sources of Solid Waste in the US

We throw away… Enough aluminum to rebuild the country’s entire commercial airline fleet in 3 months 18 billion disposable diapers yearly 30 million cell phones per year 2.5 million nonreturnable plastic bottles per hour 1.5 billion pounds of edible food per year EPA names electronic wastes as the fastest growing environmental concern

What are our options 2 methods of dealing with our solid & hazardous wastes 1.Waste management = a high waste approach – waste production is unavoidable product of growth 2.Waste & pollution prevention = a low waste approach recognizing that recycling or reducing use of materials

High-quality energy Matter System Throughputs Output (intro environment) Unsustainable high-waste economy Low-quality heat energy Waste matter and pollution Inputs (from environment)

High-quality energy Matter Pollution prevention by reducing matter throughput Sustainable low-waste economy Recycle and reuse Pollution control by cleaning up some pollutants Matter output Low-quality energy (heat) Waste matter and pollution Matter Feedback Energy Feedback Inputs (from environment) System Throughputs Outputs (from environment)

We do have options.

1st Priority2nd PriorityLast Priority Primary Pollution and Waste Prevention Change industrial process to eliminate use of harmful chemicals Purchase different products Use less of a harmful product Reduce packaging and materials in products Make products that last longer and are recyclable, reusable or easy to repair Secondary Pollution and Waste Prevention Reduce products Repair products Recycle Compost Buy reusable and recyclable products Waste Management Treat waste to reduce toxicity Incinerate waste Bury waste in landfill Release waste into environment for dispersal or dilution

Landfill Produce Less Waste Convert to Less Hazardous or Nonhazardous Substances Put in Perpetual Storage Manipulate processes to eliminate or reduce production Recycle and reuse Land treatment Incineration Thermal treatment Chemical physical, and biological treatment Ocean and atmospheric assimilation Underground injection Waste piles Surface impoundments Salt formations Arid region unsaturated zone

The Eco-industrial revolution Combine interests to achieve economic, environmental & industrial sustainability Clean production or industrial ecology Create closed systems of material flow My waste  your raw material Many benefits incl. reduced waste material, less pollution, stimulate production of cleaner products

Pharmaceutical plant Local farmers Fish farming Cement manufacturer Area homes Wallboard factory Greenhouses Oil refinery Sulfuric acid producer Electric power plant Sludge Waste Heat Waste Heat Waste Heat Waste Heat Waste Heat Surplus Natural gas Surplus Sulfur Surplus Natural gas Waste Calcium sulfate

Strategies: 1. Reuse Good form of waste reduction Conserves energy & raw materials But we live in a disposable society – paper towels, paper plates, plastic utensils … Examples Refillable glass or PET plastic bottles Tool libraries Cloth shopping bags

Aluminum can, used once Steel can used once Recycled steel can Glass drink bottle used once Recycled aluminum can Recycled glass drink bottle Refillable drink bottle, used 10 times 08162432 Energy Consumption (thousands of kilocalories)

Strategies: 2. Recycling 1.Primary (closed loop) recycling Post consumer wastes are recycled to produce new products Reduce pollution, energy use, resource use 2.Secondary (downcycling) Waste materials converted into different & usually lower quality products 3.If items are recyclable that doesn’t mean it necessarily is being recycled

Reduces global warming Reduces acid deposition Reduces urban air pollution Make fuel supplies last longer Reduces air pollution Saves energy Reduces energy demand Reduces water pollution Recycling Reduces solid waste disposal Reduces mineral demand Protects species Reduces habitat destruction Benefits of Recycling

Recycling II 60 – 80% of MSW could be recycled & composted Large scale recycling requires centralized materials recovery facilities Financial aspect often hampers recycling programs We still lack (1) government support for recycling, (2) demand for recycled products, (3) proper pricing to goods to account for environmental impact

Outside users Pipeline Shredder Energy recovery (steam and electricity) Incinerator (paper, plastics, rubber, food, yard waste) Food, grass, leaves Separator MetalsRubberGlassPlasticsPaper ResidueCompost Recycled to primary manufacturers Landfill and reclaiming disturbed land Fertilizer Consumer (user)

Removing toxic materials 1.Bioremediation  use microorganisms to remove toxins 2.Phytoremediation  plants soak up pollutants in the soil 3.Chemical methods of detoxification  cyclodextrin attracts & binds chemicals 4.Plasma torch  extreme high temperatures decompose hazardous materials

How can we quantify the impact we have? Calculate an Ecological Footprint Model for quantifying the demands that human populations make on their environment The area of land in the same vicinity as the population that would be required to provide for all of the population’s resources and assimilate all of it’s wastes It is the inverse of the carrying capacity

Ecological footprints

Different Populations, Different Problems Human pressure on the environment caused by three factors I = P x A x T Population size Affluence Technology

Ecological Footprints by World Region The average American places at least 20 times the demand on Earth’s resources as does an average person in Bangladesh Fig. 5.7 here

Consume the largest share of 11 of 20 major commodities Eat more than three times the global average in meat Lead the world in paper consumption Environment improves with increasing affluence Enables wealthy to clean up immediate environment by transferring waste to more distant locations. Affluent isolate themselves and unaware of the environmental stresses caused by their consumptive lifestyles. Affluence in the United States

Calculate a Footprint for a given group Calculations are approximations Total area required is the sum of these two per capita requirements multiplied by total population

Footprint Calculation Ignores land and water needed for aquatic and atmospheric resources for the assimilation of waste other than CO2 For production of energy or materials needed to support arable land in an area To replace productive land lost by urbanization and so on

Calculate your Footprint http://www.myfootprint.org/ Did you know that the planet takes 1 year and 4 months to regenerate the material that we consume in 1 year We are in an overshoot  liquidating the earth’s assets

Country Comparison LEDC – less economically developed country: a country with low to moderate industrialization and low to moderate average GNP per capita MEDC – more economically developed country: a highly industrialized country with high average GNP per capita

Key Nations for the future China  footprint has quadrupled in the last four decades – second only to US African Nations  individuals consume little but population growth is causing them to approach their capacity Canada  if everyone consumed like them, we would need 4.3 earths Canada is 7.4 global hectares per person but the US is 9.2!

Figure 1 tracks, in absolute terms, the average per person resource demand (Ecological Footprint) and per person resource supply (Biocapacity) in United States of America since 1961. Biocapacity varies each year with ecosystem management, agricultural practices (such as fertilizer use and irrigation), ecosystem degradation, and weather.

Figure 2 shows the components of the average per person Ecological Footprint in United States of America since 1961.

Figure 1 tracks, in absolute terms, the average per person resource demand (Ecological Footprint) and per person resource supply (Biocapacity) in Congo DR since 1961. Biocapacity varies each year with ecosystem management, agricultural practices (such as fertilizer use and irrigation), ecosystem degradation, and weather.

Figure 2 shows the components of the average per person Ecological Footprint in Congo DR since 1961.

Effects of Policy on Populations Domestic & International Policy Effects Policies target death rates  Stimulate rapid growth Agricultural development Improving public health and sanitation Improved service infrastructure These policies lower mortality without significant effects on fertility http://www.globalgiving.com/dy/v2/content/themes.html?the meName=Economic+Development http://www.globalgiving.com/dy/v2/content/themes.html?the meName=Economic+Development Examples = Oxfam, UNICEF

Effects of Policy on Populations Policies targeting birth rates Economic growth itself may lead to decreasing birth rates (Demographic Transition Hypothesis) Education about birth control Family planning service development Increasing women’s education  more economic & personal freedoms Removing parental dependence on children in old age

Policy & Waste Reduction Resource Conservation & Recovery Act 1976 Superfund Act – 1980 Identify hazardous waste dump sites Protect groundwater in those areas Clean up the sites Find parties responsible & hold accountable \$750 billion bill for total project

Role of Technology Carrying capacity may be expanded through continuous technological innovation Increase efficiency of energy & material use 2X  double use or population without increasing impact But with population growth predictions and necessary economic growth  efficiency will have to increase 4X to 10X to compensate Remember that sometimes technology itself can tax carrying capacity too

So how do we assess the actual impact? Complete an Environmental Impact Assessment A method of detailed survey required in some countries before initiating a major development Independent of but paid for by the developer Should include baseline study to measure environmental conditions before development begins Identify areas of and species of conservation importance Report produced is an environmental impact statement (EIS) called environmental management review in some countries Monitoring then should continue after the development

Evaluate the use of EIS / EIA Advantages Makes developer accountable for environmental effects Makes efforts to mitigate / conserve habitats and species Another hurdle to slow down development Disadvantages Subject to bias if funded by developer Even with considerations it will never completely eliminate the impact

http://www.unicefusa.org/ http://www.oxfamamerica.org/ http://www.footprintnetwork.org

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