Limits to Human Population Limits to Human Population Growth and Ecological Growth and Ecological

FootprintsFootprints

IB syllabus: 3.7.1-3.7.2IB syllabus: 3.7.1-3.7.2

3.8.1-3.8.53.8.1-3.8.5

Calculate your ecological footprintCalculate your ecological footprint

Video – The Human FootprintVideo – The Human Footprint

Syllabus StatementsSyllabus Statements

• 2.7.3: Describe and evaluate the use of environmental impact assessments

Syllabus StatementsSyllabus Statements

• 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 StatementsSyllabus 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.

vocabularyvocabulary

• Ecological footprint

• Environmental Impact Assessment

Carrying CapacityCarrying 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 GrowthForms 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) Time (t)

Po

pu

lati

on

siz

e (N

)

Po

pu

lati

on

siz

e (N

)

K

Exponential Growth Logistic Growth

Population Growth CurvesPopulation Growth Curves

Carrying capacity is Difficult for Carrying capacity is Difficult for HumansHumans

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

1. Technology impacts resources used and available

2. 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 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

WasteWaste

• 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

Municipal1.5%

Sewage sludge1%

Mining and oiland gas

production75% Industry

9.5%

Agriculture13%

Sources of Solid Waste in the US

We throw away…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

Ever think about Kleenex?Ever think about Kleenex?

• http://www.kleercut.net/en/

• http://www.greenpeace.org/usa/assets/binaries/tissue-guide-view-at-a-glance

What are our optionsWhat 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-qualityenergy

Matter

SystemThroughputs

Output(intro environment)

Unsustainablehigh-wasteeconomy

Low-qualityheat

energy

Wastematter

andpollution

Inputs(from environment)

High-qualityenergy

Matter

Pollutionprevention

byreducing

matterthroughput

Sustainablelow-wasteeconomy

Recycleand

reuse

Pollutioncontrol

bycleaningup some

pollutants

Matteroutput

Low-qualityenergy(heat)

Wastematter

andpollution

MatterFeedback

Energy Feedback

Inputs(from environment)

SystemThroughputs

Outputs(from environment)

We do have options. We do have options.

1st Priority 2nd Priority Last Priority

Primary Pollutionand 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

Manipulateprocesses

to eliminateor reduce

production

Recycleand

reuse

Landtreatment Incineration

Thermaltreatment

Chemicalphysical, and

biologicaltreatment

Ocean andatmosphericassimilation

Undergroundinjection

Wastepiles

Surfaceimpoundments

Saltformations

Arid regionunsaturated

zone

The Ecoindustrial revolutionThe Ecoindustrial 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

Pharmaceuticalplant

Local farmers

Fish farming

Cementmanufacturer

Area homes

Wallboardfactory

Greenhouses

Oil refinery

Sulfuric acidproducer

Electricpowerplant

Sludge

Sludge

Waste

Heat

Waste

Heat

Waste

Heat

WasteHeat

Was

te

Hea

t

Surplus

Natural gas

Su

rplu

s

Su

lfur

Surplus

Natural gas

Was

te

Cal

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m s

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ate

Strategies: 1. ReuseStrategies: 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

0 8 16 24 32

Energy Consumption (thousands of kilocalories)

Strategies: 2. RecyclingStrategies: 2. Recycling

1. Primary (closed loop) recycling• Post consumer wastes are recycled to

produce new products• Reduce pollution, energy use, resource use

1. Secondary (downcycling)• Waste materials converted into different &

usually lower quality products

1. If items are recyclable that doesn’t mean it necessarily is being recycled

Reduces globalwarming

Reduces aciddeposition

Reduces urbanair pollution

Make fuelsupplies

last longer

Reducesair pollution

Savesenergy

Reducesenergy demand

Reduceswater pollution

Recycling

Reduces solidwaste disposal

Reducesmineraldemand

Protectsspecies

Reduceshabitat

destruction

Benefits of Recycling

Recycling IIRecycling 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) goverment support for recycling, (2) demand for recycled products, (3) proper pricing to goods to account for environmental impact

Outsideusers

Pipeline

Shredder

Energy recovery(steam andelectricity)

Incinerator(paper, plastics,

rubber, food,yard waste)

Food, grass, leaves

Separator

Metals Rubber Glass Plastics Paper Residue Compost

Recycled to primary manufacturers

Landfill and

reclaimingdisturbed

land

Fertilizer

Consumer (user)

Removing toxic materialsRemoving 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 How can we quantify the impact we have?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 Ecological footprintsfootprints

Different Populations, Different Different Populations, Different ProblemsProblems

• Human pressure on the environment caused by three factors

• I = P x A x T– Population size– Affluence– Technology

Ecological Footprints by World RegionEcological 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

Affluence in the United Affluence in the United StatesStates

• 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.

Calculate a Footprint for a given groupCalculate 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 IgnoresFootprint 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 FootprintCalculate 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 ComparisonCountry 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 futureKey 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.

Table 1 outlines some basic data about United States of America in 2005. Ecological Footprint and Biocapacity are calculated by Global Footprint Network. The Human Development Index is calculated by the United Nations Development Programme.

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.

Table 1 outlines some basic data about Congo DR in 2005. Ecological Footprint and Biocapacity are calculated by Global Footprint Network. The Human Development Index

is calculated by the United Nations Development Programme.

Effects of Policy on PopulationsEffects 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?themeName=Economic+Development

• Examples = Oxfam, UNICEF

Effects of Policy on PopulationsEffects 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 ReductionPolicy & 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 TechnologyRole 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 So how do we assess the actual impact?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 / EIAEvaluate 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