2A World in Crisis Earth provides raw materials and energy for Life Earth is approx 4.5 Billion years oldModern humans appeared in Africa 195,000 yrs agoHuman populations have grown and expanded in rangeTechnology has allowed humans to live better (at least in developed nations)Humans are the most significant agent of environmental changeOverpopulationOverconsumption of natural resources: topsoil, water, airTransforming and destroying natural environmentsEradicating unique speciesHuman-induced climate change
4Human Impacts on the Environment Learning Objectives:Distinguish among highly developed countries, moderately developed countries, and less developed countries.Relate human population size to natural resources and resource consumption.Distinguish between people overpopulation and consumption overpopulation.Describe the three factors that are most important in determining human impact on the environment.
5Human Impacts on the Environment OverpopulationEarth’s central environmental problemLinks all other environmental problems togetherWorld’s population continues to grow and has grown very fast1960: 3 billion people1975: 4 billion1987: 5 billion2009: 6.8 billionPeople consume food and water, use energy and raw materials and produce wasteSeveral more billion people will be added in the 21st century, even if we are proactive about population growth
6Linear vs. ExponentialLinear growth - a quantity increases by a constant amount per unit of time: 2, 4, 6, 8 or 1, 3, 5, 7, 9 & so on.Exponential growth - a quantity increases by a fixed percentage of the whole in a given time: 1, 2, 4, 16
9Human Impacts on the Environment PovertyA condition in which people are unable to meet their basic needs for food, clothing, shelter, education, or health.One in four people lives in extreme poverty (less than $2/day): 3.3 billion peoplePoverty is associated with short life expectancy, illiteracy, inadequate access to health services, safe water, balanced nutrition
10Human Impacts on the Environment Population GrowthProjected 7.7–10.6 billion people depending on fertility rateCurrent fertility rate is 2.6 children/womanFamily planning effortsWorld’s population may stabilize by end of 21st centuryCan Earth support so many people?We don’t knowQuality of life depends on being able to produce enough food in a sustainable mannerWithout destroying the biological communities that support life on our planet
11Human Impacts on the Environment Population SizeNumber of peoplePopulation ConsumptionUse of materials and energyEconomic GrowthExpansion of the output of a nation’s goods and servicesIntimately related
12Human Impacts on the Environment Gap between Rich and PoorHighly Developed Countries (Rich, HDCs)Complex industrialized bases, low rates of population growth, and high per person incomes18 % of the world’s populationUS, Canada, Japan, most of Europe
13Human Impacts on the Environment Gap between Rich and PoorPoor Countries: 82% of world’s populationModerately Developed (MDCs)Medium levels of industrialization, lower per person incomes than highly developed countries, few opportunities for education and health careMexico, Turkey, South Africa, ThailandLess Developed (LDCs)Low levels of industrialization, high population growth, very high infant death rates, very low incomes, mostly agriculture based, cheap unskilled laborBangladesh, Mali, Ethiopia, Laos
14Human Impacts on the Environment Gap between Rich and Poor
15Human Impacts on the Environment Population, Resources, and the EnvironmentDeveloping countriesRapid population growth is overwhelmingNatural resource depletion for survival (soils, forests, water)Developed countriesSlower population growthHigher rate of consumption beyond what’s necessary for survival (TV, computers, jet skis)
16Human Impacts on the Environment Types of ResourcesNonrenewableLimited Supply: minerals, fossil fuelsOnce they are gone, they are goneRenewable/Potentially RenewableVirtually unlimited: solar power, water, soil, forestsReplenished over short periods (days to decades)Easy to overexploit nonrenewableSoil, fresh water, clean air
173 Types of Resources energy resources: metallic mineral resources coal, oil, natural gas, uranium,metallic mineral resourcesiron, copper, aluminum, &nonmetallic mineral resourcessalt, clay, sand, & phosphatesWe convert these raw materials into many everyday items we use, & then we discard, reuse, or recycle them.
18Human Impacts on the Environment Resources and PopulationRapid population growth can cause resources to be overexploitedCritical in developing countriesEconomic growth tied to natural resource exploitationChoice between short term and long termPoverty drives natural resource exploitationMust use resources to survive, which degrades them and shuts down future opportunities for development
19Human Impacts on the Environment Population Size and Resource ConsumptionA country is overpopulated if the demand on its resources results in damage to the environment.Can be overpopulated in 2 ways:People OverpopulationConsumption is high because there are too many people, even if individual consumption is lowConsumption OverpopulationConsumption is high because each individual consumes too much, even if total population is low
20Human Impacts on the Environment Population Size and Resource ConsumptionHighly developed countries have less than 20% of the world’s population, but consume:86% of aluminum76% of timber68% of energy61% of meat42% of fresh waterAlso, produce 75% of waste and pollution
22Human Impacts on the Environment Population Size and Resource ConsumptionEcological FootprintsThe amount of land, fresh water, and ocean required on a continuous basis to supply a person with food, wood, energy, water, housing, clothing, transportation, and waste disposal.Earth has 11.4 billion ha = 28.2 billion acres of productive land and water11.4/6.8 billion people = 1.8 ha (4.3 acres)Currently, average ecological footprint is 2.7 ha (6.7 acres)US footprint is 9.4 ha (23.3 acres) if everyone in the world had the same, we would need 4 Earths!!!
24Human Impacts on the Environment Population, Consumption, and Environmental ImpactI = P x A x TI: Environmental impactP: Population (number of people)A: Affluence per person (amt of resources)T: Technology used to get resourcesInterpret results with care!Ultimate goal: make consumption sustainable
26Global Climate ChangeHow do highly developed countries, moderately developed countries, and less developed countries differ regarding population growth and per person incomes?How is human population growth related to natural resource depletion and environmental degradation?
27Sustainability and Earth’s Capacity to Support Humans Learning Objectives:Define environmental sustainability.Identify human behaviors that threaten environmental sustainability
28Sustainability and Earth’s Capacity to Support Humans Ability to meet current needs without compromising the ability of future generations to meet their needsEnvironment will function indefinitelyBased on:Effects of our actions on the environmentEarth’s resources are finiteUnderstanding impacts of consumptionShared responsibility for environmental sustainability
29Sustainability and Earth’s Capacity to Support Humans We are not currently living sustainably:Using nonrenewable resources as if they were renewable (e.g., fossil fuels)Using renewable resources faster than nature can replenish themPolluting the environment beyond capacityUnchecked population growth, without regard to Earth’s finite resources and ability to deal with waste
31The Tragedy of the Commons One cause of environmental degradation is overuse of common-property resources, which are owned by none & available to all users free of charge.Most are potentially renewable.It happens because each user reasons, "If I don't use this resource, someone else will. The little bit I use or pollute is not enough to matter"
32Global Environmental Issues Global warming Deforestation
38Global Climate Change What is environmental sustainability? Which human behaviors threaten environmental sustainability?
39Environmental Science Learning Objectives:Define environmental science.Outline the steps of the scientific method.
40Environmental Science Interdisciplinary study of humanity’s relationship with other organisms and the physical environmentcombines information from many fields:biology, geology, geography, chemistry, economics, agriculture, law, politics, ethics, etc.Ecology is a basic toolAtmospheric ScienceEnvironmental ChemistryGeosciences
41Environmental Science GoalsEstablish general principles about how the natural world functionsIdentifying, understanding, and solving problems that we have createdNot just ‘doom and gloom’ list of problemsFocus on solving problems
42Environmental Science Science as a ProcessNot just a collection of factsSystematic way of studying the natural worldRequires collection of data throughObservation and experimentationData must be analyzed and interpretedNot based on faith, emotion, intuitionRequires repeatability and scrutinyNo absolute certaintyRequires reevaluationOngoing process
43Environmental Science The Scientific MethodProcess that scientists use to answer questions or solve problemsRecognize a question/problemDevelop a hypothesis (educated guess) to explain the problemDesign and perform an experiment to test the hypothesisAnalyze and interpret the data to reach a conclusionShare knowledge with scientific community
45Environmental Science The best hypotheses make predictionsPredictions provide a way to test hypothesesIf experiment refutes hypothesis, hypothesis is rejectedIf hypothesis is verified repeatedly, hypothesis is strongScience progresses from uncertainty to less uncertaintyScience is self-correcting even though it never ‘proves’ anything
46Environmental Science Experiments test hypothesesVariable: factor that influences a processTo test a hypothesis, two experiments are carried out:Experimental Group: the chosen variable is altered in a known wayControl Group: the chosen variable is not alteredWe can ask: What is the difference (if any) between the two groups?Any differences would be due to the experimental variable
47Environmental Science Scientific TheoryAn integrated explanation of many hypotheses, each supported by many observations and experiments.Simplifies and clarifies our understanding of the natural world.Solid ground of scienceGenerally accepted as ‘true’, even though there is no absolute truth in scienceContrast with general public’s use of theory, as a guess, or hypithesis
48Environmental Science Science is constantly evolvingAs new evidence comes to light, conclusions may changeTherefore, scientific conclusions are provisional, which doesn’t mean they are invalid.E.g., smoking and cancer
49Global Climate ChangeWhat is environmental science? What are some of the disciplines involved in environmental science?What are the five steps of the scientific method? Why is each important?
50How We Handle Environmental Problems Learning Objectives:List and briefly describe the five stages of solving environmental problems.
52Global Climate ChangeWhat are the five steps used to solve an environmental problem?
53EnviroDiscovery NIMBY = not in my backyard NIMTOO = not in my term of officeExamples:People don’t want power plants, landfills, incinerators nearbyPoliticians want to be reelected, so they don’t support those decisions in their districts
55Case Study The New Orleans Disaster: Hurricane Katrina Storm damage was increased because of human alteration of the natural landscape:Canals were built for navigationallowed salt water to intrude and kill marsh vegetationLevees were built to stop floodingsediments did not build up to replenish the landSettlements were built on drained wetlandsCity was subsiding due to lack of bedrock