Chapter 1Introducing Environmental Science and SustainabilityOverview of Chapter 1 Human Impacts on The Environment Population, Resources and the Environment Environmental Sustainability Environmental Science Addressing Environmental ProblemsThe Environment (Earth) Life has existed on earth for 3.8 billion years Earth well suited for life Water covers ¾ of planet Habitable temperature, moderate sunlight Atmosphere provides oxygen and carbon dioxide Soil provides essential minerals for plants But humans are altering the planet; not always in positive waysHuman Impact on the Environment Satellite view of North America at nightHuman Impacts on Environment—Population Expected to add several billion more people in 21stcentury Earth’s Human Population is over 6 billion Growing exponentiallyPopulation 1 in 4 people live in extreme poverty  Cannot meet basic need for food, clothing, shelter, health Difficult to meet population needs without exploiting earth’s resourcesGap Between Rich and Poor Highly Developed Countries (HDC) Complex industrialized bases, low population growth, high per capita incomes Ex: US, Canada, Japan Less Developed Countries (LDC) Low level of industrialization, very high fertility rate, high infant mortality rate, low per capita income Ex: Bangladesh, Mali, EthiopiaTypes of Natural ResourcesOverpopulation People overpopulation Too many people in a given geographic area Problem in many developing nations Consumption overpopulation Each individual in a population consumes too large a share of the resources Problem in many highly developed nationsEcological Footprint The average amount of land, water and ocean required to provide that person with all the resources they consumeEarth’s Productive Land and Water 11.4 billion hectaresAmount Each Person is Allotted (divide Productive Land and Water by Human Population)1.8 hectaresCurrent Global Ecological Footprint of each person2.7 hectaresEcological Footprint ComparisonIPAT Model Measures 3 factors that affect environmental impact (I)I = P A TEnvironmental ImpactNumber of peopleAffluence per personEnvironmental effect of technologiesEnvironmental SustainabilityEnvironmental Sustainability The ability to meet current human need for natural resources without compromising the needs of future generations Requires understanding: The effects of our actions on the earth That earth’s resources are not infiniteTragedy of the Commons Garrett Hardin (1915-2003) Solving Environmental Problems is result of struggle between: Short term welfare Long term environmental stability and societal welfare Common pool resources Garrett used Common Pastureland in medieval Europe to illustrate the struggleSustainable Development Economic development that meets the needs of the present generation without compromising future generationsEnvironmental Science An interdisciplinary study of human relationship with other organisms and the earth Biology Ecology Geography Chemistry Geology Physics Economics Sociology Demography PoliticsEarth As a System System A set of components that interact and function as a whole Global Earth Systems Climate, atmosphere, land, coastal zones, ocean Ecosystem A natural system consisting of a community of organisms and its physical environment System approach to environmental science Helps explain how human activities affect global environmental parametersEarth Systems Most of earth’s systems are in dynamic equilibrium or steady state Rate of change in one direction equals that in the other Feedback Negative feedback- change triggers a response that counteracts the changed condition Positive feedback- change triggers a response that intensifies the changing conditionFeedbackScientific MethodControls and Variables in Experiment Variable A factor that influences a process The variable may be altered in an experiment to see its effect on the outcome Control The variable is not altered Allows for comparison between the altered variable test and the unaltered variable testInductive and Deductive Reasoning Inductive Reasoning Used to discover general principles Seeks a unifying explanation for all the data available Ex: FACT: Gold is a metal heavier than water FACT: Iron is metal heavier than water FACT: Silver is a metal heavier than water CONCLUSION (based on inductive reasoning): All metals are heavier than water Conclusions reached with inductive reasoning may changed with new informationInductive and Deductive Reasoning Deductive Reasoning Proceeds from generalities to specifics Adds nothing new to knowledge, but makes relationships among data more apparent Ex: GENERAL RULE: All birds have wings SPECIFIC EXAMPLE: Robins are birds CONCLUSION (based on deductive reasoning): All Robins have wingsFive Stages to Addressing An Environmental Problem Five steps are idealistic Case Study: Lake WashingtonAssessing Environmental ProblemCase Study: Lake Washington Large, freshwater pond Suburban sprawl in 1940’s 10 new sewage treatment plants dumped effluent into lake Effect = excessive cyanobacteria growth that killed off fish and aquatic life Scientific Assessment Aquatic wildlife assessment done in 1933 was compared to the 1950 assessment Hypothesized treated sewage was introducing high nutrients causing growth of cyanobacteria Risk Analysis After analyzing many choices, chose new location (freshwater) and greater treatment for sewage to decrease nutrients in effluentAssessing Environmental ProblemCase Study: Lake Washington Public Education/Involvement Educated public on why changes were necessary Political Action Difficult to organize sewage disposal in so many municipalities Changes were not made until 1963! Evaluation Cyanobacteria slowly decreased until 1975 (gone)Assessing Environmental ProblemCase Study: Lake Washington ResultsAssessing Environmental ProblemCase Study: Lake