Bài giảng Environmental Sciences - Chapter 1: Introduction

Chapter 1: IntroductionToward a Sustainable FutureRachel Carson was a scientist who wrote Silent Spring in 1962.It addressed the growing use of pesticides (DDT) and their unpredicted effects on song birds.Original users of pesticides did not know that the poisons used to kill insects would accumulate in other living things and kill them too. BIOACCUMULATIONThemesSustainability: A process can continue indefinitely without depleting resources used *no sacrifice to future generations*Stewardship: Caring for something that does not belong to youScience: Use the scientific method and question authorityEcosystem Capital: Essential goods and services like food, water, and fuelPolicy and Politics: Human decisions determine what happens to the natural worldGlobalization: The interconnectedness of human activities, ideas, and culturesEnvironmental ScienceUnderstand how natural world worksUnderstand how human systems interact with natural system Accurately determine environmental problemsDevelop and follow a sustainable relationship with natural worldLessons from a Small IslandEaster Island(Rapa Nui) Island Home Page and Music ofEaster IslandArea - 166 km2In the 4th century A.D there were approximately 10,000 people living hereUse of resourcesNatural ResourcesFresh water TreesFishBrought by settlersChickensSweet potatoesTaroYamsUsed for:Building housesFoodClothingTechnologyStone statues (moai)Needed many trees to move the statuesMoaiThere are 887 moai on Easter IslandAverage Height: 13.29 feet (4.05 meters) some are more than 20 feet (6 meters)Average weight: 13.78 tons Dutch explorers arrive in 1772600 people leftConstant warFew of the natural resources left What happened!4 Global trends:Population growth and economic developmentSoil DegradationGlobal atmospheric changesLoss of biodiversityA. Human population growthMore than 6.6 billion people currently (2007)We are adding 76 million people per yearincrease pop → increase need for resourcesNote: This graph is from 1999. These predictions are based on a faster growth rate. Carrying capacity is higher in this graph.LOOK at Fig. 1-3, pg 5!!!Different lifestyles have different demands on the environment Developed (industrialized) countries like Americahot running watermore than one car per family-VS-Developing countries like Tanzaniahunting/gatheringFirewood for heat and cooking1 billion + people live in poverty B. Soil degradationDemand for food destroys the soilerosionminerals in soil are depletedsalinizationincreased use of pesticidesoveruse of fresh waterC. Global Atmospheric ChangesGlobal WarmingCO2 produced from fossil fuel burning acts like a blanket around the earth. Plants take CO2 out of the atmosphere through photosynthesis6CO2 +6H2O => 602 + C6H12O6Ozone depletionChemicals released from the surface of the earth destroy our ozone shield. No stratospheric ozone, no protection from the UV rays of the sun. D. Loss of BiodiversityHabitat destruction leads to a loss of many species starting with the plantsexact # of species lost is unknown because not all species are identifiedstrong ecosystems need biodiversity1959-1980 25% of all prescription drugs from natural resourcesWild species keep domestic species vigorousAestheticsA sustainable future is possibleNutrition levels and life expectancy are risingPopulation growth rates are fallingIt is cool to be “green”YOU are taking this classLessons from a Small IslandEaster Island(Rapa Nui)