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Environmental Science
Carl Mitchell

CHAPTER 1 AN INTRODUCTION TO ENVIRONMENTAL SCIENCE Our Island, Earth Environmental science: study of how the natural world works, how our environment affects us, and how we affect our environment NATURAL RESOURCES ARE VITAL TO OUR SURVIVAL Natural resources: the various substances and energy sources we need to survive Renewable natural resources: natural resources that are replenishable over short periods (ex. wind) Resource management: strategic decision making and planning aimed at balancing the use of a resource with its protection and preservation  Basic premise of renewable resource management is to balance the rate of withdrawal from the stock (harvestable portion) with the rate or renewal or regeneration Nonrenewable natural resources: natural resources that are in finite supply and are depletable because they are formed much more slowly than we use them (ex. coal, natural gas, copper) RESOURCE CONSUMPTION EXERTS SOCIAL AND ENVIRONMENTAL IMPACTS  Population growth affects resource use and availability Impact on the environment is the product of population, affluence (level of consumption), and technology Carrying capacity and the “tragedy of the commons” Carrying capacity: the ability of a system to support life (environmental scientists quantify carrying capacity in terms of number of individuals of a particular species that can be sustained by the biological productivity of a given area of land)  When the carrying capacity of the land system is exceeded (too many individuals), 1 of 2 things happen o Population of that species will decline or collapse o The system itself will be altered, damaged, or depleted  Garrett Hardin proposed that resources opened to unregulated exploitation become overused and, as a result, are damaged or depleted (recall first day of class, beads for extra marks)  “tragedy of the commons”. Each person who puts animals to graze on the field will be motivated to increase the number of their own animals because no single person owns the land (no incentive to limit). 1 Tragedy of the commons: each individual withdraws whatever benefits are available from the common property as quickly as possible, until the resource becomes overused and depleted  Solutions to tragedy of the commons: private ownership, voluntary organization to enforce responsible use, governmental regulation Calculating our ecological footprint  Resource consumption of an individual or a population can be quantified by using the concept of “ecological footprint” Ecological footprint: is calculated in terms of the amount of biologically productive land and water required to provide the raw materials that person or population consumes and to absorb or recycle the waste the person or population produces  The footprint calculation gives the surface area “used” by a given person or population, after all the direct and indirect impacts are totalled  Ecological footprint is essentially the inverse of carrying capacity: measure of land required to sustain an individual, rather than number of individuals that can be sustained by an area of land ENVIRONMENTAL SCIENCE CAN HELP US AVOID MISTAKES MADE IN THE PAST  Rapa Nui (Easter Island) once had lush forests, 6-30K people, and lots of species. Now there are no trees, people live in caves, no native land birds, and only 1 type of seabird left The Nature of Environmental Science ENVIRONMENTAL SCIENCE IS AN INTERDISCIPLINARY PURSUIT  Environmental science is an interdisciplinary field  Environmental science encompasses the natural sciences and the social sciences  Environmental science programs focus predominantly on the natural sciences and environmental studies focus on social sciences PEOPLE DIFFER IN THEIR PERCEPTION OF ENVIRONMENTAL PROBLEMS th  Environmental science arose in the latter half of the 20 century when people sought to better understand environmental problems and their origins  An environmental problem is any undesirable change in the environment o Ex. in 1950s, children with lice was sprayed with DDT. Today we know its toxicity ENVIRONMENTAL SCIENCE IS NOT THE SAME AS ENVIRONMENTALISM Environmental science: the pursuit of knowledge about the working of the environment and our interactions with it 2 Environmentalism: a social movement dedicated to protecting the natural world from undesirable changes brought about by human choices  Environmental scientists attempt to maintain an objective approach in their work and must be free from personal or ideological bias The Nature of Science Science: a systematic process for learning about the world and testing our understanding of it  Environmental science is a dynamic yet systematic means of studying the world THE SCIENTIFIC METHOD IS A KEY ELEMENT OF SCIENCE Scientific method: technique generally followed for testing ideas  The scientific method relies of the following assumptions o The universe functions in accordance with fixed natural laws that do not change from time to time or from place to place o All events arise from some cause and, in turn, lead to other events  The scientific method typically consists of 1. Observations 4. Predictions 2. Questions 5. Testing predictions 3. Hypothesis 6. Analysis and interpretation  Note that correlation does not mean causation THERE ARE DIFFERENT WAYS TO TEST HYPOTH
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