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Environmental Science

Our environment is more then just our surroundings  Environment is the sum of our surroundings  It includes all of earths o Biotic Components (Living Things)  Biotic Constituents(成分) = Animals, plants, soil, forests, people occupying landscape o Abiotic Components (Nonliving things)  Abiotic Constituents = Continents, oceans, clouds, rivers, icecaps In the most inclusive scene, our environment includes scientific, political, ethical, economical, and social relationships & institutions. It is the interactions that characterize environment. Most people equated environment with wilderness. Environment Canada is to preserve (保护)and enhance the quality of Canada’s natural environment, conserve(保存) our renewable resources and protect our water resources. Environmental science explores interactions between humans and the physical and biological world  We depend on the environment for air, water, food, shelter, and everything else essential for living.  Some actions have enriched our lives, bringing us longer life spans, better health o Some have damaged natural systems that sustain (维持) us  Water & air pollution, soil erosion etc.  Environmental Science is the study of how the natural world works, how our environment affects us, and how we affect our environment. o It is important to understand our interactions and our role in the environment. Natural resources are vital (重要的)to our survival  Islands are finite and have limitation in material resources  Renewable Natural Resources are natural resources that are replenishable(可补充的) over short periods (wind, wave energy, sunlight. o Become non-renewable if we use them at a rate that is faster at which they are renewed or replenished.  Resource Management is a strategic(战略上的) decision making and planning aimed at balancing the use of a resource with its protection and preservation. o Balance the withdrawal from the stock with the rate of renewal/regeneration (再生) o Stock is the harvestable(收获的) portion of the resource  Stock-and-flow resources highlight the importance of the balance  Non-Renewable Natural Resources are finite supply & depletable(可耗减的) as they are formed much more slowly (fossil fuels, mineral deposits.) o Once we use them up they are no longer available. o Fossil fuels & minerals are mined rather than harvested therefore once extraction(提取) becomes inefficient to be profitable they move on to new sites.开采低效了就换一个地方开采  Management of non-renewable mineral resources demands conservation, reuse & recycling. o Other resources are truly non-renewable and nonreplenishable (once a species has become extinct it won’t return) o A key question in managing resources is to look at the resource of interest or to look at the environmental system and how to avoid damaging the system and sustain the availability of the resource in the long term.  Important to preserve for the future, recently the consumption of natural resources has increased greatly. Human population growth has shaped our resource use  Four significant periods of societal change appear to have triggered(触发) remarkable increases in population size. o 1. The paleolithic (stone age) period > humans gained control of fire and began to shape and use stones to modify their environment o 2. Neolithic Period (agricultural revolution) Transition from a nomadic(游牧的), hunter- gatherer lifestyle to a settled, agricultural way of life. This change was 10000-12000 years ago. o 3. Industrial Revolution began in mid-1700s, entailed a shift from rural life(农村生活), and manufacturing by crafts(手工的) people, to an urban society powered by fossil fuels. Life improved, but marked the beginning of industrial-scale pollution –  Air quality declined(下降) as of reliance(依 赖) on coal.  Water quantity declined  Workplace health and safety went under dramatic decline o 4. Medical-Technological Revolution – Advances in medicine and sanitation( 卫生系统或设备 ), communication technologies, shift to modern agricultural practices (green revolution) allowed people to live longer healthier lives.  Each major transition introduced technological advancements that made life easier and resources more available, effectively increasing the carrying capacity of the environment for humans and allowing the human population to increase dramatically. Resource consumption exerts(表现出) social and environmental impacts  Population growth affects resource use and availability > at the root of many environmental problems I = P x A x T This ‘IPAT’ model shows that the impact is a function of not only population but of affluence(富裕) (which stands in for ‘level of consumption’) . Increase in number of people (P) has impacts on increased consumption of natural resources and manufactured goods by the world’s people (A), and the impacts of new technologies (T) on the environment. Carrying capacity and the ‘tragedy of the commons(平民百 姓)’  Carrying capacity refers to the biological productivity of a system; it is a measure of the ability of a system to support life. o Environmental scientists quantify(定量) carrying capacity in terms of the 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 or water is exceeded(过渡的), there are too many individuals for the system to support.  This means the system will be altered, damaged or depleted(耗尽的) or the population of the species will decline(下 降) or collapse(倒塌).  ‘Tragedy of the Commons’ o Published by Garrett Hardin o Illustrated this process while disputing(争论) the economic theory that the unregulated(为受控制的) exercise of individual self-interest serves the public good. o Tragedy of The commons example is when each person who puts animals to graze (吃草)on the commons will be motivated(有目的的) by selfish interests to increase the number of his or her animals in the pasture(牧场), no one cares for the pasture because no single person owns it.  Each individual withdraws whatever benefits are available for the common property as quickly as possible until the resource becomes overused or depleted. Calculating our ecological footprints  Ecological footprint is a tool that can be used to express the environmental impact of an individual or population o Calculated in terms of the amount of biologically productive land and water required to provide the raw materials that the population consumers and to absorb or recycle the waste produced. o Gives the surface area ‘used’ by a given population after all the direct & indirect impacts are totalled. o It is the inverse of carrying capacity  Measure of land required to sustain an individual rather than the number of individuals that can be sustained by area of land or water. o Our species is using 39% more resources than are available.  We are not only exceeding the carrying capacity but also depleting renewable resources 39% faster than they are being replenished. o Ecological footprint for average Canadian is approximately 7.6 hectares (2-4 city blocks)  If the (属于居住的) land was among 6.7 billion people alive it would be less than 1 city block.  If all of the worlds people consumed resources at the rate of North Americans we would need greater or = to 2 additional planet earths. Environmental Science can help us avoid mistakes made in the past  There is evidence that civilizations can crumble(衰落) when pressures from population and consumption overwhelm(压倒) resource availability.  Jared Diamond identified five critical factors that determine the survival of civilizations: o Climate change o Hostile(怀有敌意的) neighbours o Trade partners o Environmental problems o Society’s response to environmental problems  The only one which is controllable is society’s response to environmental problems. The Nature of Environmental Science  Environmental scientists aim to comprehend(理解) how earth’s natural systems function, how humans are influenced by those system, and how we are influencing those systems  The solutions (such as new technologies, policy decisions) are applications of environmental science, and these solutions are in turn also part of environmental science Environmental Science is an interdisciplinary(各学科间的) persuit(职业)  Environmental science is an interdisciplinary field – one that employs concepts and techniques from numerous disciplines and brings research results from these figures in a broad synthesis.  Environmental science is broad because it encompasses (encompasses) o Natural sciences (study the natural world) o Social sciences (human interactions and institutions)  Most environmental science programs focus more on natural sciences as they pertain (属于)to environmental issues.  Programs heavily on social sciences prefer the term environmental studies People differ in their perception(认识) of environmental problems  Environmental problem is any undesirable(不受大家欢 迎的) change in the environment o Although a perception of what an undesirable change is may vary from one person to another o Information about environmental health risks reaches wealth people more readily (容易的)than poor people.  Therefore, who you are, where you live, what you do, your income, gender, and socioeconomic status can have a huge effect on how you perceive your environment. Environmental Science is not the same as Environmentalism  Environmental science is not the same as environmentalism or environmental activism(激进主义) . o Environmental Science is the pursuit(职业) of knowledge about the workings of the environment and our interactions with it. o Environmentalism Is a social movement dedicated to protecting the natural world, and humans from undesirable changes brought about by human choices. o Canadian Environmental Perspectives are in each chapter of the book and contain brief profiles of Canadian environmental scientists who contribute to the understanding, protection, management and sustainable use of the natural environment.  All of them have made a difference , some are  Scientists and writers  Scientists or filmmakers  Gardeners, politicians, or musicians o Many of them are also environmentalists(环保主义者).  David Suzuki – scientist, activist & environmentalist The Nature of Science  Science is a systematic process for learning about the world and testing our understanding of it. o Term is used to refer to the accumulated body of knowledge that arises from this dynamic process of observation, testing and discovery o Most important applications of science are its use in developing technologies and its use in informing policy and management decisions.  Why does science matter? o Late astronomer Carl Sagan wrote ‘The demon- haunted world: science as a candle in the dark’  Everything depends on science  Transportation, communications, agriculture, medicine, education, entertainment, protecting the environment, voting Scientists test ideas by critically examining evidence  Scientists examine ideas about how the world works by designing tests to determine whether these ideas are supported by evidence. The scientific method is a key element of science  Scientific Method is a process that scientists generally follow o Theme with variations, scientists persue their work in many different waves. o Scientists from different fields approach their work differently.  Chemist will conduct research differently from a social scientist  Science is a broad sense to include o Natural science o Social science  Scientific Method relies on the following assumptions: o The universe functions in accordance(一致) with fixed natural laws that do not change from time to time or place to place o All events arise from some cause and lead to other events o We can use our senses and reasoning abilities to detect and describe natural laws that underlie the cause and effect relationships we observe in nature.  Researchers do the steps below o Make observations (观察)(set the scientific method in motion and function throughout the process) o Ask questions. Scientists are naturally curious. (why are certain plants or animals less common today than they once were?) o Develop a hypothesis. Hypothesis is an educated guess that explains a phenomenon or answers a scientific question.  Eg. A scientist investigating the question of why algae are growing excessively in local ponds might observe chemical fertilizers being applied on farm fields nearby.  The scientist than makes hypothesis: o ‘Agricultural fertilizers running into ponds cause the algae in the ponds to increase’  A null hypothesis is a statement that the scientist is expecting no relationship between variables. Such as between fertilizer and algael growth in a pond. o Make Predictions  Scientist uses the hypothesis to generate(生成) predictions which are specific statements that can be tested.  In the algae example, a prediction might be ‘If agricultural fertilizers are added to a pont, the quantity of algae will increase’ o A null hypothesis can also lead to predictions; for example, scientist might predict that adding agricultural fertilizer to a pond will cause no change in the amount of algae growing in the pond. o Test the predictions  Tested one at a time by gathering evidence that can disprove the hypothesis  Evidence comes from experiment which is a activity designed to test the validity of a hypothesis  Involves manipulating(利用) variables (conditions that change) o Algae example > a scientist could test the hypothesis linking algal growth to fertilizer by selecting two identical ponds and adding fertilizer to one while leaving the other in its natural state.  In this example  Independent variable is fertilizer input, which is a variable the scientist manipulates, whereas
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