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University of Toronto Scarborough
Environmental Science
Carl Mitchell

EESA01 Chapter one Introduction to Environmental “Science” -The first photographs of the planet earth were taken in 1967. A photograph of the planet earth reveals a great deal but it does not show the complexity of our environment. - Our environment is more then water land and air; it is the total of our surroundings. It includes biotic (living things) and abiotic (none living things) components. - Our environment has abiotic physical constituents such as ocean, clouds, rivers, and icecaps. It also has biotic such as animals, plants, forests, soils, and people that occupy the landscape. - People commonly use the term ‘environment’ in a narrow sense such that it is apart from human society. This is unfortunate because it masks the fact that humans are a part of the interactions that characterise the environment. - In its most inclusive sense our environment includes the complex webs of scientific, ethical, political, economic and social relationships that shape our daily lives. - Environment Canada is here to preserve and enhance the quality of Canada’s natural environment, conserve our renewable resources, and protect our water resources. International relations, politics, ethics, business management, economics, social quality, engineering, law enforcement all play a role in managing and protecting the environment. - We depend utterly on our environment for air, water, food, shelter, and everything else essential for living. However our actions modify our environment ; many of which have enriched our lives bringing us longer life spans, mobility, and leisure however many of them have damaged the natural systems that sustain us. Such impacts are air, water pollution, soil erosion, species extinction, risk to human life and threaten our ability to build a society that will survive and thrive in the long term. -Environmental Science is the study of how the natural world works, how our environment effects us, and how we effect our environment. - With these problems come opportunities for devising creative solutions. As of now global conditions are changing rapidly, we as a civilization are gaining knowledge rapidly through science, with all this happening this time is really exciting to be studying environmental science. -There are limits to our Natural resources which are vital to our survival. Natural resources lie along a continuum from perpetually renewable to non-renewable or inexhaustible also called stock-and-flow resources. - Natural resources that are replenishable over short periods are known as renewable natural resources. Some renewable resources such as sunlight, wind, and wave energy will always be there for us. - Resource management is strategic decision making and planning aimed at balancing the use of a resource with its protection and preservation. This means to balance the rate of withdrawal from the stock with the rate of renewal or regeneration. The stoke is the harvestable portion of the resource. If the stock is being harvested or withdrawn at a faster rate then it can be replenished then the stock will eventually be depleted. ( faster then trees can be seeded and grown to maturity or faster then fish can be born and grown to harvest). - Non-renewable natural resources like crude oil, natural gas, coal, copper, are in finite supply and are depletable, because they are formed much more slowly then we use them. It can take 100million years for this to form. Once we use them up they are no longer available because they will not be replenished on a humanly accessible time scale. - Iron makes steel - Copper is used in pipes, electrical wires, etc... - Aluminum used for packaging –Lead in batteries - Human population growth sts shaped our resource use. Our population has surpassed 6 billion people just before the start of the 21 century. - There are 4 significant periods which seemed to have triggered population growth. 1 – 2.5 million years ago when early humans gained control of fire and began to shape and use stones as tools. nd 2 – the transition from a hunter-gathering life style to settled agricultural way of life. Agricultural revolution. ( this began around 10000 to 12000 years ago) people began to grown their own crops and rise domestic animals. 3 – known as the industrial revolution began in the mid 1700s and entitled a shift from rural life to urban society. This is when pollution started, and air quality declined. Workplace heal and safety also affected. Introduced sanitation and medical technology. Agricultural production was greatly enhanced by introducing the fossil fuels powered equipment, fertilizers, and steam engines. th 4 – today we are in the midst of the forth transition which some have labelled the medical technological revolution. Advances in medicine and sanitation, explosion of communication technology. The shift to modern agricultural practices known as the green revolution that have allowed people to live a longer and healthier life. -Each transition introduced technological advancements that made life easier and resources more available, which allowed the human population to increase dramatically. -Population growth affects resource use and availability, and it is the root of many environmental problems. Total impact(I) = Population (P)x affluence(A) x technology(T)...I=PxAxT - This IPAT model shows that impact is a function not only of population but also of affluence and technology. An increase in the number of people (P) has impact in the environment. - When we think of the capacity of the planet we think of carrying capacity. -Carrying Capacity refers to the biological productivity of a system; it is a measure of the ability of a system to support life. Environmental scientists see it as the number of individuals of a particular species that can be sustained by the biological productivity of a given area of land. When the CC of the land system is exceeded one of two things happen: the population of that species will decline or collapse, or the system itself will be altered, damaged, or depleted. (page 11 ex: rapa nui) - Garrett Hardin made a study about this: he based his argument on a scenario on a commons that is open to unregulated grazing. He argued that each person who puts animals to graze on the commons will be motivated by selfish interest to increase the number of his or her animal in the pasture. Because no one owns the pasture no one has the right to limit the number of grazing animals. This is known as the 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. -The ecological footprint was invented by Mathis Wackernagel and William Rees. It is a tool that can be used to express the environmental impact of an individual or a population. It is calculated in terms of the amount of 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. - Our species is now using 39% more resources than are available on a sustainable basis from all the land on the planet. - An avg Canadian has 7.6 hectors Diamond could hypothesize why civilizations succeed or fail. He identified five critical factors that determine the survival of civilization: climate change, hostile neighbours, trade partners, environmental problems, and the society’s response to environmental problems. -Environmental scientists aim to comprehend how Earth’s natural systems function, how humans are influenced by those systems, and how we are influencing those systems. - Environmental science is an interdisciplinary field- one that employs concepts and techniques from numerous disciplines and brings research results from these disciplines together into a broad synthesis. (earth science, chemistry, biology, economics, political science, ethics) - Environmental science is especially broad because it encompasses not only natural science(disciplines that study the natural world) but also the social science ( disciplines that study human interactions and institution). Natural science provides us with the means to gain accurate information about our environment where as social science provides us with understanding human behaviour and weighting values. -Environmental studies highly incorporate the social and natural sciences. - An environmental problem is an undesirable change in the environment - Different countries may see environmental problems differently. An example would be in North America we do not like the use of pesticides because we know it harms us, where as in Africa because of all the Malaria they would welcome pesticides to destroy the malaria. - Environmental science is not the same as environmentalism. Environmental science is the pursuit of knowledge about the workings of the environment and our interactions with it while environmentalism is a social movement dedicated to protect the natural world. Environmental scientists attempt to maintain an objective approach in their work. -Science is a systematic process for learning for learning about the world and testing our understanding about it. (Observation, testing, and discovering) - Scientists generally follow a process called the scientific method which is a technique for testing ideas with observations. There are 6 steps to the scientific method 1-. Observations- observations set the scientific method in motion 2- ask Questions- scientists are naturally curious about the world and love to ask questions 3- develop a Hypothesis- scientists attempt to answer their questions by devising explanations. A hypothesis is an educated guess that answers a scientific question 4- make Predictions – The scientists then uses the hypothesis to generate predictions, which are specific statements that can be directly and unequivocally tested. (ex: if you add this it might increase this) 5- Test the prediction- Predictions are tested one at a time that could potently refute the prediction and thus disprove the hypothesis. The strongest form of evidence is to conduct an experiment. An experiment is an activity designed to test the validity of a hypothesis. It involves manipulating variables conditions that can change. (A scientist could test the hypothesis of algal growth to fertilizer. He picks 2 similar ponds and adds fertilizer to one. The fertilizer is the independent variable the variable in which the scientist manipulates, where as the quantity of algae that results is the dependent variable, one that depends on the fertilizer input. This experiment is known as a controlled experiment because the scientist controls the event. In this example the ponds left unfertilized serves as a control, an un-manipulated point of comparison. Sometimes a hypothesis can be convincingly addressed through correlation, that is, searching for relationships and patterns among variables. 6- Analyze and interpret results- Scientists record data or information from their studies. They particularly value quantitative data. There are different ways to test hypotheses .- An experiment in which the researcher actively chooses and manipulates the independent variable is known as a manipulative experiment. This provides the strongest type of evidence a scientist can obtain. .- Disciplines that do not quite fit the so-called physics model of science sometimes rely on natural experiments rather than manipulating ones. ( an example of this would be if a scientist wants to test whether animal species isolated on oceanic islands tend to evolve large body size over time). -The science of ecology deals with the distribution of living things, the interaction among them, and the interaction between organisms and their abiotic environment. The scientific process does not stop with the scientific method. Scientific work takes place within a context of a community of peers and to have any impact a researchers work must be published. - It starts with peer review in which when a researchers work is done he or she writes of the findings and submits them for publication. Conference presentation then takes place in which the scientist presents his or her work to their colleagues and receives comments. Research scientists spend large portions of their time writing grant applications requesting money to fund their research(grants and funding). Repeatability then takes place in which the experiment is done many times to ensure the findings were not just a onetime occurrence. If a hypothesis survives repeated testing by many research teams it may b potentially incorporated in to a theory. A theory is a widely accepted, well tested explanation of one or more cause and effect relationships, which has been validated by extensive research. -Results obtained by the scientific method may sometimes later be reinterpreted to show that earlier interpretations were incorrect. (one scientific paradigm, or dominant view is abandoned for another). An example of this would be in the 16 centaury scientists believed that earth was at the center of the universe, until it was proven wrong that the sun was. -We add about 78million people to the planet each year, more than 200000 people per day - out door air pollution, indoor air pollution, and water pollution contribute to the deaths of millions of people each year. - Today earth`s biodiversity, the cumulative number and diversity of living things is declining dramatically. Loss of biodiversity is the most serious thing right now because the extinction of species is irreversible; once a species has become extinct, it is lost forever. The Millennium Ecosystem Assessment occurred in 2005 when 2000 of the worlds environmental scientists discussed the conditions of the worlds ecological system and supporting our civilization. -The main findings were that over the past 50 years humans have changed ecosystems more rapidly than any other period of time. The changes made to the ecosystem have contributed to a net gain in human well being st and economic development, things can get worse during the 1 half of the century, reversing this is possible but many changes will have to be made. -Our reliance on fossil fuels to power our civilization has intensified virtually every negative impact we have on the environment. We have started the change by recycling and also laws have reduced pollution. - Sustainability is a goal for the future. - Sustainability means leaving our children and grandchildren a world as rich and full as the world we live in now. - Economists employ the term development to describe the use of natural resources for economic advancement. Examples include construction of homes, schools, hospitals, power plants, factories, and transportation net works which are activities in support of development. - Sustainable development is the use of renewable and non-renewable resources in a manner that satisfies our current needs without without compromising future availability of resources. (meeting the needs of the present without sacrificing the future). Chapter 6 Humans, Population and the Environment - Human population is approaching 7 billion; while china works to slow its population growth and speed its economic growth, population continues to rise in most nations. - Most of this occurs in poverty-stricken nations. - India is on course to surpass China as the world’s most populated nation. - To estimate the doubling time just take the number 70 and divide it by the annual percentage growth rate. - China is expected to stabilize at 1.4billion people - Environmental scientists recognized that few resources are by humans, and that not all resources could be replaced such as land, or a species of animals. Unless resource availability keeps pace with population growth, the average person in the future will have less space in which to live, less food to eat, and less material wealth than the average person does today. This shows that the increase in population is indeed a problem. - The IPAT model represents how our total impact (I) on the environment results from the interaction among population (P), affluence (A), and technology (T): I= PxAxT - This shows that increase in population intensifies impact on the environment as more individuals take up space, use resources, and generate waste. - Sensitive factor (S) might also be added to the equation to denote how sensitive a given environment is to human pressures: I=PxAxTxS (an example of this would be western china and south-eastern china; plants grow more slowly in the west, making deforestation and soil degradation more likely. Thus adding an additional person to western China should have more environmental impact then adding one to the south-east. - Technology (T) has helped the population a lot. For instance we have employed technological advances to increase global agricultural production faster than our population has risen. - Demography is a social science that applies the principles of population ecology to the study of statistical change in human populations. - Environmental factors set limits on our population growth, and the environment has a caring capacity one that we have increased by developing technology to overcome natural limits on population growth. - An estimate of 1 to 2 billion are living in a healthy environment and 3 billion living in extreme poverty. - Demographers stud y population size, density, distribution, age structure, sex ratio, and rates of birth, death, immigration, and emigration of humans, just as population ecologists study these characteristics in other organisms. (China has 1,3billion and India has 1.2 billion) - Population size is the number of individual organisms present at a given time. - People are distributed very unevenly around the globe. - Population density is the number of people per unit of land area. It is normally high in places with tropical and subtropical climates such as China, India, Mexico, and really low in regions with extreme climate biomes such as desert, and deep rainforest. - The dramatic shift in age structure will change China’s economy, health care system, families, and military forces because fewer working-age people will be available to support social programs that assist the increasing number of older people. The reduced number of young adults may mean a decrease in crime rate. Whereas older people are often productive in volunteering. - The ratio of male and female can also affect population dynamics. An example would be having two Islands one with 99men and 1 woman the other with 50 men and 50 women. Population would increase with the 50 men and 50 women. - The natural occurring sex ratio in human population at birth is for every 100 female infants born, 105 to 106 male infants are born. - Rates of birth, death, immigration, and emigration help determine whether a human population grows, shrinks, or remains stable. - It is convenient to express birth and death rates as the number of births and deaths per 1000 individuals for a given period- the crude birth rate and crude death rate. - Technological advancements have lead to a dramatic decline in death rates, widening the gap between death rates and birth rates resulting in global human population expansion. - Total fertility rate influences population growt
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