Transcript sustainable
The Environmental Challenges We Face Day 1 Questions of the Day • How do we impact the environment? • What environmental challenges does your generation face? • What are some examples of positive steps to lessen our human impact? • Image available through pdf file A World in Crisis A World in Crisis – Earth provides raw materials and energy for Life – Earth is approx 4.5 Billion years old • Modern humans appeared in Africa 195,000 yrs ago • Human populations have grown and expanded in range • Technology has allowed humans to live better (at least in developed nations) – Humans are the most significant agent of environmental change • • • • • Overpopulation Overconsumption of natural resources: topsoil, water, air Transforming and destroying natural environments Eradicating unique species Human-induced climate change Human Impacts on the Environment • Overpopulation – Earth’s central environmental problem – Links all other environmental problems together – World’s population continues to grow and has grown very fast – 1960: 3 billion people – 1975: 4 billion – 1987: 5 billion – 2009: 6.8 billion • People consume food and water, use energy and raw materials and produce waste • Several more billion people will be added in the 21st century, even if we are proactive about population growth What does this image tell you? Population Increase Human Impacts on the Environment • Population Growth – Projected 7.7–10.6 billion people depending on fertility rate – Current fertility rate is 2.6 children/woman • Family planning efforts – World’s population may stabilize by end of 21st century • Can Earth support so many people? – We don’t know • Quality of life depends on being able to produce enough food in a sustainable manner – Without destroying the biological communities that support life on our planet Human Impacts on the Environment • Population Size – Number of people • Population Consumption – Use of materials and energy • Economic Growth – Expansion of the output of a nation’s goods and services • Intimately related Human Impacts on the Environment Population, Resources, and the Environment • Developing countries – Rapid population growth is overwhelming – Natural resource depletion for survival (soils, forests, water) • Developed countries – Slower population growth – Higher rate of consumption beyond what’s necessary for survival (TV, computers, jet skis) Human Impacts on the Environment Human Impacts on the Environment Types of Resources • Nonrenewable – Limited Supply: minerals, fossil fuels – Once they are gone, they are gone • Renewable/Potentially Renewable – Virtually unlimited: solar power, water, soil, forests – Replenished over short periods (days to decades) – Easy to overexploit nonrenewable • Soil, fresh water, clean air Human Impacts on the Environment Resources and Population • Rapid population growth can cause resources to be overexploited – Critical in developing countries – Economic growth tied to natural resource exploitation – Choice between short term and long term Human Impacts on the Environment Population Size and Resource Consumption • A country is overpopulated if the demand on its resources results in damage to the environment. Can be overpopulated in 2 ways: • People Overpopulation – Consumption is high because there are too many people, even if individual consumption is low • Consumption Overpopulation – Consumption is high because each individual consumes too much, even if total population is low Human Impacts on the Environment Population Size and Resource Consumption • Highly developed countries have less than 20% of the world’s population, but consume: – 86% of aluminum – 76% of timber – 68% of energy – 61% of meat – 42% of fresh water • Also, produce 75% of waste and pollution Human Impacts on the Environment Human Impacts on the Environment Population Size and Resource Consumption • Ecological Footprints – The amount of land, fresh water, and ocean required on a continuous basis to supply a person with food, wood, energy, water, housing, clothing, transportation, and waste disposal. – Earth has 11.4 billion ha = 28.2 billion acres of productive land and water – 11.4/6.8 billion people = 1.8 ha (4.3 acres) – Currently, average ecological footprint is 2.7 ha (6.7 acres) – US footprint is 9.4 ha (23.3 acres) if everyone in the world had the same, we would need 4 Earths!!! Human Impacts on the Environment Day 2 Global Climate Change 1. How do highly developed countries, moderately developed countries, and less developed countries differ regarding population growth and per person incomes? 2. How is human population growth related to natural resource depletion and environmental degradation? Sustainability and Earth’s Capacity to Support Humans • Learning Objectives: 1. Define environmental sustainability. 2. Identify human behaviors that threaten environmental sustainability Human Impacts on the Environment Sustainability and Earth’s Capacity to Support Humans • Sustainability: – Ability to meet current needs without compromising the ability of future generations to meet their needs – Environment will function indefinitely – Based on: • • • • Effects of our actions on the environment Earth’s resources are finite Understanding impacts of consumption Shared responsibility for environmental sustainability Sustainability and Earth’s Capacity to Support Humans • We are not currently living sustainably: – Using nonrenewable resources as if they were renewable (e.g., fossil fuels) – Using renewable resources faster than nature can replenish them – Polluting the environment beyond capacity – Unchecked population growth, without regard to Earth’s finite resources and ability to deal with waste Environmental InSight Global Environmental Issues Global warming Deforestation Global Environmental Issues Threatened Oceans Desertification Global Environmental Issues Polar Ice caps Ozone Depletion Global Environmental Issues Environmental stress factor Sustainability and Earth’s Capacity to Support Humans • If we continue to live unsustainably, Earth may not recover • What changes are we willing to make? Focus on Sustainability Global Climate Change 1. What is environmental sustainability? 2. Which human behaviors threaten environmental sustainability? Environmental Science • Learning Objectives: 1. Define environmental science. 2. Outline the steps of the scientific method. Environmental Science • Interdisciplinary study of humanity’s relationship with other organisms and the physical environment – combines information from many fields: • biology, geology, geography, chemistry, economics, agriculture, law, politics, ethics, etc. – Ecology is a basic tool – Atmospheric Science – Environmental Chemistry – Geosciences Environmental Science • Goals – Establish general principles about how the natural world functions – Identifying, understanding, and solving problems that we have created – Not just ‘doom and gloom’ list of problems – Focus on solving problems Environmental Science • Science as a Process – Not just a collection of facts – Systematic way of studying the natural world – Requires collection of data through • Observation and experimentation – – – – – – Data must be analyzed and interpreted Not based on faith, emotion, intuition Requires repeatability and scrutiny No absolute certainty Requires reevaluation Ongoing process Environmental Science The Scientific Method – Process that scientists use to answer questions or solve problems 1. Recognize a question/problem 2. Develop a hypothesis (educated guess) to explain the problem 3. Design and perform an experiment to test the hypothesis 4. Analyze and interpret the data to reach a conclusion 5. Share knowledge with scientific community The Scientific Method Environmental Science • The best hypotheses make predictions • Predictions provide a way to test hypotheses – If experiment refutes hypothesis, hypothesis is rejected – If hypothesis is verified repeatedly, hypothesis is strong • Science progresses from uncertainty to less uncertainty • Science is self-correcting even though it never ‘proves’ anything Environmental Science • Experiments test hypotheses – Variable: factor that influences a process – To test a hypothesis, two experiments are carried out: • Experimental Group: the chosen variable is altered in a known way • Control Group: the chosen variable is not altered – We can ask: What is the difference (if any) between the two groups? – Any differences would be due to the experimental variable Environmental Science • Scientific Theory – An integrated explanation of many hypotheses, each supported by many observations and experiments. – Simplifies and clarifies our understanding of the natural world. – Solid ground of science – Generally accepted as ‘true’, even though there is no absolute truth in science – Contrast with general public’s use of theory, as a guess, or hypithesis Environmental Science • Science is constantly evolving – As new evidence comes to light, conclusions may change – Therefore, scientific conclusions are provisional, which doesn’t mean they are invalid. – E.g., smoking and cancer Global Climate Change 1. What is environmental science? What are some of the disciplines involved in environmental science? 2. What are the five steps of the scientific method? Why is each important? How We Handle Environmental Problems • Learning Objectives: 1. List and briefly describe the five stages of solving environmental problems. How We Handle Environmental Problems Global Climate Change 1. What are the five steps used to solve an environmental problem? EnviroDiscovery • NIMBY = not in my backyard • NIMTOO = not in my term of office • Examples: – People don’t want power plants, landfills, incinerators nearby – Politicians want to be reelected, so they don’t support those decisions in their districts EnviroDiscovery Case Study The New Orleans Disaster: Hurricane Katrina – Storm damage was increased because of human alteration of the natural landscape: – Canals were built for navigationallowed salt water to intrude and kill marsh vegetation – Levees were built to stop floodingsediments did not build up to replenish the land – Settlements were built on drained wetlands – City was subsiding due to lack of bedrock Case Study