Presentation on theme: "The Environmental Challenges We Face Chapter 1. A World in Crisis –Earth provides raw materials and energy for Life –Earth is approx 4.5 Billion years."— Presentation transcript:
The Environmental Challenges We Face Chapter 1
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
A World in Crisis
Human Impacts on the Environment Learning Objectives: 1.Distinguish among highly developed countries, moderately developed countries, and less developed countries. 2.Relate human population size to natural resources and resource consumption. 3.Distinguish between people overpopulation and consumption overpopulation. 4.Describe the three factors that are most important in determining human impact on the environment.
Overpopulation –Earths central environmental problem –Links all other environmental problems together –Worlds 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 21 st century, even if we are proactive about population growth Human Impacts on the Environment
Linear vs. Exponential Linear growth - a quantity increases by a constant amount per unit of time: 2, 4, 6, 8 or 1, 3, 5, 7, 9 & so on. Exponential growth - a quantity increases by a fixed percentage of the whole in a given time: 1, 2, 4, 16
Poverty –A condition in which people are unable to meet their basic needs for food, clothing, shelter, education, or health. –One in four people lives in extreme poverty (less than $2/day): 3.3 billion people –Poverty is associated with short life expectancy, illiteracy, inadequate access to health services, safe water, balanced nutrition 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 –Worlds population may stabilize by end of 21 st century Can Earth support so many people? –We dont 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 nations goods and services Intimately related Human Impacts on the Environment
Gap between Rich and Poor Highly Developed Countries (Rich, HDCs) –Complex industrialized bases, low rates of population growth, and high per person incomes –18 % of the worlds population –US, Canada, Japan, most of Europe Human Impacts on the Environment
Gap between Rich and Poor –Poor Countries: 82% of worlds population –Moderately Developed (MDCs) Medium levels of industrialization, lower per person incomes than highly developed countries, few opportunities for education and health care Mexico, Turkey, South Africa, Thailand –Less Developed (LDCs) Low levels of industrialization, high population growth, very high infant death rates, very low incomes, mostly agriculture based, cheap unskilled labor Bangladesh, Mali, Ethiopia, Laos Human Impacts on the Environment
Gap between Rich and Poor 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 whats necessary for survival (TV, computers, jet skis) 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
1.energy resources: coal, oil, natural gas, uranium, 2.metallic mineral resources iron, copper, aluminum, & 3.nonmetallic mineral resources salt, clay, sand, & phosphates We convert these raw materials into many everyday items we use, & then we discard, reuse, or recycle them. 3 Types of Resources
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 Poverty drives natural resource exploitation –Must use resources to survive, which degrades them and shuts down future opportunities for development 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 worlds 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
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
Population, Consumption, and Environmental Impact I = P x A x T I: Environmental impact P: Population (number of people) A: Affluence per person (amt of resources) T: Technology used to get resources Interpret results with care! Ultimate goal: make consumption sustainable Human Impacts on the Environment
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 Earths Capacity to Support Humans Learning Objectives: 1.Define environmental sustainability. 2. Identify human behaviors that threaten environmental sustainability
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 Earths resources are finite Understanding impacts of consumption Shared responsibility for environmental sustainability Sustainability and Earths 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 Earths finite resources and ability to deal with waste Sustainability and Earths Capacity to Support Humans
The Tragedy of the Commons One cause of environmental degradation is overuse of common-property resources, which are owned by none & available to all users free of charge. Most are potentially renewable. It happens because each user reasons, "If I don't use this resource, someone else will. The little bit I use or pollute is not enough to matter"
Global Environmental Issues Global warming Deforestation
Global Environmental Issues Threatened Oceans Desertification
Global Environmental Issues Polar Ice capsOzone Depletion
Global Environmental Issues Environmental stress factor
Sustainability and Earths 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 humanitys 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 publics 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 doesnt 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 dont want power plants, landfills, incinerators nearby –Politicians want to be reelected, so they dont support those decisions in their districts
Case Study The New Orleans Disaster: Hurricane Katrina –Storm damage was increased because of human alteration of the natural landscape: –Canals were built for navigation allowed salt water to intrude and kill marsh vegetation –Levees were built to stop flooding sediments did not build up to replenish the land –Settlements were built on drained wetlands –City was subsiding due to lack of bedrock