Environmental Science

4.1 Notes 

Human Population and Environmental Impact 

• Global Population: Over 8 billion people. 

• Environmental Impact: Determined by population size and per-person impact. 

• Solution: Address high birth rates, focusing on social justice, particularly for women. 

Case Study: Kerala Model (India) 

• Goal: Achieve full literacy, resulting in a lower birth rate. 

• Outcome: Higher literacy led to lower population growth. 

• Importance: Kerala is a model for sustainable development without high resource consumption. 

Human Population Growth Phases 

1. Agricultural Revolution: 

1. Transition from hunter-gatherer societies to farming. 

2. Increased food production, better diets, higher birth rates. 

2. Industrial Revolution: 

1. Improved health and sanitation. 

2. Life expectancy more than doubled since 1800. 

3. Current Trends: 

1. Slowed growth rate (around 1%). 

2. Zero population growth when birth and death rates equalize. 

Global Population Distribution 

• Top 10 Countries: 60% of the world’s population lives in China, India, the U.S., Indonesia, Pakistan, Nigeria, Brazil, Bangladesh, Russia, and Mexico. 

• Migration Patterns: Urban areas attract the most growth; 50% of the U.S. population lives near coasts. 

Factors Influencing Population Growth 

• Pro-natalist Pressures: Cultural or economic pressures for larger families (e.g., high infant mortality, lack of contraception). 

• Demographic Factors: 

• Crude Birth Rate: Higher in less developed countries. 

• Crude Death Rate: Generally stable, higher in aging populations in developed countries. 

Demographic Transition Model 

1. Preindustrial: High birth and death rates; low population growth. 

2. Industrializing: Death rates drop; rapid growth. 

3. Mature Industrial: Birth rates start to drop; growth slows. 

4. Postindustrial: Birth and death rates stabilize; low growth. 

Social Justice and Population Control 

• Women's Education: Empowers women, reduces fertility. 

• Employment Opportunities: Lower childhood mortality, delayed marriages. 

• Kerala's Advantages: Matrilineal culture, accessible education/healthcare, missionary schools. 

Earth's Carrying Capacity 

• Carrying Capacity: The maximum population an environment can support sustainably. 

• Ecological Footprint: Reflects resource use and waste production. 

• Sustainability: Many experts believe we have exceeded Earth's sustainable carrying capacity. 

4.2 Notes 

Urbanization and Green Cities 

• Key Message: Cities can help or harm the environment. With green strategies, cities can improve quality of life, reduce health risks, and conserve resources. 

• Importance: More than half of the global population lives in cities, making sustainable urbanization essential. 

Case Study: Revitalizing the Bronx 

• Environmental Issues: Poor air quality due to waste facilities and power plants. 

• Initiative: Majora Carter developed a waterfront park to provide a healthier environment. 

• Goal: Equitable access to a clean and safe environment, regardless of income level. 

Urbanization Trends 

• Urban Population Growth: Over 54% of the world’s population lived in urban areas by 2014. 

• Megacities: Cities with over 10 million people; their numbers have increased significantly since 1950. 

Pros and Cons of Urban Living 

• Advantages: 

• Job opportunities, better education and healthcare access, cultural amenities. 

• Smaller carbon footprint per capita, recycling, and mass transit options. 

• Disadvantages: 

• Requires resource import, waste export, and has issues with pollution and urban heat. 

Environmental Justice in Urban Areas 

• Definition: Everyone should have access to a clean and healthy environment. 

• Issues: Low-income communities often face worse environmental conditions (e.g., Bronx, Flint, Michigan). 

Suburban Sprawl and Environmental Impact 

• Definition: Expansion of low-density developments outside cities, leading to higher environmental impact. 

• Consequences: Loss of farmland, increased car dependence, larger homes with higher energy use. 

Urban Green Spaces 

• Benefits: 

• Improve mental and physical health, decrease crime, support wildlife, and reduce air pollution. 

• Example: Vancouver, Canada, aims to make green spaces accessible within a five-minute walk. 

Green Cities and Sustainable Design 

• Green Cities: Focus on reducing environmental impact while enhancing social equity. 

• New Urbanism: Promotes mixed-use, compact communities to lower per capita environmental impact. 

• Examples: Vienna, Berlin, and Madrid among the top green cities. 

Smart Growth and Urban Planning 

• Smart Growth: Encourages walkable communities, redevelopment of empty lots, and vertical rather than horizontal expansion. 

• Goal: Minimize sprawl and associated pollution. 

Green Buildings and LEED Certification 

• Green Building: Emphasizes efficient use of energy and water, and sustainable materials. 

• LEED: A certification by the U.S. Green Building Council; levels include standard, silver, gold, and platinum. 

Green Roofs 

• Benefits: Reduced cooling costs, decreased greenhouse gas emissions, stormwater retention, and urban heat reduction. 

• Case Study: NYC green roofs could save millions in cooling costs and significantly reduce greenhouse gases. 

Summary 

• Cities can be sustainable through green strategies that reduce environmental harm and support healthier urban living. The Bronx’s transformation demonstrates how urban renewal can promote social equity and environmental justice. 

4.3 Notes 

1. Connection Between Environment and Health 

• Human health is deeply tied to environmental factors; changes in the environment caused by human actions can either facilitate disease or reduce its spread. 

• Public health initiatives focus on minimizing environmental health risks through improved sanitation, clean water access, and targeted health programs. 

2. Guinea Worm Disease (GWD) Overview 

• GWD is caused by consuming water contaminated with copepods that carry Guinea worm larvae. 

• The larvae mature in the body, where female worms grow up to 3 feet and cause painful blisters from which larvae are released, perpetuating the cycle. 

• There are no vaccines or medications for GWD, and infection does not confer immunity. 

3. Environmental Hazards and Their Health Impacts 

• Humans face various environmental hazards, such as air and water pollution, chemical and physical hazards (e.g., radiation, asbestos), and biological hazards like infectious diseases. 

• Air pollution is a primary environmental health threat globally. 

4. Disease Transmission and Human Impact 

• Waterborne and vector-borne diseases are major infectious disease threats, often exacerbated by environmental disruptions. 

• Examples: 

• Waterborne: Guinea Worm Disease. 

• Vector-borne: West Nile Virus, Black Death, Lyme Disease. 

• Human activities such as deforestation and urbanization increase disease vulnerability by expanding habitats for pathogens. 

5. Role of Public Health 

• Public health efforts aim to improve population health by addressing environmental and social factors, focusing on disease prevention, and creating solutions like improved water filtration. 

6. Environmental Health Challenges 

• Factors like contaminated air, water, and soil, alongside human behaviors (e.g., improper sanitation practices), are major focuses of environmental health. 

• Efforts to remediate toxic exposures are ongoing, including in locations like Endicott, NY, where vapor intrusion remediation systems are installed. 

7. Chemical Hazards and Toxicology 

• Industrial chemicals improve life quality but also introduce natural and synthetic toxins into the environment. 

• Toxic substances have varying effects: 

• Acute Effects: Rapid reactions, like death from poison. 

• Chronic Effects: Long-term health issues, such as those from air pollution. 

• Factors like potency, persistence, and solubility of toxins affect their potential for harm. 

8. Disease Eradication Efforts and Challenges 

• Guinea Worm Disease eradication efforts include water treatment, filtration education, and the application of pesticides to eliminate the copepod vector. 

• Public health campaigns faced obstacles due to local beliefs, but interventions were successful in regions like Nigeria after gaining community trust. 

• Eradication efforts now include controlling GWD in animal hosts like dogs, as seen in Chad. 

9. Environmental Health Disparities 

• Developed nations experience more noncommunicable diseases (e.g., heart disease), while low-income nations face higher rates of infectious diseases due to environmental conditions. 

• Globally, 23% of annual deaths are linked to environmental factors, primarily noncommunicable diseases, with a smaller portion due to infectious diseases like diarrheal illnesses and malaria. 

10. Addressing Environmental Health and Sustainability 

• Actions to reduce environmental health risks include policies for air and water quality improvement and public empowerment. 

• Solutions often require financial support, education, and cultural sensitivity, especially in developing regions. 

• Education on simple health technologies, like water filters, can be crucial for disease prevention and sustainability efforts. 

Summary 

• Guinea Worm Disease serves as a case study of how environmental health initiatives can lead to successful disease control. 

• The Carter Center’s involvement, educational campaigns, and international support have significantly reduced GWD cases in Africa. 

5.1 Notes 

Core Message of Ecological Economics 

• Human activities impact Earth primarily through resource use, often prioritizing short-term gain over sustainability. 

• Sustainable decisions should consider economic, social, and environmental costs. Emulating nature’s processes can help create a sustainable economy. 

2. Ecosystem Services and Economic Importance 

• Ecosystem Services: Essential processes like oxygen production, water purification, and pollination sustain life and are economically valuable. 

• Economic Importance: Recognizing ecosystem services can encourage resource protection and sustainable practices. 

3. Measuring Human Impact: The Ecological Footprint 

• Ecological Footprint: Represents the amount of land needed to supply resources and absorb waste for an individual or population. 

• If global lifestyles matched the average U.S. lifestyle, five Earths would be needed to sustain humanity, highlighting the unsustainable nature of high-consumption societies. 

4. Natural Capital and Natural Interest 

• Natural Capital: Earth’s resources (e.g., forests, water, fish) and the systems that generate them. 

• Natural Interest: Using resources at or below replacement rates helps maintain natural capital. 

• Sustainability Example: Ray Anderson aimed to make Interface Carpet a "restorative enterprise" by reducing environmental impact and replenishing natural capital. 

5. IPAT Model for Environmental Impact 

• IPAT Equation (Impact = Population × Affluence × Technology): Measures environmental impact, highlighting how population growth, consumption, and technology affect ecosystems. 

• Some technologies reduce impact, as seen with Interface’s TacTiles, which reduced VOC emissions and waste. 

6. True Cost Accounting 

• Internal vs. External Costs: Traditional pricing often ignores environmental and social costs (external costs), impacting public health and ecosystems. 

• True Cost: Incorporating both internal and external costs offers a more accurate product value, encouraging sustainability by making pollution and resource depletion financially visible. 

7. Environmental Economics and Mainstream Economic Assumptions 

• Environmental Economics: Advocates for sustainable resource use by valuing long-term environmental impacts and reducing dependence on nonrenewable resources. 

• Mainstream Economic Flaws: 

• Assumes unlimited growth and resource substitutes, ignoring ecological limits. 

• Discounts future impacts, leading to unsustainable practices like overfishing and pollution. 

8. Linear vs. Circular Economic Models 

• Linear Model: “Take, make, dispose” process, leading to waste and resource depletion. 

• Circular Model: Emphasizes reusing materials; waste is repurposed as a resource, seen in Interface’s ReEntry 2.0 program, which recycles carpet into new products. 

9. Sustainable Business Practices 

• Cradle-to-Cradle Management: Considers environmental impacts across a product's life cycle, focusing on recyclability and reduced waste. 

• Green Business: Businesses reduce their environmental impact by investing in renewable energy, durable materials, and take-back programs. 

• Examples: Tesla (electric vehicles), Beyond Meat (sustainable food). 

10. Sustainable Consumer Choices 

• Transparency and Ecolabeling: Clear labeling on product origins and production methods enables consumers to choose sustainable options. 

• Avoiding Greenwashing: Consumers must verify environmental claims to avoid supporting misleading eco-friendly marketing. 

• Fair Trade and Share Programs: Fair Trade promotes ethical labor and environmental sustainability. Sharing programs reduce consumption by providing access rather than ownership. 

Summary 

• Sustainable economics requires valuing environmental resources and adopting practices that minimize waste and environmental impact. 

• Interface’s efforts in sustainability demonstrate the feasibility of reducing waste and rethinking product life cycles. 

• Consumers play a crucial role by making low-impact choices and supporting sustainable businesses, helping shift the economy toward long-term ecological health. 

5.2 Notes 

ore Message of Environmental Policy 

• Environmental policies aim to protect the environment and public health by defining acceptable behaviors for individuals and groups. 

• Policy development is challenging due to the complexity of environmental issues, requiring responses to both ongoing and emerging problems. 

2. Case Study: Ozone Layer Depletion 

• Ozone Depletion: Caused by chlorofluorocarbons (CFCs) and other chemicals, which break down ozone (O₃) in the stratosphere, allowing more harmful UV radiation to reach Earth. 

• Health and Environmental Risks: Increased UV radiation can cause skin cancer, cataracts, disrupt ecosystems, and harm plant and animal life. 

• Susan Solomon’s Research: Her studies linked CFCs to ozone depletion, providing critical evidence for international action. 

3. Understanding Environmental Policies 

• Environmental Policy: Government or organizational actions intended to protect public health and the environment. 

• Transboundary Problems: Issues like ozone depletion that cross borders, necessitating international cooperation for effective solutions. 

4. Evolution of U.S. Environmental Policy 

• Modern Environmental Laws: Many key U.S. environmental laws were enacted in the 1960s and 1970s, including: 

• National Environmental Policy Act (NEPA): Established environmental protection as a policy goal and introduced the Environmental Impact Statement (EIS) requirement for federal actions. 

• Citizen Suit Provision: Allows citizens to sue violators of environmental laws to ensure enforcement. 

5. Policy Development and Implementation 

• NEPA and EIS: NEPA requires that potential environmental impacts are evaluated before a federal action is approved. 

• Environmental Protection Agency (EPA): The EPA enforces environmental laws and ensures compliance at state and federal levels. 

6. Influences on Policy Formulation 

• Science and Public Opinion: Effective policy should be based on sound science, but political lobbying, media, and public opinion also strongly influence decisions. 

• Political Lobbying: Industries often lobby for or against environmental regulations based on their interests. 

7. Tools for Enforcing Environmental Policies 

• Command-and-Control Regulation: Sets pollution limits with fines or penalties for violations. 

• Economic Incentives: Include: 

• Green Tax: Tax on harmful environmental activities. 

• Tax Credits: Financial incentives for environmentally friendly actions. 

• Cap-and-Trade: Limits emissions and allows companies to trade emissions permits. 

• Subsidies: Financial support for sustainable activities, like switching to renewable energy. 

8. International Environmental Policies 

• Treaties and Protocols: International agreements (treaties, conventions, and protocols) aim to address global issues like climate change and ozone depletion. 

• Enforcement Challenges: Achieving compliance is difficult; treaties rely on incentives (e.g., financial assistance) and disincentives (e.g., economic sanctions) for enforcement. 

9. Responding to Ozone Depletion: The Montréal Protocol 

• Montréal Protocol (1987): An international treaty to phase out CFCs and other ozone-depleting substances. 

• Adaptive Management: The protocol was revised over time to phase out harmful substances more quickly as new data emerged. 

• Success of the Protocol: The Montréal Protocol slowed ozone depletion, and scientists project full recovery of the ozone layer by 2050. It is seen as a model for successful international environmental policy. 

10. Policy on Climate Change 

• Paris Agreement: Signed by over 150 countries to address climate change, but implementation has faced challenges, especially from large greenhouse gas emitters like the U.S. 

• Future Prospects: The success of the Montréal Protocol shows that international cooperation on environmental issues is possible, but achieving consensus on climate change remains a global challenge. 

Summary 

• Environmental policies, like NEPA in the U.S. and the Montréal Protocol globally, aim to protect ecosystems and public health by setting standards and regulating harmful activities. 

• Addressing environmental issues is complex, particularly with transboundary problems that require international collaboration. 

• While the ozone depletion response was successful, the international community faces ongoing challenges with climate change policy, highlighting the importance of public engagement and adaptive management in environmental protection. 

5.2 Notes 

Core Message 

• Environmental policies protect both the environment and public health, but achieving consensus is challenging. 

• Policies must address both existing and new environmental problems. 

Case Study: Ozone Layer Depletion 

• Susan Solomon's Research: In 1986, Solomon’s work linked chlorofluorocarbons (CFCs) to ozone depletion. 

• Ozone Depletion Cause: CFCs and other chemicals break down ozone, allowing more UV radiation, which harms health and ecosystems. 

Ozone Layer and UV Radiation 

• Ozone: Located in the stratosphere, it blocks harmful UV rays. 

• UV Exposure: Increases skin cancer, harms plant growth, and disrupts ecosystems. 

Environmental Policy Basics 

• Purpose: To improve the environment and public health. 

• Transboundary Problems: Issues like CFCs require international cooperation, as pollution crosses borders. 

Evolution of U.S. Environmental Policy 

• 1960s-70s Legislation: Environmental protection became a focus with laws like the Clean Water Act and Clean Air Act. 

• National Environmental Policy Act (NEPA): Required environmental consideration for federal actions and established the Environmental Impact Statement (EIS) for project assessment. 

Policy Making and EPA's Role 

• Environmental Protection Agency (EPA): Enforces environmental laws, ensuring compliance with standards set by laws like NEPA. 

• Citizen Suit Provision: Allows private individuals to sue violators of environmental laws. 

Influences on Policy 

• Science: Ideally, policy decisions are based on sound science, but political lobbying, public opinion, and media can also influence outcomes. 

Policy Enforcement Tools 

1. Command-and-Control Regulation: Sets pollution limits, with penalties for non-compliance. 

2. Economic Incentives: 

1. Green Taxes: Tax undesirable activities (e.g., pollution). 

2. Tax Credits: Reward environmentally friendly actions. 

3. Cap-and-Trade: Limits emissions, allowing companies to trade permits. 

International Policy Framework 

• Treaties and Protocols: Address global issues like ozone depletion. 

• Convention: Broad goals. 

• Protocol: Specific targets (e.g., Paris Agreement on climate change). 

Montréal Protocol on Ozone Depletion 

• 1987 Protocol: Phased out CFCs, later adjusted for stronger impact. 

• Success: Ozone recovery is projected by 2050 due to international cooperation. 

Challenges in Climate Policy 

• The Paris Agreement, aimed at reducing greenhouse gases, faces obstacles due to varying national commitments. 

• The U.S.'s fluctuating support underscores the difficulty of unified global action. 

Summary 

• Environmental policies establish acceptable behaviors and protect public health, though consensus is complex. 

• The success of the Montréal Protocol shows international cooperation is possible, but challenges remain for issues like climate change. 

6.1 Notes 

• Freshwater is a limited and essential resource for life. Some areas use water faster than it is replenished. 

• Unequal distribution: Many regions lack access to enough clean water, requiring purification and conservation efforts. 

Case Study: Colorado River 

• Supplies water to over 36 million people but often doesn't reach the Gulf of California due to overuse. 

Water Distribution and Sources 

• Earth's water: 3% is freshwater; very little is accessible to humans. 

• Water Cycle: Constantly recycles water through evaporation, transpiration, condensation, and precipitation. 

Groundwater and Aquifers 

• Aquifer: Underground layer holding water; critical for irrigation but prone to depletion. 

• Saltwater Intrusion: Saltwater enters freshwater aquifers, especially if over-pumped. 

Global Water Use by Sector 

1. Agriculture: Uses most freshwater, particularly for irrigation. 

1. Example: The Ogallala Aquifer supplies 30% of U.S. irrigation water but may be 70% depleted by 2060. 

2. Domestic Use: Smallest water consumption but increases with income. 

3. Industrial Use: Thermoelectric plants use significant water, especially in developed countries. 

Water Scarcity Causes and Impacts 

• Types: 

• Physical: Insufficient water availability. 

• Economic: Lack of funds for infrastructure and clean water. 

• Consequences: Poor sanitation leads to health issues; political conflicts, or "water wars," can arise when upstream regions take more than their share. 

Wastewater Treatment 

1. Rural: Septic systems allow wastewater to drain into the ground, where soil organisms help purify it. 

2. Urban: More advanced, with filtration, settling tanks, and chemical treatments. 

3. Wetland Systems: Some areas use wetlands as natural filtration for wastewater. 

Water Supply Solutions 

• Dams and Reservoirs: Provide water storage but cause evaporation losses and may lead to conflicts. 

• Desalination: Removes salt from seawater but is expensive and produces waste brine. 

• Recycled Wastewater: Purification technologies (e.g., Las Vegas returns water to Lake Mead) offer potable options. 

Water Conservation and Footprint 

• Water footprint: Total water used for products and energy consumption. 

• Personal Conservation: Reducing water usage, choosing products with lower water footprints (e.g., used clothing, fewer cotton products) is effective. 

Summary 

• Freshwater is a limited, unevenly distributed resource, with increased demand creating conflicts and scarcity. 

• Conservation, sustainable management, and technology (dams, desalination, recycling) are essential to maintaining supplies. 

6.2 Notes 

Core Message 

• Water pollution reduces usable water, harms ecosystems, and is mainly caused by human activities. Addressing pollution involves controlling discharges, restoring natural areas, and minimizing pollutants. 

Case Study: Gulf of Mexico Hypoxia 

• Hypoxia (low oxygen levels) in the Gulf affects marine life and local economies, especially seafood and tourism. 

• Initially suspected to be oil-related, hypoxia was linked to nutrient pollution (nitrogen, phosphorus) from agricultural runoff, which leads to eutrophication. 

Types and Sources of Water Pollution 

1. Point Source Pollution: Easily identified sources like discharge pipes from factories and wastewater plants. 

1. Effluent: Wastewater released into the environment, sometimes containing harmful substances. 

2. Nonpoint Source Pollution: Diffuse sources like stormwater runoff carrying sediments, nutrients, and waste into water bodies. 

1. Main pollutant type in the Gulf, causes sediment pollution that clouds water and disrupts habitats. 

Eutrophication and Hypoxia 

• Eutrophication: Excess nutrients (nitrogen, phosphorus) cause algae blooms, which block sunlight and reduce oxygen levels. 

• Results in hypoxic (oxygen-depleted) zones, harming aquatic life and affecting economic activities. 

• The Gulf of Mexico’s dead zone expanded from 15 square miles in 1988 to over 8,500 square miles by 2002. 

Watersheds and Pollution 

• Watershed: Land area draining into a water body; pollutants can enter water bodies through runoff. 

• Land uses that promote infiltration reduce pollution and replenish groundwater. 

Water Quality Assessment 

• Biological Assessment: Identifying species to gauge health. 

• Chemical Assessment: Monitoring pH, dissolved oxygen, and pollutants. 

Clean Water Act (CWA) 

• Regulates point source pollution and sets water quality standards. 

• Supports best practices to control nonpoint source pollution, inspired by events like the Cuyahoga River fire (1969). 

• Citizen Suit Provision: Allows public lawsuits if CWA standards are not met. 

Watershed Management 

• Effective watershed management, such as maintaining vegetated riparian areas, can reduce nonpoint pollution by filtering runoff and absorbing nutrients. 

Reducing Agricultural Runoff 

1. Best Practices: Controlled drainage, targeted fertilizer use, winter crops, windbreaks, and precision agriculture to minimize soil and nutrient loss. 

Urban and Suburban Runoff Control 

• Strategies: Plant native vegetation, rain gardens, porous pavement, green roofs, and curb cutouts to increase water infiltration. 

Aquatic Ecosystem Restoration 

• Holistic Approaches: Address sources of pollution, protect watersheds, and restore wetlands to mitigate problems like hypoxia. 

Summary 

• Water pollution is a complex issue with multiple stakeholders and causes. While progress has been made in watershed health and nonpoint source reduction, challenges continue, especially with climate change impacting water quality and agricultural productivity. 

 7.1 Notes

Key Terms

• Mineral: a naturally occurring chemical compound that exists as a solid with a predictable, three-dimensional, repeating structure

• Examples: copper, zinc, aluminum, quartz, feldspar

• Metal: a malleable substance that can conduct electricity; usually found in nature as part of a mineral compound

• Example: Lithium

Earthquake: sudden shaking of the ground caused by movement of tectonic plates at a plate boundary or an intraplate fault, as well as volcanic activity

Volcano: an opening (vent) through which lava, gases, and other material escape from beneath Earth’s crust, often accumulating to form a mountain or hill.

Landslide: the sudden movement of unstable rock or soil material down a slope due to the force of gravity, often triggered by heavy rain or an earthquake Tsunami: a series of high, long, fast-moving water waves caused by the displacement of a large volume of water by an underwater earthquake, landslide, or volcanic eruption.

Tsunami: a series of high, long, fast- moving water waves caused by the displacement of a large volume of water by an underwater earthquake, landslide, or volcanic eruption

Mining: the extraction of natural resources from the ground

• Subsurface mines: Sites where tunnels are used to access underground fossil fuel or mineral resources

• Examples: gold, diamonds, coal

• Vein: Distinct region within a rock that contains a mineral ore

Surface mining: a form of mining that involves removing soil and rock that overlay a mineral deposit close to the surface in order to access that deposit

• Strip mining: a surface mining method that accesses fossil fuel or mineral resources from deposits close to the surface on level ground, one section at a time

• Overburden: the rock and soil removed to uncover a mineral deposit during surface mining

Solution mining: Extraction method where desired minerals are dissolved by a liquid

injected into the deposit, then pumped back out and purified.

Example: lithium is already in solution, so it only needs to be pumped out.

Open-pit mining: a surface mining method that extracts rock or mineral from a pit excavated for that purpose

• Examples: copper, iron, sand, gravel

Mountaintop removal (MTR): a surface mining technique that involves using explosives to blast away the top of a mountain to expose the coal seam underneath; the waste rock and rubble are deposited in a nearby valley.

• Smelting: mineral processing step in which the material is melted at high temperatures and mixed with chemicals that separate the mineral from the rock

• Electrolysis: processing step that uses an electric current to separate metal from ore

Placer mining: The mining of underwater sediments (e.g., streambeds) for minerals.

Mine tailings: the waste of mining operations; includes mill tailings, the finely ground rock left over from processing mineral ores

• Acid mine drainage: Water that flows past exposed rock in mines and leaches out sulfates. These sulfates react with the water and oxygen to form acids (low pH solutions).

Reclamation: The process of restoring a damaged natural area to a less damaged state.

• e-waste: unwanted electronic devices that are discarded contain valuable metals that can be recovered but also contain toxic chemicals

• Wide-scale recycling programs still need to be developed.

7.2 Notes

Forests: ecosystems made up primarily of trees and other woody vegetation

• Currently cover about 30% of the planet’s landmass

• Are home to more than 50% of Earth’s terrestrial life

• Contain more than 60% of Earth’s green, photosynthesizing leaves

• Many types of forest biomes are found around the globe

• Each biome characterized by temperature and rainfall

Boreal forest (taiga): coniferous forest found at high latitudes and altitudes characterized by low temperatures and low annual precipitation

• Dominated by evergreen species like spruce and fir

• Covers vast tracts of land in the higher latitudes and altitudes

• Characterized by low temperatures and precipitation levels

• Comprises some of the most expansive forests left on Earth

• Some primary or old growth forest still exist; other areas that were harvested for timber have regrown into secondary forests.

Temperate forest: forest found in areas with four seasons and a moderate climate, which receives 30 to 60 inches of precipitation per year, and which may include conifers and/or hardwood deciduous trees, which lose their leaves in the winter

• Dominated by deciduous trees like oak, hickory, and maple

• Covers wet areas of the midlatitudes

• Not as expansive as the boreal forests because they are found in latitudes

with high human populations

• Mostly secondary growth rather than primary due to extensive timber harvesting

Tropical forest: forest found in equatorial areas with warm temperatures year round and high rainfall; some have distinct wet and dry seasons, but none has a winter season

• Contain a diverse mix of tree and undergrowth species

• Expansive tracts of primary tropical forest still remain, but these forests are experiencing the highest losses of any forest biome

Canopy: the upper layer of a forest, formed where the crowns (tops) of the majority of the tallest trees meet

• Emergent layer: the region where a tree that is taller than the canopy trees rises above the canopy layer

• Understory: the smaller trees, shrubs, and saplings that live in the shade of the forest canopy

• Forest floor: the lowest level of the forest, containing herbaceous plants, fungi, leaf litter, and soil

Ecosystems services: essential ecological processes that make life on Earth possible

• Forests provide many ecosystem services for the planet, including:

• Formation and maintenance of soil

• Reducing impacts from storm water runoff--water that flows across the land

surface under the force of gravity, usually after a rainfall

• Adding oxygen to the atmosphere

• Acting as the world’s largest terrestrial carbon sink, that is, an area such as a

forest, ocean sediment, or soil, where accumulated carbon does not readily

reenter the carbon cycle

• Providing food and habitat for animals, fungi, and microbesClear-cut: timber-

harvesting technique that cuts all trees in an area

• Very damaging

Selective harvesting: timber-harvesting technique that cuts only the highest value trees; the remaining trees reseed the plot

• More environmentally sound

• Used in temperate forests

• Shelterwood harvesting: timber-harvesting technique that cuts all but the best trees, which reseed the plot and are then harvested

• More environmentally sound

• Used in temperate forests

Strip harvesting: timber-harvesting technique that clear-cuts a small section of a

forest, allowing regrowth in that section before moving on to another

• Less destructive

• Used in boreal forest

Forest ecosystem management (FEM): a system that focuses on managing the forest as a whole rather than for maximizing yields of a specific product

• Utilizes a variety of techniques for timber harvesting, vegetation removal, and controlled burns

• The United States established the National Forest Service in 1905.

• The U.S. National Forest Service: administered by the U.S. Department of

Agriculture

• Oversees 155 national forests and 20 national grasslands

• Primary objective is the management of these areas in an ecologically sustainable manner.