Human Population & Earth Resources

Human Population

• The Earth's population is over 8 billion people
• Environmental refugees are displaced due to environmental degradation and weather events from global climate change
• Factors contributing to the poverty of less developed countries (LDCs) include:
  • Lack of resources
  • Limited educational opportunities
  • Lack of skills
  • Economic, social, and political systems which hinder growth
• The wealth of highly developed countries (HDCs) leads to
  • Higher consumption rates and large amount of waste
  • Greater demands on earth resources
  • Contribution to global environmental issues, such as toxic waste
• An ecological footprint represents the productive area needed to support an individual's lifestyle in a given population, including land for crops, grazing, forests, housing, and ocean area for food. The average ecological footprint is 6.84 acres
• Ingenuity and technology will not save humanity and make the world more sustainable

Food Resources

• The Green Revolution (1950-1984) introduced high-yield crops and energy-intensive agriculture
• 30% (one-third) of edible food is wasted worldwide
• Grain, at 60%, is the primary global food source, while marine sources are declining (20%)
• Environmental vegetarianism refers to a vegetarian diet that addresses meat production's environmental unsustainability relating to land, air, water pollution, fossil fuel use, and water consumption
• All the best land is already exploited, and most deforestation (70-80%) results from agricultural expansion
• Water is the major limiting factor in agricultural production
• About 40% of the world's cropland produces grain for livestock
• Sustainable technologies in agriculture involve
  • Water and soil conservation through soil management and tillage like contouring furrows
  • Planting dryland crops, developing better harvest varieties and planting nitrogen-fixing legumes for crop variety
  • Preserving genetic diversity in crops, i.e. 500,00 seeds from every country is needed to maintain biodiversity
  • Sustainable intensification to increase food production on existing farmland with fewer inputs
  • Alternative food sources like microlivestock (bugs)
• Freezing baked goods (breads, cakes, bagels, crackers, and cookies) or nuts and seeds increases food shelf life
• Storing eggs and milk on the fridge door decrease food shelf life

Soil and Soil Erosion

• Soil is both a physical and biological factor
• Litter forms the top layer of freshly added, non-decomposed matter
• Humus, partially decomposed organic matter, is rich black earth indicative of soil quality
• Natural soil formation takes 500 years from bare rock, while composting can produce humus in 1-2 years
• Erosion is when soil and humus particles are carried away by wind or water
• Desertification occurs when the topsoil loses its water-holding capacity due to erosion, creating desert-like conditions and when there is a decrease in precipitation thus causing a loss or destruction of the biological productivity of the landscape.
• Overgrazing involves animals grazing in numbers that exceed the land's capacity
• Deforestation involves removing forests from a site
• Sedimentation refers to when lakes and reservoirs are filled with soil particles from erosion, causing clogged channels, increased flooding and reduced freshwater wildlife
• Organic farming is more beneficial for the soil than conventional farming

Water

• 25% of the world’s population has a chronic water shortage
• Major river systems are shared by two or more countries, leading to disputes
• The Middle East faces its worst drought in 900 years, contributing to political instability
• No developing nation in Asia and the Pacific is considered water secure
• The overuse of water leads to
  • Depletion of aquifers and falling water tables
  • Diminishing surface water
  • Saltwater intrusion, consequently decreasing groundwater in coastal areas
• Solutions for water scarcity in the U.S. are:
  • Drip irrigation distributes water to plants through pinhole networks
  • Xeroscaping uses drought-tolerant plants in landscaping
  • Gray water from sinks, showers, etc., is used to wash cars, flush toilets, and water lawns
  • Desalination removes salt from seawater, but it is an expensive process

Water Pollution

• Point sources of water pollution release pollutants through specific locations like pipes, ditches, or sewers (e.g., factories, sewage treatment plants)
• Non-point sources of water pollution cannot be traced to a single discharge point (e.g., acid rain, chemical runoff)
• Infectious agents in water sources are from untreated human and animal waste which causes health problems
• Endocrine disruptors, such as personal care products, agricultural chemicals, plastics, and PCBs, lead to health problems. These include increased cancer rates and lower sperm counts
• Organic chemicals, like pesticides, plastics, detergents, oil and gas, cause health problems
• Bioaccumulation: a chemical accumulating in specific organs or tissues
• Biomagnification: the increased concentration of a pollutant as it moves up the food chain
• Plant nutrients from fertilizers, sewage, manure, and detergents lead to ecosystem disruption
• Cultural eutrophication occurs when water bodies get excess nutrients from fertilizers, detergents, and animal/human waste
• Wetlands are land areas covered by shallow water at certain times
• Plastics, mostly from land (80%) and ships/ocean dumping (20%), cause health and ecosystem disruption
• Solutions to water pollution include
  • Prevention
  • Reducing pesticide use
  • Conserving energy
  • Recycling
  • Using solar or wind energy
  • Land disposal or sewage sludge
  • Restoring wetlands and estuaries
  • Reducing water use and the use of household chemicals
  • Controlling sediments from deforestation, construction, and mining

Sewage Treatment

• Pathogens are disease-causing bacteria, viruses, and other parasitic organisms
• Primary sewage treatment involves screening and settling to remove large materials and separate solids from liquids, removing 5-15% of pollutants
• Secondary sewage treatment reduces biochemical oxygen demand
• Tertiary treatment removes nutrients, often involving chlorination before water is released
• The Clean Water Act of 1972 aims to keep waterways clean, provide sewage treatment, and control point source pollutants

Air Pollution

• Air pollutants are harmful substances in the atmosphere
• Smog is a combination of smoke and fog with poor visibility and high air pollutant concentration
• The Air Quality Index (AQI) reports air quality, indicating health risks from 0 (no pollution) to 500 (extreme health risk)
• Air pollution can have the following impacts on human health
  • Chronic: gradual deterioration of physiological functions
  • Acute: life-threatening reactions within hours/days
  • Carcinogenic: pollutants initiate changes within cells that lead to uncontrolled growth and division (cancer)
  • The Clean Air Act, originally in 1970 and later amended in 1990, sets standards controlling major pollutants like sulfur dioxide, nitrogen oxides, carbon monoxide, lead, and ozone
• Sick building syndrome: pollutants in buildings causing headaches, dizziness, eye irritation, coughing, nausea, fatigue, and flu-like symptoms

Global Climate Change

• Global climate change (GCC) refers to changes in Earth's climate, including temperature, precipitation, and storm activity
• Arctic region consequences of GCC are
  • Arctic temperatures have risen twice as fast as the rest of the world in the past 50 years
  • Melting glaciers and floating ice
  • A projection that the Arctic will be ice-free during warm months by 2037
• GCC affects plants and animals by
  • Spreading diseases to new areas via migrating animal and insect vectors
  • Increasing the spread of insect pests and plant diseases
  • Many animals and plants face extinction due to increased heat and extreme weather
• Oceans and forests are carbon dioxide sinks and help moderate Earth's average surface temperature
  • Oceans remove 25-30% of CO2 through human activities
  • Forests remove about 25% of the carbon dioxide created by human activities
• Individuals can mitigate climate change by
  • Voting for politicians supporting climate mitigation
  • Reducing energy usage at home and in transit
  • Using recycled products to preserve trees
  • Reducing food waste
  • Eating more plant-based foods
  • Carpooling
• Governments can mitigate climate change by regulating and enforcing carbon dioxide and methane as pollutants and instituting carbon and energy taxes

Alternative/Renewable Energy

• Individuals can reduce their fossil fuel impact by
  • Installing solar panels and wind turbines
  • Unplugging appliances to decrease vampire power, which can lower electricity bills by 5-10%
• Four forms of solar energy:
  • Passive solar heating absorbs and stores sun's heat within the structure
  • Active solar heating uses heat-absorbing fluid pumped through collectors to store and supply heat/hot water
  • Solar thermal energy collects and transforms radiant energy to high-temperature heat, which can be used directly or converted into electricity
  • Photovoltaic converts solar energy to electrical energy using solar cells
• Other types of alternative energy include
  • Wind: electricity generated by wind turbines, and the world's fastest-growing energy source since 1990
  • Geothermal: using Earth's stored heat to heat/cool buildings and produce electricity
  • Burning solid biomass: combusting waste, plant matter, and animal waste to generate heat or electricity
  • Hydroelectric: power produced by trapping flowing water behind dams and releasing it to spin turbines

Nuclear Power

• Meltdown describes when a nuclear reactor loses control or cooling water, leading to melting/explosion
• Radiation sickness prevents normal tissue repair and may cause death
• Most of the world's radioactive waste is stored at nuclear power plant sites
• The risk and fear of meltdowns keeps the growth of nuclear power static

Toxic Chemicals and Toxic Waste

• The Food and Drug Administration (FDA) oversees the safety of personal care products but cannot ensure their safety
• The Toxic Substance Control Act in 1976 grandfathered in 100,000 chemicals without testing for toxicity
• Endocrine disruptors can cause health problems, and they are found in personal care products such as sunscreens and cosmetics
• Hazardous wastes from homes, factories, businesses, and military sites can be toxic
• Superfund is funded by the government to clean up hazardous waste sites
• E-waste (discarded electronics) is the fastest-growing waste problem

Wildlife Conservation

• Extinction and biodiversity decline are caused by habitat destruction, commercial products trade, and exotic species introduction
• Habitat destruction leads to habitat fragmentation, reducing breeding populations
• The trade of commercial products/live specimens is when people import skins and live animals
• The Endangered Species Act (ESA) of 1973 protects endangered and threatened species in the USA
• Problems with ESA Enforcement: issues with listing, recovering endangered species, and decreased funding
• Species should be preserved for philosophical (aesthetics of extinction) and utilitarian (benefits to humans) reasons
• Ecological reasons: species maintain the stability and integrity of ecosystems

Ocean Conservation

• Oceans moderate Earth's temperature by removing 25-30% of human-created CO2 and provide storm protection
• Coastal development destroys coastal habitats, erodes beaches, and causes overfishing
• Nonpoint source pollution from land creates dead zones in the ocean from fertilizer and animal waste runoff
• Warming oceans lead to coral reef loss due to bleaching