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ESS SL All Topics
1.1 - Environmental value systems
Environmental value system (EVS): a worldview that shapes the way an individual or group perceive and evaluate environmental issues
Examples: culture, religion, economic and socio-political context
Categories of EVS:
Ecocentric worldview: puts ecology and nature as central to humanity (less materialistic lifestyle)
Deep ecologists → no development
Soft reliant → small scale communities, minimal development
Anthropocentric: believes humans must sustainably manage the global system
Soft reliant → small scale communities, minimal development
Environmental managers → manage natural resources and human population
Technocentric: believes that technological developments can provide solutions to environmental problems
Cornucopians → technology will solve any problems so development can continue
1.2 - Systems and Models
System: set of interrelated parts working together to make a complex whole, can be living or nonliving. Systems are all more than the sum of their parts
Can be open (exchange matter and energy, e.g. a pond), closed (exchange energy, e.g. carbon cycle), or isolated (exchange nothing, e.g. universe)
All systems have:
Systems (stores of matter/energy), flows (into, through, and out of the system), inputs, outputs, boundaries, processes
Matter (material) and energy flow through ecosystems as:
Transfers: when energy or matter flows and changes location but does not change its state
Movement of material → in a non-living process
The movement of energy
Movement of material through living organisms
Transformations: when energy or matter flow and changes its state, a change in the chemical nature, a change in state or energy
Matter to matter
Matter to energy
Energy to energy
Models are simplified versions of systems
Advantages of Models:
Easier to work with than complex reality
Used to predict the effect of a change of input
Can be applied to other situations
Used to visualise small and large things
Can help us observe patterns
Disadvantages of models:
Predictions may be inaccurate
Accuracy is lost
Model will be wrong if our assumptions are wrong
1.3 - Energy and Equilibrium
First law of thermodynamics: states that energy in isolated systems can be transformed but not created or destroyed
Second law of thermodynamics: states that energy is transformed through energy transfers
Entropy: a measure of the amount of disorder in a system
Refers to the spreading out of dispersal of energy
More energy = less order
When entropy is used to do work, some energy is always wasted as heat energy
Efficiency: the useful energy, the work or output produced by a process divided by the amount of energy consumed being the input to the the process
Efficiency = work or energy produced / energy consumed
Efficiency = useful output / input
TIP: multiply by 100% if you need the answer in a percentage
Equilibrium: the tendency of the system to return to an original state following disturbance. At an equilibrium; a state of balance exists among the components of a system
Steady-state equilibrium: a characteristic of an open system where there are continents inputs and outputs of energy and matter, the system remains in constant state
No long-term changes, however, small fluctuations occur in the short term
Static equilibrium: no change occurs over time. Most non-living systems are in a state of static equilibrium
This cannot occur in a living system, it can only occur in an isolated system
Stable equilibrium: the system tends to return to the same equilibrium after a disturbance
Unstable equilibrium: the system will return to a new equilibrium after a disturbance
Negative feedback loop: stabilises steady state equilibria, occur when the output of a process inhibits or reverses the operation of the same process in such a way to reduce change, counteracts deviation.
Returns back to its original state
Stabilising as they reduce change
Positive feedback loop: will amplify changes and bring the system towards a new tipping point where a new equilibrium is adopted
Change a system to a new state
Destabilising as they increase change
Albedo: reflecting ability of a surface
Resilience: the ability of a system to return to its initial state after a disturbance
Biodiversity increases resilience
Species that can shift their geographical range → more resilient
Fast reproductive rate means faster recovery
An ecological tipping point: is a reached when an ecosystem experiences a shift to a new state
Significant changes occur in biodiversity and services it provides
Changes are long lasting and hard to reverse
Lake eutrophication: nutrients added to a lake may not change much until enough nutrients are added to change its state
Occurs when bodies of water are overly enriched with minerals and nutrients which promotes the growth of algae
Extinction of a keystone species: A keystone species within an ecosystem is fundamental to keeping the ecosystem stable and supported
Their extinction can negatively affect the ecosystem
1.4 - sustainability
Sustainability: the use of resources that allows full natural replacement of the resources used and full recovery of the ecosystems affected by their extraction
Sustainable development: development that meets the needs of the present without compromising the ability of future generations to meet their own needs
Ecological overshoot: when a sustainable resource is exploited to its maximum
Replenishing the resources will take longer
This increased demand is due to level of overall consumption, per capita consumption
Natural capital: natural resources that can produce a sustainable natural income of goods or services
Environmental impact assessments (EIA): is a report prepared before a development project changes the use of lans. It weighs up the advantages and disadvantages of the development
Will qualify changes to microclimate, biodiversity, scenic and amenity value resulting from the changes
These measurements represent the “baseline study”
Baseline study: an analysis of a current situation to identify the starting points for a project
Ecological footprint (EF): the area of land and water required to sustainability provide all resources at the rate which they are being consumed by a given population
A model used to estimate the demands that human populations place on the environmental
1.5 - Humans and Pollution
Pollution: the introduction/addition of a substance to the environment by human activity. This addition is considered harmful to the environment
Pollutants released by human activities: matter, energy, living organisms
Matter (gasses, liquids, solids) which is organic (contains carbon atoms) or inorganic
Energy (sound, light, heat)
Living organisms
Primary pollutants: are active on emission (carbon monoxide) from the incomplete combustion of fossil fuels
Causes headaches, fatigue, and can kill
Secondary pollutants: are formed by primary pollutants undergoing physical or chemical changes
Point source and nonpoint source pollutants:
Nonpoint course (NPS):
Release of pollutants from dispersed origins, example: exhaust gases from vehicles
Has many sources (hard to detect its origin)
Rainwater can collect nitrates which are used as fertilisers
Air pollution can be blown and mix with other chemicals
Point source (PS):
Release of pollutants from a single site
Easier to locate pollution
Easier to manage and can be found more easily
Persistent organic pollutant (POPs): a toxic environmental contaminant which requires special handling and disposal
Resistant to breaking down and remain active in the environment for a long time
Can cause significant harm, Health wise, due to the heavy pollution we are inhaling
High molecular weight
Not soluble in water
Highly soluble in fats and liquids (can pass through cell membranes)
Biodegradable pollutants: do not persist in the environment and break down quickly. May be broken down by decomposer organisms or physical processes. Example: Light, heat
Acute pollution: when large amounts of pollutants are released causing a lot of harm
Chronic pollution: long term release of a pollutant but in small amounts
Often goes undetected for a long time
More difficult to clean up
Often spreads widely
How can pollution be managed?
Human activity: promoting alternative technologies through
Controlling release of pollutant/release of pollutant into environment
Impact of pollution on ecosystems
Campaigns, education, community groups, governmental legislation, economic incentives/disincentives
Controlling release of pollutant/release of pollutant into environment:
Legislating and regulating standards of emission
Developing/applying technologies for extracting pollutant from emissions
Impact of pollutant on ecosystems:
Extracting and restoration of damaged systems
Replanting/restocking lost or depleted populations and communities
2.1 - Species and Populations
Ecology: the study of how organisms interact with the environment.
Species: is a group of organisms (living things) sharing common characteristics that interbreed and produce fertile offspring
Population: a group of organisms of the same species living in the same area at the same time, which are capable of interbreeding
Three factors affecting populations:
Natality (birth rate)
Morality (death rate)
Migration: immigration (moving into the area), emigration (moving out of the area)
Habitat: the environment in which a species normally lives
Abiotic factors: non-living physical factors that influence the organisms and ecosystems. Example: temperature, sunlight, pH, Salinity, pollutants
Biotic factors: living components of an ecosystem that directly or indirectly affect another organism.
A niche describes the particular set of abiotic and biotic conditions and resources to which an organism or population responds
Fundamental niche: describes the full range of conditions and resources in which a species could survive and reproduce
Realised niche: describes the actual conditions and resources in which a species exists due to biotic interactions
Limiting factors: factors which slow down growth of a population as it reaches it carrying capacity
Carrying capacity: maximum number of species or load that can be sustainably supported by a given area
Population dynamic: the study of the factors that cause changes to population sizes
Intraspecific competition: between members of the same species. As population grows, competition increases
Interspecific competition: individuals of different species could be competing for the same resource
Predation: when one animal (predator), eats another animal (prey). Broad definition, consumption of one organism by another
Herbivory: a herbivore animal eating a green plant some plants may have defence mechanisms
Forms of symbiosis:
Parasitism: relationship between two species in which one species lives in or on another (host), gaining food from it.
The parasites are not preys and will not kill the host
Mutualism: relation between two species where everyone benefits and no one suffers
Form of symbiosis (living together)
Commensalism: when one partner is helped and another is significantly harmed
Exponential or geometric growth: if no limiting factors are affecting or slowing down growth
S and J population curves describe a generalised response of populations to a particular set of conditions:
S shaped growth: starts with exponential growth, no limiting factors affect the growth. Growth rate gradually slows down after a certain population size
J shaped growth: population grows exponentially at first then collapses → called diebacks
2.2 - Communities and Ecosystems
Community is a group of populations living and interacting with each other in a common habitat (same place)
Ecosystem: is a community and the physical environment it interact with
Respiration is the conversion of organic matter into carbon dioxide and water in all living organisations, releasing energy
Photosynthesis: the process by which green plants make their food from water and carbon dioxide using energy from sunlight
A Trophic level is the position that an organism occupies in a food chain, or a group of organisms in a community that occupy the same position in food chains. A food chain is the flow of energy from one organism to another.
Producers:
Autotrophs: make their own food from carbon dioxide and water using energy from sunlight
Chemosynthetic organism: make their own food from simple compounds
Consumers: feed on other consumers to get energy
Ecological footprint: are quantitative models which are usually measured for a given area and time. These include pyramids of number, biomass, and productivity
Pyramid of productivity: shows the rate of flow of energy or biomass through each trophic level
2.3 - Flows of Energy and Matter
Productivity: conversion of energy into biomass over a given period of time. It is the rate of growth or biomass in plants and animals
Gross: total amount of something made as a result of an activity
Net: amount left after deductions are made; what you have left, always lower than the gross amount
Gross productivity: total gain in energy or biomass of an organism before any reductions
Net productivity: gain in energy or biomass that remains after deductions due to respiration
Gross primary productivity: total gain in energy or biomass by green plants. It's the energy converted from light to chemical energy by photosynthesis in green plants
Net primary productivity: total gain in energy or biomass by green plants after allowing for losses to respiration. The increase in biomass of the planet and is the biomass that is potentially available to consumers that eat plants
Glucose produced in photosynthesis:
Provides for growth, maintenance and reproduction with energy being lost as heat during respiration
Rest is deposited in and around the cell
NPP = GPP - R
Net secondary productivity (NSP): total gain in energy or biomass by consumers after allowing for losses to respirate
GSP = food eaten - faecal loss
Biogeochemical cycles: the natural pathways by which essential elements of living matter are circulated
4 main cycles: water, carbon, nitrogen, sulphur
plants use carbon dioxide to make food (photosynthesis) carbon becomes stored food
Nitrogen Cycle:
nitrogen fixation: when atmospheric nitrogen is made available to plans through fixation of atmospheric nitrogen
nitrification: nitrifying bacteria in the soil which are able to convert ammonium to nitrates
denitrification: denitrifying bacteria in waterlogged and anaerobic conditions
decomposition of dead animals provides nitrogen for uptake by plants
Efficiency of assimilation: gross productivity * 100 / food eaten
Efficiency of biomass productivity: net productivity *100 / gross productivity
→ Maximum sustainable yield: largest crop or catch that can be taken from the stock of a species without depleting the stock
2.4 - Biomes, Zonation, and Succession
Biome: is a collection of ecosystems sharing similar climatic conditions
Aquatic: fresher and marine, freshwater, marine.
Deserts, forest, tundra, grassland
Biosphere: part of the earth inhabited by organisms
Latitude: distance north or south from the equator
Altitude: height above sea level
Zonation: change in community and ecosystem aking and environmental gradient due to changes in altitude, latitude, tidal level or distance from shore/coverage by water
Primary succession: process of creating life in an area where no life previously existed
Secondary succession: when an established community is suddenly destroyed, an abridged version of succession starts
A sub-climax community is one which will only continue its development if the limiting factor is removed
→ K - strategies: long life, slower growth, late maturity. Fewer large offspring, predator, high trophic level
→ R-strategist: short life, rapid growth, early maturity, prey, lower trophic level
3.1 - An Introduction to Biodiversity
Biodiversity: broad concept encompassing total diversity which includes diversity of species, genetic diversity, habitat diversity
Species diversity: usually in communities, product of number of species and their relative proportions
Habitat diversity: range of habitats in an ecosystem or biome
Genetic diversity: range of genetic material present in a population of a species
Smaller populations have lower genetic diversity than a larger one because of the small gene pool
Scattered populations (animals) / plant-wise (humans) have high genetic diversity
Many ecological niches due to layering of forests result in habitat diversity
The number of species present in an area is often used to indicate general patterns of biodiversity.
Richness is a measure of the number of different species in an area; more species means a richer environment
Abundance is the number of individual organisms in a species. We can measure abundance on a small scale as they appear in a forest, for a larger scale, environmentalists tend to measure abundance by the amount of organisms all around the world
Richness does not take into account the rarity of a species
A biodiversity hotspot is a region with high levels of biodiversity that is under threat from human activities
70% of the habitat has been lost
They cover 3.2% of the land surface
Tend to have large densities of human habitation nearby
contains more than 1.5k of plants which are endemic
The Diversity Index is a quantitative measure of the diversity of a species in a community, it includes calculations and information about the availability and rarity of species in a specific community.
measuring species is important for biologists and environmentalists to comprehend the structure of the community which habitats a diverse number of species
3.2 - Origins of Biodiversity
Biodiversity arises from evolutionary processes
variation in biological areas can be beneficial to, damaged to, or have no impact on the survival of the individual
Environmental change gives new challenges to the species, those that are suited survive, and those that are not suited will not survive
Natural selection: those more adapted to their environment will flourish and reproduce and those less adapted do not survive for long
survival of the fittest
contributions to evolution of biodiversity over time
give new challenges to the species so those better suited will survive
Speciation: gradual change of a species when populations of the same species become separated. They cannot interbreed since they inhabit the characteristics of other species
a slow process can be sped up by humans using artificial selection
only processes of animals and plants, also by genetic engineering
separation may have geographically or reproductive causes
Isolation of species can be caused by:
physical barriers: will split up gene pool, which results in species developing in different directions
Examples: Mountain range, ocean
land bridges: allows species to invade new areas and for species to relocate, created from lowering of sea levels
Created from the lowering of sea levels
Isolation factors are:
Geographical factors: island formation, loss of land bridges and mountain ranges
Behavioural factors: reproductive displays, songs, daily activity
Genetic factors: inability to produce fertile offspring due to genetic different
Reproductive factors: anatomical different especially in reproductive organs
Continental drift: caused from drifting of the globe, results in new and diverse habits
changing climate conditions force species to adapt which increases biodiversity
distribution of continents caused climatic variations and variation in food supply, both contribute to evolution
Plate tectonics: study of the movement of the plates. When plates move and meet due to continental drift, they might:
slide past each other, diverge
converge: collide and both face upwards
collide and one sinks underneath the other
The earth is 4.6 billion years old
Current era: Cenozoic
Current time period: quaternary tertiary
Isolation of populations → caused by environmental changes the surface is divided into curstal, tectonic plates which moved throughout geological time
Mass extinctions have been caused by a contribution of factors, some of which are tectonic movements, super volcanic eruption, climate change, and meteor impact which resulted in a new direction in evolution and increased biodiversity.
Extinctions are caused by:
Climate change over a period of time, as the dust incoming from volcanic eruptions led to increasing solar radiation which causes plants to die due to a lack of ability to photosynthesize. Many species are affected by this as well since food webs collapse over time.
Volcanic eruptions and the impact of meteors which release large amounts of harmful dust and ashes into the atmosphere.
3.3 - Threats to Biodiversity
Estimates of the total number of species vary considerably
Most are animals and most are terrestrial
⅔ rds are in the tropics, mostly tropical rainforests
50% of tropical rainforests have been cleaned by humans
When nearly all that habitat goes, extinction rates increase rapidly
current rates of species loss = greater than the past due to increased human influence
extinction can be caused by human activities, such as: habitat destruction, invasive species, pollution, overharvesting, haunting
Factors maintaining biodiversity:
complexity of the ecosystem: the more complex a system is, the more resilient its species will be
stage of succession: older, more resilient and stable ecosystems which undergo succession are less vulnerable than in young ecosystems
limiting factors: changes to materials provided will make it harder and result in species disappearing system is more likely to manage it one of abiotic factors is reduced
Inertia: property of an ecosystem to resist when subjected to a disruptive force
Factors which lead to loss of biodiversity:
Natural hazards: naturally occurring events that may have a negative impact on the environment and humans
are considered natural disasters when the impact worsens
major cause of loss of biodiversity = loss of habitat
Fragmentation of habitat: the process where a large area is divided up into patchwork of fragments
separated from each other by roads, towns, factories, fences
Pollution: caused by humans can degrade or destroy habitats and make them unsuitable to support the range of species
local pollution, environmental pollution, eutrophication, climate change which alters weather patterns and shifts biomes
Overexploitation: has escalated as human populations expand
Introducing non-native species → can upset a natural ecosystem
Spread of a disease → decrease biodiversity
Modern agricultural practices: can reduce diversity with monocultures, genetic engineering and pesticides
Vulnerability of tropical rainforests:
Tropical biomes: contain some of the most globally biodiverse areas in their unsustainable exploitation results in massive losses in biodiversity and their ability to perform globally impotent ecological services
most tropical biomes occur in less economically developed countries and there is conflict between exploitation and sustainable development and conservation
International Union for conservation of nature (IUNC): published the red list of threatened species in several categories
Extinct (EX): inability to record an organism, all individuals are dead
Extinct in the wild (EW): captivity as a naturalised species outside past range
Critically end (CE): considered to be in extremely high risk of extinction
Vulnerable (VU): high risk of extinction
Near threatened (NT): close to qualifying for one of the threatened once in the category
Not evaluated (NE): not evaluated against the criteria
3.4 - Conservation to Biodiversity
Diversity of species: in the ecosystem promotes healthy and good environment
extinction = normal
A community thrives when species evolve and adapt to changes, every species has its own ecological importance
Why should we conserve biodiversity?
Direct value: food species, natural products
Indirect value: human rights, environmental services, scientific education values, human health, and ecocentrism
Conservation biology: sustainable use and management if natural resources
Preservation biology: attempts to exclude human activity in areas where humans have not yet encroached
Conservation → protect natural resources and proper use of nature
Use water from water sources such as lakes
Preservation → protect what has been built from resources and protection of nature from use
From water sources such as cleaning and washing
Organisations of biodiversity conservation:
IGO (intergovernmental organisation): composed of different groups from different countries
Governmental organisations (GO’s): composed of groups funded by a national government
Non-governmental organisation (NGO): composed of groups run by volunteers, no relation to governments non-profit
Approaches to conservation:
CITES (conservation pn the international trade in endangered species):
Appendix 1: species cannot be traded internationally as they are threatened with extinction
Appendix 2: species can be traded internationally but with strict regulations to ensure sustainably
Appendix 3: a species included at the request of a country which needs help of other countries to prevent illegal exploitation
Captive breeding and zoos:
Holding and caring for species in captivity for research and maintenance of species
Maltreatment and poor habitats of reserves and zoos
Reintroduction of species does not guarantee survival and may cause a loss of money
Botanical gardens and seed banks:
Protection and cultivation of different species whether common or rare
Some plants need extra care or technology to grow and survive
Flagship species:
Prioritised over other species
Most common species and known worldwide
If they become extinct, we failed to take care of them
Keystone species:
Species that are considered to have a critical role in maintaining the structure of the ecosystem
Designing protected areas: where a conservation area is within a country is a significant factor in the success of the conservation effort
Surrounding areas including land formations and urban areas
Location in a remote area where people don't usually live
high biodiversity
low population density
4.1 - Introduction to Water systems
Hydrological cycle: system of water flows and storages that may be disputed by human activity
energy from solar radiation driven this cycle
Water budget: quantitative estimate of the amount of water in storages and flows of the water cycle
Renewable resources: atmosphere, rivers
Non-renewable resources: oceans, icecaps
Middle group: groundwater aquifers
Human impact on the water cycle:
Withdrawals: domestic use, irrigation in agriculture and industry
Discharges: by adding pollutants to water
Changing speed at which water can flow and where it flows
Diverting rivers or sections of rivers
Transfers: occur when it stays in the same state:
Flooding
Surface runoff
Stream flows and current
Transformations: when it changes state to and from water:
Evaporation: liquid to water
Condensation: water vapour to liquid
Freezing: solid snow to ice
Ocean currents: are movements of water both horizontally and vertically
have an important role in energy discharges that influence changes
Surface currents: moved by the wind
earth’s rotation deflects them and increases their circular movement
Deep water currents (thermohaline currents): influenced by the oceanic conveyor belt
difference in water density (salt and temperature)
warm water vs. cold water
movement of water (warm and cold)
Cold ocean currents run from poles to the equator, warm water currents flow from the equator to the poles
Water has higher specific heat capacity (amount of heat needed to raise the temperature of the unit of matter by 1 degree celsius)
Ocean currents and climate:
Affects location in terms of climate
Difference temperature and whether
Land close to seas and oceans has mild climate with moderate winters and cool summers
4.2 - Access to Freshwater
Access to an adequate supply of freshwater varies widely
Climate change may disrupt rainfall patterns and further affect thus access
Demand for freshwater increases as population, irrigation and industrialization increases
Freshwater supply may become limited
Scarcity of water resources can lead to conflict between human populations especially when resources are shared
Humans use freshwater for:
Domestic purposes used at home
Agriculture, irrigation for animals
Hydroelectric power generation
Transportation
Making boundaries between nation rivers
Sources of freshwater:
Surface freshwater
Underground aquifers (water can be extracted from surface or wells)
Freshwater conflict:
climate change distributing rainfall patterns (causing inequalities)
irrigation which leads to soil degradation
Solutions:
increase freshwater supplies by reservoirs, desalination plants rainwater and harvesting
irrigation: select drought resistant crops
Irrigation: results in soil degradation especially in dry areas
Our water supply is sufficient, however, like food, distribution is uneven
Salinization: process of naturally dissolving minerals in the top layer of the soil which makes it too salty (saline) for further agriculture
4.3 - Aquatic Food production systems
Continental shelf: extension of continents under the seas and oceans (creates shallow water)
has 50% of oceanic productivity but 15% of its area
light reaches shallow seas so producers can be photosynthesize
countries can claim, exploit, and harvest it
Zooplankton: single-celled animals that eat phytoplankton and their waste
Fishery: when fish are harvested in a certain way
90% oceans and 10% freshwater
70% of the world’s fisheries are exploited
Aquaculture: farming aquatic organisms (coastal and inland) involving interventions in the rearing process to enhance production
Impacts of fish harms: loss of habitat, pollution, spread of diseases, escaped species may survive to interbreed with wild fish, escaped species may autocomplete native species
Maximum Sustainable yield (MSY):
SY: increase in natural capital (natural income that can be exploited each year without depleting original stock)
MSY: highest amount that can be taken without permanently deleting the stock
4.4 - Soil degradation and conservation
Pollutants can be: anthropogenic or natural, point or nonpoint source, organic or inorganic, direct or indirect
Organic
pollutant: sewage, animal waste, pesticide
example: human waste, insecurities
effects: eutrophication, loss of biodiversity
Inorganic:
pollutant: nitrates and phosphates radioactive material, heavy toxic material
example: industry, nuclear power stations, fertilisers
effects: eutrophication, bioaccumulation, biomagnification
Both:
pollutant: solid domestic waste, debris, suspended solids
example: silt form construction, household garage
effects: damage controls, plastics
Freshwater pollution: agricultural runoff, sewage, solid domestic waste
Marine pollution: rivers, human pollution, pipelines
Measuring water pollution:
BOD: amount of dissolved oxygen required to breakdown organic material in a given volume of water
Indicator species: plants and animals that show something about the environment by their presence, absence, abundance
Biotic index: indirectly measures pollution by assessing the impact on species within the community according the their tolerance, diversity, and relative abundance
Eutrophication: when lakes and coastal waters receive inputs of nutrients (nitrates and phosphates) that result in an excess growth of plants and phytoplankton
The eutrophication process:
Fertiliser enters rivers/lakes
High level of phosphates, algae grows faster
More algae, more food for zooplankton or small animals that feed on them. A lack of zooplankton animals means that these are less to eat algae
Algae die and are decomposed by aerobic bacteria
Not enough oxygen is present therefore everything dies and the food chain collapses
oxygen levels fall lower, dead organic material sediments on the lake or the river bed and turbidity increases
All life is gone and sediment settles to leave a clear blue lake. This process in which bodies of water become enriched with nutrients and minerals
Biochemical oxygen demand: amount of DO required to break down organic material in a given volume of water
biological monitoring and indicator species can be used to determine levels of pollution
strengths: stationally, sensitive and representative
weaknesses: identification
5.1 - Introduction to soil systems
Inputs: minerals, organic matter, gases, water
Stores: minerals, organic matter, organisms, air, water, nutrients
Outputs: losses of minerals, water > the soil profile
Processes:
Transfers: of materials within the soil including biological mixing, leaching, contribute to the organisations of the soil. (horizons) (leaching and evaporation)
Transformation: The complete change of materials in the soil(decomposition, weathering, nutrient cycling)
Soil Horizons: (O,A,B,C) and sometimes E:
O: organic, leaf litter, comes from organisms that die and end up on top of the soil. Fungi, bacteria, and animals will decompose dead materials
A: mineral layer, topsoil, upper layer, where humus builds up. Humus is formed when partially decomposed organic matter is mixed with fine material particles, when decomposition is incomplete, a layer dark organic matter is formed → humus layer
E: leached horizon
B: subsoil, where soluble minerals and organic matter are deposited from the layer above. For example: clay, iron salts are deposited
C: parent material, bedrock or another medium
Soil structure and texture:
Ideal soil: loam which is the balance between clay and soil. Is known for its porosity and permeability, water holding ability, aeration, proportion of materials (sand, silt, clay)
Pore spaces determine water drainage
Surface area determines water and nutrients retained
Light, medium, heavy
Soil texture triangle: illustrates the differences in composition of soils
Horizons:
Top layers → rich in organic material
Bottom layers → consist of inorganic material (derived of weathering of rocks, within this, translocation takes place)
Translocation: process in which materials stored and layers are formed by water carrying particles either up or down
Also occurs in irrigation and in warmer climates where precipitation < evaporation
Leaching: occur when water flows down in the soil, dissolving minerals and transporting them downwards
Happens in cooler climates when precipitation > evaporation
Loam soils are ideal for agriculture, as they are a mixture of sand, clay, and silt
Sand particles: ensure good drainage and a good air supply to the roots
Silt particles: help hold sand and clay particles and can be worked easily
Clay: retains water and supplies nutrients (fertile)
Porosity: amount of spaces between particles
Permeability: the ease at which gases and liquids pass through the soil
Acidification of soil: acid rain causing pollution, adversely affecting soil and causing damage to evergreen forestry
Fertile soil = non-renewable resource
Nitrates for leaf and stem
Phosphates: root system
Potassium: flower head/fruit
5.2 - Terrestrial food production and food choices
LEDC’s: less economically developed countries
Country with low to moderate industrialisation and low to moderate average GNP per capita
MEDC: more economically developed countries
Highly industrialised country with high average GNP per capita
Agribusiness: business of agriculture production
Includes farking, seed supply, breeding, machinery, and food harvesting
Commercial agriculture: large scale production of crops and livestock for sale
Subsistence agriculture (or farming): farming or self sufficing to grow enough for a family
Our food choices are determined by:
Climate, ecological conditions: adapt through irrigation/greenhouses
Cultural and religious reasons
Political reasons: determined by governments to manipulate production
Socio-economic reasons: market forces determine supply and demand in a free market economy
Livestock: useful means of converting plant material
Harvesting: requires the removal of biomass from the field, net loss of biomass, nutrients, minerals. Crop rotation addresses loss of soil fertility
Factors which cause a decrease in agricultural land: soil erosion, salinisation, desertification, urbination
How to increase sustainability of food supplies:
Maximising yield: improving tech
Reduce food storage: improve storage → LEDC: waste of production and storage. MEDC → consumption (applying stricter standards in supermarkets)
Monitoring and control: regulate imports and exports to reduce unsustainable agricultural practices
Diet and food: reduce meat, different crops, more protein
Reduce food processing: decrease use of transport and packaging → overall decrease in energy use
5.3 - Soil degradation and conservation
Processes:
Erosion is a process which takes away the soil. Occurs when there is no vegetation in the soil
Making soil less sustainable for use:
Chemicals entering soil → renders soil useless (long term)
Human activities, overgrazing, deforestation, unsustainable agriculture
Overgrazing: too many animals graze in the same area, leaves bare patches (roots done hold soil together
Overcropping: depletes soil nutrients and makes soil dry (risk of erosion), reduced soil fertility
Deforestation: removal of forests, removal of vegetation leads to erosion
Unsustainable agricultural techniques: cannot be applied long term, removal of crops after harvest (erosion), ploughing in direction of the slope, excessive use of pesticide, irrigation → can cause salinisation as minerals
Monocropping: nutrients are depleted and soil loses fertility
Urbanisation: increasing number of people that live in urban areas, potential land for agricultural land for agriculture has cities built on it
Soil erosion
Soil conditions: chalk, crushed limestone, counters soil acidification, lime
Wind reduction: plant trees/bushes between fields
Soil conserving cultivation techniques: terracing, ploughing, counter farming
Improve irrigation techniques
7.1 - Energy Choices and Security
Fossil fuels contribute to the majority of human energy supply and these vary widely in the impacts of their production and emissions and their use if unexpected to increase tp met global energy demand
Fossil fuels are formed through a natural process, such as in anaerobic decomposition (buried dead animals) which contains energy
The formation of fossils has been advantageous in terms of technological advances such as extraction of fossil fuels and inspired better transportation advances and industry development. However, as fossil fuels have largely contributed to industrialisation, that lead to a huge negative environmental burden in the form of pollution. This results in harmful greenhouse gases, acid rain, and global climate change
Fossil fuels are stored as solar energy
Fossils fuels contribute to the majority of humankind’s energy supply, and they differentiate in their impacts of production and their emissions, which is expected to meet global energy demands
Per capita energy use in MEDC’s is much higher than LEDC’s due to higher usage of energy, fossil fuels, and technology
Sources of energy with lower carbon dioxide emissions than fossil fuels include renewable energy ( such as biomass, solar, hydropower, wind, wave, tidal, and geothermal) and their use is unexpected to increase
Fossil fuels are non-renewable, as they cannot be naturally retrieved at the same rate in which it is being used up. Renewable energy is able to reduce greenhouse gas emissions, as when renewable energy sources are used, demand for fossil fuels is reduced.
It is important to note that non-biomass renewable energy sources do not emit greenhouse gases
Renewable energy: energy which can be gathered from natural sources which is able to be replenished faster than they are used
Nuclear Power is a low carbon low emission non-renewable resources but is controversial due to radioactive waste and potential scale of any accident
Nuclear power does not emit any greenhouse gases, acidic gases, or any harmful gases related to the deterioration of the environment
Energy security depends on adequate, reliable and affordable supply of energy that provides a degree of independence
Energy security is known as the uninterrupted availability of energy sources at an affordable price
Uneven distribution of energy may lead to conflict
The energy choices adopted by a society may be influenced by availability, sustainability, scientific and technological developments, cultural attitudes and political, economic and environmental factors
Energy choice is known as the choice that is made a to who supplies your energy. the sustainable energy sources include wind, solar and water
Improvements in energy efficiencies and energy conservation can limit growth in energy demand and contribute to energy security
Advantages and Disadvantages of Energy Sources:
Fossil fuels:
Advantages: has available technology, cheap
Disadvantages: not sustainable to the environment, contributes to climate change and pollution
Nuclear power:
Adv: has available technology, can produce large amounts of technology, does not emit carbon dioxide
Disadv: Radioactive and can remain harmful for thousands of years, huge risk of disaster, takes a long time to build
Hydroelectric power:
Adv: reliable form of energy, cheap to run once constructed
Disadv: Has a large effect on the environment, initial building cost is expensive
Tidal power:
Adv: renewable
Disadv: expensive, has a negative impact on wildlife
Solar Power:
Adv: cheap for heating homes, renewable
Disadv: is not always reliable to work, expensive
Wind power:
Adv: renewable, cheap once set up
Disadv: limited to the area it is built in, is a hazard to wildlife, dangerous for some species
Biofuel:
Adv: renewable
Disadv: produce emission, requires large amount of land to grow the area
Wastes:
Adv: does not deplete natural capital, already has available resources
Disadv: Produces carbon dioxide, harmful to the environment
7.2 - Climate Change: Causes and Impacts
Climate describes how the atmosphere behaves over relatively long periods of time whereas weather describes the conditions in the atmosphere over a short period of time
Weather and climate are affected by ocean and atmospheric circulatory systems
Human activities are increasing levels of greenhouse gases in the atmosphere
Human activities include:
Increase in the mean global temperature
Increases frequency and intensity of extreme weather events
Potential for long-term change in climate and weather patterns
Rise in sea level
One location to another can vary in potential impacts of climate change as it may be perceived as either adverse or beneficial. these impacts may include changes in water availability, distribution of biomes and crop growing areas, loss of biodiversity and ecosystem services, coastal inundation, ocean acidification and damage to human health
Positive feedback: is a feedback that increases initial warming, positive feedback accelerates temperature rise
Examples: melting polar ice lowers albedo, tropical deforestation increases warming and drying, increases forest cover decreases albedo
Negative feedback: is a process where climate feedback decreases the severity of some initial change, negative feedback slows down temperature increase
Examples: increases evaporation in low altitudes due to high levels of precipitation, increase in carbon dioxide in atmosphere leads to increases plant growth
Positive and negative feedback mechanisms are associated with climate change and may involve long time lags
Greenhouse gases effect is normal and necessary condition for life on earth. The role of these greenhouse gases are to maintain mean global temperatures, maintain normal and necessary conditions for life, and allow short wavelengths of radiation to pass through the earth’s surface, however, they trap the longer wavelength such as infrared radiation
Global climate models are complex and there is a degree of uncertainty regarding the accuracy of their productions
Climate is the average weather patterns over many years for a location on earth
Climate change is long term change to temperatures and weather patterns, these changes can be natural or vary through variations in solar cycle
Global warming potential (GWP): is a relative measure of how much heat a known mass of a GHG traps a number of years compared to the same mass of carbon dioxide
7.3 - Climate Change - Mitigation and Adaptation
Mitigation: attempts to reduce the causes of climate change. It is the use of technology and substitution to reduce resource inputs an emissions per unit of output. Involves reducing the flow of heat trapping greenhouse gases into the atmosphere, either by reducing these gases, or enhancing them which accumulate and store them.
The goal of mitigation is to avoid significant human interference with the climate system
Mitigation strategies to reduce GHGs:
Reduction of energy consumption
Reduce of emissions of oxides of nitrogen, and methane from agriculture geo engineering
Mitigation strategies for carbon dioxide removal:
Protecting and enhancing carbon sinks through land management reduction of emissions from deforestation and forest degradation in developing countries
Uses biomass and fuel source
Enhancing carbon dioxide absorption by the oceans through fertilizers of oceans to encourage biological pump
Even if nitrogen can reduce future effects and maximise any positive effect
Adaptation: attempts to manage the impacts of climate change. This involves adjusting to actual or expected future climate. The goal is to reduce our vulnerability to the harmful effects of climate change.
Adaptive capacity varies from place to place and can be dependent on financial and technical resources. MEDCs can provide economical and technical support to LEDCs
International efforts and conferences to address mitigation and adaptation strategies for climate change
8.1 - Human Population Dynamics
Human population can be calculated using many formulas, some of the ways to measure population changes are:
Crude birth rate: is the number of live births per 1000 people in a population. CBR does not calculate the age and gender structure of the population
Total number of births / total population * 1000 = CBR
Fertility: Total Fertility rate (TFR) is the average number of births per women of childbearing age. The average number of children each woman will have in her lifetime.
GFR: General fertility rate is the number of births per thousand women aged between 15-49 years old
ASBR: Age specific birth rate is the number of births per 1000 women of any specific year group
Death rate: CDR, crude death rate: is the number of deaths per thousand people in population. CDR not a completely accurate indicator as many old people (MEDC’s) have higher CDR’s than countries with more younger populations.
CDR = number of deaths/total population *1000
ASMR: Age specific mortality rates is the number of deaths per 1000 women of any age group
IMR: infant mortality rates is the number of deaths in children under 1 years old per 1000 live births
Doubling time: is the time it takes for a population to double in size/value
DT = 70/percentage growth rate
Natural increase:
NIR: natural increase rate in the CDR from the CBR
CBR - CDR = NIR. This formula excludes migration
Crude birth rate - CDR / 10
A NIR of 1% will make a double of a population in 70 years. This doubling time is 70 divided by the NIR
Human development Index (HDI): is a statistic composite index of health (life expectancy), wealth (gross domestic product, GDP), and education, all in one value
Factors influencing birth rates:
Level of education, low education will lead to people having kids with little to no plans to sustain their lifestyle (lack of knowledge about birth control for example)
Political Policies, such as taxes and poor job security
Economic prosperity, urbanisation which reduces the physical space needed to raise a large family
Need for children, for example, businessmen need children in order to pass on the family business
Factors affecting mortality:
Age structure, areas which house older adults are more likely to be subject to death and health problems than younger populations
Social class, low social class cannot afford medical care to sustain a healthy lifestyle
Occupation, some occupations put the employees health at risk due to their socioeconomic position
Child Mortality, higher child mortality leads to lower fertility and reproduction
Global human population has followed a rapid growth curve, but there is uncertainty as to how this may be changing. It is also considered to be a rapid and unprecedented growth in recent years. Exponential growth or geometric growth is when the population is growing, but there are no limiting factors slowing the growth. The impacts of exponential growth are huge amount of extra resources needed to sustain the basic needs of the population.
The world’s population is increasing very fast, due to many factors such as education, economic growth, health, poverty, and so on.
For this reason, population growth in less economically developed countries is more common as they are less educated and do not have proper education to help them be able to lead a healthy sustainable life. Population growth mainly occurs in LEDC’s. In order to reduce birth rates in LEDC’s, the standard of living in those countries must be improved.
MEDC’s, More economically developed countries, believe that they cannot raise children with low income, which is why they only have children if they do not affect their current way of life or lifestyle
An Increase in human populations leads to an increase in stress on Earth’s systems. As population number increase, resources will deplete.
Fossil fuels: is the burning of fuels which leads to an increase in sulfur dioxide in the atmosphere, which causes acid rain. The effects of acid rain are devastating for the environment, such as the dissolvement of nutrients which treets need for healthy growth. Therefore, the aluminium released into the soil due to acid rain makes it difficult for trees to take in water.
Sewage: untreated sewage left to be released as food for bacteria, which use up a lot of oxygen supply of the water. As a result, there will be a decrease in species diversity since only low oxygen concentrations species will survive.
Deforestation: is the clearing of forested land on purpose, which is intended for other uses. As a result, this also causes habitat destruction for certain species as there will be a reduction in soil fertility and soil structure which leads to a decrease in biodiversity
Grazing: livestock grazing is the feeding of herbivores which feed on plants such as grass and other organisms. This method contributes negatively to the environment, such as deforestation, overgrazing, soil degradation, and ecosystem stability
DTM: Demographic transition model shows us that countries progress through recognized stages through the process in transition from LEDC to MEDC. This is a pattern of decline in mortality and fertility of a country as a result of social and economic development
DTM has 5 stages:
High stationary (pre-industrial societies): high birth rate due to lack of birth control, high child mortality. This is due to the population’s low education and low socioeconomic status
Early Expanding (LEDC’s): death rate decreases as quality of life improves, and diseases decrease which ensures that their lifespan increases. However, birth rate is still high which is still high which means that population increases rapidly as well. Also, as a result of improved healthcare, child mortality decreases
Late Expanding (Wealthier LEDC’s): as a country develops, contraception becomes more evolved which leads to decreased birth rates. Healthcare improves, education improves, and emancipation of women improves. Population levels off and the desire for material goods decreases, and people have smaller families due to low infant death rates.
Low stationary (MEDC’s): population sizes stabilise, birth and death rates decrease in industrialised countries
Declining (MEDC’s): Here occurs problems with the aging workforce, as population may not be replaced may not be replaced as fertility rate is low
8.2 - Resource Use in Society
Renewable Natural Capital: can be generated and/or replaced as fast as it is being used. It includes living species and ecosystems that use solar energy and photosynthesis. It also includes non-living items, such as groundwater and the ozone layer
Natural Capital is a resource which has some value to humans, these are the goods and services that we use
Natural income: is the rate of replacement of a particular resource or natural capital
Capital includes: natural resources which have value to us, trees, soil, water
Natural resources that provide services, such as flood and erosion, photosynthesis, and the water cycle
Renewable natural capital can be utilized sustainable or unsustainable. If renewable natural is used beyond its natural income this use becomes unsustainable
Non-Renewable Natural capital: is either irreplaceable or only replaced over geological timescales, such as fossil fuels, minerals, soil, water in aquifers. These are resources that exist in infinite amounts on earth and are not renewed or replaced after they have been used or depleted. As resources are used, natural capital or stocks are depleted, new sources of resources need to be found
Natural capital as a concept is dynamic, the marketable value of that capital varies regionally and over time. These changes are influenced by technological, political, environmental, economic, social, and cultural factors
Renewable natural capital:
Use valuation: natural capital we can put a price on, such as the economic price of marketable goods, ecological functions, recreational functions
Non-use Valuation: natural capital that is impossible to put a price tag on, such as if it has intrinsic value, future uses we do not know yet, if it has value by existing for future generations
Organisms or ecosystems have value:
Intrinsic values: values that are not determined by their potential use to humans, their value is given vary by different factors such as culture, religion
Ecological value: value that have no formed market price byt are essential to humans (photosynthesis for example)
Economic value: value that is determined from the market price of the good and service a resources produce
Aseptic Value: no market price, similar to ecological value
8.3 - Solid Domestic Waste
Solid Domestic Waste (SDW): or municipal solid waste is the trash, garbage, rubbish from residential and urban areas which we produce. This is a mixture of paper, packaging, dust, glass, metals, plastic, and others. This waste is different from other waste due to the fact that even though it is collected from homes and shops and makes up around 5% of total waste, we are able to control that waste
There are different types of SDW of which is the volume and composition changes over time
Types of SDW:
Biodegradable: such as food waste, paper, green waste
Recyclable: glass, paper, metals, plastics, clothes, batteries
Toxic: pesticides, herbicides
Medical: needles, syringes, drugs
Mixed: tetra packs, plastic toys
Waste electronic and electronic equipment: TVs, computers, phones, fridges
Waste electrical and electronic equipment (WEEE): is a term from the european community.
The abundance of non-biodegradable pollution in particular has become a major environmental issue
The Circular Economy: we find the raw materials or natural capital (take) as we use energy to produce goods (make). These goods either break down or get replaced. Our economy is built on sustainability, which indicates that our resources are finite, and will eventually run out, no matter how much we decrease the usage of fossil fuels. Waste disposal options include landfill, incarceration, recycling, and composting.
It is a sustainable model which aims to:
Be restorative of the environment
Use renewable energy sources
Eliminate or reduce toxic waste
Eradicate waste through careful design
There are many varieties of strategies that can be used to manage SDW influenced by cultural, economic, technological and political barriers. Economies depend on goods and these require raw materials. These include:
Altering human activity: includes reduction of consumption and composting of food waste
Controlling release of pollutant: separate waste into different types, legislate about waste separation, educate for waste separation, tax disposable items
Clean-up and Restoration of Damages Systems: reclaim landfills, incinerate SDE for energy, collect plastics.
Managing SDW:
Strategies to minimise waste: These can be summarised into the three R’s, reduce, reuse, recycle.
Reduce: Means to use fewer resources and to stress Earth’s resources less. Some examples of this include: purchasing items with less plastic packaging, buying products made from recycled material, avoiding imported products, being mindful of the resources being used in your home
Reuse: This is where the products are used for something other than their original purpose, or they are returned to their manufacturer and used once more. Examples of this would be Reusable bottles, composting of food waste, reusing old clothes as cleaning rags, reading e-books instead of physical books
Recycle: This waste is converted into reusable material. This includes recycling bins in homes, charging households more if they produce more than the standard amount of waste, producing little food waste (feeding leftovers to dogs for example). Recycling involves collecting and separating waste materials and processing them for reuse, if the materials are reused without processing in some way, this is called reuse
Strategies for waste disposal:
The other forms of waste disposal are landfills, composting, and incinerators, however, if waste is not disposed through these forms, waste is thrown in the sea or composted into organic waste. Landfills are the main method of disposal, where it is taken to a site and buried there, and hazardous waste can be buried with everything else and and the initial cost is cheap.
Incinerators are able to burn the waste at high temperatures up to almost 2,000 degrees celsius. Waste is pre-stored to remove materials which could be recycled instead of burned, and to remove incombustible materials as well. The heat produced from incinerators is used to generate steam to provide electricity to areas such as turbines or to heat buildings. This process is called waste-to-energy incineration.
Anaerobic digestion is when biodegradable matter is broken down by microorganisms in the absence of energy. Methane produced here can be used as fuel. While domestic organic waste can be composed or put into anaerobic bio-digesters. Composting is as easy that it can be done at home. Anaerobic digestion is able to break down waste and produce methane, which is used as fuel and digestate that is used as a fertilizer.
8.4 - Human Population Carrying Capacity
Carrying capacity: maximum number of species or ‘load’ that can be sustainably supported by a given area
Difficulties in Measuring Human Capacities:
Humans use a greater range of resources than any other animal, therefore, measuring human carrying capacity requires more than just understanding what we eat and drink, and the space needed for housing.
We are able to substitute some resources with others, such as using coal instead of wood. However, this depends on our lifestyle as depending on our cultural and economic situation, our usage of resources also varies.
We are also able to import resources from their environment, and the way it’ll react depends on its geographic position, which is why we cannot just look at its local environment to see how many people it can support.
Developments in technology are able to change the resources we use, this means that machines become more efficient or it means that we use more resources as we can exploit new ones.
Ecological Footprint (EF): Human beings have enormous impact on natural environment, and ultimately on each other. The way we function and treat Earth’s resources determines and effects the long term availability of those resources and also the well-functioning Earth systems such as climate change, hydrological cycle, and other nutrient cycles in the atmosphere.
Ecological Footprint can be increased by:
More reliance on fossil fuels
Higher usage of technology (it can also decrease footprint)
Large per capita production of carbon waste (high energy and fossil fuel use), and large per capita consumption of food
Ecological Footprint can be reduced by:
Reducing use of resources, Recycling resources, reusing resources
improving efficiency of resource use, reducing amount of pollution produced
Transporting waste to other countries to deal with
Improving country to increase carrying capacity
Importing resources from other countries, reducing the population to reduce resource use
Using technology to intensify land and increase carrying capacity
Personal ecological footprint:
A fair Earthshare is the amount of land each person would get is all the ecologically productive land on Earth were divided evenly among the present world population
A person’s geographical location affects their measure of sustainability, as individuals in MEDC’s usually tend to have a technocentric view, in which people increase their consumption of resources in the expectation that technology will replenish these resources and decrease the harmful impact on the environment.
Individuals in LEDC’s tend to be ecocentrists, who try to reduce their use of non-renewable resources to decrease their use of renewable ones. People in LEDCs do not extra resources to waste, which is why they opt to decrease their personal usage of resources.
6.1 Introduction to the Atmosphere
Atmosphere as a Dynamic System: The Earth's atmosphere is a dynamic system influenced by both natural processes and human activities. It consists primarily of nitrogen (78.1%), oxygen (20.9%), and carbon dioxide (0.4%). Without the biosphere's influence, atmospheric composition would differ significantly, highlighting the close relationship between the biosphere and the atmosphere.
Variations in Composition with Altitude: Gas concentrations and temperatures vary with altitude. The tropopause acts as the upper limit of weather systems. In the stratosphere, temperature increases due to the presence of ozone, then decreases in the mesosphere, and rises again in the thermosphere.
Earth’s Energy Budget: The Earth receives solar energy (insolation), with 31% reflected back to space and 69% absorbed by the Earth and atmosphere. This balance is crucial for maintaining the planet's temperature.
Human Activities and Atmospheric Composition: Human actions, such as burning fossil fuels, deforestation, intensive cattle farming, and the use of fertilizers, release greenhouse gases like carbon dioxide, methane, and nitrous oxide, impacting the atmosphere's composition.
The Greenhouse Effect: A natural phenomenon where certain gases (e.g., water vapor, carbon dioxide, methane, nitrous oxide, ozone) trap heat, maintaining Earth's temperature. This process is vital for life but can be intensified by increased greenhouse gas emissions.
6.2 Stratospheric Ozone
Ozone Depletion: Ozone-depleting substances (ODS), including halogenated organic gases like chlorofluorocarbons (CFCs), are used in aerosols, gas-blown plastics, pesticides, flame retardants, and refrigerants. Halogen atoms (e.g., chlorine) from these pollutants increase the destruction of ozone in a repetitive cycle, allowing more ultraviolet (UV) radiation to reach the Earth.
Effects of Increased UV Radiation: More UV radiation reaching Earth's surface can damage human tissues, increasing the incidence of cataracts, mutations during cell division, skin cancer, and other health effects.
Pollution Management Strategies: Reducing the manufacture and release of ODS can be achieved by recycling refrigerants, developing alternatives to gas-blown plastics, halogenated pesticides, propellants, and aerosols, and developing non-propellant alternatives.
International Agreements: The Montreal Protocol (1987) is an international agreement aimed at reducing the use of ODS. National governments complying with the agreement have implemented laws and regulations to decrease the consumption and production of substances like CFCs.
6.3 Photochemical Smog
Primary and Secondary Pollutants: Primary pollutants from fossil fuel combustion include carbon monoxide, carbon dioxide, black carbon (soot), unburned hydrocarbons, oxides of nitrogen, and oxides of sulfur. Secondary pollutants, like tropospheric ozone, form when primary pollutants react with other chemicals in the atmosphere in the presence of sunlight.
Impacts of Tropospheric Ozone: Tropospheric ozone is highly reactive and damages plants (crops and forests), irritates eyes, creates respiratory illnesses, and damages fabrics and rubber materials.
Factors Influencing Smog: The frequency and severity of smog depend on local topography, climate, population density, and fossil fuel use.
Pollution Management Strategies: Strategies include altering human activity to consume less fossil fuels (e.g., using energy-efficient technologies, public transit, walking, cycling), regulating and reducing pollutants at the point of emission through government regulation or taxation, using catalytic converters to clean car exhaust, regulating fuel quality, and adopting clean-up measures like reforestation and conservation to sequester carbon dioxide.
6.4 Acid Deposition
Causes of Acid Deposition: The combustion of fossil fuels produces sulfur dioxide and oxides of nitrogen as primary pollutants. These gases can be converted into secondary pollutants that result in acid deposition, including dry deposition (ash and dry particles) or wet deposition (rain and snow).
Effects on Soil, Water, and Organisms: Acid deposition can have direct effects (e.g., acid on aquatic organisms and coniferous forests), indirect toxic effects (e.g., increased solubility of metals like aluminum ions affecting fish), and indirect nutrient effects (e.g., leaching of plant nutrients).
Pollution Management Strategies: Strategies include altering human activity to reduce fossil fuel use or using alternatives, regulating and monitoring the release of pollutants (e.g., using scrubbers or catalytic converters to remove sulfur dioxide and oxides of nitrogen from power plants and cars), and clean-up and restoration measures like spreading ground limestone in acidified lakes or recolonization of damaged systems.
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