Environmental Systems and Societies Summary IB Topic 1 EVS: Environmental Value System. An EVS is a worldview or paradigm that shapes the way
an individual or group of people perceive and evaluate environmental issues. Can be
influenced by cultural, religious, economic, and socio-political context.
● Cultural influences
● Economic factors
● Socio political factors
● Courses of action
Range of EVS:
● less materialistic approach to life
● self-sufficiency of societies
● self-restraint in human behaviour
● deep ecologists
● sustainable management of the global system
● environmental regulation and legislation (taxes)
● environmental managers
● technological developments can provide solutions to environmental problems
● Optimistic view of human role
● systems can be controlled, manipulated or changed to solve resource depletion
Systems: An assemblage of parts and the relationships between them.
● Consists of storage and flows. Storages are places where matter or energy is kept in
a system. Flows provide inputs and outputs of energy and matter.
● The flows are processes that may be either transfers (a change in location) or
transformations (a change in the chemical nature, state or energy).
Types of systems:
● Open: Both matter and energy are exchanged across the boundaries of
the system. They are organic → living, thus, it must interact with
● Closed: Energy but not matter is exchanged. The Earth is a closed system.
● Isolated: Neither energy nor matter is exchanged → Do not exist
naturally. The entire universe is an isolated system.
Models: It’s a simplified version of reality. They can be used to understand how systems
work and predict how they will respond to change. For example, a model can be used to
predict the earth's surface temperatures. Strengths:
● Allows scientists to simplify complex systems and use them to predict what will
● Input and outputs can be changed rapidly.
● Allow results to be shown and are easy to understand
● It is impossible to take all variables into account
● Models themselves are very complex.
● Any model is only as good as the data used.
1.3 Energy and Equilibria Laws of thermodynamics:
● First law: Energy can neither be created nor destroyed, it can only change form.
● Second law: Energy is lost in any transformation and transfer process, increasing
Open system → equilibrium
Steady state and static equilibrium:
● Steady-state equilibrium: Most open systems in nature. No changes over the longer
term. Oscillations in the short term. The system can return to the steady state
following a disturbance.
Static equilibrium: No changes in the system
over time. No inputs or outputs. No natural system is in
static equilibrium. For example, a chair.
Stable and Unstable equilibrium:
● Stable: If a system returns to the original equilibrium after a disturbance.
● Unstable: A system that does not return to the same equilibrium → it
forms a new equilibrium.
Feedback: It's a mechanism that can either change a system to a new state or return it to its
original state. Positive feedback: When a change in the state of a system leads to additional and increased
● Occurs when a change in the state system leads to additional and increased change.
● It will tend to amplify changes and drive the system towards a tipping point where a
new equilibrium is adopted.
Negative feedback: Counteracts any change away from equilibrium, contributing to stability.
● Occurs when the output of a process inhibits or reverses the operation of the same
process in such a way as to reduce change.
● It tends to reduce, neutralize or counteract any deviation from equilibrium
Tipping point: A critical moment when even a small change can have dramatic effects.
● The minimum amount of change within a system that will destabilize it, causing it to
reach a new equilibrium.
● Related to positive feedback.
Resilience: The tendency of a system to avoid tipping points and maintain stability through
● Related to the recovering capacity of a system and its resistant to change.
● Complex ecosystem with high biodiversity are more resilient.
Sustainability: The use of global resources at a rate that allows natural regeneration and
minimizes damage to the environment. Natural Capital: Resources that can produce a sustainable natural income of a good or
service. Can be renewable or nonrenewable. Natural Income: Yield obtained from resources. Natural resource → if produce good/services → Natural capital → if we use
it → Natural income: Sustainable: Allowing natural regeneration. Minimizing damage to the environment.
Exploitation of the resource at maximum sustainable yield.
Unsustainable: Exploitation of the resource at maximum economic yield. Sustainable Development: Meeting the needs of the present without compromising the
ability of future generations to meet their own needs.
Ecological Services: Provide a service that cannot be replaced artificially. Millenium Development Goals: Nations signed the Declaration. 8 Goals to be achieved by
● Eradicate Extreme Poverty & Hunger
● Universal Primary Education
● Gender Equality and Empower Women
● Reduce Child Mortality
● Improve Maternal Healthcare
● Combat HIV/AIDS, malaria, and other diseases
Ecological Footprints: Focuses on a population and its current rate of resource consumption
and estimates the area of environment necessary to sustainably support the lifestyle of that
Pollution: the contamination of the earth and atmosphere to such an extent that normal
environmental processes are deeply affected. Includes the release of substances which
harm air, water and soil quality.It can be:
● Natural → Volcanic eruption
Point Source Pollution: Discrete sources of contaminants that can be represented as single
points on a map and the source of pollution can be tracked.
Non-Point Pollution: More dispersed sources from which pollutants originate and enter the
Types of Pollutants: Can be divided into 2 categories:
● Primary Pollution: Pollutant active on emission.
● Secondary Pollution: Pollutant arising from primary pollutants undergoing physical
or chemical change.
● Persistent Pollutant: Are the ones that cannot be broken down by living organisms
and so are passed along food chains are organic compounds that are resistant to
environmental breakdown through biological, chemical, or photolytic process.
● Biodegradable Pollutant: Are the ones that are not stored in the biological matter or
passed along food chains. Most modern pesticides, used to treat crops to as to
ensure maximum yield, are biodegradable, although earlier chemicals were
Effects of Pollution:
● Acute effects: occurring after a short, intense exposure. Symptoms
are usually experienced within hours. Example: Air Pollution →
● Chronic effect: Occurring after low-level, long-term exposure.
Disease symptoms develop up to several decades later. Example: Air
pollution → Lung cancer
Pollution management strategies:
● Altering human activity: by promoting alternative technologies, using renewable
energy sources, changing lifestyles (legislation, taxes and economic incentives)
● Controlling release of pollutant: by regulating standards of emission or applying
technologies for extracting pollutants (from cradle to grave, end-of-pipe pollution
● Clean-up and restoration: of damaged systems by extracting and removing pollutant
or restocking lost or depleted populations and communities. This is the last option
and the most expensive.
Human causes of pollution: farming, industrial practices, urbanization, development of
transport, burning of fossil fuels.
Stages of pollution:
Human activity produces pollutant → Pollutant released into environment →
Long-term impact on ecosystems.
Species, population, habitat. Definitions. Concept.
● Species: A group of organisms sharing common characteristics that can interbreed
and produce offsprings.
● Population: A group of organisms of the same species living in the same area at the
same time, and which are capable of interbreeding.
● Habitat: environment in which a species normally lives.
● Niche: an ecological niche is where, when and how an organism lives. It describes
the particular set of abiotic and biotic conditions and resources to which an
organism or population responds.