The Systems Approach (HL IB Environmental Systems & Societies (ESS))

The Systems Approach

• A systems approach is the term used to describe a method of simplifying and understanding a complicated set of interactions

  • Systems and the interactions they contain can be environmental or ecological (e.g. the water cycle or predator-prey relationships), social (e.g. how we live and work) or economic (e.g. financial transactions or business deals)

• There are two ways of studying systems:

  • A reductionist approach means breaking a system down into its parts and studying each one individually

    • This can be useful for studying specific interactions in detail but it doesn't show what's going on in the system as a whole

  • A holistic approach looks at all of the system's processes and interactions as a whole

• For example, sustainability or sustainable development depends on a highly complex set of interactions between many different factors

  • These include environmental, social and economic factors (sometimes referred to as the three pillars of sustainability).

  • A systems approach is required in order to understand how these different factors combine and interact with one another, as well as how they all work together as a whole (the holistic approach)

Components & Interactions in Systems

Storage and flow

• A system is comprised of storages and flows

  • The flows provide inputs and outputs of energy and matter

• The flows are processes that may be either:

  • Transfers

  • Transformations

Transfers and transformations

• These are two fundamental concepts in systems (and systems diagrams) that help to understand how matter and energy move through a system

• Transfers are the movement of matter or energy from one component of the system to another without any change in form or quality

  • For example, water flowing from a river to a lake is a transfer

• Transformations, on the other hand, involve a change in the form or quality of matter or energy as it moves through the system

  • For example, when sunlight is absorbed by plants, it is transformed into chemical energy through the process of photosynthesis

• Transfers and transformations are often represented in systems diagrams by arrows that connect the different components of the system

  • Arrows that represent transfers are usually labelled with the quantity of matter or energy being transferred (e.g., kg of carbon, kJ of energy), while arrows that represent transformations may include additional information about the process involved (e.g., photosynthesis, respiration)

• Systems diagrams can help identify the key transfers and transformations that occur within a system and how they are interconnected

• By understanding these processes, it is possible to identify opportunities to improve the efficiency or sustainability of the system

• Transfers and transformations can occur at different scales within a system, from the molecular level to the global level

  • For example, at the molecular level, nutrients are transferred between individual organisms, while at the global level, energy is transferred between different biomes

Systems diagrams

• Systems are often represented as simplified diagrams made up of storages and flows

  • Storages are commonly drawn as shapes with defined boundaries (such as a circle or rectangle)

  • Flows are commonly drawn as arrows

    • These arrows represent the various inputs and outputs occurring within a system

  • The size of the shapes and arrows can be representative of the size of the particular storage or flow (although often they are not drawn this way)

Emergent properties

• The interactions within a system, when looked at as a whole, produce the emergent properties of the system

• Emergent properties are properties of a system that appear as individual system components interact; the components themselves do not have these properties

  • For example, in an ecosystem, all the different ecological interactions occurring within it shape how that ecosystem looks and behaves

  • If the interactions change for some reason (e.g. a new predator is introduced), then the emergent properties of the ecosystem will change too

  • Predator–prey cycles and trophic cascades are good examples of emergent properties, where patterns of change occur that would not occur in the isolated components