WCC: Systems Flashcards
Systems concepts and their application to the water and carbon cycles.
Define input
An input into the system from outside
Define output
An output from the system to the outside
Define stores/components
The individual parts of a system
Define flows/transfers
The links or relationships between the components
Define energy
Power or driving force of the system
Define dynamic equilibrium
A state of balance within a constantly changing system
Define positive feedback
A cyclical sequence of events that amplifies or increases change. Positive feedback loops exacerbate the inputs of a system, driving it in one direction and promoting environmental instability
Define negative feedback
A cyclical sequence of events that dampens down or neutralises the effects of a system, promoting stability and a state of dynamic equilibrium
On a global scale, are the water and carbon cycles open or closed systems?
Closed systems
On a local scale, are the water and carbon cycles open or closed systems?
Open systems
Give an example of positive feedback in the water cycle
Sea levels rise Ice shelves are destabilised Rate of calving increases Increase in melting Sea levels rise
Give an example of negative feedback in the water cycle
Surface temperature increases Increases evaporation from oceans More low clouds in the atmosphere Clouds reflect radiation Surface temperature decreases Increase in greenhouse gases Surface temperature increases
Give an example of positive feedback in the carbon cycle
Temperature increases Permafrost melts Trapped greenhouse gases released Greenhouse effect enhanced Temperature increases further
Give an example of negative feedback in the carbon cycle
Fossil fuels burned
Increased atmospheric co2, increased temps
Promoted plant growth and rate of photosynthesis removes co2
Temperature decreases
What is a system?
A system is a type of model that makes it easier to understand relationships between components in order to see how energy is transferred between them
What are the attributes of a system?
The perceived characteristics of the elements of a system
Why are systems models useful?
They help us to appreciate how natural and human change can impact the environment
What are Earth’s 4 major subsystems? (at a global level)
Lithosphere, Biosphere, Hydrosphere, Atmosphere
What is an isolated system?
A system that has no interactions beyond its boundary layer
What is a closed system?
A system that transfers energy, but not matter, across its boundary to the surrounding environment
What is an open system?
A system that transfers both matter and energy can cross its boundary to the surrounding environment
What type of system can the Earth’s 4 major subsystems be seen as?
A cascading system - each subsystem is an open system forming part of a chain
