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smaller- scale elements. For example, farming systems operate with regional
agricultural ecosystems that define what types of farming are practical, and
agricultural ecosystems exist within larger economic systems, which operate
within sociopolitical systems that shape investment and policy drivers. A second example is the U.S. Power Grid, which has three physical “interconnections” (Eastern, Western, and Texas), but within each interconnection, there are
various “balancing regions” that govern power quality, and within those multiple power utilities produce and distribute the power.
• Emergence: The characteristics of the whole system cannot be adequately
understood from the separate study of individual parts and the bottom-up aggregation of the properties of disconnected components. Instead, characteristics of
the entire system “emerge” from the interconnections between the fine-scale
parts of the system. For example, epidemics that destroy food crops or livestock
emerge from a combination of bad luck and bad management practices at individual farms and processing facilities and then spread widely only if enough
facilities follow bad management practices.
A simple way to visualize emergent properties is to consider how the features of a building are distinct from the separate properties of the various
elements of construction, such as the joists, bricks, windows, doors, wiring,
and paint. One might say that the properties of the building, its rooms, its
controlled environment, and so forth emerge from how the building elements
interact with each other.
Food, energy, and water markets, where they exist, are emergent properties
that result from the interaction between consumers, policymakers, energy producers, and the technologies and infrastructure required to produce, move, and
utilize the various forms of food, energy, and water.
• Feedback (Coevolution, Synchronization): As one part of the system changes
or “evolves” over time, other parts of the system will change or evolve as a result.
That change will influence the change of the first part, a phenomenon known as
“feedback.” As a result, parts of the system “coevolve” based on their interactions with each other, yielding synchronized or partially synchronized subsystem
states. In the presence of feedback, “cause” and “effect” lose their classical or
original simplistic meaning. Complex systems may exhibit forms of relative stability or equilibrium even as they include dynamic processes. However, slow or
small changes may lead to rapid or abrupt changes, which can sometimes occur
at “tipping points” where nonlinear change can “cascade” through a system.
For example, food production coevolves with energy and water systems
because of the importance of water for irrigation and energy for fertilizers and
machinery. In a second example, decreased electrical power demand decreases
demand for water to generate power and then decreases the demand for power
to pump the water.
• Self-organized criticality: The dynamics of complex systems often grow toward
one or more critical limits where “catastrophe” (rapid and large-scale change) is
just a small step away, and where a small disturbance to push them over that edge
into a new system state. Forest fires, earthquakes, and avalanches are examples
2 Systems Science
smaller- scale elements. For example, farming systems operate with regional
agricultural ecosystems that define what types of farming are practical, and
agricultural ecosystems exist within larger economic systems, which operate
within sociopolitical systems that shape investment and policy drivers. A second example is the U.S. Power Grid, which has three physical “interconnections” (Eastern, Western, and Texas), but within each interconnection, there are
various “balancing regions” that govern power quality, and within those multiple power utilities produce and distribute the power.
• Emergence: The characteristics of the whole system cannot be adequately
understood from the separate study of individual parts and the bottom-up aggregation of the properties of disconnected components. Instead, characteristics of
the entire system “emerge” from the interconnections between the fine-scale
parts of the system. For example, epidemics that destroy food crops or livestock
emerge from a combination of bad luck and bad management practices at individual farms and processing facilities and then spread widely only if enough
facilities follow bad management practices.
A simple way to visualize emergent properties is to consider how the features of a building are distinct from the separate properties of the various
elements of construction, such as the joists, bricks, windows, doors, wiring,
and paint. One might say that the properties of the building, its rooms, its
controlled environment, and so forth emerge from how the building elements
interact with each other.
Food, energy, and water markets, where they exist, are emergent properties
that result from the interaction between consumers, policymakers, energy producers, and the technologies and infrastructure required to produce, move, and
utilize the various forms of food, energy, and water.
• Feedback (Coevolution, Synchronization): As one part of the system changes
or “evolves” over time, other parts of the system will change or evolve as a result.
That change will influence the change of the first part, a phenomenon known as
“feedback.” As a result, parts of the system “coevolve” based on their interactions with each other, yielding synchronized or partially synchronized subsystem
states. In the presence of feedback, “cause” and “effect” lose their classical or
original simplistic meaning. Complex systems may exhibit forms of relative stability or equilibrium even as they include dynamic processes. However, slow or
small changes may lead to rapid or abrupt changes, which can sometimes occur
at “tipping points” where nonlinear change can “cascade” through a system.
For example, food production coevolves with energy and water systems
because of the importance of water for irrigation and energy for fertilizers and
machinery. In a second example, decreased electrical power demand decreases
demand for water to generate power and then decreases the demand for power
to pump the water.
• Self-organized criticality: The dynamics of complex systems often grow toward
one or more critical limits where “catastrophe” (rapid and large-scale change) is
just a small step away, and where a small disturbance to push them over that edge
into a new system state. Forest fires, earthquakes, and avalanches are examples
2 Systems Science