CSSS 2009 Santa Fe-Complexity-Science

Complexity Science Approaches to Problems of Sustainability

Christa Brelsford, Joe Geddes, Gina LaCerva

Questions and Notes

How to couple together models of social, economic, and technical systems?

Complexity applied to urbanization could be very helpful since urbanization is so important for sustainability.

if global systems succumb to a catastrophic event, they were (by definition) not sustainable.

Various authors have listed catastrophic events that threaten civilization (Weizman, Diamond, Rees).

An important element of sustainability is to avoid catastrophic events.

SOS definition of resilience: Resilience is the amount of disturbance a system can withstand and remain in the same region of state space, dominated by the same set of processes.

In 70s or 80s there was a field called catastrophe theory (trying to predict large changes in physical and other types of systems), but it is now often referred to as a failure. Why? We don't want to repeat mistaken research programs of the past and so we should know why they failed, or if abandoning them was unjustified.

limits of knowledge

- what we don't know vs what we can't know

- understand limits of predictive power of models

some aspects of complexity:

- emergence

- sensitive dependence on initial and boundary conditions

- steady state but also novel behavior

- scaling laws and self organized criticality

- perpetual novelty

- can have underlying simplicity (but may not!)

complexity and technology topics

- studying development of more sustainable technologies and their learning curves; helping to create good portfolios of promising technologies

- studying how technologies are adopted (or not)

- many materials that could be useful for renewable energy and/or efficiency and/or catalysis, etc. exhibit complex systems behavior in their own right

- better understand complex technologies and technical systems to optimize them for much better efficiency; figure out ways to at least semi automate radical resource efficency in computer aided design

Does sustainability require that the rich help the poor?

Resilience, Avoiding Catastrophe, and Complexity

(original text by Christa Brelsford)

The first step in saving the world is keeping it from falling apart. In order to keep the world from falling apart, we have to know how it might fail. One method of increasing our understanding of global resilience is to provide methods to identify and quantify the interactions between systems dominated by human choices and behavior, systems dominated by economic decisions and institutions, and physical systems like ecosystems, human constructed infrastructure, and geophysical systems.

Quantitative models exist in each of the three spheres of sustainability, but few methods exist for linking these highly interactive spheres. Systems with behavior highly dependent on human choice can be modeled assuming the absence of a human presence. This provides useful insight into the behavior of the system, but if it is highly managed or feedbacks exist, a combined model of human choice and the complete system may provide better insight. I propose developing and codifying methods to model and validate interactions between each of the three major spheres.

The clearest closed system that involves humans is the entire earth, and all the physical, social and economic processes that it contains. A closed system is one in which external driving forces are not affected by the state of the system. Our recent economic troubles have shown that human economic institutions are global in scope, and each national economy is driven in part by the state of others. The driving forces behind the physical climate can also only be modeled on a global scale. Therefore, any human system smaller than the globe will not be a truly closed system, and it may not be possible to define if it is in a sustainable state or not. A closed system that never experiences failure is sustainable. The threshold that defines failure depends on ethical choices, but could range from complete global ecosystem collapse where few humans survive and no modern institutions do, to any period of rapid and unexpected change in human institutions. Phrased differently, a system that is always resilient is sustainable. Resilience is defined as the magnitude of disturbance a system can withstand and remain in the same state space, governed by the same set of processes (). Some resilience thresholds induce a shift from a sustainable state, with others may not. Careful examination of the major system domains and their interactions on a global scale may help us understand the essential characteristics of a sustainable system.

However, a model that links complex and interacting systems on a global scale risks becoming too general and dependent on assumptions to provide useful information. Therefore, as an intermediate step, regional scale models that primarily consider interactions between two of the three major domains can be built. Insights from regional models may scale to the global system.

On a regional scale, one method for increasing understanding of the interactions between human and physical systems uses agent based modeling. I propose developing an agent based model of dams on the Colorado river basin. The agents follow hierarchical rule structure that mimics the existing legal hierarchy of water rights, in-stream flow requirements and other regulations from EIS’s, and optimization of water releases to maximize the value of hydroelectric power generation. This model will then be layered on top of a 2 dimensional hydrological model of the river basin created using SWWM5. Water speed, temperature and quality will be included. Once the tool is developed, trade-offs between hydroelectric power generation and ecosystem health, biodiversity, and endangered species survival can be quantified. Additionally, when the model includes rigorous water demand models, the first area of failure under different policy and climate scenarios can be modeled. The model can be validated against historical data and also by layering the ABM part on IEISS.