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Can you gradually fall off a cliff? – A glimpse at complex, self-organising systems

Explore the transition from mechanistic models to complex self-organizing systems in the 20th century. Learn about the contributions of various scientists and the awakening of complexity in science.

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Can you gradually fall off a cliff? – A glimpse at complex, self-organising systems

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  1. Can you gradually fall off a cliff?– A glimpse at complex, self-organising systems Roger N. Jones AIACC Training Workshop on Adaptation and Vulnerability TWAS, Trieste June 3-14 2002

  2. Mechanical world of the 19th century Few mysteries left for science to solve The universal machine Mastery over nature The march of progress Modernism The 20th century – transition Quantum physics Chaos and “strange attractors” isolated “frame of reference” exposed as a scientific construct search for a process to counterbalance reductionism Postmodernism The awakening of complexity

  3. Contributions to complex systems science • Adam Smith “The invisible hand” • Einstein, Bohr, Pauling et al. – quantum physics • Schroedinger et al. – uncertainty • Turing and Von Neumann – self-replicating automata and game theory • Kuhn – the scientific process is linked to social processes • Prigogine – complex chemistry • Lorenz, Gleick et al. – chaos • Holland, Conway et al. – artificial life • Bak et al. – self organising systems • Arthur – law of increasing returns (economics) • Capra – role of eastern philosophy and many others

  4. Simple system • Mechanistic • Replicable • Largely linear • Can be isolated from other systems • Predictable

  5. Complex system • Organic/chaotic (often described as on the edge of chaos because both organised and chaotic behaviour are recognised) • Non-replicable • Cannot be isolated from other systems • Non-linearity and thresholds both common • Self-organising (self-adapting) • Bifurcations occur over time • Uncertainty is intrinsic

  6. Examples • Qwertyuiop • VHS/Beta • DOS/CPM • Extinctions/radiation (evolution)

  7. Fractal patterns are “natural”

  8. Glacial cycles are driven by changes in the Earth’s orbit

  9. Holocene rainfall and evaporation – W. Victoria

  10. Weather events

  11. CO2 emissions and concentrations

  12. Global warming

  13. Likelihood Probability can be expressed in two ways: 1. Return period / frequency-based (Climate variability) 2. Single event (Mean climate change, one-off events)

  14. Return period / frequency-based probability Recurrent or simple event Where a continuous variable reaches a critical level, or threshold. Eg. Extreme temperature (max & min), Extreme rainfall, heat stress, 1 in 100 year flood Discrete or complex event An event caused by a combination of variables (an extreme weather event) Eg. tropical cyclone/hurricane/typhoon, ENSO event

  15. Frequency-based probability distributions

  16. Coping range under current climate

  17. Thresholds A non-linear change in a measure or system, signalling a physical or behavioural change Climate-related thresholds are used to mark a level of hazard

  18. Single-event probability Singular or unique event An event likely to occur once only. Probability refers to the chance of an event occurring, or to a particular state of that event when it occurs. Eg. Climate change, collapse of the West Antarctic Ice Sheet, hell freezing over

  19. What is the probability of climate change? 1.Will climate change happen? • IPCC (2001) suggests that climate change is occurring with a confidence of 66% to 90% 2. What form will it take? Uncertainties are due to: • future rates of greenhouse gas emissions • sensitivity of global climate to greenhouse gases • regional variations in climate • decadal-scale variability • changes to short-term variability

  20. Range of uncertainty

  21. 100 100 80 80 75 cm 75 cm 60 60 Sea Level Rise (cm) Sea Level Rise (cm) 50 cm 50 cm 40 40 25 cm 25 cm 20 20 0 0 0 100 0 100 Probability (%) Probability (%) 100 100 100 100 80 80 80 80 75 cm 75 cm 75 cm 75 cm 60 60 60 60 Sea Level Rise (cm) Sea Level Rise (cm) Sea Level Rise (cm) Sea Level Rise (cm) 50 cm 50 cm 50 cm 50 cm 40 40 40 40 25 cm 25 cm 25 cm 25 cm 20 20 20 20 0 0 0 0 0 5 10 0 100 0 5 10 0 100 Probability (%) Probability (%) Probability (%) Probability (%) 75 cm 50 cm 25 cm

  22. Non-linear climate change • Non-linear climate events - ice ages, Younger Dryas, collapse of the WAIS • Climate surprises - climate events that occur unexpectedly • Climate surprises are likely to occur on a regional basis under climate change but when and where remains unknown.

  23. System responses • Resistance (e.g. seawall) • Resilience (e.g. regrowth, rebuilding after storm or fire) • Adaptation (adjustments made in response to stress) • Transformation (old system stops, new one starts) • Cessation (activity stops altogether)

  24. Can you gradually fall off a cliff? Yes, if you use a model But not in the real world

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