Feedback Dynamics
AbstractThis presentation was given to an international conference on Managing the Interconnected Challenges of Climate Change, Energy Security and Water organised by the Club of Rome in Switzerland, 6-7 November 2008. It provides a brief introduction to the conceptual top-down systems-dynamics approach to modelling the whole earth system as a global entity. Analysis of the feedback dynamics in climate change alerts us to the existence of a "tipping point" in the whole earth system - not to be confused with the set of sub-system, energy redistribution tipping points identified by John Schellnhuber, Tim Lenton et al. A "Critical Threshold" exists. The closer we come to that critical threshold, the more massive and costly the required intervention becomes, until the power of positive feedback overwhelms the capacity for human intervention. Current strategies assume no limit to the time-scale within which it is still possible intervene effectively. They also ignore any degrade in the ability of emissions-reduction to control the rate of global heating however high it becomes. In so doing they gravely underestimate the power of the second-order positive feedback. These false assumptions are placing the future of our civilisation and its holding environment in extreme danger. We cannot afford any further delay in effective action. Any procrastination increasingly risks global bankruptcy in financing the needed intervention, and massive human suffering in carrying it through to completion. It also threatens our ability to regain control before the system is overwhelmed by the positive feedback loops and drifts inexorably into unstoppable runaway global heating. Global heating has already been pushed far out of equilibrium. "Radiative Forcing" or Global Heating, is currently running at about 2 watts per square meter, which works out at a million giga-watts over the whole earth. This is equivalent to the heating from a million million 1 kilowatt fires and it is increasing by about 25% per decade and the rate is accelerating. Climate stabilisation means reducing that to zero. Climate stabilisation is the strategic imperative for tomorrow's world. All other objectives pale into insignificance in the light of that overarching agenda. Can we do it? The current answer appears to be "Yes, we can". Will we do it? The answer to that hangs precariously in the balance. In the words of Gene Kranz, mission controller of Apollo 13 - "Failure is not an option" 
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