Feedback Dynamics, Sensitivity

and Runaway Conditions in the

Global Climate System

For over three decades, the search for a definitve and accurate value of Climate Sensitivity has been the "Grail Quest" of climate science. The assessment of climate risk and the development of a strategic international response to global warming depend on answering two fundamental questions:

"The first question concerns the amount by which the feedback processes of the global climate system amplify the effects of the anthropogenic contribution to climate change"

"The second question addresses the dilemma of the possible existance of a critical threshold, or tipping point, in the global climate system beyond which climate change might be precipitated into a period of self-amplification, or runaway behaviour.

The current ensemble of climate models has great difficulty dealing with the complexity of the feedback processes involved. Their outputs are known to be too conservative and have a high degree of uncertainty. In constrast this paper presents a definitive value of climate sensitivity with much lower levels of uncertainty. The multi-disciplinary approach is independent of global climate models and is grounded in empirical data concerning the dynamics of the whole earth system. The derived value of climate sensitivity is significantly higher than current estimates which it should now replace. It will require a radical revision of the strategic approach to the mitigation of climate change. It lays the foundation for a new assessment of non-linearity and the relationship between feedback dynamics and sensitivity. It also enables exploration of the critical threshold between equilibriating and runaway behaviour in the global climate system.

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