On the ocean heat engine, stiffness of chaotic systems and climate prediction

The oceans are looked on as a heat engine, and the points are made, firstly, that the effect operating this engine is modest, and, secondly, that the engine efficiency is extremely small. It is argued that a parameter, called the “thermal stiffness”, generally increases when certain phenomena: new instabilities, turbulence, noise, etc., appear in thermodynamically forced systems. For the ocean system, this indicates that the temperature rise associated with the greenhouse effect may be overestimated in numerical ocean models which do not include, or do not properly resolve, such phenomena.