Archives for April 2009

CENTRAL to discussion of climate change models is the concept of “forcing” and “feedback”.   So, reference is made to global warming from radiative “forcing” from elevated concentrations of carbon dioxide in the troposphere and then “positive feedback from water vapour”, adding to global warming.  

Everyone talks in these terms, and it is politically correct to do so.  But there are two problems.

According to the United Nation’s Intergovernmental Panel on Climate Change (IPCC) formalism, their “forcing” can include any amount of internal state variable contribution, as well as external driving function contributions.  And according to this IPCC formalism, there is only one dynamically distinct internal state variable, the climate temperature, that functionally determines the apparently distinct but really merely functionally dependent “feedbacks” of their formalism.

In physics, an external driving function qualifies unequivocally as a cause. But internal state functions must always be counted as effects that are themselves caused by external drivers interacting with internal state functions acting as internal causes.

This important cause-effect structure is erased in the “forcing” concept of the IPCC formalism. It follows that cause and effect will be muddled in work that uses the IPCC formalism for simplified models. The simplified models are made of ordinary differential equations as in the qualitative theory of dynamical systems including deterministic chaos originated by Henri Poincaré in the 1880s. Poincaré used the method of phase portraits, which make explicit the presence of several dynamically distinct internal state variables.

The IPCC limitation to only one dynamically distinct internal state variable makes the IPCC concept of “feedbacks” verge on nonsense.

[Read more…] about Climate Models Confuse Physics of Cause and Effect: A Note from Christopher Game