As Dr Judith Curry has tried to communicate to me, the physical science of Climatology is full of deep complexity, with strong ranging on a number of processes.
Just to take a typical example – the Hurricane storm track in the Caribbean. Different years produce different levels of risk, and a constantly updated projection is needed as short-term relevant climatic factors shift.
But despite the likelihood of any particular Tropical Depression forming, the range of its strength and the eventual pathway, there is still a clearly identifiable track that storms take – that Stephen Schneider called “Hurricane Alley”.
This kind of “big picture” of regional and even global phenomena means that we can safely scale out from the inner workings of individual changes in air pressure, prevailing winds and humidity and take in the larger-scale, longer-term trends.
In Paleoclimatology, the study of the history of glaciation and de-glaciation of the planet has shown a remarkable regularity despite numerous interworking complexities – so much so that relatively simple models can be applied :-
Hogg, A. M. (2008). “Glacial cycles and carbon dioxide: A conceptual model”, Geophysical. Ressearch Letters, 35, L01701, doi:10.1029/2007GL032071
“Abstract : The correlation between Antarctic temperature and atmospheric carbon dioxide concentration is a key feature of Quaternary climate cycles. The cycle is characterised by pronounced temporal asymmetry; with rapid increase in both temperature and CO2 at the glacial termination. Here I compare observed climate cycles with results from a simple model which predicts the evolution of global temperature and carbon dioxide over the glacial-interglacial cycle. The model includes a term which parameterises deep ocean release of CO2 in response to warming, and thereby amplifies the glacial cycle. In this model, temperature rises lead CO2 increases at the glacial termination, but it is the feedback between these two quantities that drives the abrupt warming during the transition from glacial to interglacial periods.”
The sum of the complexities is a clearly recognisable, repeated saw-tooth in the ice core records :-
Andrew Hogg notes : “The role of CO2 in the glacial cycle has been the source of much misinformation in recent public debate on climate change, largely because there is no scientific consensus on the mechanism controlling glacial cycles. Here I propose a simple model which predicts the evolution of global temperature and carbon dioxide over the glacial-interglacial cycle. In this model, CO2 acts to amplify, but not trigger, the glacial cycle. Deglaciation is triggered by variation in the earth’s orbit; thus, temperature rises lead CO2 increases at the end of glaciation, but it is the feedback between these two quantities that drives the abrupt warming during the transition from glacial to interglacial periods…”
In his Conclusions he writes, “The model has some features in common with observed temperature records: the temperature range far exceeds that due to global mean insolation alone.”
What this means is that changes in sunlight falling on the Earth due to changes in its orbit around the Sun and its tilt, on their own cannot account for the sawtooth swings.
Complexities in the response of the various parts of the Earth system add up to what is called “non-linear” changes – things are not straight-forward within each tooth of the saw – even though the sawtooth shape is very regular.
The reason why scientists are concerned about the state of the Earth’s climate is that this regular saw-tooth pattern has been broken :-
The sum of complexity has been overshot by an obvious forcing – a pulse of Carbon Dioxide pumped into the Atmosphere by mankind’s activities, including cutting down the trees (to burn them) and digging up hydrocarbon fuels dating from periods of mass extinction on Earth (to burn them).
Citing complexity in the internal workings of the Climate system is not a sufficient reason to prevent Judith Curry, and everyone else, considering the probable implications of this very unusual and quite possible dangerous fact.