the facts about global warming

[Richard S Courtney.]

jason 85:

You say:

(03-04-2010 02:22 AM)jason_85 Wrote:  I haven't ignored anything, but it's simply not possible for me to address every critique, because it takes a lot of time. I think that historically the only external things significantly affecting the climate were Milankovich cycle and sunspots. Of course, these factors don't work alone, and we have secondary effects such as changes in ice coverage, greenhouse gas emissions, cloud coverage, etc.

Today I think the dominant force is CO2. I have tried to address why I think CO2 overtook sunspots as the leading cause for rapid changes in the climate, in "Sunspots and the 20th century" section of my article on global warming, and I will try to get to the other things as well, but as I said it takes time...

Sorry, but you have completely ignored the most likely cause of climate change and have made an assumption instead.

The basic assumption used in the numerical climate models is that change to climate is driven by change to radiative forcing. And it is very important to recognise that this assumption has not been demonstrated to be correct. Indeed, it is quite possible that there is no force or process causing climate to vary. I explain this possibility as follows.

The climate system is seeking an equilibrium that it never achieves. The Earth obtains radiant energy from the Sun and radiates that energy back to space. The energy input to the system (from the Sun) may be constant (although some doubt that), but the rotation of the Earth and its orbit around the Sun ensure that the energy input/output is never in perfect equilbrium.

The climate system is an intermediary in the process of returning (most of) the energy to space (some energy is radiated from the Earth’s surface back to space). The Northern and Southern hemispheres have different coverage by oceans and, therefore, as the year progresses the modulation of the energy input/output of the system varies. Such a varying system could be expected to exhibit oscillatory behaviour and it does: the mean global temperature increases by 3.8K from July to January and falls by the same amount from January to July each year.

Hence, the system is always seeking equilibrium but never achieves it.

Iimportantly, the oscillations could induce harmonic effects which have periodicity of several years. Of course, such harmonic oscillation would be a process that – at least in principle – is capable of evaluation.

However, there may be no process because the climate is a chaotic system. Therefore, the observed oscillations (ENSO, NAO, etc.) could be observation of the system seeking its chaotic attractor(s) in response to its seeking equilibrium in a changing situation.

Very, importantly, there is an apparent ~900 year oscillation that caused the Roman Warm Period (RWP), then the Dark Age Cool Period (DACP), then the Medieval Warm Period (MWP), then the Little Ice Age (LIA), and the present warm period (PWP). All the observed rise of global temperature in the twentieth century could be recovery from the LIA that is similar to the recovery from the DACP to the MWP. And the ~900 year oscillation could be the chaotic climate system seeking its attractor(s). If so, then all global climate models and ‘attribution studies’ utilized by IPCC and CCSP are based on the false premise that there is a force or process causing climate to change when no such force or process exists. Indeed, glacial and interglacial states may be the result of there being two chaotic attractors.

It seems likely that the climate system exhibits both harmonic oscillation and chaotic attractor seeking.

But the assumption that climate change is driven by radiative forcing may be correct. If so, then it is still extremely improbable that – within the foreseeable future – the climate models could be developed to a state whereby they could provide reliable predictions. This is because the climate system is extremely complex. Indeed, the climate system is more complex than the human brain (the climate system has more interacting components – e.g. biological organisms – than the human brain has interacting components – e.g. neurones), and nobody claims to be able to construct a reliable predictive model of the human brain. It is pure hubris to assume that the climate models are sufficient emulations for them to be used as reliable predictors of future climate when they have no demonstrated forecasting skill.

Hence, empirical assessments such as those of Idso and that of Eschenbach are essential if we are to evaluate the validity of the assumptions which form the basis of existing numerical climate models.

Richard