The only mesoscale experiment likely to be of any value is the last 10 years where CO2 levels have risen by some accounts another 20% and temperatures seem to have plateaued, depending on who you believe, somewhere between 1999 and 2003.
No laboratory experiment is likely to be able to reproduce at anything like a reasonable scale the vast complexity of variables that appear to go into climate change. This then is the attraction towards models, as computational speeds and architectures continue to approach the throughput capacities required for such a vast array of variables and parameterizations. The model therefore becomes the "laboratory", if you will, where these experiments, by necessity, have been carried out and continue to be carried out.
The problems here are vast, which is precisely as it should be for such a young science. This has been magnified by the politicization of the prognostications emanating from not only the models, but the modelers and the natural avarice of the politicos. Nevertheless, the wealth of data that has emerged for the astonishing paleoclimatic changes where we have hi-resolution data (the Greenland cores going back to the Eemian), as well as from auspicious locations of the ocean deep drilling programs, literally do not compute in the present day iterations of the models, regardless how they are paramaterized.
The present crop of models cannot produce the speed, magnitude or character of the well known D-O events, and fail quite miserably at the major transitions, coming a bit unglued when faced with the ride from Termination I into the Holocene.
The upshot being that there is at least one major variable missing in our preset climate soup recipe. What causes abrupt, reliable and seemingly unavoidable natural climate changes? They are not predictions, they are facts. Extremely well documented facts. And they do not change, the resolution just keeps getting better as more evidence is cunningly prized out from the better locations we continue to find.
With models continually receiving new code, new models being developed, and a slew of paramaterizations constantly being applied, an irrational person should be able to readily conclude that not only are the models complete and correct, but that we should take drastic action as a result thereof.
For the irrationally disinclined, there is a disturbing similarity between the current experimental domain, e.g. oodles of models woefully inadequate to date, and the rather undisciplined world of virtual reality games. What with new model results being published almost daily, one is left with the choice of which religion is the correct one? Should we wait until one more favorable to our belief structures arrives? Mormonism is a fairly recent religion for that matter, but Christian Science is a more recent development, and it has the added benefit of having science in its very name. Should Mormons, Baptists, Presbyterians, Lutherans, Catholics etc convert?
So goes the belief structures of modeling. Truth or Dare anyone?
For a smashing good time in the real world of climate change, I recommend the following:
Physics Letters A 366 (2007) 184–189
Classification of Dansgaard–Oeschger climatic cycles
by the application of similitude signal processing
Jordi Solé a,b,∗, Antonio Turiel b, Josep Enric Llebot
But this time, you will have to put your money where your climate change mouth is and go to Science Direct and plunk down a tad over $30. Which just happens to be where the reality rubber hits the climate change road.
Here is a taste:
There are different works that relate the CO2 air concentration
with temperature changes, supposing that CO2 may [12]
or may not drive this temperature increase [20]. In this work
ice-core CO2 time evolution in the period going from 20 to
60 kyr BP [15] has been qualitatively compared to our temperature
cycles, according to the class they belong to. It can be
observed in Fig. 6 that class A cycles are completely unrelated
to changes in CO2 concentration. We have observed some correlation between B and C cycles and CO2 concentration, but of
the opposite sign to the one expected: maxima in atmospheric
CO2 concentration tend to correspond to the middle part or the
end the cooling period. The role of CO2 in the oscillation phenomena
seems to be more related to extend the duration of the
cooling phase than to trigger warming. This could explain why
cycles no coincident in time with maxima of CO2 (A cycles)
rapidly decay back to the cold state.
Using our technique, we have been able to put into correspondence
and to compare cycles happening at different locations
in the time series. We have so being able to identify three
different types of cycles, all of them sharing the first warming
phase but differing in the speed at which they relax back
to the cold state. Some striking consequence appearing from
the mere classification is that Younger/Dryas–Bolling/Allerod
(Y/D–B/A) cycle cannot be considered a unique cycle any
longer, as it is just a class B cycle similar to the other six we
have identified. Due to the importance given in recent scientific
literature to Younger–Dryas because of its influence in global
climatology [11], we have tried to identify the causes justifying
the apparition and type of the observed oscillations. One
key point is to explain the observed different cooling phases,
what we have done by crossing our evidences with independent
data on CO2 atmospheric concentration and testing the results
with theoretical reasoning about astronomical cycles. Nor CO2
concentration either the astronomical cycle change the way in
which the warming phase takes place. The coincidence in this
phase is strong among all the characterised cycles; also, we
have been able to recognise the presence of a similar warming
phase in the early stages of the transition from glacial to
interglacial age. Our analysis of the warming phase seems to
indicate a universal triggering mechanism, what has been related
with the possible existence of stochastic resonance [1,13,
21]. It has also been argued that a possible cause for the repetitive
sequence of D/O events could be found in the change in the
thermohaline Atlantic circulation [2,8,22,25]. However, a cause
for this regular arrangement of cycles, together with a justification
on the abruptness of the warming phase, is still absent in
the scientific literature.
And now for a word from one of our non-sponsors. Real Climate. Personally, I find this site to be one of the more distasteful sites out there. An astonishing number of their prognosticated hypotheses are regularly discredited, and unless I am grossly mistaken, it seems like the major players at this site are Gavin Schmidt and Michael Mann, two of the most hallowed turd polishers in the world of climate change. Personally, I suspect, though I have no empirical data, so this must necessarily be classified as a religious belief, that this single site could itself be a strong forcing of global warming. Since it has only recently come into existence (geologically speaking) there is no precedent for this forcing in the paleoclimate record.