Martin A, dung

Martin A

Not quite.

Good data tells you something useful about reality.

Bad data tells you nothing about reality or, worse, misleads you.

The trap is to define good data as supporting ones belief and bad data as opposing ones belief.

I hope none of those here think like that.

Dung

Not a fool, but sometimes ill-informed. You have a higher IQ than me, but seem to have trouble applying it properly.

Remember the old adage.

"Intelligence is a tool for achieving goals, but goals are not chosen intelligently."

Like Alan, I'm late to this discussion too. It's a curious fact that many, if not all, studies of climate in 'deep' geological time attempt to shoehorn the data into a paradigm that has CO2 as the control knob for Earth's surface temperature. A case in point is Entropic Man's calculation of the effect of CO2 on the Devonian Climate. First the data he quotes is originally from a paper by Royer et al (2004). This paper takes data of Jan Veizer et al. on the oxygen isotope composition of marine carbonates and fossils (mostly bivalves) which shows that Earth's climate has oscillated with a long periodicity between a warm and cool state. The Royer study then applies a pH correction term to the oxygen isotope data. The pH estimates are constrained by a model of atmospheric CO2 levels during geologic time. There is no justification for such a correction. Whilst there have been studies of a pH effect on oxygen isotope fractionation between water and foraminifera there are no data I am aware of that apply to (i) inorganic carbonate precipitates and (ii) biogenic carbonate from bivalves. More importantly the pH effect cannot be a thermodynamic effect. At equilibrium the oxygen isotope fractionation between water and carbonate is independent of the reaction path and speciation of dissolved inorganic carbon. So a very brief review throws up a number of issues with this study and Entropic Man's calculations. The fact that he gets a mean surface temperature of +7.2 degrees relative to the present day bears no comparison with data that may or may not show what the Devonian marine climate was like.

Whilst it is a worthy aim to attempt to characterise aspect of Earth's surface environment in the past one must be aware of the many challenging technical issues associated with using proxies (mostly isotopic for such deep time studies), the lack of high resolution dating, the inadequate geographic coverage etc.

What we need are detailed studies to test different theories and models for the evolution of Earth's surface condition throughout geologic time. We are ill served by trying to shoehorn every observation and study into a paradigm that has CO2 as the control knob. With data that is as loose and surrounded by caveats as many deep time proxies one could 'shoehorn' it into any of a number of differnt theories. I'm with Alan on this and wonder why geologists feel they have to do it.

Alan Kendall

The big CO2 reservoirs are the ocean and the NH circumpolar permafrost. When you increase the energy reaching the high NH latitudes (I think 65N is the critical latitude) at the beginning of an interglacial the ice sheets retreat a little.the ocean warms and starts releasing CO2. The southernmost permafrost thaws and decays. This increases CO2 and creates more warming. This continues until the easily released CO2 is back in the atmosphere.

When insolation starts to decrease, temperatures drop slightly. Cooling oceans and growing permafrost start to take up CO2. The greenhouse effect weakens and allows further cooling.

Amplification works both ways.

Dung, you write about only a single negative piece of evidence being sufficient to destroy a scientific theory. This simply isn't so. The confounding evidence may be due to special circumstances such that the overarching theory is not seriously under threat, or the evidence used to challenge the theory may itself be suspect. This explains the persistence of theories well beyond their sell by dates. People supporting/defending outdated theories commonly have vested interests in maintaining them despite refuting evidence that they call into question.

If you tread Into the area of scientific theory (and I strongly advise that you don't) you will enter a logical minefield. The only textbook I have ever thrown across a room was on this subject - and I've sampled some real dozos on other subjects in my time.

EM. Please excuse my misuse of your moniker. No offence was intended; I blame my deteriorating eyesight.

Paul Dennis

As a professional geologist you will know this better than me . The suggestion that geologists want to ascribe all temperature changes to CO2 is a sceptic straw man.There is a lot more than that involved.

Over shorter timescales from a few years to a few million years CO2, insolation, plate tectonics, orbital cycles, albedo and vulcanism have all play a major role in forcing temperature change. Different control knobs, individually or in combination, dominate at different times.

Over the very long term, 600 million years, a combination of decreasing insolation and the gradual decrease in CO2 due to weathering fits the temperature trend since the Precambrian better than any of the proposed alternatives. That is two control knobs, not one.

When looking at modern AGW all six control knobs are in play. Settings vary.

Albedo, orbital cycles, vulcanism and solar insolation are set to "Slow cool". Plate tectonics is set to "Icehouse Earth" .

The only control knob set to "Rapid warming" is CO2. Since the climate is rapidly warming the two are probably linked.

Perhaps this is why the sceptics get confused. It is easy, and politically convenient, to make the logically fallacious jump from

"Of the six main control knobs, CO2 is the only one driving current warming"

to

"CO2 is the only control knob"

CO2 is the Earth's temperature control knob (as any fule kno).!

The transitions between glacial and interglacial - type climates ( and the transitions between stadials and interstadials ) often occurred extremely rapidly- over decades to centuries rather than over thousands of years. The climate of glacials, and to a lesser extent interglacials is far less stable than was previously assumed and environmental feedback processes must be implicated to to speed up the changes induced by variations in orbital parameters. And indeed the changes in climate have been far to rapid to be reasonable attributable to changes in CO2 concentration which could not happen sufficiently rapidly to be the cause of such rapid climate changes.

For example d18O analysis of the Dye 3 ice core ( Dansgaard et al1989) suggest that the mean average temperature in Greenland rose by 7ºC in less than 50 years.

Similarly there rae at least 24 of these D-O cycles and they represent air temperature shifts of around 15ºC occurring, at most a centennial timescale. The most recent of such cycles was the oscillation from the warm Allerod interstadial to the cold younger Dryas around 13,000 ya.

The similarity in timing between fluctuations in the Laurentide and Fennoscandian ice sheets throughout the last glacial has given rise to speculation that external forcing was important.( Fronval et al 1995). Variations in the Earth's orbit have been interpreted as a "pacemaker" of Pliestocene glacial/interglacial cycles ( Imbrie 1979) because detailed statistical analysis of ocean sediment cores shows they possess statistically significant , wave like fluctuations with amplitudes of 100,000, 43,000 and 19-24,000 years.Spectral analysis of Chinese loess profiles dating back to the mid Pleistocene revolution show spectral peaks at 41,700 and 25,000 years seemingly correspond to the obliquity of the ecliptic and the precession of the equinox respectively.( Imbrie 1984, Hays et al 1976, Lu 1981).

There are a variety of feedback hypotheses involving interactions of land, oceans, the atmosphere and ice related mechanisms but our knowledge of the causes of climate change is still highly imperfect.

"It is not a field in which many people can dwell comfortably for a long time because it is almost entirely speculative.No completely acceptable explanation of climate change has ever been presented, and it is also clear that NO ONE PROCESS ACTING ALONE can explain all scales of climate change.We are dealing with an immensely complex series of of interrelated systems; the solar system , the atmosphere, the oceans and the land. It is thus VERY UNLIKELY that any simple hypothesis , or model of climatic change will have very wide applicability and it is clearly impossible in the present state of knowledge to make any safe prognosis of the climatic developments of the future. As yet because of the complexity of the atmospheric system and the large number of possible causes, it is difficult to assess and quantify the role that man has played - although certain mechanisms of man-induced climate change , on a global - as opposed to a micro-climatic scale) can be recognised"( Anderson, Goudie and Parker 2007).

Have fun with the discussion!

EM, you presuppose that you know what the temperature trend has been over the Phanerozoic or longer. Do you? The point I was making about the Devonian example brought up by someone that you chose to comment on was that your understanding of the method used to derive past temperatures is incomplete. The Royer et al study on which the early part of the Wikipedia plot is based is deeply flawed in several ways. Not least is the fact that they use a modelled CO2 level to modulate the temperature trend and then say that CO2 is a major control. The modulation is through a correction of the secular isotope record to correct for a supposed pH effect. i say supposed because at equilibrium the partitioning of heavy oxygen isotopes between water and carbonate is not a function of pH or dissolved inorganic carbon speciation. A pH effect has been reported for foraminifera though this is disputed by other studies. The isotopic record in the Palaeozoic is not based on foraminifera but largely on mostly brachiopods. One interpretation of this record is that it represents a climate oscillating between a warm and cold phase with a wavelength on the scale of a hundred million years or so (see Veizer, Godderis and Francois, 2000, Evidence for decoupling of atmospheric CO2 and climate during the Phanerozoic, Nature, 408, 698-701). The trend obtained by Royer et al is based on that of Veizer but modified to account for modelled atmospheric pCO2 through the supposed pH effect.

So given that we don't really have a good handle on global temperatures other than broad patterns of periods of glaciation and no glaciation throughout the greater part of the Phanerozoic how are you going to test your controls of decreasing CO2 due to weathering and insolation. It is simply not possible. One can, and this is done many times, say data are consistent with your hypothesis. These are not tests of your hypothesis. In fact they are weasel words because the data are also consistent with, for example, the cosmic ray models for climate. One might say that using ab initio calculations of cosmic ray fluxes based on supernovae and position within the spiral arms of the galaxy actually do a better job of constraining the broad scale patterns of climate development as revealed by the isotopic record than those models based on atmospheric CO2 levels and insolation. That is not to say that the data can be used to test such models. It is simply an illustration of the weakness of the 'is consistent with' approach that is often used.

Dung, might I seek your advice? Reading through other discussions I came across that hosted by entropic man where I discovered the nature of the man (being banned by WUWT for example). My question is, is it worth continuing to respond to his only part understood posts or should he be left to wither on the vine? I note that my friend and former colleague Paul Dennis has become similarly enmeshed.

Alan Kendall, dung

No worries re monicker.

All theories have faults and areas of uncertainty. This is why the Kuhnian phliosophy (consensus on the basics, while continuing to argue over and investigate the details) better reflects the reality of scientific research than the Popperian ideal. It is also why a paper showing that one small detail is wrong does not falsify the whole theory.

Martin A

Of course, if the data had been doctored, selected, or even fabricated, to lead to a specific conclusion, then it would indeed deserve the epithet 'bad'.

Agreed. Most scientists are in the game because they want to know how reality works. From a scientific viewpoint that.type of dishonest data is a disaster. Bad data wastes the time of anyone trying to replicate or build on it. It starts a false trail which can take years to identify and correct.
Ultimately bad data is identifiable. It is a jigsaw piece which does not fit the picture that everybody else's research is building..

The trap is to define good data as supporting ones belief and bad data as opposing ones belief.

EM, do you have a strategy for avoiding that trap? How do you think it is working for you?

Several strategies.

You know my fondness for using BOE calculations to check whether something is reasonable or not. If my calculation is a reasonable match to published numbers it increases my confidence in their validity.

Another is to check an idea against other science. If some climate related physics is wrong, it means that related physics is also suspect For example, if the radiative physics underlying the CO2 greenhouse is wrong, so is a lot of other radiative physics. Yet spectroscopy, lasers and LEDs and heat transfer equations still work.

Looking at energy budgets is useful. If something does not make energetic sense, it is probably wrong.

I have read a lot of science down the years. My knowledge is not deep, but it is extensive. If something does not agree with what I have read elsewhere, it rings a mental alarm bell.

I read sceptic sites as well as consensus sites and try to apply the same tests to both. One reason I remain a warmist is that a much greater propostion of sceptic blogs fail my reality checks.I also have an informal bullshit test. If I see a lot of emotional trigger words in a post I tend to reject it as propaganda.

Do they work for me? Yes, I think so. I have toried to build an evidence based view of climate and see AGW as the best fit.

Alan Kendall

Paul Dennis is a professional geologist, I am a retired science teacher. Martin A was an electronics engineer.I don't know dung's qualifications.

We all have different levels of expertise, experience and education. If you want a graduate seminar level of discussion you are definitely on the wrong site.

For the record, I have been banned by WUWT, Tallbloke and Bob Tisdale, mostly for pointing out errors. I don't know about Tallbloke's, but WUWT now has articles about Velikovsky and sees conspiracies everywhere. Bob Tisdale has given up on the 2nd law of thermodynamics and creates or destroys heat at will

This is .the hazard of creating an echo chamber. Exclude the dissenters and you lose the contact with reality that they force on you.

EM, I'm not a professional geologist having never worked as a geologist in industry. I'm an academic geologist/geochemist. Alan Kendall has a professional geology background as well as being an academic. We are friends and former colleagues.

The problem with most blogs is they tend to be echo chambers. The accusation could be levelled at Real Climate, Skeptical Science etc. as much as it can at WUWT, BH etc. If one wants discussion at a serious technical level then there are few sites I would go to with the obvious exception of Climate Audit.

I have tried to engage in discussion here many times and have simply given up because instead of discussion and exposition one gets regurgitated statements of position.