Soren wrote on Nov 16^th, 2009 at 8:41pm:


I was talking about the radiative forcing of CO2. Mathematical was perhaps the wrong word. In the last few posts I have been trying to present a logical chain of causation between CO2 levels and increasing global temperatures. I believe that I have demonstrated that such a causal relationship exists, that  the effects can be measured by different means, and we can test the hypothesis very easily  using a considerable amount of ingenuity. (Please read the additional posts in the sticky thread).

What I meant was that there is a well established relationship between CO2 concentration and temperature based on parameters that we can measure. We can confirm the degree of radiative forcing by such things as the reduction of transmitted longwave radiation over time, and we can measure the magnititude of this effect for each greenhouse gas, because they each have their individual IR spectral lines..

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Without seeing it, I can't comment on the validity of the 'learned exposition'.  I have tried to explain the question of 'saturation' in another post.  Show me the link and I'll read it and comment.  If you mean that it's a logarithmic relationship - yes we've known that for over 100 years and the calculations take that into account.

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The Earth's climate system has natural variability built into it. We can measure and account for the sources of that natural variability to a great extent. It's very facile to say that there is no correlation when we can characterise that natural variability extremely well.

I haven't even touched on climate models in my explanation. It's not necessary to do so, because we're talking about increased heat accumulation by the Earth via an extremely well-defined mechanism. If you continue to add heat to a system, then it's going to heat up, regardless of its complexity.

However, it's of note that the latest generation of climate models can actually predict and reproduce the effects of the natural variability due to ENSO and solar cycles and just about every other natural event short of a major stratospheric volcanic eruption or a major meteor impact.


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We do know - at least enough to be able to account for natural influences in the climate system.

I'll try to summarise what I've said so far in terms of confirming the causal relationship between greenhouse gases and global temperature rise in the next point. If you are not convinced by a particular point, please let me know and I'll expand on it.

Initially I tried to explain how there seems to be a cottage industry devoted to creating confusion in this field. I eventually realised that they are skilled communicators who sound very convincing to a person who has had no formal training in science.

To try to knock holes in their arguments is probably not the best approach since it's a bit like hiring a demolition crew to knock down an imaginary building then continually telling them that they missed the imaginary wall with the demolition ball every time.

How do you think they would feel? frustrated? That's how I feel too.

- So I'll stick to what I know. The basic science.

The radiative forcing equation for CO2 is one of the best established relationships. The mathematics are fiendishly difficult to understand, but the fact remains that it has been tried and tested using a variety of techniques, including the measurement of longwave radiation.

I'll see if I can find something on the web, but I have a feeling I'll have to scan something out of one of my textbooks, and even so, unless you have a good grounding in maths, it might be pointless.

I'm slightly surprised that you're latching on to that because it is so well established, and even accepted by the likes of Richard Lindzen and widely quoted by denialists.  

The area I was expecting to find some resistance from you was that of water vapour feedback and climate sensitivity. Until recently, that was an area which was not very rigorous, and the error was around 50%.

You obviously didn't read my explanation because you are mischaracterising it.

Again - read the post with the texts in blue (Reply #76).  That's a summary of the salient points made in the previous posts.

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That would be true over a very short period only - such as 10 years, and is a consequence of some very well characterised natural variations in climate. Even if you're driving up a hill on a bumpy road, you're still driving up a hill.

It's a simplistic argument that is recycled again and again.

I believe that I have demonstrated a causal relationship too. It exists as a consequence of the physical properties of CO2.

Your premise that all atmospheric gases are greenhouse gases was ludicrously wrong.

Muso just doesn't get it does he Soren, natural variation obviously sees temps rise and fall.
So what if we now will have natural variation +2.
As I sit here after the hottest november night ever recorded, coincidentally, it was natural variation plus 1.9, and look forward to the hottest november ever , and the hottest summer ever, I take comfort knowing it is just natural variation, and will definitely not get any hotter in the future, because humans have definitely not done anything to exacerbate this natural variation we have.

Now even though natural variation plus 2 may be annoying, I can cool my conscience knowing that I did not contribute to it at all, and I can support continued massive overuse of fossil fuels for as long as they last.
Good to know, now just get it through muso's head, he is stuck on wanting actual facts though, bloody scientists.

Soren wrote on Nov 19^th, 2009 at 4:30pm:



Soren,

Just feeling the back of my head, I have natural variation in my bald spot, but at this rate, I'm going to have an extremely rapid onset of anthropogenic baldness with a clear causal link to your posts.

Let me explain the logical fallacy in your statement:
(How many times have I explained this already?)

Yes. We do have natural variations- do you honestly think you're telling me something new - something that is new to the science of climatology?   To say that the increase in CO2 in the last 50 years and the associated temperature rise, ocean acidification etc are just part of a natural cycle is a logical fallacy, especially since we know perfectly well, based on voluminous data, that it is no such thing. The causal relationship is now crystal clear. The Copenhagen Synthesis report uses the term "overwhelming evidence".

In the past, there were indeed natural cooling periods, such as the glaciations and warming periods. The commonly observed pattern was a very gradual decrease in temperatures leading into the glaciation and a rapid rise in temperature and CO2 following the glaciation. However the rate of increase in CO2 and temperature in the last 50 years is about 100 times faster than anything we have previously observed over those periods.

We have natural variations in temperature between Night and Day for that matter, and I'm pretty sure that the atmospheric CO2 doesn't change significantly between night and day.  

We expect to find natural variations.

Don't you understand this? The CO2 induced warming is superimposed on such well understood natural variations.

(Actually there is a seasonal cycle in CO2 too. This is due to the fact that there is more landmass in the Northern Hemisphere. The Northern Winter should see an increase, and there should be a drop in seasonal CO2 during the peak North Hemisphere growing season.  )

Soren wrote on Nov 19^th, 2009 at 8:07pm:


I could probably also give you complicated maths and fiendishly complex theory that explains  why the computer you are using actually works.

- but then that would all be mere theory. Computers and internet? The fact that you can see computers and use them is just correlation - and correlation is not causation.  

The mathematics is far too complex for anybody to understand. (well do you understand it? - of course not!)  

Everybody knows that the elfs make them at the North Pole under the supervision of Santa Claus.

The concept of man made computers is a Liliputian fantasy. It's a global plot by IBM I tell you, and the IBM scientists are all involved in this worldwide plot because they are scared of losing their jobs  

Pull the other one, Soren.

Soren wrote on Nov 20^th, 2009 at 8:45pm:


It's actually a very good analogy to your argument. The basis of your argument is that it's a complex system and therefore it's way too difficult to understand.    

We deal with complex systems in virtually all the sciences. Fortunately complex systems often allow deterministic predictability of certain characteristics. An example of such a deterministic prediction is the ability to predict the correct dosage of certain drugs in a complex system such as the human body. The deterministic calculation often comes down to some basic parameters such as the age of the patient, their body mass etc.

A further subset of predictions in complex systems may be made by using statistical predictions - probabilities, and finally we get down to the bottom of the barrel - stochastic modelling, which involves such esoteric aspects as chaos theory. Stochastic modelling can be put to good use in stock market analysis, but it is not required for the simple relationship between atmospheric carbon dioxide and radiative forcing.

In the case of CO2 and radiative forcing, the relationship is deterministic to an accuracy of better than 10%. We don't even need to look at statistical analysis, and have no need to visit the fuzzy logic world of stochastic modelling.    

The relationship is so well established that it can be tested by several independant methods.

It is as deterministic as the design basis of your computer. In fact, probably more so, because the tolerance of certain electronic components is often 20%.  

If you look in the literature, there are very few papers in the past 5 years that deal with radiative forcing (actually there was one in October this year, but it did not relate directly to CO2 radiative forcing. That's because the science behing radiative forcing is well and truly settled.

The evidence is that the computer works and it does what it was predicted to do. In the case of radiative forcing, it's a fairly fundamental thing. It relates to basic properties of the CO2 molecule.
The relationship is logarithmic.

If you don't accept the radiative forcing relationship, what do you accept? Ian Plimer? He states that water vapour accounts for 98% of the greenhouse effect.

Do you agree with him?

"No - it's too complex - don't understand  - don't want to understand"

We're not talking about climate here. We're talking about a very specific aspect of climate - an input. That input relies on a well understood property of the carbon dioxide molecule to absorb infrared radiation.

We can stick some CO2 in a spectrophotometer cell and we can measure what it does in terms of how much infrared it absorbs, what frequencies it absorbs it at and we can determine how effective it is as a greenhouse gas. We can do the same for water vapour.

These are absolute determinations.

We can't predict the output of the Copenhagen Conference. We can't predict the reponses of the major countries over the next 40 odd years. Those the the major uncertainties.

Plimer talks about running models backwards. What we can do is to  input measured atmospheric concentrations of greenhouse gases over a historical period of time, and the models will provide basic parameters such as global mean temperatures. They actually reproduce these parameters extremely well. They already have a track record of predictions stretching back to the early 80's.

Climate modelling is a very advanced deterministic-based science. 

However we don't require climate models to tell us that global temperatures will increase. That part is basic science that is blatantly obvious when you consider such elementary aspects as energy balance.