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But that's not what we're being told is it? The AGW lobby would have us believe that it's only our influences that are causing problems, almost as if the atmosphere would notice the difference between a few gigatonnes of extra naturally produced CO2 and a few gigatonnes of the anthropogenic variety. Nonsense, obviously, since CO2 is CO2 is CO2 and levels have been varying since long before the first cavemen thought of banging two lumps of flint together, much less the modern industrial age. So the question is if high levels of natural CO2 failed to produce feedback induced runaway warming, why would CO2 from another source do so? It seems doubtful that the balance is even remotely as delicate as that or natural variations would have already had the effects we're being warned about. Are we having an effect on climate? Undoubtably, but the natural noise is such that our contribution can't even be positively identified yet. To put it crudely it may be like pissing into the Pacific Ocean - it'll have some sort of effect, but what and how big is impossible to measure on an oceanic scale.

That said I'm all in favour of bio-fuels for three reasons. One, we need an alternative ready for when the oil does run out, whenever that may be. Two, hopefully it would be cheaper to run on grog (hmm Shell Optimax or Gordon's Gin ), actually it almost certainly would be when the the remaining oil reserves start getting hard to extract. And three, the fact that it's a sustainable fuel would hopefully get the greenhouse mob to pipe down and the money being wasted on that could go to proper environmental projects instead. However, I think I'm hoping for a miracle with number three.

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Make everything as simple as possible, but not simpler - Einstein

Just checked some web sites and found that biodiesel is only about 4-6p/litre cheaper than DERV. Is that due to taxation and duty or just economies of scale?

I still would be seriously interested in using it as I have space for another oil storage tank. Do I need a licence to store 2500 litres of heating oil AND 2500 litres of biodiesel?

Well, of course, these runaway effects have occurred in the past, without human intervention, and would certainly happen again in the future, the question is whether the current problems would be happening right now without our contribution.

Take a look at the first graph on this page, for example:
http://www.eia.doe.gov/oiaf/1605/ggccebro/chapter1.html
Correlation is not causation, but it seems to be one heck of a coincidence.

The graph shows concentrations etc. of just one greenhouse gas. It doesn't explain the proportion of all greenhouse gases represented by carbon dioxide.

With regards to BioFuels, it seems like a good idea, but I very much doubt there is enough land to grow the crops on in the first place. I'm not knocking it but it isn't a solution, at best it maybe a helpful stop-gap.

Yes, but so far the discussion in this thread has only been about whether human emissions of CO2 are having a significant impact on atmospheric levels of CO2.

Yes, if we chopped down loads of forests to create land to grow biofuels on, for example, that would be unlikely to have a positive overall impact.

As someone who knows something about statistics, I'm surprised that you take that graph at face-value.

Firstly, they use the trick of suppressing the zero on the concentration graph - to make the rise in concentration appear more dramatic.
Secondly, they use entirely different scales and units for two superimposed graphs. If they used the same scales and units it would probably tell a very different story.
Thirdly, although not so obviously, since 1958 they've measured CO2 levels at Mauna Loa - they used different methods prior to that, and proxy data for periods much prior to that. So the shape of the graph is probably nowhere near accurate.
Fourthly, they still have have no really reliable means of measuring current anthripogenic emissions - let alone a hundred years ago. Are we really expected to believe that the humungous amounts of coal burned during the industrial revolution amounted to little or no CO2 emissions prior to about 1850?

They also don't mention that much (most?) of the rise in CO2 concentration is possibly (probably?) down to the warming trend between the 19th and 20th centuries (from the little ice age) causing the oceans to liberate vast amounts of CO2 (cart before the horse?)

Why use tricks and omissions like that if you're not trying to fool people?

Cheers
Peter

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Only when ideology, prejudice and dogma are set aside does the truth emerge - Kepler

What positive feedback?

Cheers
Peter

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Only when ideology, prejudice and dogma are set aside does the truth emerge - Kepler

In what you said previously, you appeared to agree with the concept:

I did spot the axes trick on the graph, but decided it didn't affect my understanding of it as the relative gradients are unaffected by it. As for emissions prior to 1850, the population was much smaller, we didn't have anything like modern transportation, I don't find it hard to imagine the possibility that current emissions are hugely greater:
http://www.gcrio.org/CONSEQUENCES/summer95/table2.html

No, I didn't agree.
What that strongly suggests is that natural warming is the cause of the increased atmospheric concentration.
By what possible mechanism can a fraction of a degree of atmospheric warming at high latitudes lead to around two degrees warming in tropical oceans? Especially when there are evidently very powerful negative feedback mechanisms in operation.

Cheers
Peter

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Only when ideology, prejudice and dogma are set aside does the truth emerge - Kepler

Okay, so you agree that warming can cause increased atmospheric levels of what are commonly termed greenhouse gases. The other half of positive feedback is the gases causing warming, so you must disagree with that? You don't believe that the gases we term "greenhouse gases" actually cause warming?

http://www.lenntech.com/greenhouse-effe ... hanism.htm
So you dispute this bit?
"Greenhouse gases in the atmosphere (table 1) contribute to global warming by absorption and reflection of atmospheric and solar energy. This natural phenomenon is what we call the greenhouse effect."

How does a small temperature increase in the atmosphere result in a much larger increase in ocean temperatures? If the second law of thermodynamics is true then this is an impossibility - besides the large thermal inertia of water.

Now for some facts:

1) CO2 absorbs infrared energy very strongly in a very narrow band between 13 and 17um wavelength, and negligible outside this band.

2) That band is the dominant wavelength of black body emission at a temperature of -80 C. (according to Wien's Law) In other words, IR in that band is principally emitted by extremely cold ground. (besides which, that's well below the freezing point of CO2)

3) At current atmospheric CO2 concentrations, the absorption of IR in that band is very close to saturation - in other words, increased CO2 concentrations will not lead to increased absorption.

4) It's been long established (from over 100 years ago) that a doubling of CO2 concentrations from (assumed) pre-industrial levels (and it's arguable whether there's enough fossil fuel left to result in anywhere near a doubling) will, by itself, cause a global average atmospheric temperature rise in the order of 0.75 to 1.4 C above pre-industrial levels.

5) Predictions of temperature increases larger than that rely on large positive-feedback effects - principally from water vapour. Water vapour is a very powerful 'greenhouse' gas (absorbs a broad spectrum of IR), and is in concentrations much larger than CO2. The theory goes that warming from CO2 results in more water vapour, which results in yet more warming. The problem with that theory is that water vapour in current concentations would, by itself, cause the atmospheric temperature to be in the order of 70 C, and the very fact that we're not all being boiled to death very strongly suggests the existence of very powerful negative feedback mechanisms. The largest negative feedback mechanism is water vapour itself - in the form of clouds. Clouds not only reflect large amounts of UV back into space, but they also - by convection and rain formation - vault huge amounts of heat energy up into the upper atmosphere, from where it's re-radiated into space.
In short, water acts as a natural global thermostat.

6) The extreme predictions come from computer models, which cannot even agree amongst themselves, and which cannot even predict today's temperature based on known historical data. Clouds, which play a very highly significant part, are very poorly handled by the computer models.

Cheers
Peter

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Only when ideology, prejudice and dogma are set aside does the truth emerge - Kepler

Pete317 has beaten me to the punch with that bit about the dodgy graph. But I'd add another comment on that point. The two y scales both refer to CO2 but, as Pete said, do so in different terms - ppmv for atmospheric levels and gigatonnes for anthropogenic emissions. I can't see any reason not to express them both in the same units unless it's to assist you in getting across the image you wish to present - AKA how you spin it.

Here's a graph I did a while ago (sources Mauna Loa CO2 measurements by Keeling et al and anthropogenic emissions by Marland et al):

It's fairly typical of the sort of graph you see in AGW scare stories in the media in that the two trends are nicely lined up to show an apparent correlation. All I did differently was to convert ppmv into gigatonnes for atmospheric CO2, and as it happened Excel lined up the trendlines just so without me having to play with the scales. Which is what I did next:

Even leaving the supressed zero alone and just stretching the emssions scale from 10 to 30 gigatonnes presents a different picture. By the time you present the data honestly, i.e. no supressed zero, same units and same scale you end up with this:

By this stage I had to remove the trendline for emissions since it was hiding the X axis, but the X axis is so close to the trend anyway it doesn't make a lot of difference.

The data is all the same, but presented this way it wouldn't scare anybody, and IMO that's what a lot of this sort of thing is about. Why use graphs like the first one if you're sure you're right? Unless it's to scare the public into giving their unquestioning support (and their money been there, which is at least part of the reason I'm such a sceptic now).

Edit: incidentally, does anyone know what proxy was used for the atmosphreic CO2 in that CDIAC graph on the page stevei linked to? I've got emissions esitmates going back to 1750 but I'm using the Mauna Loa atmospheric ones for CO2, which is why my graphs only go back to 1959. I've always wanted to make a bigger graph with the Marland data. I'm also interested to find out if, as Pete suggests, they've got two data series on one line there or if they've used the pre-1959 CO2 proxy for the latter half of the C20th as well.

Edit: actually it looks like an ice core (probably Stiple Station in Antarctica judging from the dates) rather than a proxy, in which case it certainly looks like some of the Manua Loa or similar data has been tacked on there.

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Make everything as simple as possible, but not simpler - Einstein

I see no difference between the three presentations - as you say, the data is the same in each. There are many examples where even a constant input into a system causes another measure to continually rise. If you gain 1lb of bodyweight every month, it might seem like a small change, but you will eventually become very fat indeed. A graph showing weight gain and bodyweight would look very much like your third graph, but would nonetheless be cause for concern.

Edit: Ah, I see yours is showing the other way round. Still, you can make anything seem like a straight line with a sufficiently large scale, why not make them both go from 0 to 10^50, and show both to be insignificant?

As a newcomer to this forum can I throw my hat in the ring.

I don't believe that we are running out of oil. I believe that it is self regulating. As it gets more difficult to extract so the price goes up and it becomes more profitable to spend more money to extract. They have been telling us we are about to run out of oil since it was first discovered.

I also believe we are in the start of the next ice age but at the moment there is an unprededented amount of undersea volcanic activity which is having an affect on ocean temperatures which in turn, as the water warms, will release more CO2 into the atsmosphere. As somebody said the air doesn't warm the water but it is possible for the water to warm the air.

So to blame the poor motorist for the state of the planet seems a bit harsh and I would be very against any enviornmental tax on motoring. You produce a biofuel and the Government will find a way of taxing it.

I have no scientific qualifications(or any other qualifications for that matter) and therefore these thoughts are only expressed as my beliefs.

Does anybody else have a similar point of view or should I believe what I read in the newspapers about global warming?

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Shooting is good for you and too good for some people.

Five years ago I would have thought you were barking. Then I studied the 'science' surrounding speed cameras and found wall to wall bunk. And I've listened to so-called climate scientists say many entirely unscientific things. Why would they do that if they had sound science to tell us about?

These days there's a money motivation behind a lot of modern science and the truth is being buried in a dash for research cash. It used to be that science was the master of policy; but now policy has the cash and has (most unfortunately) become the master of science.

I haven't studied the AGW 'science', nor the peak oil 'science' but there's a very strong smell of bunk in the air.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Because that would be spinning it the other way and IMO is just as deceptive as playing games with scaling to make curves fit, playing supressed zero games etc. Of course, I could have scaled it differently so the increasing curve in anthropogenic CO2 was more visible, but I'd have ended up with it being so tall as to be unwieldy. I think it's worth having both curves visible on the same page, and in the interests of honesty I put the data on instead. Unfortunately that hasn't really come out on the JPG, but it is there.

At the moment I'm not commenting on significance. I'm commenting on how data in climate science is usually displayed in a form most likely to scare the bejasus out of the general public (i.e. first option) rather than in a neutral fashion (i.e. third option). I know why I believe that is, but then I'm a cynical bastard . However, I'm interested to know why you think it is.

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Make everything as simple as possible, but not simpler - Einstein

the goverment knows they won't be able to keep using the same old lame excuses such as global warming for taxing the motorist left, right and center which is why we are now all going to be ripped off by being charged by the mile depending on 'congestion'

They'll start supporting all the 'green' fuels now because they know soon theres going to be a new way to rip off the motorist, if there isn't enough congestion, or when people get forced off the road because they can't afford a car they'll simply resync all the lights that are on every corner to 'up' the congestion levels to keep the cash in...

We all know Tony is the king of Spin... how long before ID cards are intruduced and then linked as a 'keyless' entry for cars, linked to bank details so next time you do 31 in a 30 you'll have 3 points and £60 taken from your account before you get home from work... never mind the cost of the trip?

I have just asked a friend who is a combustion engineer about this, and he is not aware of any such effect existing. Here is his explanation to me:

"The absorbtivity of a gas mixture consisting of a majority of non-absorbing species is generally a monotonically increasing function of the concentration of the minority absorber. This is certainly true of air/CO2/H2O systems. I have more than a casual knowledge of such systems since they are vital to the understanding of radiative heat transfer within gas turbine combustion chambers. Thus, the IR absorbtivity and emissivity are still increasing with CO2 concentration at the 10%+ levels encountered in combustion."