mgcvk

Watched that very interesting documentary on Channel 4 and I found hearing the top boffins' views very interesting. Maybe I can stop feeling guilty now. Where's me car keys!

Gear Head

iTrader: (2)

Most people don't realise that the sun is actually getting 'hotter'!
Going green is just a gimmick. I'm sure there will be something else to waste your time and money on in a few years time.

speedking

Not exactly balanced, no right of reply, but seemed fair enough to me. Certainly had some (apparently) senior scientists on side.

r32

It had plenty of data, they can absolutely prove that CO2 increases follow temperature rises by about 800 years. The claim is that CO2 is the result of temp increases and not the other way round ................

Its made me think.

tath

Did they mention the fact that 'severe climate change' was horse****, and the probable result of an increase in temp was a net positive?

CrisPDuk

Whereas the eco-fascists' argument is competely balanced and they are more than willing to entertain an alternative view.

It's about time the media stood up and started questioning the junk science behind the global warming industry instead of blithely peddling the party line

Well done Channel 4

Martin2005

I watched the show last night and thought it was good to hear the other side of the debate.

The problem for me was that it the evidence stated (which at times was compelling) is not new and has been kicking around for years. Most of this 'new' evidence has been debunked.

I think it wise to keep an open mind on this issue.

What I want to see is a real debate where we can hear from both sides.

Remember there are zealots on both side of this arguement, and we the general public are caught in the middle.

PeteBrant

Sums up my feelings entirely.

warrenm2

so martin and pete - you both beieve that the sun has constant output and the earths climate hasnt varied before then?

WRXMATT

We the undersigned petition the Prime Minister to Stop using the natural phenomenon of climate change as an excuse to raise taxes, when there is no scientific proof that it is man's actions that are causing it.

tath

He ain't listening bud.

WRXMATT

Ha ha i know, does he ever?

||VaNDaL||

one would like to point out i have already devised an easy solution to this problem on another thread

https://www.scoobynet.com/non-scooby...ml#post6732299



dont thank me it was nothing

andyhaase1

Thats the point though,the mentalists don't want a debate.They insist they are right and anyone who doubts their mantra is mad/bad.
Andy

tath

If Bliar was serious about controlling CO2 emissions, he'd try and help/coerce China, not us

It's so obvious it's just another tax to shore up the horlicks he's made of every public service I can't believe I'm typing it.

jonc

Increase tax on air fares to persuade people against air travel to reduce CO2 emmissions.
Increase capacity and encourage expansion at all major airports in the UK.

There's a flaw to this plan somewhere........

tath

Well I can't see it. A career in politics beckons methinks

Martin2005

I struggle to see how you can of drawn that conclusion from my post

_Meridian_

iTrader: (1)

Much like the people here who are saying that man has nothing to do with it? Both sides seem equally fanatical to me.


BTW, in answer to the original question, I should clarify: there is not the slightest doubt that carbon dioxide in the atmosphere causes global warming - if it didn't the average surface temperature of the earth would be about minus 15oC. The important is: does the contribution from man make any difference?


M

jonc

The level of concentration of CO2 in Earth's atmoshpere is only 0.04% of which a small fraction of that is man made. CO2 is a green house gas, but is a relatively poor green house gas. However, water vapour makes up 3% of the atmosphere and is the biggest contributor to the natural green house effect. It is this plus the density of the atmoshpere keeping Earth at a habitable temperature, not the level of CO2.

warrenm2

Kind of true - just to clarify, water vapour produces 95% of the warming effect (which is +33C above how hot we should be given distance from sun).

oblong

The documentary contained a series of misleading arguments like that "moon landing hoax" one a while back. Would actually back this up with examples, but many of the misleading arguments are well summed up at realclimate already, so link: RealClimate » Swindled!

Sprint Chief

Please remember that RealClimate is a political advocacy site, hosted by an environmental media services company, and written by a very carefully selected group of scientists who conform to a strongly held set of beliefs. I would hold their views in no higher regard than the scientists who were involved in the channel four program.

See also prometheus, quoting prof. Roger Pielke Jr:

oblong

Their views are really irrelevant to this. The documentary contained misleading information whether you read that from me, from realclimate or google for the info.

It's like the apollo moon landing hoax documentary (think that was on Channel4 too) a few years back which contained arguments that convinced me (like "how come there's only one source of light in space but the shadows in the moon photos went in multiple directions?" and "how come the US flag on the moon is waving in the photos when there is no wind on the moon?")

But later when I looked them up online I found there were answers to all of them. Plus the obvious fact that anyone hoaxing something like that is hardly going to screw up on those kind of details.

Sprint Chief

I agree the moon landing hoax conspiracy theory is a farce; but that does not extend to global warming (this is an association fallacy). RealClimate makes its own misleading claims, although I don't agree entirely with the line of argument developed by the channel 4 programme either (both over-simplify the complexity of climate, assuming it reduces to a linear system. Any physicist worth his/her salt should be wary of that).

Let me take one of the RealClimate points as an example; the claim about T-CO2 being a positive feedback. This claim is what scientists refer to as a hand-waving argument, or conjecture. There is no observational evidence to support this claim. If you click on their link, they just point out CO2 could be a feedback. There isn't even modelling "evidence": climate models so far have failed to replicate the transitions in to and out of glacial periods.

(An aside as to why this is: you can set up a model to go from an interglacial to a glacial period; or, you can change the parameters and make it go the other way; no one set of parameters will allow it to go both in and out of these states, as the actual climate does. This is just one of many ways in which climate models fail to behave like the real world.)

Furthermore, there is one example - I think it was around 100kyrs ago - when the lag was longer; near to 10,000 years between a transition between interglacial and glacial, the temperature plummeted around 3-4 degrees without any change in CO2. The CO2 level then fell over the following 5,000 years during which temperature hardly changed at all. If you work from the principle of falsification (Karl Popper) there is more evidence to falsify RealClimate's hand-waving argument than there is to support it.

oblong

Seeing as the documentary made simplisitic misleading claims I find the association is very clear with the moon landing conspiracy documentary which used the same technique.

They don't assume it reduces to a linear system. If it were linear there would be no need for models, it could all be represented as one long equation.

Yes there is, the absorption properties of the co2 molecule demonstrate that it is a greenhouse gas and as levels of it rise in the atmosphere it will result in warming of the surface and lower atmosphere.

There is also plenty of evidence that co2 levels rise as a result of temperature increases (the oceans disolve less co2 as they warm for example). So temperature/co2 does have positive feedback.

Temperature increase about 3C per doubling for co2
I reckon that co2 increases roughly by about 10ppm per 1C rise (from interglacial period and the little ice age)

Severinghaus who was a guest contributor pointed that out. As he authored one of the papers making the cause for a ~800 year lag time, the point he makes is coming directly from the scientists involved in this research. In contrast the argument about this lag time which omits half the story (ie from the documentary) is (mis)using research like his, but isn't coming from any researchers.

Severinghaus is debunking a misleading argument that is based on research like his. He is not making any kind of positive claim. So yes he is pointing out that co2 could be responsible for some of the interglacial warming, precisely because some people (like this documentary) are making a misleading argument that co2 can't be responsible simply because there is an 800 year lag time between initial temp rise and co2 rise. Severinghaus correctly points out that the word "initial" is the critical word here. The warming occurs over thousands of years, not just 800, and so warming does occur after the co2 starts rising, therefore debunking the argument that interglacial periods show co2 cannnot cause temperature rise.

The main mistake seems to be that people assume that scientists are claiming the entire ~10C interglacial warmings were caused by co2 rises. No they are not. It's quite clear given the regularity of them that there is perhaps something orbital causing them, the co2 rise simply causes some of the temperature rise. In fact not even a lot of it. co2 rises from about 180-280ppm during interglacial warmings. That's a 55% increase. Going by the IPCC figures for a doubling of co2 causing about 3C warming, that means interglacial co2 rise could be expected to have contributed about 1.5C of the ~10C rise. So noone is even claiming it caused a lot of the temperature rise.

Seeing as co2 isn't cited as causing much of the interglacial warmings, this just reflects that models are unable to reproduce this specific situation (which probably involves causes like orbital variation which aren't significant in the short space of the last 100 years). It doesn't reflect that the co2 forcings used in models are incorrect.

Which would reflect the fact that the interglacial temperature rise and later fall is not caused by co2 rise and fall, but is caused by something else.

Reflecting the long residence time of co2.

As already mentioned it's about 1.5C of cooling that can be expected from the 100ppm co2 fall all the way from interglacial to glacial levels. And the temperature fall from these events does not rule this out (ie co2 did not fall 100ppm followed by absolutely no temperature drop)

Sprint Chief

As noted below, the RealClimate website also makes misleading claims. However I am not so foolish (or politically motivated?) to attempt to draw comparisons with conspiracy theories. You do your argument few favours, coming across as arguing from a political perspective, not a scientific one.


Whenever you isolate individual "forcings" you are implicitly linearising the model, imputing the individual components are separable, and adhere to associative and distributive assumptions. EBMs, for example, implicitly assume linearity. Any direct comparison of isolated forcings implicitly assume linearity. Furthermore, In what way is "one long equation" not a model? It is a scientific model of the behaviour of a system, distinct to (and ideally derived from) from observations.


You are confusing the properties of CO2 in a controlled system (e.g. as analysed - albeit incorrectly - by Arrhenius) and the behaviour of an incredibly complex climate system in response to changes in concentration CO2. These are different things; one does not imply the other.

The former claim has some reasonable observational support. The latter claim is a fairly gross extrapolation from lab experiments incorporating the assumption of linearity in the climate system. This is conjecture at this stage (unless you assume a linear system). It is a valid hypothesis but far from proven; there are many competing hypotheses which could be equally valid.

I would argue your temperature "sensitivity" to CO2 (implicitly linearising the climate system) is based on weak ground. I'm amazed you can't see the linearisation that you are implicitly applying continuously through your argument.


I'm aware of around three different groups who have analysed the lag, producing lags of between around 400 and 800 years. I don't know how independent these groups are of Severinghaus; I also don't believe it is a controversial point.

The trouble is those who support the CO2 warming hypothosis are the ones who use the correlation as a proof. But any "CO2 causes warming" claim is clearly swamped by the "warming causes CO2" claim that you acknowledge yourself above. The programme is (as far as I can tell), just pointing out that the vostok measurements are not strong supporting evidence of a causation between CO2 and warming. They do not disprove it, but they don't support it either, because the warming could have been caused by something else. In fact we know without doubt that the warming was at least triggered by something else. I think you are distorting the claims made by the programme a little here.

Once again I think you are creating a straw man here. The correlation between CO2 and temp is traditionally used as observational evidence as a link between CO2 and temp. But they are not sound evidence. There are other causal mechanisms that must be involved. These may, or may not, dominate. We simply don't know enough at this stage. And our current understanding fails to replicate the behaviour of climate through the last 600kyrs, even with CO2 feedback, so it is clear something beyond our comprehension is taking place.

There is a recent published paper that relates orbital forcing and CO2 forcing as you describe and comes to a CO2 doubling sensitivity of 1.3K. I have little faith in this as it implicitly linearises the system.



The models run on this scale include orbital forcing. (Do you really think climate scientists running these would not include it?) It does falsify the models (which are only of diagnostic merit, not predictive merit, at present anyway).


Isn't that Severinghaus' point? It is primarily caused by something else. CO2 may have had a role, but it was a secondary role and could have been negligible - the ice core evidence provides neither credible support nor refutation.



This is severe cherry picking and quite misleading. For someone criticising the original programme for being misleading, you're doing a pretty good job of it yourself. Sometimes it falls sharply, sometimes it doesn't. The point is that the times it doesn't falsifies the theory that *any* CO2 change is necessary to transition between interglacial and glacial. However, the presence of faster transitions falsifies the idea of a long residence time.



That is a plausible hypothesis, but then so is Severinghaus' hypothesis, and there are doubtless countless others that are yet to be discovered. The real answer may be "none of the above". FWIW I don't think much of the explanations in the programme: they are no better (or worse) than the stuff trotted out by the journals at the moment. The best I can say is "interesting area for further research". One day I hope we will remember the lessons we have been taught from great scientists such as Friedrich Paschen.

oblong

The forcing for co2 is an output of the climate models. The models themselves are non-linear.

All I am saying is there wouldn't be any need for climate models if they assumed a linear relationship. It's because it's non-linear that computer models are needed, ie noone can possibly have the time to work it all out on paper.

Yes, the first is reproducable by experimentation in a controlled environment, which in turn is input into climate models. The second (ie the effect of increasing co2 on global temperature) is an output of the climate models.

I don't. The climate models are non-linear, including components like ice albedo feedback. The result from them shows that the warming from co2 alone is amplified by feedbacks, leading to a

You are refering to the forcing derived from the output of climate models. But the climate models themselves are non-linear.

I have no doubt some do, the documentary made it look like Gore did this (although I haven't seen inconvenient truth so I cannot be sure)

Well decide for yourself. Here is a link to the entire documentary on google video:
The Great Global Warming Swindle - Google Video

The part about this is about 23minutes in. I certainly thought it was misleading - as misleading as someone doing the opposite and implying that co2 caused all the temperature increase. And seeing what various people concluded from watching this documentary confirms this to me. Many people have taken the conclusion that warming causes co2 rise and therefore co2 rise doesn't cause warming. No wonder they think this when you hear the claim in the documentary made about 24 minutes in.

If you wait 25minutes in you get to see their (very false) claim that volcanoes emit more co2 than man. If you wait a few more minutes you see their odd graphs for 20th century warming that don't match anything from nasa, ncdc or cru.

Not by realclimate. Not by the IPCC. Not by any scientists I am aware of. If the documentary wanted to dispell a "traditional" argument they could have just done that, but they are clearly using the temperature lag to imply that co2 doesn't cause warming. That is precisely the "traditional" misleading argument which severinghaus is addressing in that realclimate article.

I wasn't saying they didn't. But I don't believe the correlation between orbital variation and temperature is that good.

I agree that it's most likely primarily caused by something else, and that as far as the lag shows the warming from co2 could be negliable.

The documentary though implied otherwise.

When specifically has it ever fallen sharply? What I am asking for is an example of the falsification. Ie an example when co2 fell sharply but temperature remained constant. Enough examples of that would be sufficient falsification, but I don't believe any exist in the resolution of ice core data available.

Sprint Chief

Oblong,

We need to take a step back here. Your definition of "model" is rather narrow and peculiar, you do not appear to understand the issues surrounding scientific models (in general) as opposed to specific climate models (e.g. GCMs) and the issues of linearisation.

First, let me clarify that I am referring to models in the broader scientific sense rather than your narrow sense of specifically GCMs.

A model is merely a perceived relationship between parameters used to relate mathematically our observations of the real world. These can be fantastically complex or fantastically simple, and different models can be used to describe the same thing (e.g. models of different fidelity). We can have physical models and statistical models; linear and non-linear.

For example, to describe the sensitivity of climate to increasing CO2, you can run a very complex model (such as a GCM), and use that to feed another model (e.g. the climate sensitivity model, which is a simple linear model). These are both models. You seem to be using the term model to describe the former, but not the latter.

By arguing that the earth has some response (e.g. the statement that a doubling of CO2 imposes a 3C increase in global temperature), this in itself is a simplified model of the real world. It assumes a linear relationship between global average temperature and the logarithm of the CO2 concentration. This is, in itself, a model that has implicitly linearised the earths climate.

Hence my example of Friedrich Paschen. He is known for Paschen's law. This is a classic example of a simple system (far simpler than climate) in which attempting to isolate effects (in the same way you attempt to isolate influences on climate, e.g. CO2 concentration on global temperature) does not - indeed can not (pure luck excepting) - lead to a correct answer. Paschen's law used to be introduced as a lesson to physicists of the danger of linearisation. Unfortunately, it seems we have forgotten a great deal about such teachings.

Your entire answer to my post shows you are unaware that your "output" from your first model simply drives a second model (the climate sensitivity model).

This means your second model (the climate sensitivity model) is being driven purely by the outputs of another complex model of dubious physical meaning. Your complex model is unable to reproduce the historical behaviour of climate, i.e. your complex model fails basic validation tests against observational evidence.

This makes me think of a great essay recently published on a climate science website, "unlicensed engineers", showing a new breed of physicist (climate scientists) failing to learn from the teachings of scientists many years ago (e.g. Paschen). It makes an entertaining read (although I disagree with his prediction - bridges fail quickly and are easily detected. GCMs fail over a long period of time and are not easily detected) Links below.

Climate Science: Roger Pielke Sr. Research Group Weblog » Unlicensed Engineers, Part 1 By Hendrik Tennekes
Climate Science: Roger Pielke Sr. Research Group Weblog » Unlicensed Engineers, Part 2 By Hendrik Tennekes