Come on Chaz - most of Mars' atmosphere did one when the magnetic field collapsed. Venus, I seem to remember has loads of CO2 and is unpleasantly hot - though not, as I understand because of the CO2. There is loads of quantitative research, it's just that the media thinks no one can be arsed with any of it. You are conflating a 'tiny amount' of CO2 with its trace presence on a scale of vastness you don't grok. Your point has a compelling logic - when I put it to non- scientists their heads start to nod. It's reasonable initial thinking, but fades when the facts come out. The essential argument starts with the properties of CO2 as a molecule. Light generally doesn't affect it much, but three frequencies of infrared make the molecule bend because it absorbs them. All this kind of stuff is known as the result of experiments - in my day you'd go to some volume of The Handbook of Physics and Chemistry for the data. We can measure the amount of sunlight hitting the Earth, know the Earth's size and can apply standard black body calculations. These leave a discrepancy between the Earth's theoretical temperature and actual measurements, so either black body is bolloxs or we look for a model to explain this. This leads to greenhouse theory (which in conjunction with orbital forcing brings the sums back in order. Small experiments done by other than BBC patronising goons give the basic figures which can them be expanded into the estimates of total greenhouse gases, of which CO2 is a minor but substantial part. The models are quite complicated and have to take collisions between molecules into account. The sums are basically what the IPCC has put out. Most people are simply so poor at science they can't get this far. The models may be wrong. Orbital forcing, for instance, is thought to vary the amount of sunlight hitting certain latitudes by as much as 25% (hence the ice ages), which is obviously big in comparison with CO2 effects, though the amplification model of greenhouse warming may be enough to prevent the 'next' ice age. The role of CO2 in this is marginal, but marginal effects often amplify. 96% of sweet FA is, of course, much more marginal than parts per million in a lot. Spark plugs are a negligible weight in my car, but the sod won't run without them.
There is a wider point similar to yours as to whether the marginal effects are enough given the percentage variations in the models, but this really starts in quantitative review and qualitative questions as to whether the models are right even in the sense of being approximate enough. Somewhere in this Chaz, is something like me trying to teach the electro-chemistry of rusting to 12 years old who don't know what iron is (one classic answer because I'd just done something explosive with magnesium to wake them up, was that rusting happens because of the magnesium - you must have had similar classics in your own teaching). Sue and I started a conversation to establish what we really knew about 'global warming' and the answer was pretty alarming and not far off sweet FA. We found a few papers and a book, had a bit of a read, noticing we were excluding the vast majority of Internet bull. Our conclusion so far is that the real arguments are still in the margins of a load of hot air. We didn't find reason to doubt the CO2 basics though - it lets sunlight in because it doesn't absorb those frequencies, but does absorb the bounce back infrared and this is retained in a complex collision network and stays in part of the atmosphere. This is a confirmation of basic science. The models hang together and the sums work. The questions are not about basic CO2 absorption, but there are questions about the complex models of exchange and balances. One would hope these scientific arguments are defeasible, subject to change on new facts and new models. Many papers are, in fact, of the 'you left this out' or 'what if' kind. They themselves have to be subject to being bagged-off. I'm afraid this is the fate of your initially interesting conjectures, a bit like the creationist asking 'where are the transition fossils then, evil atheist bastard?' - the answer being 'over there, have a look'. You just don't know enough here. What's really interesting is that the case hasn't been made properly and concisely even for people like us. Answers to your question start with getting to grips with black body radiation, the sums of that and then looking about in basic science for reasons to change the sums to retain the basic science - this information is widely available, both in qualitative modelling and as the spreadsheet sums. On 21 Dec, 10:50, chazwin <[email protected]> wrote: > All the stuff that is out there point to CO2 as a GHG, but none of it > has quantitative information. > What worries me is the tiny amount of CO2, what the limits are due to > the narrowness of the radiation spectrum it can absorb, is CO2 able to > change the properties of the air as a whole or does the temperature > change rely on its concentration. > There seems to be an implication that CO2 prevents heat leaving. Would > Mars not be hotter with nearly 96% CO2? There has to be limits. > > On Dec 21, 1:41 am, archytas <[email protected]> wrote: > > > > > The work on this is not new - a Swede called Arenheus (spelling) did > > the work around 1900. This from Wiki: > > Arrhenius developed a theory to explain the ice ages, and first > > speculated that changes in the levels of carbon dioxide in the > > atmosphere could substantially alter the surface temperature through > > the greenhouse effect.[3] He was influenced by the work of others, > > including Joseph Fourier. Arrhenius used the infrared observations of > > the moon by Frank Washington Very and Samuel Pierpont Langley at the > > Allegheny Observatory in Pittsburgh to calculate the absorption of CO2 > > and water vapour. Using 'Stefan's law' (better known as the Stefan > > Boltzmann law), he formulated his greenhouse law. In its original > > form, Arrhenius' greenhouse law reads as follows: > > if the quantity of carbonic acid increases in geometric progression, > > the augmentation of the temperature will increase nearly in arithmetic > > progression. > > This simplified expression is still used today: > > ÄF = á ln(C/C0) > > Don't mistake any of this with 'greenhouse science' - it's basic > > physics and chemistry and works at the bench in every experiment we do > > in stuff like how much heat comes out if we lob a sliver of magnesium > > in an acid etc. - stuff you will have done - and in stuff like > > creating Bose-Einstein Condensates in which to trap light as matter > > (Lene Hau). You should grok after a trip to Wiki. This question is > > at the level of trying to get 12 year olds into a chemical explanation > > of how rusting takes place, not at all easy as scientific > > understanding is as rare as rocking horse droppings. > > > On 21 Dec, 00:57, archytas <[email protected]> wrote: > > > > I'd start at New Scientist Chaz. > > > > On 20 Dec, 10:44, chazwin <[email protected]> wrote: > > > > > I have searched in vain for any evidence that CO2 is a significant > > > > greenhouse gas. > > > > According to radiometric dating of Carbon isotopes it is thought the > > > > the amount of CO2 has increased from 0.028% - 0,038% in the last 100 > > > > years. > > > > Unless Carbon has some magical properties is seems unlikely that such > > > > tiny concentrations should cause any significant increase in > > > > temperature, even-though it is a greenhouse gas. > > > > Can any one help me find the scientific evidence? > > > > I don't want to the political answer, nor the circumstantial answer, > > > > nor any sceptic/denier/doubter information as I have heard it all. > > > > What I want is the basic physical science of carbon that suggests that > > > > a 0,01% increase can be held responsible for a proposed 1 degree > > > > increase in temperature. -- You received this message because you are subscribed to the Google Groups "Epistemology" group. 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