In May 1859, six months before the publication of On the Origin of Species, Irish physicist John Tyndall proved that some gases have a remarkable capacity to hang onto heat, so demonstrating the physical basis of the greenhouse effect. He was familiar with the notion of the "greenhouse effect", first mooted in the 1770s and developed in the 1820s by Frenchman Joseph Fourier, one-time secret policeman, governor of Egypt and physicist. Fourier pondered the question of why the Earth was warmer than physics suggested it should be, and concluded that while the light from the sun penetrated the atmosphere easily and heated the Earth, the heat radiated by the Earth couldn't pass back through the atmosphere quite so easily. He suspected that the atmosphere blocked the passage of radiant heat - infrared radiation - from the Earth, preventing its escape into space. A few years later, another Frenchman, Claude Pouillet, speculated that certain gases in the atmosphere were responsible for trapping radiant heat. The BBC 'experiment' was a piss-ant repro of this stuff. "On the origin of 'the greenhouse effect': John Tyndall's 1859 interrogation of nature" by Mike Hulme (Weather, vol 64, p 121). Mike Hulme's new book Why We Disagree About Climate Change is published a couple of months ago by Cambridge University Press. Your basic concern is that the small amounts of CO2 in percentage terms are claimed to have such a big effect, let's say like a tenth of a teaspoon of lemonade screwing a decent Riocha into Sangria. A fair question. But what do we know of the complex spreadsheets about global temperature and how these molecules absorb radiation and at what frequencies and so on? We'd grant that small changes sometimes create big ones, that catalytic presence is often 'trace' and so on. If CO2 was removed from the atmosphere, only 15% less infrared would be absorbed. If CO2 was the only greenhouse gas, it would absorb 26% of the infrared currently absorbed by the atmosphere. A simplified summary is that about 50% of the greenhouse effect is due to water vapour, 25% due to clouds, 20% to CO2, with other gases accounting for the remainder. The question remains as to how the 'piss-ant' levels of CO2 can make such significant difference.
The spreadsheet is complex, as what's in the atmosphere overlap in terms of what they take out. We assume the water-cycle is stable, but the CO2 one ain't. The question becomes how much energy the CO2 absorbs that other atmospheric components won't, which can be worked out from the tonnage we can measure and what we know of it chemically as an absorber. This retained energy is assumed to have effects and so we can see what could cascade. I assume the shit spreads out (Boyle) as a bubble, and the thicker it is, the more heat is retained, at least in certain bits of the atmosphere, which is complex. We know a 10 degree rise more or less doubles chemical reactions, so should be worried if these trace amounts have significant effects and unlike the water-cycle are building because the balances don't work. If they have the 20% figure right - that is already a serious effect based on 'trace' levels, so small increases in parts per million are serious. The general problem in this area and many others is that there is science, but we need a lot of background to understand it. It's much easier for most to go with the media crap and take sides rather than learn. I'm reminded a lot of the creationist twaddle in all this, say with some cretin asking 'where are the transition fossils' because he read some 100 year old turkey entrails and hasn't read the growing evidence. This is not a tilt at you mate - I suspect we are both exasperated because people with the resources to draw up a convincing picture and let us ask our questions let us down. Some serious scientists remain unconvinced and I certainly don't think I'm in the know. The patronising Beeb can engage in sex and travel. I go with Lomberg at the moment in believing the carbon stuff is a sideshow, at least in the way we are treating it. On 16 Dec, 23:27, chazwin <[email protected]> wrote: > If you were watching Newsnight on 16/11/09 then > you have just witnessed the cheapest conjuring trick ever devised by > TV. Not even Derren Brown could have pulled off such a feat. ALL the > dopes on the set were bowled over. > Here is what happened--- > Introduce a large amount of CO2 into an empty water bottle and watch > the temperature soar!! > But what you saw was quite simply a lie. > Not one serious sceptic denies that CO2 is a greenhouse gas, the > argument is if it IS A SIGNIFICANT greenhouse gas. The mount of CO2 > that was put into the bottle, which incidentally only increased the > temperature by 4 degrees, if extrapolated to the earth atmosphere > would require the burning 10 times the amount of coal and oil that now > exists on earth. > The simple fact is that there is only 0.038% of CO2 in the atmosphere > and has only increased by 0,01% in over 100 years. This is what is > called a TRACE amount. The amount used in the "experiment" was massive > by comparison. > In the "experiment" no one stood by to assess the amount of CO2 that > the nice science lady had spent time generating, but if you dump a > spoonful of bicarb into vinegar you could easily introduce a > significant percentage into a 5 litre empty bottle. > THis was a cheap trick and totally unworthy of the BBC which seems to > have joined the faithful throng, by toeing the government line that is > being uses as yet another excuse to tax, tax and tax again. -- You received this message because you are subscribed to the Google Groups "Epistemology" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/epistemology?hl=en.
