Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!

 


Forgot your password?
Close
typodupeerror
×
Earth Science

150th Anniversary of Greenhouse Climate Theory 407

Posted by samzenpus from the it's-getting-hot-in-here dept.
An anonymous reader writes "It was 150 years ago that John Tyndall, one of history's truly great physicists, published a scientific paper with the far-from-snappy title On the Absorption and Radiation of Heat by Gases and Vapours, and on the Physical Connexion of Radiation, Absorption, and Conduction. The BBC has an article on John Tyndall and his contributions 150 years ago to the physics behind the study of climate change."
This discussion has been archived. No new comments can be posted.

150th Anniversary of Greenhouse Climate Theory More

150th Anniversary of Greenhouse Climate Theory

Comments Filter:

  • What truly makes me sad however... (Score:4, Interesting)

    by Fluffeh ( 1273756 ) on Wednesday September 28, 2011 @11:22PM (#37549620)

    What truly makes me sad when I see things like this, is that it ultimately makes me think that a bit of science has been lying around for 150 years - and there are still people who try to disclaim it, pretend it simply isn't true and make all manner of excuses as to why it doesn't mean what it clearly states. All to either keep making money, keep doing what they have been doing or because it is simply easier to not have to change the way things are done.

    • It's rare to see someone attack this particular bit of science. Ignorant people merely don't trust science, but once they gain the level of understanding to be able to comment on this part of the theory, they rarely disagree with it. They may still be 'deniers' and disagree with other parts of the catastrophe facing the human race, but not this part.
      • Heh, try being a meteorologist (not even a climate scientist), and those people come out of woodworks. I had one guy trying to argue against it based on (his understanding of) the laws of thermodynamics. Another trying to claim that because it couldn't accurately forecast the temperature outside his house, it must be wrong.
        • Sure. Did you show them the equation? Or did you mess around trying to explain something that you would never be able to convince them of? Really, choose your argument ground in a place that is easy to win.

    • Re: (Score:2)

      by Belial6 ( 794905 )
      Yeah, and Phrenology and Haruspex!

      Less sarcastically... Irrelevant to what a persons opinion is on global warming, the fact that a paper was written 150 years ago does not mean people have their heads in the sand. There were a lot of ridiculous papers written 150 years ago. It would be foolhardy for us to assume that because they are old, that they are true.

      • Less sarcastically... Irrelevant to what a persons opinion is on global warming, the fact that a paper was written 150 years ago does not mean people have their heads in the sand

        The fact that the science has a 150 year history does. The rough conclusions were correct 100 years ago -- 4-5C warming for a doubling of CO2.

        But no! Anything but accept that there might be such a thing as an environmental issue! Those guys are socialist nutcases!!!!

        • But wait, we haven't seen a doubling of CO2 in the past 100 years...or even the past 1000 years, and we certainly haven't seen 4-5C of warming that would go with it.

          So while you might be able to create an equation that matches our current data, and which also asserts that we'll see a 4-5C warming for a doubling of CO2, that's an extrapolation of assumptions - we haven't actually *observed* that.

          FWIW, CO2 from say, 1000AD to today has gone from 280ppm to around 390ppm (about a 39% increase, as opposed to a d

          • The reason (I believe) is that CO2 is not the only greenhouse gas. The other ones have a dampening effect. So you need to take into consideration the entire composition of the atmosphere, not just CO2. There was a study several year back that did exactly that. So don't worry, scientists are on top of this; or at least, are aware of the problems you describe and are actively trying to solve them.

            • Okay, so we've got a theoretical "4-5C warming if we double CO2 and everything else stays *exactly the same*". I might even buy that.

              A world where any significant portion of it stays *exactly the same*? That's fantasy :)

              The real question is this - we could have started with the theory "0.04-0.05C warming if we double CO2 and everything else stays *exactly the same*", and made the same excuses we're making today for the warming prediction 100 times higher. How could we discern between those two hypotheses

              • Okay, so we've got a theoretical "4-5C warming if we double CO2 and everything else stays *exactly the same*". I might even buy that.

                A world where any significant portion of it stays *exactly the same*? That's fantasy :)

                The real question is this - we could have started with the theory "0.04-0.05C warming if we double CO2 and everything else stays *exactly the same*", and made the same excuses we're making today for the warming prediction 100 times higher. How could we discern between those two hypotheses? What observations would exclude one or the other from being true?

                IOW: since not all other things can be the same, everything will be okay. PERIOD.

            • The reason (I believe) is that CO2 is not the only greenhouse gas. The other ones have a dampening effect.

              Well, hydrogen and oxygen can have a dampening effect, in that if you put them together they make water, and that makes stuff wet. The only thing the other gases could do would be to have a damping effect, but they don't. CO2 is not the only greenhouse gas we are emitting.

    • We know that global warming is happening. We also know that it has happened in the past.

      I think that we can agree that human activity is contributing to it.

      The big questions are:

      What are the causes of global warming? I don't think that it is settled that human activity is the SOLE cause. There is still more science to do on this.

      How much of an effect can a change in human activity have in solving global warming? Is it enough?

      Is it worth putting our society (democracy) in jeopardy over it as it puts us i

      • Re:The biggest issue isn't the science... (Score:4, Informative)

        by phantomfive ( 622387 ) on Thursday September 29, 2011 @12:02AM (#37549850) Journal

        What are the causes of global warming? I don't think that it is settled that human activity is the SOLE cause.

        If you believe the IPCC report, then you can be assured that it IS settled that human activity is the primary cause.....or at least, very likely. Here is what it says:

        "Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations."

      • Of course human activity is not the "SOLE" cause of global warming. But the science (based on the work of John Tyndall) says the increase in greenhouse gases (GHG's) in the atmosphere is the cause of most of the climate change that is occurring now and that humans are the source of most of that increase in GHG's. If we quit adding GHG's to the atmosphere it won't solve global warming, it will simply put a limit on how bad it gets. We put our entire civilization in jeopardy if global warming gets bad enou

    • Re: (Score:2)

      by elrous0 ( 869638 ) *

      a bit of science has been lying around for 150 years - and there are still people who try to disclaim it

      I agree. Global warming is our enemy and has always been our enemy. Anyone who says otherwise is doubleplus wrong.

    • What truly makes me sad when I see things like this, is that it ultimately makes me think that a bit of science has been lying around for 150 years

      No, it hasn't. The number of people who claim that carbon dioxide is not a greenhouse gas is a tiny group of crackpots. The debate is over whether the earth is really warming (because many of our climate stations are returning bogus data), followed by whether man's activity is the cause. However, since humankind is full of blowhards, incompetents, and narcis

    • Re: (Score:3)

      by sorak ( 246725 )

      I think the same way about evolution. I had someone tell me that there was no evidence for evolution. So, I looked it up, and Origin of Species was published two years before the civil war. We are literally arguing about civil war era science, and the majority of my home state is trying to keep their understanding of biology stuck at that point in time.

  • Ever since blackbody radiation (Score:3, Insightful)

    by werepants ( 1912634 ) on Wednesday September 28, 2011 @11:40PM (#37549714)
    The basic science of global warming isn't too tough or very modern(clearly), although most people don't understand it very well. This article seems to make things fairly confusing as well, although the quote from Tyndall himself is pleasantly concise and clear: "heat in the state of light finds less resistance in penetrating the air, than in re-passing into the air when converted into non-luminous heat." My favorite explanation, I think, is how Carl Sagan explained it in Cosmos, which is roughly as follows:
    The idea is that visible light hits the earth, and warms it up. Some of that light is reflected straight back, so it leaves the atmosphere the way it came in and we're done. A lot of that light, though, gets absorbed by trees or rocks or walruses, causing them to heat up. They'll slowly re-radiate it out again because of blackbody radiation (all things radiate continually, even the universe itself) but it will be in the form of lower energy, lower frequency wavelengths. This means that energy from visible light gets absorbed and often radiated back out again as infrared.

    CO2 and other "greenhouse" gases let light in the visible part of the spectrum pass unimpeded, but they don't let IR through as easily. So, energy comes in but it can't get back out again.
    • Calculating global warming in terms of black body radiation isn't easy. You never hear any scientist say, "x% of the earth's heat comes from the sun, y% from the atmosphere, z% is radiated back from the reflectiveness of the earth....."

      You will never hear any scientist say that because we don't know. We can only estimate what the earth's temperature would be without an atmosphere to an accuracy of +-10 degrees, which isn't near good enough for global warming purposes. So instead, we focus on the change in

    • CO2 and other "greenhouse" gases let light in the visible part of the spectrum pass unimpeded, but they don't let IR through as easily. So, energy comes in but it can't get back out again.

      That's more or less true, although one of the big arguments in the first half of the 20th century was that water vapour in the atmosphere completely masks the IR absorption spectra of CO2, and thus it doesn't matter how much CO2 you have in the atmosphere. It took until the 50s for scientists to realise that while this is fairly accurate (although not entirely) at sea level, it's most certainly not true in the upper atmosphere where (a) there's not much water vapour and (b) the absorption spectra don't ove

  • Doon't forget Fourier, Pouillet and Arrhenius (Score:5, Informative)

    by G3ckoG33k ( 647276 ) on Wednesday September 28, 2011 @11:42PM (#37549724)

    Svante Arrhenius "was the first to calculate on the heating of the Earth in 1903. But, he refers to Fourier, Pouillet and Tyndall as predecessors. He was the first person to predict that emissions of carbon dioxide from the burning of fossil fuels and other combustion processes would cause global warming. Arrhenius clearly believed that a warmer world would be a positive change. From that, the hot-house theory gained more attention. Nevertheless, until about 1960, most scientists dismissed the hot-house / greenhouse effect as implausible for the cause of ice ages as Milutin Milankovitch had presented a mechanism using orbital changes of the earth (Milankovitch cycles). Nowadays, the accepted explanation is that orbital forcing sets the timing for ice ages with CO2 acting as an essential amplifying feedback.

    Arrhenius estimated that halving of CO2 would decrease temperatures by 4–5 C (Celsius) and a doubling of CO2 would cause a temperature rise of 5–6 C.[5] In his 1906 publication, Arrhenius adjusted the value downwards to 1.6 C (including water vapour feedback: 2.1 C). Recent (2007) estimates from IPCC say this value (the Climate sensitivity) is likely to be between 2 and 4.5 C. Arrhenius expected CO2 levels to rise at a rate given by emissions in his time. Since then, industrial carbon dioxide levels have risen at a much faster rate: Arrhenius expected CO2 doubling to take about 3000 years; it is now estimated in most scenarios to take about a century."

    Some quotes:

    "To a certain extent the temperature of the earth's surface, as we shall presently see, is conditioned by the properties of the atmosphere surrounding it, and particularly by the permeability of the latter for the rays of heat." (p46)

    "That the atmospheric envelopes limit the heat losses from the planets had been suggested about 1800 by the great French physicist Fourier. His ideas were further developed afterwards by Pouillet and Tyndall. Their theory has been styled the hot-house theory, because they thought that the atmosphere acted after the manner of the glass panes of hot-houses." (p51)

    "If the quantity of carbonic acid in the air should sink to one-half its present percentage, the temperature would fall by about 4; a diminution to one-quarter would reduce the temperature by 8. On the other hand, any doubling of the percentage of carbon dioxide in the air would raise the temperature of the earth's surface by 4; and if the carbon dioxide were increased fourfold, the temperature would rise by 8." (p53)

    "Although the sea, by absorbing carbonic acid, acts as a regulator of huge capacity, which takes up about five-sixths of the produced carbonic acid, we yet recognize that the slight percentage of carbonic acid in the atmosphere may by the advances of industry be changed to a noticeable degree in the course of a few centuries." (p54)

    "Since, now, warm ages have alternated with glacial periods, even after man appeared on the earth, we have to ask ourselves: Is it probable that we shall in the coming geological ages be visited by a new ice period that will drive us from our temperate countries into the hotter climates of Africa? There does not appear to be much ground for such an apprehension. The enormous combustion of coal by our industrial establishments suffices to increase the percentage of carbon dioxide in the air to a perceptible degree." (p61)

    "We often hear lamentations that the coal stored up in the earth is wasted by the present generation without any thought of the future, and we are terrified by the awful destruction of life and property which has followed the volcanic eruptions of our days. We may find a kind of consolation in the consideration

    • Ironic that in the preceding century we seem to have lost the appreciation that climate changes in cycles, and that the results can be both negative and positive but in a basic sense - like every other living creature - we're stuck with simply coping or dying.

      Earth, regardless, will continue to spin merrily along whether we infest its skin or not. 99%+ of all species that have ever existed are extinct, so clearly that doesn't have squat for an impact.

      • Ironic that in the preceding century we seem to have lost the appreciation that climate changes in cycles, and that the results can be both negative and positive but in a basic sense - like every other living creature - we're stuck with simply coping or dying.

        No, that would be unfortunate. What's ironic is that what you take away from this is that the environment is cyclical, while what I take away from this is that man has an influence on his environment. You believe we are powerless. I believe we are powerful. You believe the party line that the defilers of this planet who are changing it daily want us to believe. Guess what that leaves?

  • ... for some it was never conceived!

Slashdot Top Deals

"The vast majority of successful major crimes against property are perpetrated by individuals abusing positions of trust." -- Lawrence Dalzell

Close