Greg Laden's Blog

…I’d like to talk about an observation I made while writing for a now defunct monthly rag about global warming back in the early 1990s, and have always wanted to pursue formally, as a research project. Since I’ve not gotten to it yet, I thought it might be fun to outline the idea more informally, to give you, literally, a sketch or two that makes the point….

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  1. #1 Alan
    October 14, 2011

    Just a minor nitpick on the 1965 thing. The National Academies of Science first informed the US government that it had found a man made warming signal way back in the 1950’s. Here’s a 1958 clip on the subject.

  2. #2 Greg Laden
    October 14, 2011

    Alan, I definately did not mean to suggest that we didn’t know about greenhouse effects and warming prior to 1965. But the mid to late 60s was a convergence of environmental concern and a mixed signal from the environment.

    That’s a great clip!

  3. #3 StevoR
    October 15, 2011

    Actually Svante Arrhenius first came up with the idea in 1896 :

    … in 1896 he [Arrhenius] was the first scientist to speculate that changes in the levels of carbon dioxide in the atmosphere could substantially alter the surface temperature through the greenhouse effect.[4] 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 infrared radiation by atmospheric CO2 and water vapour. … 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.

    Source :

    So we’ve known about Global Overheating and the role carbon dioxide plays in causing it for over a hundred years now (115 to be precise) although with ever increasing sophistication and more refined understanding.

    Minor nit & already noted but I just thought I’d add this extra info. in case folks were interested.

  4. #4 Alan
    October 17, 2011

    Hi Greg,

    My bad, I misread the bit about 1965, I get it now.


    I didn’t mention Svante Arrhenius for two reasons. Firstly I can never remember his name (let alone spell it) and secondly the NAS study was the first to observe a clear and credible warming signal in the temperature record, as opposed to the theoretical (but remarkably accurate) calculations of Arrhenius.

    Fourier of course was an exceptional polymath who predicted the GHG properties of CO2 while basically inventing spectral analysis.

    Ask most deniers what E=MC^2 is and they can give you a reasonable answer, ask them what RF = 5.35*ln(C2/C1) is and they don’t have a clue.

  5. #5 yogi-one
    October 17, 2011

    The link takes me to part I on the Culture of Science blog.
    Where’s part II?

  6. #6 Greg Laden
    October 17, 2011

    Right after it.

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