UK United Kingdom

A brief history of climate science

Climate change is often seen as a recent phenomenon, but its roots are actually far older - the effects of human activity on the global climate have been discussed for more than 150 years. In the 1820s…

The future of the globe used to look a lot brighter. ToastyKen

Climate change is often seen as a recent phenomenon, but its roots are actually far older - the effects of human activity on the global climate have been discussed for more than 150 years.

In the 1820s, the French mathematician Joseph Fourier was trying to understand the various factors that affect Earth’s temperature. But he found a problem – according to his calculations, the Earth should have been a ball of ice.

The most obvious factor, the Sun, did not seem to provide enough energy to raise the temperature of Earth above freezing. Fourier’s initial ideas, that there must be additional energy coming from the Earth’s core or from the temperature of outer space, were soon dismissed. Fourier then realised that the atmosphere, which at first seemed transparent, could be playing a crucial role.

Tyndall’s experiment to measure the properties of various gases

Then, in 1861, the Irish physicist John Tyndall performed an experiment which changed our view of the atmosphere. Tyndall demonstrated that gases such as methane and carbon dioxide absorbed infrared radiation, and could trap heat within the atmosphere. He immediately realised the implications and remarked that these gases “would produce great effects on the terrestrial rays and produce corresponding changes of climate.”

Although this discovery would have profound consequences for understanding future climate, Tyndall, like most of his colleagues, was primarily interested in understanding the causes of ice ages, which had been discovered in 1837 by Louis Agassiz.

What was missing however was an estimate of how much these gases could warm or cool the planet. Svante Arrhenius, a Swedish chemist, provided the first numerical estimates of “climate sensitivity” – defined as the temperature change corresponding to a doubling of carbon dioxide in the atmosphere. He suggested a value around 4°C in 1896.

While the scientists continued to debate the causes of the ice ages, the Earth was warming. From the 1920s onwards meteorologists began to realise that the climate of various regions had changed. Joseph Kincer suggested in 1933 that temperatures in individual cities had been rising. At the same time, others had started measuring carbon dioxide in the atmosphere. But it took an amateur meteorologist to put the puzzle together.

Guy Stewart Callendar, taken in 1934

Guy Stewart Callendar was a steam engineer who was fascinated by the weather. He meticulously collected temperature records from around the world, examined the carbon dioxide measurements and studied the work of Arrhenius and others. In his spare time, and without the aid of a computer, he performed the tedious calculations required to measure the temperature of the planet. These efforts produced the first evidence that Earth’s surface was warming.

Exactly 75 years ago, in 1938, Callendar delivered his analysis to the Fellows of the Royal Meteorological Society. He revealed evidence for a 0.3°C rise in global temperatures over the previous 50 years and suggested that this was largely due to the increase in atmospheric carbon dioxide from fossil fuel burning. His findings were found to be interesting, but were not viewed as conclusive by the esteemed Fellows.

Callendar’s original graph showing an increase in global temperatures.

Undeterred, Callendar continued his research, gathering additional evidence. In later years he published the first estimates of the change in carbon dioxide over time, prompting Charles Keeling to set up the first dedicated observatory for measuring gases in the atmosphere.

In 1961, Callendar updated his estimates for global temperatures with more observations, and these agree remarkably well with our current understanding. Callendar also felt that a warmer climate would be beneficial as it would “delay the return of the deadly glaciers” and allow crops to be grown at higher latitudes.

In the 75 years since Callendar’s discovery that carbon dioxide was warming the planet, much more has been learnt about the climate. But the basic picture has not changed. We are now more confident than ever of the role of human activity on global temperatures. We also have a more complete understanding of the consequences of a warmer planet.

With all the attention on the IPCC’s 5th Assessment Report in 2013, the considerable efforts of Callendar and his contemporaries in advancing our understanding of the climate should not be forgotten.

Sign in to Favourite

Join the conversation

11 Comments sorted by

  1. Barry Woods

    logged in via Twitter

    Hi Ed

    Is it true that Arrhenius later revised down hos initial calculation?

    as it's from asking,! I thought I would check it with you.

    "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.[10] In his 1906 publication, Arrhenius adjusted the value downwards to 1.6 °C (including water vapor feedback: 2.1 °C)"

    the 1906 paper appears to be in only German, so perhaps why less well known (can't find a translation).

    IF this is correct, we appear to have got precisely no where in last 100 plus years.(ref 'sensitivity') ie that 1.6 -2.1C looks very similar to lower end of IPCC range just published in AR5 SPM.

    it is interesting to note that both Callendar and Arhenius thought warming beneficial
    (at the moderate level suggested by 1.6C, magnitude of water vapour feedbacks still unknown)

    1. Barry Woods

      logged in via Twitter

      In reply to Barry Woods

      looks like I still can't type (or check properly)
      as the link is from Wiki - did Arrhenius actually revise down his calculation to 1.6C. It seems to be quite common knowledge & often mentioned, but I can't find an English translation.

    2. Ed Hawkins

      Climate scientist at University of Reading

      In reply to Barry Woods

      Hi Barry,
      Thanks for the comments. I don't think the exact values calculated by Arrhenius are too important. There are no cloud feedbacks in any of his calculations for example. And the absorption coefficients of CO2 were not that well known until the 1950s when more sensitive measurements were made by Gilbert Plass, amongst others. But, the fact that they all realised the importance of CO2 and other greenhouse gases is of wider interest I think.
      PS. I can't read German either so can't answer your question directly!

    3. Barry Woods

      logged in via Twitter

      In reply to Ed Hawkins

      I'm a little disappointed Ed...

      Arrhenius more scary figures were 'important' enough for you to quote.. but not a later revised downwards figure...

      Initial inaccurate guesses/measurement leading to a later revised figure and understanding, is how science usually operates. Are you not interested in seeing whether later paper that did this as this is about the history of the subject?

      Puzzled if you are not.

      Also interesting is Callendar's models seem to be out performing the GCM's (apparently)

    4. Mike Hansen


      In reply to Barry Woods

      So let us get this straight.

      You are criticising Ed for not quoting a lower figure from Arrhenius which you believe must exist but you cannot find.

      And this figure that you cannot find "looks very similar to lower end of IPCC range just published in AR5 SPM." even though you cannot find it.

      Apparently Ed cannot find the figure because he just wants to be scary whereas you omit to mention that the upper end of climate sensitivity in AR5 SPM is 4.5C because you want to be "non scary"?

    5. Barry Woods

      logged in via Twitter

      In reply to Mike Hansen

      Mike, please note - I Was ASKING Ed - IF the second paper was real or not!

      If it is real (as Prof Jonathan Jones seems to think so), I think my comments are perfectly valid

      It exists,but in German only, maybe University of Reading (or Met Office), could arrange a translation of the later paper, for the history of climate science's sake...

    6. Mike Hansen


      In reply to Barry Woods

      "I'm a little disappointed Ed..." is a bit more than asking.

      You may find what you are looking for here.

      From Spencer Weart's bibliography
      "5. Arrhenius (1896); revised calculations, finding a somewhat lower effect, were given in Arrhenius (1901a) ; popularization: Arrhenius (1908), chap. 2."

      which points to

      "Arrhenius, Svante (1908). Worlds in the Making. New York: Harper & Brothers."

      which is available here

      I did not bother looking.

      I was more interested in the following character who appears to have inspired some modern day oped writers in the Wall Street Journal.
      "Another highly respected scientist, Walter Nernst, even fantasized about setting fire to useless coal seams in order to release enough CO2 to deliberately warm the Earth's climate."

    7. Ed Hawkins

      Climate scientist at University of Reading

      In reply to Barry Woods

      Hi Barry - as I have said already, many feedbacks are not in any of these earlier calculations, so none of the numbers should be taken too seriously. I quoted the 4C because it was the first, and best well known. It is only a short article.

      As for Climate Audit's analysis - the GCMQ model used has no time delay so is not a good comparison. Neither are the skill scores a fair comparison as the GCMQ model has no variability.


  2. Mike Hansen


    Thanks for the article Ed.

    For people interested in more detail, the Center for History of Physics of the American Institute of Physics has an online version of Spencer Weart's "The Discovery of Global Warming"

    Skeptical Science also recently had an interesting article on the 1979 "Charney Report; Carbon Dioxide and Climate: A Scientific Assessment, drawn up by a National Research Council study group led by Jule Charney, at the behest of the US National Academy of Sciences. "

  3. Account Deleted

    logged in via email

    Gad, the cunning of Tyndall, Arrhenius and Callendar, perpetrating this massive hoax so that climate scientists could claim massive grants, even before there were government grants for science!