Thomas C. Chamberlin: The Global Carbon Cycle
Thomas Chowder (T.C.) Chamberlin (1843 – 1928), was born on 25 September 1843, in Mattoon, Illinois, the third of five sons of John Chamberlin and Cecilia Gill. A few years after Thomas’ birth, the family moved to the town of Beloit in Wisconsin, where the father Chamberlin, a farmer and Methodist minister, preached to small congregations by riding around to several different meeting places each Sunday. In 1862, Thomas entered Beloit College, a classical education institution which also offered some philosophy and science courses. Thomas was most interested in philosophy and mathematics, but he attended a few science courses as well, including geology.
The 19th century was a time of great change in industry, technology and science. People started using coal for fuel instead of wood or peat. New machines were invented that could work much faster and on a bigger scale than human hands, which led to a relentless quest for coal. It was from this need for coal that motivated the governments of Canada, Australia, Great Britain and the United States to explore and understand the subsurface of stratigraphy and study the formation of different sedimentary layers based on fossil content. It also initiated geological surveying that could produce geological maps and provide the location of useful rocks and minerals, which could be used to benefit the country's mining and quarrying industries. This transition marked the emergence of modern geology and a divergence between the scientific study of geology and the spiritual teaching of theology.
Due to his religious background, Chamberlin had a sceptical attitude towards geology. He was a supporter of Neptunism, [1] a discredited and obsolete scientific theory which was developed by the German geologist Abraham Werner. According the Werner’s theory, the Earth was once completely covered by an ocean and the rocks had been formed from the crystallisation of minerals in this vast ocean. As the ocean receded, all of these rocks, were precipitated out of the ocean in a definite order to form the current Earth’s landscape.
In 1862, the physicist William Thomson, 1st Baron Kelvin, reasoned that the Earth cooled form a molten state and that the entire rate of cooling could be determined by measuring the present rate of heat flow. Based on his calculations, the age of Earth at between 20 and 400 million years, and ultimately settled on an estimate that the Earth was 20–40 million years old. Brilliant as he was, Thomson was not aware of the plate tectonics and the nuclear fusion that creates the heat of the sun or radioactivity, so his calculations were wrong. Nevertheless, it was an amazing achievement. He did the first calculation to determine the age of Earth and he demonstrated that the Earth is not infinite as many thought in the 19th century.
Chamberlin was not convinced by Thomson’s reasoning. To prove that his religious beliefs were right, he decided to investigate the subject further. But his studies had the complete opposite result. They led him to reject Neptunism as unscientific and to pursue a career as a geologist instead.
The Planetesimal Hypothesis and the Global Carbon Cycle
In 1896, Chamberlin, together with the astronomer Forest Ray Moulton (1872-1952), developed the planetesimal hypothesis of the Earth’s formation. He suggested, against the prevailed nebular hypothesis which was formulated by Laplace and said that the solar system was formed from an extremely hot and rotating cloud (nebula), that the planets were formed by accretion of cold solid particles, a result of a collision between the Sun and another star.
The bolts that had ejected from the Sun’s near side were thrown out to form the original cores of the planets. Eventually, these bolts developed into planets by accumulating in planetesimals, rock-type objects formed in the early solar system from collisions with other objects in the solar system. To support his theory, Chamberlin used the kinetic theory of gases, first formulated by the Irish physicist G. Johnstone Stoney (1826-1911). [2] He calculated that molecules at the high temperatures assumed by the Laplacian nebular hypothesis, would be moving so fast that they would be able to escape the Earth's gravitational attraction. This convinced him that the Earth's atmosphere was not originally superheated and was not the remnant of solar planetary nebula. [3]
Thomas Chrowder Chamberlin
During the same period, Chamberlin also developed his views on the global carbon cycle and the possible role of CO2 as an agent of climatic change. By investigating the mechanisms of change that could explain the oscillations between cold and warm epochs, he was able (he was the first geologist to draw this conclusion) to portray the Great Ice Age as a series of multiple glaciations. The same year, Svante Arrhenius published his paper “On the Influence of Carbonic Acid in the Air upon the Temperature of the Ground” (Philosophical Magazine, 1896), where he argued that variations of atmospheric CO2 concentrations could have an effect on the heat budget and the surface temperature of the planet. Arrhenius also suggested that such variations in temperature might explain the climatic changes in geological times, especially the Ice Ages. After reading Arrhenius’ paper, Chamberlin became totally convinced that small changes in CO2 were quantitatively sufficient to bring about geological climate change. In his paper “A Group of Hypotheses Bearing on Climatic Changes,” published in the journal of Geology in 1897, he outlined his carbon dioxide theory of glaciation and proposed that if enough carbon dioxide (CO2) was added to the atmosphere the temperature would rise. [4] (Chamberlin R. , 1934), (Fleming, T. C. Chamberlin, Climate Change, and Cosmogony, 2000, pp. 293-294)
“How do we explain the profound glacial oscillations?”
“The idea hinges (1) on the action of the ocean as a reservoir of carbon dioxide and (2) on the losses of the organic cycle under the influence of cold. Cold water absorbs more carbon dioxide than warm water. As the atmosphere becomes impoverished and the temperature declines, the capacity of the ocean to take up carbon dioxide in solution increases. Instead, therefore, of resupplying the atmosphere in the stress of its impoverishment, the ocean withholds its carbon dioxide to a certain extent, and possibly even turns robber itself by greater absorption, though the diminution of the tension of the carbon dioxide of the atmosphere as its amount is reduced tends to increase the discharge of carbon dioxide from the ocean to restore the equilibrium, and, to the degree of its efficiency which is undetermined, offsets the increased absorption of the cold water. So also, with increased cold the process of organic decay becomes less active, a greater part of the vegetal and animal matter remains undecomposed, and its carbon is thereby locked up, and hence the loss of carbon dioxide through the organic cycle is increased. The impoverishment of the atmosphere is thus hastened and the epoch of cold is precipitated. With the spread of glaciation the main crystalline areas, whose alteration is the chief source of depletion, become covered and frozen, and the abstraction of carbon dioxide by rock alteration is checked. The supply continuing the same, by hypothesis, reanrichment begins, and when it has sufficiently advanced warmth returns. With returning warmth, the ocean gives up its carbon dioxide more freely, the accumulated organic products decay and add their contribution of carbonic acid, and the reinrichment is accelerated and interglacial mildness hastened. With the reixposure of the crystalline areas, alteration of the rocks is renewed and depletion re-established and a new cycle inaugurated. And so the process is presumed to continue until a change in the general topographic conditions determines a cessation.” __ (Chamberlin T. , 1897, pp. 681-682)
Chamberlin also argued that variations of the carbon dioxide content of the atmosphere combined with water vapour feedbacks could account for the advance and retreat of the ice sheets and other geological puzzles. He suggested that oceans act as a reservoir of CO2 – soaking up the carbon dioxide humanity added to the atmosphere, forestalling any such warming. Therefore, he argued, oceans are great regulators of climate.
“The ocean is an atmosphere in storage. It is not improbable that every portion of it has once been a constituent of the atmosphere and may be again. In atmospheric studies it must be recognized as a potential atmosphere. According to the best data at command, the ocean holds in solution about eighteen times as much carbon dioxide as the atmosphere. But even this reserve supply if fully available leaves the perpetuity of atmospheric conditions congenial to life very short, viewed geologically. This threat of disaster is not, however, a scientific argument, whatever function it may have in awakening interest and neutralizing inherited prejudice.” _ (Chamberlin T. , 1897)
A few years after Chamberlin published this paper, in 1900, another scientist, the Swedish physicist, Knut Ångström, asked an assistant, Herr J. Koch, to measure the passage of infrared radiation through a tube filled with carbon dioxide. The amount of carbon dioxide in the atmosphere was thought to be equivalent to a column of the pure gas 250 cm in length, but he used a 30cm long tube. He reported that the amount of radiation that got through the tube scarcely changed when he cut the quantity of gas back by a third. Further experiments in 1905 showed that “at atmospheric pressure, a column of carbon dioxide 50cm long is ample for maximum absorption, since one of this length absorbs quite as completely as does a column 200cm long at the same density.” W. J. Humphreys used these experiments to argue that either doubling or halving the amount of carbon dioxide makes little difference in the total amount of radiation absorbed by the atmosphere and, therefore, could not change the average temperature of the Earth.
We now know that these experiments, and the arguments, had fundamental flaws. Apart from the inefficient measurement devises, Ångström treated the atmosphere as a single layer unit , like a single sheet of glass. But the atmosphere is made up of five layers composed of different gases and water vapours. When the infrared radiation emitted by the Earth’s surface moves up through the atmosphere, some of this radiation is transmitted through the atmosphere back out into space, and some is absorbed by greenhouse gases in the atmosphere. Molecules of carbon dioxide and water vapour absorb energy that would otherwise go back into space, which has the effect of heating up the atmosphere. Eventually, the molecules give up a bit of this energy by emitting infrared photons. Sometimes, the photons continue out into space. But other times, they rebound back into the Earth’s atmosphere, where their heat remains trapped.
At first, Chamberlin acclaimed Arrhenius’s discover. Moreover, in 1897 article, he indicated that he had discussed Arrhenius ideas with his students before he reading Arrhenius’ paper, but he was hesitant to express these ideas in public.
“I may here remark that the main features of the ideas herein advanced were entertained and expressed to my students some time before I saw Dr. Arrhenius' important paper, but I fear I might not have felt justified in giving them a more public statement but for the encouragement of his weighty opinion on the vital point of quantitative sufficiency.” (Chamberlin T. C., 1897, p. 681)
But after Ångström’s experiment and W.J. Humphreys argument that the atmosphere is already absorbing all the heat radiation that it is capable of absorbing, therefore adding more CO2 would not cause more warming, Chamberlin embraced Ångström’s finding and turned against the carbon dioxide theory. In a letter, letter to Charles Schuchert, stratigrapher and palaeogeographer at Yale University, he said,
“I have no doubt that you may be correct in thinking that the number who accept the CO2 theory is less now than a few years ago. The original suggestion of Tyndall that a deficiency of CO2 might be the cause of the glacial period received little attention and seems to have been so nearly forgotten that when Arrhenius made a similar claim it seemed to most scientists new and original and as it seemed to be founded on mathematical deductions from Langley's observations and to come with a high authority, it drew a large following. Unfortunately, however, Arrhenius' deductions from Langley's observations appear to have been unwarranted and when this was discovered a reaction was inevitable. […] I greatly regret that I was among the early victims of Arrhenius' error” (Fleming, T. C. Chamberlin, Climate Change, and Cosmogony, 2000, p. 301).[4]
Most of the scientists at the time embraced Ångström’s finding and the carbon dioxide theory has been regrettably weakened. We had to wait until 1931, when the physicist E.O. Hulburt disproved Ångström’s findings and demonstrated that “doubling or halving the carbon dioxide in the atmosphere changes to by 4°C” rise or fall of surface temperatures. Hulburt argued that “… Such changes in temperature are about the same as those which occur when the earth passes from an ice age to a warm age, or vice versa” and thus “the carbon dioxide theory of the ice ages, originally proposed by Tyndall, is a possible theory.” He added that the “objections which have been raised against it by some physicists are not valid.” Unfortunately, Hulburt’s paper has been largely ignored by the scientific community.
By the 1920s, Chamberlin, besotted with his own theory of earth’s origins, jumped into a new field and had a major impact on it. The Chamberlin-Moulton theory was the subject of a lively controversy, but it did not survive Chamberlin’s death.
Notes
[1] It was named after Neptune, the ancient Roman name for the ancient Greek god of the sea, Poseidon. There was considerable debate between its proponents and those favouring a rival theory known as Plutonism which gave a significant role to volcanic origins, and in modified form replaced Neptunism in the early 19th century as the principle of uniformitarianism was shown to fit better with the geological facts as they became better known. In modern geology, many different forms of rock formation are acknowledged, and the formation of sedimentary rock occurs through processes very similar to those described by Neptunism.
[2] He is mainly known for inventing the concept and the name of electron.
[3] The Nebular Hypothesis was first formulated in the 1730, by the Swedish, philosopher, theologian, scientist and mystic Emmanuel Swedenborg. Immanuel Kant, developed the theory further in his treatise, Universal Natural History and Theory of the Heavens (1755), where is argued that gaseous clouds (nebulae) slowly rotate, gradually collapsing and flattening due to gravity, forming stars and planets. Pierre-Simon Laplace developed a more detailed model in 1796. He theorised that the Sun originally has an extremely hot and extended atmosphere and that this “protostar cloud” condensed to form the planets. Today is widely accepted that the formation of our solar system is based on the Nebular Hypothesis.
[4] Chamberlain theory proposed that cycles of CO2 outgassing by volcanoes and uptake by weathering of rocks could explain the cycles of glacial and interglacial periods. Reference to the source?
[5] Initial source in Fleming’s article (Chamberlin to Schuchert, 27 October 1913, T. C. Chamberlin Papers, Department of Special Collections, Joseph Regenstein Library, University of Chicago, addenda 3.5 (hereafter CP))
References
Chamberlin, R. (1934). Biographical Memoir of Thomas Chrowder Chamberlin,1843-1928. Biographical Memoirs of Fellows of the National Academy of Science, 15, pp. 305-407. Retrieved from http://www.nasonline.org/publications/biographical-memoirs/memoir-pdfs/chamberlin-thomas-c.pdf
Chamberlin, T. (1897). A Group Hypotheses Bearing on Climatic Changes. Journal of Geology(5), 653-683.
Fleming, J. R. (2000, September). T. C. Chamberlin, Climate Change, and. Studies in the History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics, 31(3), pp. 293-303.
Hulburt, E. (1931, November). The Temperature of the Lower Atmosphere of the Earth. Physical Review, 38(10), 1876-1890. doi:10.1103/physrev.38.1876
Humphreys, W. J. (1920). Physics of the Air. Philadelphia: Lippincott.
Livio, M. (2013). Brilliant Blunders: From Darwin to Einstein - Colossal Mistakes by Great Scientists That Changed Our Understanding of Life and the Universe. Simon & Schuster.
Wikipedia . (n.d.). Retrieved from William Thomson, 1st Baron Kelvin: https://en.wikipedia.org/wiki/William_Thomson,_1st_Baron_Kelvin#Age_of_the_Earth:_geology