Glacial theory and early global climate models

The connection between global warming and an interest in the Arctic goes back to a major scientific controversy in the mid-1800s: the riddle of the ice ages.1 The key question then was what could have caused the ice sheet that have left scraped bedrock and landscape features that resembled those seen close to glaciers in the Alps. Could changes in the atmosphere possibly lead to such cooling that the ice could begin to grow and later melt again? A French physicist - Joseph Fourier - had already shown that the atmosphere could trap heat much like a "hot house" or what later became labeled the

1 Spencer R Weart, The Discovery of Global Warming (Cambridge, MA: Harvard University Press, 2003), 5.

greenhouse effect, and the British scientist John Tyndall was trying to figure out how this actually worked. At the time, most scientists believed that the gases in the atmosphere were transparent, but in his laboratory he had shown that carbon dioxide was, in fact, opaque. It could thus help the atmosphere keep solar energy that would otherwise reflect back into space. There is very little carbon dioxide in the atmosphere, and Tyn-dall did not think change in its concentration would be sufficient to cause an ice age. Water vapor was another matter and if something dried up the atmosphere then that could be the explanation: "Remove for a single summer-night the aqueous vapour from the air ... and the sun would rise upon an island held fast in the iron grip of frost," he wrote about England in a paper in 1863.2 The scientific community involved in the 19th century ice-age debate was also aware that snow and ice covering a region during an ice age would reflect sunlight back into space and keep it cool, which in turn could change wind patterns and ocean currents in ways that would cool the region even further.3

The question of what could have caused the ice ages was high on the agenda in scientific discussion in Stockholm, Sweden, in the 1890s at the time, Svante Arrhenius created the Stockholm Physical Society to discuss "cosmic physics." Arrhenius is most known for his 1896 paper on the influence of carbon dioxide on Earth's temperature, which links the burning of fossil fuels to global warming, but in the historical context he was working the key question was cooling.4 His Physical Society was an interdisciplinary environment, which Crawford has described as "an effort to bring together the phenomena of the seas, atmosphere, and solid earth into the domain on the physical sciences and to produce new theories taking into account the interrelatedness of terrestrial, atmospheric and cosmic events."5 Parts of the discussion concerned geological findings showing that ice had played a major role in shaping Sweden's recent past.

The glacial theory - that the northern hemisphere had been covered by ice - was also a major inspiration for early Swedish polar research and the first Swedish polar expeditions in 1858 and 1861.6 An example is an account of the how "the discovery of the ice age" had had a critical role in "research desire" concerning the Arctic.7 People who were active in polar research were also part of the Stockholm Physical Society.8 It is easy to imagine an intellectual environment where it was natural to make connections between the knowledge gained from the emerging Swedish polar research and the theo

John Tyndall, "On Radiation Through the Earth's Atmosphere," Philosophical Magazine ser. 4, no. 25 (1863): 204 cited in Weart, The Discovery of Global Warming, 4. Weart, The Discovery of Global Warming, 5.

As elaborated by Elisabeth Crawford, "Arrhenius' 1896 Model of the Greenhouse Effects in Context," in The Legacy of Svante Arrhenius Understanding of the Greenhouse Effect, eds. Henning Rodhe and Robert Charlson, 21-32 (Stockholm: Royal Academy of Sciences and Stockholm University, 1998);

Svante Arrhenius, "On the Influence of Carbonic Acid in the Air upon the Temperature of the Ground," The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science 41 (1896): 237-276.

Crawford, "Arrhenius' 1896 Model of the Greenhouse Effects in Context," 22. Tore Frangsmyr, "Polarforskning - fran hjalte till vetenskapsman," in Polarforskning. Forr, nu och i framtiden, ed. Swedish Royal Academy of Sciences, 34-39 (Stockholm: Swedish Royal Academy of

Sciences, 1982).

Karl Chydenius' account of the Swedish polar expedition in 1861 as cited in Frangsmyr, "Polarforskning - fran hjalte till vetenskapsman," 37.

Crawford, "Arrhenius' 1896 Model of the Greenhouse Effects in Context," 23.

retical models of how the composition of the atmosphere could affect Earth's climate. And this is what Arrhenius did. From the international scientific scene, he drew on Fourier's theories about the heat-absorbing capacity of the atmosphere, Tyndall's recognition that carbon dioxide played an important role in this process, and observations by the American astronomer and physicist Samuel P. Langley of "dark heat" from the moon. In the intellectual environment of the scientific network that he had created in the Stockholm Physical Society, he connected this to knowledge on the carbon cycle developed by his Stockholm colleague Arvid Gustaf Hogbom to the hotly debated question regarding the causes of the ice ages and the ice masses that had shaped the geology of Scandinavia.

The riddle of the ice ages remained a major scientific challenge and scientists continued to make observations that have become significant in the light of today's understanding of climate change. Oceanographers, for example, started to understand the role of ocean currents, not least the fact that water sinks in the Arctic regions and flows towards the equators along the bottom of the sea. Already at the turn of the century, the American scientist T. C. Chamberlin speculated that this helped maintain "uniform global warmth" in the distant past.9 In 1942, these currents had been mapped, and the Norwegian oceanographer Harald Sverdrup wrote about how cold dense water sinks near Iceland and Greenland, a topic that has increased in importance with today's discussion on potential shifts in the North Atlantic Current.10 Sverdrup had a keen interest in the Arctic and had been in charge of the scientific work of an Arctic expedition in 1917-25.11 Arrhenius' idea about global warming as a result of rising levels of carbon dioxide resurfaced in 1938 when the engineer Stewart Callendar presented calculations before the Royal Meteorological Society in London that indicated some global warming that may be connected to increasing levels of carbon dioxide in the atmosphere.12

The early work on climate change research appears to be driven more by scientific curiosity than societal need. It was based on ideas by individuals who connected with each other in scientific networks. One of the local networks was the Stockholm Physical Society, created at a young university, with an outspoken interdisciplinary focus aimed at producing new theories. This may have played a role in Arrhenius' theoretical contribution on the role of carbon dioxide in global climate change, but the issue was one of scientific rather than political importance. In 1896, the question of global warming due to carbon dioxide went against a common notion at the time, that nature was in balance and the magnitude of human actions were "puny" in relation to the vast natural powers that governed the planet as a whole.13 According to Crawford, much of the current picture of Arrhenius' work is a result of a recontextualization of his 1896 paper revisited in emerging discussion about global warming in the1970s.

In relation to polar research, intellectual centers, such as that in Stockholm, can be described using Latour's term, from actor-network theory, as "centers of calculation" of a national colonial science. Images of the Arctic were brought from the colonial periph

9 Weart, The Discovery of Global Warming, 13.

10 Weart, The Discovery of Global Warming, 14.

11 "Sverdrup, H.U." Encyclopedia Britannica. 2006. Encyclopedia Britannica Premium Service. 9 Jan.


12 Weart, The Discovery of Global Warming, 2, 18.

13 Weart, The Discovery of Global Warming, 8.

eries to be presented in the metropolis by these centers.14 The political context then was one of nationalism, through which interests in the Arctic were part of the colonial history of the region, and the use of northern imagery bolstered a national identity. In contrast to the present, early climate science was thus not part of any internationally coordinated effort to understand Earth as a system. The impetus for international coordination became apparent based on more immediate concerns, namely how to predict weather, rather than issues of climate change.

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