Many of us today might understand the relationship between carbon dioxide (CO2), the atmosphere, and climate change. However, we have been provided with little historic background on how the issue of global warming draws increasing attention from the likes of world leaders as highly regarded as Pope Francis.
Aside from a plenitude of global warming/CO2 climate change naysayers (far more than solid logic should allow), there is convincing evidence the CO2/global warming relationship was first reported in 1856. Historian and physicist John Perlin continues with an interview about this too-little-understood phenomenon. Perlin, for those who recall our past interview series on photovoltaics, is the author of the comprehensive work on the step-by-step development of all solar energy technologies: Let It Shine: The 6,000-Year Story of Solar Energy.
Meyers: We concluded our last session discussing Eunice Foote and an 1856 paper she published in the Journal of American Science, titled “Circumstances Affecting the Heat of the Sun’s Rays.” What was the basis of this work?
Perlin: Unlike Saussure, she placed various atmospheric gases in the glazed receivers into which thermometers were inserted. She wanted “to determine the different circumstances that affect the thermal action of the rays of light that proceed from the sun.”
Meyers: Please provide us with the specifics in her research.
Perlin: Neither oxygen nor hydrogen, when pumped into the glass containers and exposed to the sun, displayed much difference in temperature in comparison to the control vessel containing air. But upon pumping carbon dioxide into another receiver, also exposed to sunlight, Mrs. Foote wrote the mercury in the thermometer leaped, with the one “containing the carbon dioxide becoming much hotter, “more so than the others.” She added on being removed from sunlight the temperature took many times as long in cooling as the other gases did.
Meyers: Foote’s conclusion?
Perlin: She wrote, “An atmosphere of that gas — i.e., carbon dioxide, would give to our earth a high temperature.”
Meyers: Something we are quite familiar with today. Where did Foote’s work then lead?
Perlin: Several decades later, the Swedish Nobel Laureate Svante Arrhenius tested how much heat carbon dioxide could trap. Arrhenius, as did the rest of the scientific community of his day, had read about the reenactment of Saussure’s hot box experiment by the astrophysicist Samuel Pierpont Langley at Pike’s Peak. While the outside temperature stayed a little under 60 degrees Fahrenheit, the temperature inside the insulated glass-covered box, when exposed to the sun, rose to temperatures above the boiling point of water. The amazing heat trapping quality of glass, as demonstrated by Langley, piqued Arrhenius’ interest in the ideas of Fourier, Pouillet and Foote’s endowment to the atmosphere glass-like properties of transparency to incoming solar radiation and opaqueness to its subsequent emission as heat radiation after striking the earth.
Meyers: So what did Arrhenius discover?
Perlin: The heat-retaining qualities of carbon dioxide in the sunlight/sunheat exchange between the earth and the sky especially aroused his curiosity. Extrapolating data supplied by Langley, Arrhenius calculated that the doubling of carbon dioxide in the air, though it only composes an extremely minute proportion of the atmosphere’s volume – just .03 percent – increases the earth’s temperature by a little over seven degrees Fahrenheit.
Meyers: What did many in the scientific community in 19th century conclude from these discoveries?
Perlin: An 1856 issue of Scientific American praised Eunice Foote’s experiment for linking the high amount of carbon dioxide in the atmosphere that had prevailed before the Carboniferous Age – when plants and tress began to cover the earth – to the high temperatures on earth that also existed in this earlier period. Indeed, beginning in Carboniferous times, according to Arrhenius, “a great portion of the carbonic acid [carbon dioxide] has disappeared from the atmosphere of the earth and has been stored up as coal, lignite, peat, petroleum or asphalt [plant and tree remains]. Oxygen was liberated at the same time and passed into our atmospheric sea. [And] it has been calculated that the amount of oxygen in the air corresponds to the mass of fossil coal. The suggestion appears,” the Swedish scientist concluded , “that [much of] the oxygen of the air may have been formed at the expense of the carbonic acid in the air.”
But by the end of the 19th century, Arrhenius observed, the combustion of coal by industry was already upsetting this balance, overwhelming the earth’s natural removal of carbon dioxide seven times over. And on a more ominous note for future generations, he wrote, “Carbonic acid in the air must be increasing at a constant rate as long as the consumption of coal, petroleum, etc., is maintained at its present figure and a still more rapid rate, if this consumption continues.” Then the question naturally arose, do we want to return to a pre-Carboniferous earth where the fossil record clearly warns that only the tiniest of creatures could survive on land?Then the question naturally arose, do we want to return to a pre-Carboniferous earth where the fossil record clearly warns that only the tiniest of creatures could survive on land.