1. John Tyndall, The Glaciers of the Alps (Boston: Ticknor and Fields, 1860), p. 11.

2. Tyndall, The Glaciers of the Alps, p. 21 (“sentiment”); A. S. Eve and C. H. Creasey, Life and Work of John Tyndall (London: Macmillan, 1945), p. 23 (“language”).

3. Tyndall, The Glaciers of the Alps, p. 17 (“ancient glaciers”).

4. Horace Bénédict de Saussure, Voyage dans de Alps (Geneva: Chez Les Principaux Libraires, 1834).

5. James Rodger Fleming, Historical Perspectives on Climate Change (New York: Oxford University Press, 1998), p. 61 (“mathematical theory”).

6. Elizabeth Cary Agassiz, ed., Louis Agassiz: His Life and Correspondence, vol. 1 (Cambridge: Riverside Press, 1886), pp. 263–64 (“shroud”); Edward Lurie, Louis Agassiz: A Life in Science (Baltimore: Johns Hopkins University Press, 1988), pp. 80–102 (“beloved fossil fishes,” “God’s great plough”).

7. Eve and Creasey, Life and Work of John Tyndall, p. 86 (“gases not natural”); Fleming, Historical Perspectives on Climate Change, pp. 68–69 (“in my hands”); Mike Hulme, “On the Origin of the ‘Greenhouse Effect’: John Tyndall’s 1859 Interrogation of Nature,” Weather 64, no. 5 (2009), pp. 121–23 (“experimentally based account”).

8. Fleming, Historical Perspectives on Climate Change, pp. 58–71 (“tendency to accumulate,” “every variation”); Eve and Creasey, Life and Work of John Tyndall, p. 279 (“my poor darling”).

9. 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, April 1896, pp. 237–76 (“absorption of the atmosphere”); Julia Uppenbrink, “Arrhenius and Global Warming,” Science 272, no. 5265 (1996), p. 1122.

10. Spencer Weart, “The Discovery of Global Warming” and “The Carbon Dioxide Greenhouse Effect,” The Discovery of Global Warming, at (three thousand years); Svante Arrhenius, Worlds in the Making: The Evolution of the Universe, tr. H. Borns (New York: Harper & Brothers, 1908), p. 63 (“more abundant crops”).

11. Gustaf Arrhenius Oral History, Scripps Institution of Oceanography Library, April 11, 2006.

12. John Steinbeck, The Grapes of Wrath (New York: Penguin Books, 2006), p. 4.

13. G. S. Callendar, “Can Carbon Dioxide Influence Climate?” Weather 4 (1949), pp. 310–14 (“chequered history”).

14. Fleming, Historical Perspectives on Climate Change, p. 115.

15. Weart, “The Discovery of Global Warming” and “The Carbon Dioxide Greenhouse Effect,” (“marketplace of ideas”); Fleming, Historical Perspectives on Climate Change, p. 113 (“abandoned”).