1861

Irish physicist John Tyndall demonstrates experimentally that water vapor and other gases warm the atmosphere

John Tyndall, in the article “On the Absorption and Radiation of Heat by Gases and Vapours, and on the Physical Connexion of Radiation, Absorption, and Conduction,” reports on an experimental apparatus to demonstrate and measure the heat-trapping impact of atmospheric gases. His later comment underscores his surprise at this discovery: “Those who, like myself, have been taught to regard transparent gases as almost perfectly diathermanous (transparent to heat), will probably share the astonishment with which I witnessed the foregoing effects… I was indeed slow to believe it possible that a body so constituted, and so transparent to light as olefiant gas, could be so densely opake to any kind of calorific (infrared) rays; and to secure myself against error, I made several hundred experiments with this single substance.”* In 1862, Tyndall provides the following analogy: “As a dam built across a river causes a local deepening of the stream, so our atmosphere, thrown as a barrier across the terrestrial rays, produces a local heightening of the temperature at the Earth’s surface.”** In his 1863 book Heat Considered as a Mode of Motion, Tyndall notes the importance of this finding for conditions amenable to life on Earth: “Aqueous vapour [water vapor] is a blanket, more necessary to the vegetable life of England than clothing is to man. Remove for a single summer night the aqueous vapour from the air which overspreads this country, and you would assuredly destroy every plant capable of being destroyed by a freezing temperature. The warmth of our fields and gardens would pour itself unrequited into space, and the sun would rise upon an island held fast in the iron grip of frost.”***

^*Richard Black, “Tyndall’s climate message, 150 years on,” BBC News, September 28, 2011,
^**John Tyndall, “On Radiation through the Earth’s Atmosphere.” Philosophical Magazine ser. 4, 25 (1863), 200-206; Cited in: Spencer Weart, The Discovery of Global Warming (Feb. 2016),
^***John Tyndall, Heat Considered as a Mode of Motion (1863); Cited in: NASA Data, “Measuring the Earth’s Water Blanket,”

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1824

French mathematician and physicist Jean Baptiste Joseph Fourier first hypothesizes that the atmosphere plays a significant role in mediating temperature on Earth

Fourier, in the article “General Remarks on the Temperature of the Earth and Outer Space,” likens the effect of the Earth’s atmosphere in regulating global temperature to a glass covered box: “The temperature [of the Earth] can be augmented by the interposition of the atmosphere, because heat in the state of light finds less resistance in penetrating the air, than in re-passing into the air when converted into non-luminous heat.” This analogy would ultimately inspire the term “greenhouse effect.”*

^*Joseph Fourier, “Remarques GĂ©nĂ©rales sur les TempĂ©ratures Du Globe Terrestre et des Espaces PlanĂ©taires.” Annales de Chemie et de Physique 27: 136-67 (1824), translation by Ebeneser Burgess, “General Remarks on the Temperature of the Earth and Outer Space,” American Journal of Science 32: 1-20 (1837). Cited in: Spencer Weart, The Discovery of Global Warming: A hypertext history of how scientists came to (partly) understand what people are doing to cause climate change,” ´ł˛ą˛ÔłÜ˛ą°ů˛âĚý2017, ; Dr. Weart’s website is a valuable resource for those who would like to delve deeper into climate science.  He also offers a rich collection of photographs of key players, graphs, and other illustrations at .

Photo: Public Domain,

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