Summary. Scientific research is pursued as an unbiased, objective inquiry into the properties of the natural world. The foundations of climate science were laid over the last two hundred years, establishing that man-made production of carbon dioxide induces an atmospheric greenhouse effect. Current political influence seeks wrongly to raise doubts about these immutable facts.
He considered that de Saussure’s heliothermometer provided an analogy for the Earth. As described by Dufresne (cited above), Fourier first noted that the heat accumulated within the box is not dissipated by circulation to its exterior, and second, that the heat arriving from the sun as (visible) light differs from what he calls “hidden (i.e. invisible) light”. Rays from the sun penetrate the glass covers of the box and reach its bottom. They heat the air and walls that contain it. These rays are no longer “luminous” (i.e. are not visible) and preserve only properties of “dark” (or invisible) heat rays. Heat rays do not freely pass through the glass covers of the box, or through its walls. Rather, heat accumulates within it. The temperature in the box increases until a point of thermal balance is reached such that the heat added from the sun is balanced by the poor dissipation of heat through the walls.
Heat radiation had been discovered earlier during Fourier’s lifetime and he probably was familiar with this phenomenon. Today we identify heat as infrared radiation, and de Saussure’s heliothermometer as a fine example of a greenhouse. Indeed any car standing closed in the sun becomes a greenhouse. When we get in it we are immediately immersed in a very hot atmosphere.
John Tyndall showed that carbon dioxide absorbs heat radiation. Tyndall was a British physicist whose research centered around radiation and energy. He became a fellow of the Royal Society in 1852, and became a professor at the Royal Institution of Great Britain.
Tyndall’s differential spectrometer for measuring radiant heat absorption by a gas. The gas was introduced into the long tube in the upper center. Loss due to absorption of radiant heat by the gas was compared to a reference heat signal produced at the left. The losses were compared in the double-conical thermopile at left center, and the resulting electrical signal was measured by the galvanometer (a sensitive measuring device) at the lower center.
© 2017 Henry Auer