The 19th Century roots of Climate Science

Joseph Fourier and the Greenhouse Effect

Writers and researchers in the second half of the 19^th century credited Fourier with being the first to allude to the greenhouse effect.

In an article in 1924 (and reprinted in English in 1927) he wrote:

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 repassing into the air when converted into non-luminous heat.

Source: Fourier J (1824). "Remarques Générales Sur Les Températures Du Globe Terrestre Et Des Espaces Planétaires". Annales de Chimie et de Physique 27: 136-67, quoted at this link.

The quotation sounds remarkably like the modern understanding of the greenhouse effect, but Fourier's understanding of the phenomenon is often overstated. He seems to mean by the quote something like the operation of greenhouses, which do not work the same way as the modern effect named (erroneously) after them. Fourier also thought that the atmosphere was warmed more effectively by other factors including the internal heat of the planet and heat from the stars.

For a detailed discussion of Fourier and the greenhouse effect see this link, from pages 55 to 64. A brief analysis can be found on pages 2 and 3 of this document.

The Discovery Greenhouse Gasses by John Tyndall

John Tyndall (1820 - 1893) was a very active and prominent 19^th physicist who made many original discoveries but is best remembered for his work on greenhouse gasses. His main experimental work in this field was in 1859. He discovered that the main constituents of the atmosphere, nitrogen and oxygen are transparent to infrared radiation, but that a number of trace gasses in the atmosphere were effective in absorbing infrared radiation. The main ones were water vapour and carbon dioxide (CO₂).

Tyndall's experimental apparatus is shown in the drawing below.

Tyndall was aware of the implications of his finding when he noted:

To the eye, the gas within the tube might be as invisible as the air itself, while to the radiant heat it behaved like a cloud which it was almost impossible to penetrate. Thus, the bold and beautiful speculation has been made an experimental fact. The radiant heat of the sun does certainly, pass through the atmosphere to the Earth with greater facility than the radiant heat of the Earth can escape into space.

A source for the quotation can be found here.

(It is interesting to note that in the chair of Tyndall's demonstration of his discovery was Albert the prince consort. It is a sad reflection on the current political classes that a significant fraction of today's politicians do not take the active interest in science that Prince Albert did. Many of the current crop of politicians and journalists reject and distort the science on political and ideological grounds.)

Like many scientists of his time, Tyndall was particularly interested in explaining changes of climate in the past, as it was becomming increasingly clear that Europe had suffered ice ages in the past.

Tyndall was aware that the growth of industry was putting CO₂ into the atmosphere but it was almost four decades before scientists seriously investigated the effect of increasing CO₂ in the atmosphere.

For more information on Tyndall see this link.

Svante Arrhenius's Greenhouse Calculations

Arrhenius was a Swedish physicist who published a study in 1896 into the effect on climate of changing the amount of CO₂ in the atmosphere. Tyndall had shown that increasing CO₂ would warm the climate and decreasing it would have a cooling effect. The interesting question was by how much would temperature be effected? Arrhenius performed long and tedious pen and paper calculations to provide an answer to this question. He realised that the effect of CO₂ is complicated by feedbacks, what he called "the mutual reaction of the physical conditions". A major feedback process involves water vapour, which is a much more effective greenhouse gas than CO₂. The increase in temperature caused by an increase in CO₂ would result in more water vapour in the atmosphere which would amplfy the warming produced by increasing CO₂.

Arrhenius calculated that doubling the amount of CO₂ in the atmosphere would result in a 4⁰C increase in global temperature. This wasn't a bad result as the currently accepted value is about 3⁰C.

A few years after Arrhenius published his result Ångström published a strong criticism of it. Ångström's basic argument was that the infrared is already saturated and that increasing the CO₂ in the atmosphere would not effect the absorption of the infrared radiation. This argument is still used by climate science deniers today. For an explanation of why this argument by Ångström was incorrect see the posts here and here.

For biographies of Arrhenius see posts here and here.