A little history on the Earth as a greenhouse

The Weather Experiment: The Pioneers Who Sought to See the Future is not my favorite book but it does contain some interesting history.

At the time of the American Civil War people were only speculating about the size and function of the Earth’s atmosphere:

People still lived in general ignorance about the state of the upper atmosphere. No one knew for sure just how far the atmosphere extended. In the 1840s Edgar Allan Poe had written a story about a balloonist who had ascended to the moon, and although few thought this possible no one had actually demonstrated it was not. Over the century various estimates had been made of the height of the atmosphere. John Dalton had suggested about fifty miles, while FitzRoy thought the limit was more likely ten. The highest a balloon had reached was Gay-Lussac’s world record of five miles, and breaking this was one objective in the British attempts.

[James] Glaisher was in a perilous position [in a hot air balloon ride]. Mammoth had reached what is today called the ‘death zone’, a realm of atmosphere where the concentration of oxygen is not sufficient to support animal life. On the edge of the stratosphere, Glaisher’s body was shutting down. At 1.56 p.m., at an altitude of about 29,000 feet, the height of the newly triangulated tallest mountain in the world, Deodunga, or as it was later to be called, Everest – Glaisher’s mind went blank.

At roughly the same time people began looking into carbon dioxide:

On 7 February 1861, the evening before FitzRoy issued the first ever British storm warning to the north-east ports, John Tyndall, Professor of Natural Philosophy at the Royal Institution, stood to deliver the prestigious Bakerian Lecture at the Royal Society. Forty-one-year-old Tyndall was an Irish scientist and one of the rising stars on the London scene. He was a gifted experimenter, communicator and popular author, well known for his written accounts of his climbing exploits in the Alps, where he had summited many of the hardest peaks. Already he had been at the Royal Institution for about a decade and his reputation as a lecturer was well established. In a year’s time he would be invited to serve alongside FitzRoy, Glaisher, Herschel and Airy on the British Association’s Balloon Committee, but this night he had other things on his mind. Tyndall’s lecture was titled ‘On the Absorption and Radiation of Heat by Gasses and Vapours’, the latest update on a scientific enquiry that had been occupying him since 1859. Like Glaisher, Tyndall had developed an interest in the transfer of heat throughout the global system. And just as Glaisher had tracked the flow of radiation through solid bodies, Tyndall had resolved to do the same – but this time with gases. His interest was born of the realisation that for the earth to be hot enough to support life some of the gases had to trap and retain some of the sun’s heat. This seemed obvious but, as Tyndall realised, the question had been almost completely ignored by science. It was, he announced, ‘perfectly unbroken ground’. For two years Tyndall had sought to answer the question, testing which gases were the strongest absorbers of radiant heat – what we today call infrared radiation. He had constructed his apparatus at the British Institution, a rig which let him pass heat through tubes of gas and monitor the amount of absorption. The task had been difficult but he had stuck at it and from 9 September 1860 until 29 October he had ‘experimented from about eight to ten hours daily’. Now Tyndall was ready to reveal his results. He told his audience it seemed that a negligible amount of heat was soaked up by the typical atmospheric gases: oxygen, hydrogen, nitrogen. Other gases, however, had dramatic absorptive powers, as did water vapour. One of his discoveries related to carbonic acid (carbon dioxide). He was eager to correct a misapprehension: In the experiments of Dr Franz, carbolic acid appears as a feebler absorber than oxygen. According to my experiments, for small quantities the absorptive power of the former (carbonic acid) is about 150 times that of the latter (oxygen); and for atmospheric tensions, carbonic acid probably absorbs nearly 100 times as much as oxygen.

In the late nineteenth century the Swedish meteorologist Svante Arrhenius dabbled with the riddle, producing calculations on the correlation between carbon dioxide levels in the atmosphere and surface temperature on earth. It was not until 1938 that the subject was revisited again, this time by G.S. Callendar, a British steam engineer, who wondered what the consequences of a high-carbon atmosphere would be. By then Britain was producing about 250 million tonnes of coal a year, the burning of which along with other hydrocarbons was emitting increasing volumes of carbon dioxide into the atmosphere. Callendar calculated the upshot in temperature that should result from a 20 per cent rise in carbon dioxide levels and concluded that it was probably a good thing: rising temperature helping to stave off another ice age.

Who was enough of a systems thinker to wonder if perhaps we could have too much of a good thing?

The issue hit the political mainstream in 1988. That year saw Margaret Thatcher give an anxious address on global warming to the Royal Society, cautioning that humanity had ‘unwittingly begun a massive experiment with the system of the planet itself

[And of course, as with global warming, we have also ignored her expressed concern that “The problem with socialism is that eventually you run out of other people’s money.” (possibly never expressed in this precise form)]