Some history of the science of AGW

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Some history of the science of AGW

Postby HBS Guy » 24 Jan 2018, 19:20

TODAY GUY CALLENDAR is a historical footnote, but tomorrow he will have a chapter of his own. Born in 1898, Callendar was the son of Britain’s leading steam engineer, a successful academic and inventor who raised his children in a 22-room mansion. A greenhouse on the grounds was converted into a laboratory for the children until one of Callendar’s three brothers blew it up trying to make TNT. The same brother put out Callendar’s left eye. Undeterred by the subsequent lack of depth perception, he became his father’s successor as the nation’s most important steam engineer.



I had not heard of this guy, I must admit. Must be the last amateur scientist. Why did he decide to study climate? Remember, he was a steam engineer:

Callendar himself attributed it to ordinary curiosity: “As man is now changing the composition of the atmosphere at a rate which must be very exceptional on the geological time-scale, it is natural to seek for the probable effects of such a change.”

In the early 1930s Callendar began collecting measurements of the properties of gases, the structure of the atmosphere, the sunlight at different latitudes, the use of fossil fuels, the action of ocean currents, the temperature and rainfall in weather stations across the world, and a host of other factors. It was a hobby, but a remarkably ambitious one: He was producing the first rough draft of the huge climate models familiar today. After years of calculation, in 1938 he came to a surprising conclusion: People were dumping enough carbon dioxide into the air to raise the world’s average temperature.


Years of calculation, just like Svante Arrhenius before him Callendar had to do ALL the tedious calculations by hand: no computers or calculators in those days! So 1905 and 1938 the same conclusion was reached.

Callendar did not have a PhD, but he had enough academic status to be allowed to present his ideas that year in front of a panel of six professional climate scientists at the Royal Meteorological Society. The pros were familiar with the claim that carbon dioxide affected climate, which other researchers—notably Sweden’s Svante Arrhenius—had made in previous decades. But these ideas, in their view, had been thoroughly debunked. Years before Callendar’s presentation, British Meteorological Office head George Clarke Simpson had stressed the scientific consensus that carbon dioxide in the air had “no appreciable effect on the climate.” Now he was one of Callendar’s commentators. Callendar, unlike his predecessors, had a coherent model and decades of new data. Nonetheless Simpson was not kind. The problem with people like Callendar, he sniffed, was that “non-meteorologists” simply didn’t know enough about climate to be helpful. The other five commentators were no more appreciative. Although Callendar had spent years gathering evidence, they were “very doubtful” that his work meant anything.


Hidebound idiots :bgrin The problem is one some still can’t accept: there is just so little CO2 in the atmosphere:

the biggest reason for skepticism was that there simply wasn’t—and isn’t—very much carbon dioxide in the air. When Callendar was scribbling away, carbon dioxide comprised about .03 percent of the atmosphere by volume (the level has risen slightly since then). If somebody collected 10,000 scuba tanks of air, the carbon dioxide in them would be enough to fill up three tanks. How could anything so tiny be important to a huge, super-complex system like the atmosphere? It was like claiming that a toy bulldozer could level Manhattan. The idea seemed absurd on its face.

A few were grappling with an even crazier idea: that people were pumping enough carbon dioxide into the air to reshape the face of the Earth and put human existence at risk.

Undeterred, Callendar kept working on what came to be called the “Callendar effect.” This was not because he feared the impacts of rising carbon dioxide. In fact, Callendar believed that this warming business sounded like a good thing. “Small increases in mean temperature” would help farmers in cold places, he argued. Better yet, they would “indefinitely” postpone “the return of the [ice ages’] deadly glaciers.”


Trouble is, that tiny increase in temperature is not spread evenly and the warming created feedbacks that increased the effect of the increase in CO2.

Callendar died in 1964. By that time, many climate scientists had reconsidered their opposition to his ridiculous-sounding belief that slightly increasing the small amounts of carbon dioxide in the air could affect global temperatures. A few were grappling with an even crazier idea: that people were pumping enough carbon dioxide into the air to reshape the face of the Earth and put human existence at risk. But nobody was imagining that the possible solution to our inadvertent transformation of the planet would be to transform the planet even more.


There was a scientist or two, apparently, in the 1970s who said something about a coming ice age, temperatures had dropped since the 50s but that soon turned around—this ice age stuff then (and now, lots of hysteria here and there on the www about a GSM causing an ice age) was not based on real science.

Now, why is this trace amount of CO2 so important? It is opaque to wavelengths water vapor is transparent to:
few non-climatologists have even a rudimentary understanding of why airborne carbon dioxide raises temperatures—of what Callendar figured out in 1938. The Sun washes the Earth with every imaginable type of light: ultraviolet, microwaves, infrared, radio waves, visible light, you name it. Roughly half of this light is either reflected by clouds or absorbed by the atmosphere. The rest, mostly visible light, passes through the air and is soaked up by the land, oceans, and plants. Having taken in all of this energy, the ground, water, and vegetation naturally warm up, which makes them emit infrared light (the kind of light that we can see with night-vision goggles in old James Bond movies). This release of energy prevents the surface of the Earth from getting unbearably hot.

More than 95 percent of the atmosphere consists of nitrogen and oxygen. A trivial-sounding but important fact about nitrogen and oxygen is that they cannot absorb infrared light. If our air consisted entirely of these two gases, the infrared from the surface would pass through the atmosphere into space like a shotgun blast through tissue paper and our planet would be unbearably cold. Happily, there is something else in the atmosphere: water vapor, which can and does absorb the majority of this outgoing infrared energy. If water vapor caught all of it, the air would become unbearably hot. Instead, a little bit of the infrared energy slips by water vapor—just enough to prevent the atmosphere from heating to intolerable levels.

Two mechanisms are responsible for the escape. The first is that the water vapor releases some of its absorbed energy, also as infrared light. It is re-absorbed and re-emitted by water vapor many times in our atmosphere, but eventually some of that light passes beyond the atmosphere, into outer space. The second is that water vapor doesn’t absorb all the Earth’s infrared radiation—the vapor is effectively transparent to certain wavelengths. Through these transparent “windows” some infrared passes into the vacuum.[of space]


So, we have some “windows” where IR can escape to space, losing heat it picked up from sunlight. Some frequencies of IR can’t escape to space so the world doesn’t freeze at night. Now the matter of CO2:

So far, both Callendar and his critics would have been in agreement. But what Callendar realized—and his critics initially didn’t believe—is that carbon dioxide absorbs some of the wavelengths that water vapor lets through—it shuts the windows, so to speak. The more carbon dioxide, Callendar said, the more firmly shut the windows. With the escape route cut off, the atmosphere heats up.


That this is very true has been verified by spectrometry on satellites and on the surface.
Abbott & Co are going to cause the mother and father of all recessions—be prepared!
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Re: Some history of the science of AGW

Postby HBS Guy » 24 Jan 2018, 21:23

How fast the globe can be expected to warm is complicated by all sorts of feedback loops:

Warmer, more moisture leading to more IR trapped.

More moisture means more clouds. Clouds trap heat underneath but also reflect sunlight back out into space, etc.

https://www.wired.com/story/meet-the-amateur-scientist-who-discovered-climate-change/
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Re: Some history of the science of AGW

Postby HBS Guy » 16 Jul 2018, 02:59

https://history.aip.org/climate/co2.htm

Nice history of AGW science.
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