For those of you not so fired up to read all my boring text below, you may prefer to view one or more of these excellent videos, each about ten minutes long or so...
Peter Sinclair's "Climate Science 1956: A Blast from the Past":
Peter Sinclair's "Climate Science 1958: The Bell Telephone Science Hour":
Peter Sinclair's "Isaac Asimov on the Greenhouse Effect: 1989":
the gist of it all is that "global warming" was not invented by Al Gore, and is not some sort of new or rogue theory... it has been developed progressively from the early 1800s through to present day... it started as a barely understood concept that was largely dismissed by the scientific community, until over time and with improved monitoring technologies and better data accumulation... it has become widely accepted by relevant researchers in the field - 97% of practicing climate scientists (that's a higher percentage than dentists who recommend chewing Trident gum to patients who chew gum) ... http://www.skeptical...ntermediate.htm
A Brief History of Global Warming, As It Were…
The 1800s: Fourier, Tyndall, and Arrhenius, oh my
In the 1820s, Joseph Fourier, French mathematician and physicist, most likely became the first scientist to seriously consider that the earth’s atmosphere played a role in warming the planet. He calculated that the earth, given its distance from the sun, should be considerably colder than it is (a simple blackbody calculation yields the result that the earth should be about 30-33 degrees C colder than it actually is on global average. Rather than averaging about 14-15 degrees C, we “should” be about -15 degrees C). He investigated potential sources for the additional warmth that we observe. One of the sources he considered was the atmosphere acting as some sort of insulator, slowing down the radiation of heat back out to space, and raising the surface temperature. Ultimately, Fourier settled on interstellar radiation as the most likely source of most of the additional warmth, which only goes to show even legendary scientists like Fourier, who gave us Fourier series and Fourier transform in mathematics and statistics as well as Fourier’s Law in thermodynamics, were capable of making mistakes or drawing poor conclusions. But Fourier is largely credited with developing what eventually came to be known as the Greenhouse Effect.
Irish physicist John Tyndall figured out that carbon dioxide was a greenhouse gas in the 1850s. He was able to determine the absorption spectra of numerous atmospheric constituents, including water vapor, carbon dioxide, and methane. But, I don’t think he predicted doom and gloom – I he just observed that without the greenhouse gases, the planet would be inhospitably cold – he built on the earlier work of Fourier, essentially resurrecting the “atmosphere as an insulator” idea, but developing it further by identifying how individual gases in the atmosphere absorb outgoing infrared radiation, thereby leading to the warming effect. Tyndall is interesting because he was an Alpine climber, and he was one of the earliest to believe that tens of thousands of years ago, northern Europe had been covered with enormous glaciers. One of his main interests was in trying to figure out how this “ice age” came to be.
In 1896, Swedish physicist and chemist Svante Arrhenius, who was one of the founders of physical chemistry, became the first person to forecast that human activity would inevitably lead to climate change. He used a very simplistic model, but he predicted that fossil fuel emissions would lead to increased global mean temperature through the 1900s. Now, basically, Arrhenius was just observing that there is a natural carbon cycle at work, and fossil fuel emissions were necessarily adding carbon to the system, and as this carbon accumulated in the atmosphere, it would raise the earth’s temperature because it is a greenhouse gas, as demonstrated decades earlier by Tyndall. One of Arrhenius’s colleagues, Arvid Hogbom, had been studying the carbon cycle. Hogbom decided to calculate the amount of carbon dioxide emitted by factories and other sources. To his surprise, he found that human activities were adding CO2 to the atmosphere at a rate on a par with natural processes. Though the amount was very small, he reasoned that the additional CO2 could add up over a long time, and perhaps significantly affect the earth’s temperature.
Arrhenius calculated that for a doubling of atmospheric CO2, the Earth’s temperature would increase about 5-6 oC. Arrhenius wasn’t alarmed, though. He calculated that at the rate of emissions in 1896, it would take civilization 3,000 years to double the CO2 concentration. He and Hogbom also calculated that the oceans would absorb about 83% of the CO2 emissions, further slowing the accumulation. The problem though, is that neither considered that if CO2 emission rates increased, the ocean absorption rate would not keep pace. But, in Sweden, global warming didn’t sound so bad – in fact, scientist Walter Nernst even dreamed up an idea to set fire to coal seams in order to deliberately release carbon dioxide to warm the climate!
Arrhenius eventually published his calculations in a book in 1908, and the rate of fossil fuel emissions had already increased to the point where Arrhenius predicted warming would occur on the order of centuries rather than millennia. But, this was really a side point of his work – his main focus was on trying to explain the cause of the ice ages.
1900-1950: Rise of the American Scientists
In the early 1900s, American geologist T.C. Chamberlin picked up on Arrhenius’ work and wondered how the gas cycled through the Earth’s oceans, minerals, forests, and atmosphere. Chamberlin believed that the atmospheric concentration of CO2 probably varied over the long term and might explain gradual shifts in climate over millions of years. Chamberlin was the founder of the Journal of Geology and served terms as the chief geologist for the Wisconsin Geological Survey, head of the glacial division of the U.S. Geological Survey, president of the University of Wisconsin, founder of the geological department at the University of Chicago, and president of the Chicago Academy of Sciences.
But aside from that, most scientists seemed to find Arrhenius’ calculations indicating that CO2 could raise global temperatures to be implausible. They felt his climate model was too simplistic; they felt he didn’t account for potential changes in cloud cover if the Earth warmed and became more humid. Then, a few years after Arrhenius’ published hypothesis, an assistant of Knut Angstrom conducted an experiment with a limited amount of CO2 in a tube and concluded that, even at low concentrations, the gas would “saturate” with respect to its absorption properties (i.e., in the wavelength that CO2 blocked radiation, it accomplished it so efficiently that a small amount of gas would block virtually all the radiation at that band, and additional gas would have no additional effect). Other scientists argued that water vapor is far more abundant in the air and it also intercepts infrared radiation, and in the crude spectrographs of the time, the smeared bands of the two gases overlapped one another. Therefore, they presumed that a little more CO2 could not increase the blocking of radiation that was surely entirely blocked by water vapor and existing CO2 anyway.
But, those arguments were flawed. Angstrom’s assistant, Koch, had a couple problems with his experiment – the first in measurement precision, and the other in the fundamental assumption that a little CO2 in a tube was representative of the Earth’s atmosphere. Even if the absorption in the Earth’s lower atmosphere was completely “saturated,” the greenhouse effect will still operate because the planet’s temperature is regulated by the thin upper layers of the atmosphere, where radiation escapes into space. Adding more greenhouse gases will upset the balance, and even a small increase will change the planet’s surface temperature. Fundamentally, the term “greenhouse gas” reflects the lack of understanding of the atmosphere at that time. The Earth’s atmosphere acts more like a set of interacting layers rather than a single, thin slab, like a greenhouse glass, as in Koch’s experiment.
So, nobody took Arrhenius seriously. Or at least few did. In 1931, American physicist E.O. Hulburt determined that investigators were too interested in the absorption bands and not the absorption coefficients of individual greenhouse gases. He set about to obtain more accurate estimates of the absorption coefficient of carbon dioxide, and eventually calculated that a doubling of atmospheric CO2 would create a 4 oC rise in temperature. But Hulburt was a pretty obscure scientist (heck, I never heard of him) at the Naval Research Laboratory, and the American Meteorological Society, even as late as 1951, believed that the idea that increasing CO2 could have an effect on climate “was abandoned when it was found that all the long-wave radiation [would be] absorbed by CO2 and water vapor.” Scientists also generally believed that the Earth was too “big” and “balanced” for man to have an effect on it. The oceans had 50 times as much CO2 as the atmosphere, so it should soak up any excess CO2 humans emit. If not the oceans, then certainly the forests would.
In 1938, a guy by the name of Callendar – actually his name was Guy Callendar – first compiled empirical evidence that Arrhenius was correct. He is the first to compile weather measurements from the 19th century on – he did this as a hobby, after observing that, based on personal anecdotes, people seemed to be thinking that there was a warming trend underway. Callendar found that the stories were right. So, he dug up old records of carbon dioxide concentrations and concluded that the gas had increased by about 10% over the prior 100 years. Callendar attributed the warming to the CO2 rise and estimated that a doubling of CO2 could result in a 2 oC increase in temperature. But Callendar, like Arrhenius and Chamberlin, was more interested in explaining the ice ages than in worrying about global warming. Still, most scientists believed the overlapping absorption band with water vapor was decisive (Callendar argued that the spectrographs were too crude to be decisive), and the U.S. Weather Bureau even stated that because of the masking of CO2 by water vapor, “no probable increase of atmospheric CO2 could materially affect” the balance of radiation.
1950-1980: Development of the Science
Then in the 1940s and 1950s, the complacent view that humans could not upset the balance of nature began to be eroded. It started in the 1940s when military funding led to improved experimentation. Scientists discovered that the overlapping, smeared spectral bands from the old experiments conducted at sea-level pressure and temperature were misleading. At low pressure and temperature, each band resolved into a cluster of sharply defined lines with gaps where radiation could pass through. The most important CO2 absorption lines did not lie exactly with the water vapor lines. Between this observation, and observations that the atmosphere was layered, with more water vapor in the lower atmosphere, and little water vapor in the upper atmosphere, scientists began to realize that changes in atmospheric CO2 could in fact have a significant effect on the Earth’s climate. Lewis D. Kaplan used a digital computer in 1952 to calculate that adding more CO2 to the upper atmosphere must change the balance of radiation significantly. In 1956, physicist Guy Plass calculated that human activity would raise the average global temperature at the rate of 1.1 oC per century. “If at the end of this century the average temperature has continued to rise,” Plass wrote, then it would be “firmly established” that CO2 could cause climate change.
It was about this time that scientists also developed the ability to track the movement of carbon through the radioactive isotope carbon-14. In the upper atmosphere, cosmic rays create C-14, which then decays over thousands of years. The carbon from fossil fuels is millions of years old – there is no C-14 in it. In 1955, chemist Hans Suess first reported that he had detected fossil carbon in the atmosphere. Though his initial results were very preliminary, he continued to develop more accurate results over the next decade. He teamed with Roger Revelle at the Scripps Institution of Oceanography. They measured isotopic concentrations in the atmosphere and in the oceans, and they determined that the ocean surface waters absorbed a typical carbon dioxide molecule from the atmosphere in a decade or two, and that the oceans would completely “turn over” in several hundred years. Other independent researchers confirmed this.
Revelle was an oceanographer, and had been studying the oceans his entire career. He knew that the oceans were not composed of simple salt water, but contained a veritable “stew” of chemicals that create a buffering mechanism, stabilizing the acidity of sea water. He knew that the buffering effect would prevent the oceans from retaining as much carbon dioxide as simple calculations might suggest they would absorb. He determined that the ocean surface waters would take up only about 10% of the carbon predicted by calculations. Assuming a constant rate of emission of CO2 by industries, Revelle calculated that the atmospheric carbon dioxide concentration would level off after a few centuries at a total increase of about 40%. But, he cautioned…
Still, other scientists missed the full ramifications of Revelle’s studies and continued to deny that there was a greenhouse effect problem. In 1958, Callendar again published a paper concluding that atmospheric carbon dioxide continued a steady climb since the 19th century, but expressed consternation that “the oceans have not been accepting additional CO2 on anything like the accepted scale.” In 1959, two Swedish meteorologists, Bert Bolin and Erik Eriksson explained the sea water buffering originally described by Revelle so clearly that they were often cited as the original source of this observation for many years. The oceans could absorb the carbon dioxide, but they lost most of the gas through evaporation before currents could sweep it to the depths. The atmosphere and oceans would theoretically reach equilibrium, but it could take thousands of years.
So, by the late 1950s, a handful of scientists had started informing the public that greenhouse gases could become problematic. Plass may have been the first American scientist. Revelle warned journalists and government officials that greenhouse warming could arrive within the foreseeable future and deserved attention. Bolin and Ericksson assumed that industrial production would continue to rise exponentially and calculated that atmospheric CO2 would rise by about 25% by the end of the 20th century (it actually rose from about 316 ppm in 1960 to about 370 ppm by 2000 – 17%). Soviet climatologist Mikhail Budyko predicted that exponentially increasing industrial emissions would create “drastic” global warming over the next century.
However, most scientists seemed to remain skeptical. Carbon dioxide measurements were not particularly precise, and by the mid 1950s, researchers began attempting to establish more accurate monitoring stations. Most of them only re-affirmed that accurately measuring carbon dioxide was difficult, and they were frustrated by “noisy data” and various interferences. But then Revelle and Suess hired Charles Keeling, who had developed infrared instrumentation for improved precision in measuring gases like CO2. Keeling established monitoring stations in Antarctica and atop the Mauna Loa volcano in Hawaii. Within two years, he had collected enough data to demonstrate a discernible rise in atmospheric carbon dioxide consistent with calculations using the recently demonstrated limited absorption capacity of the oceans. The Antarctica station was shut down because of funding issues, but the Mauna Loa station operated almost uninterrupted. As the record extended, it became increasingly significant – jagged but rising inexorably year after year. http://earthobservat...iew.php?id=5620
During the 1960s, there was a growing community of scientists from many fields communicating and collaborating. Biological scientists studying natural cycles of nitrogen and carbon got in touch with geochemists, who in turn communicated with atmospheric scientists (from primarily government-funded laboratories like the National Center for Atmospheric Research in Boulder, Colorado, and the Geophysical Fluid Dynamics Laboratory in Princeton, New Jersey). In 1965, President Johnson commented on carbon dioxide in his Special Message to Congress. Later in the year, the President’s Science Advisory Committee warned:
“…by the year 2000, there will be about 25% more CO2 in our atmosphere than at present [and] this will modify the heat balance of the atmosphere to such an extent that marked changes in climate… could occur.”
In 1966, the National Academy of Sciences Panel on Weather and Climate Modification was helmed by geophysicist Gordon MacDonald, who later served on President Richard Nixon’s Council on Environmental Quality. While examining (primarily military) potential for deliberate weather modification, MacDonald’s committee concluded that increased CO2 might also lead to “inadvertent weather modification.”
Although a few groups of scientists were determining that CO2 drivers could be significant, most only viewed it as one parameter in a larger system that they were attempting to understand. Most still thought that the Earth’s geochemistry was dominated by mineralogical processes that occurred over millions of years. By 1970, veteran climate experts like Helmut Landsberg and Hubert Lamb doubted that greenhouse warming was a possibility, and the observed general decline in global mean temperatures since 1940 seemed to justify the doubters.
In the 1970s, there were a few notable scientists, or groups of scientists, that indicated that perhaps those scientists who had warned of global warming should be listened to more closely. In 1978, Robert White, the first administrator of the National Oceanic and Atmospheric Administration, commented:
In 1979, the JASON committee looked into the subject. The JASON committee is a group of elite scientists with high-level security clearances, who gather annually to advise the U.S. government. This panel was chaired by Gordon MacDonald. The JASON scientists concluded in their report “Long Term Impact of Atmospheric Carbon Dioxide on Climate,” that atmospheric CO2 might double by the year 2035, and this increase could raise global mean temperature by about 2-3 oC. They also estimated that polar temperatures might increase by four or five times as much.
Note: here is a NASA temperature anomaly map taken from the Washington Post:
Frank Press, Science Advisor to President Carter, after reading the JASON report, asked the National Academy of Sciences to research the state of knowledge on the subject. The resulting report by special committee, chaired by MIT meteorologist Jule Charney, and including such noted scientists as Bert Bolin (University of Stockholm), Robert Dickinson (NOAA), Henry Stommel (Woods Hole Oceanographic Institution) and Carl Wunsch (MIT), stated:
“We conclude that the predictions of CO2-induced climate changes made with the various models examined are basically consistent and mutually supporting. The differences in model results are relatively small and may be accounted for by differences in model characteristics and simplifying assumptions. Of course, we can never be sure that some badly estimated or totally overlooked effect may not vitiate our conclusions. We can only say that we have not been able to find such effects. If the CO2 concentration of the atmosphere is indeed doubled and remains so long enough for the atmosphere and the intermediate layers of the ocean to attain approximate thermal equilibrium, our best estimate is that changes in global temperature of the order of 3 oC will occur and that these will be accompanied by significant changes in regional climatic patterns.”
This really set the stage for the first international efforts to study climate change – what eventually led to the Intergovernmental Panel on Climate Change (IPCC). But, it also set the tone for climate research in the U.S. in the 1980s. The potential for the greenhouse effect to cause or contribute to global warming was being taken much more seriously by most researchers.