Although the Industrial Revolution began around 1750, the science necessary to detect atmospheric change did not exist. Indeed, the element “oxygen” and gas “carbon dioxide” had not been identified. The “scientific method” had been developed, but there were probably no more than a hundred scientists in the world.
Observed First: 1700’s
In the 1750s, Joseph Black observed that limestone, when treated with various acids, produced a gas more dense than air and that smothered flames. He called it “fixed air” and showed that it was also produced by animal respiration and fermentation.
In 1770s France, Antoine-Laurent Lavoisier and his wife began an analytic study of combustion. They very carefully weighed all the components and products involved in burning. They showed that “inflammable” air, now called hydrogen, combined with a new element they called oxygen, to produce water. Moreover, they showed that oxygen was necessary for combustion and resulted in Black’s “fixed air,” which we now call carbon dioxide.
These discoveries were collected in Lavoisier’s book “Traité élémentaire de Chimie,” which established the science of chemistry and guided the 1800s stunning development of the chemical industry.
In the 1770s, Dutch physiologist Jan Housz discovered photosynthesis, determining that plants took up carbon dioxide in amounts equivalent to their weight increase. Botanists soon realized that plants gave off oxygen in this process. It is by this cycle that atmospheric oxygen and carbon dioxide are kept in balance.
In the early 1800s, John Dalton proposed that carbon dioxide was composed of one atom of carbon and two atoms of oxygen. In 1824, Joseph Fourier, a French mathematician and physicist, using this knowledge and discoveries of the thermodynamics of gases, calculated how the heat from the sun is trapped by the atmosphere. He determined that without any atmosphere, the earth would be 60-degrees colder. Although Fourier’s observations gave rise to the phrase “greenhouse effect,” there was no appreciation that the earth’s atmospheric and ocean temperatures might be changing away from the balance. The first realization that the temperature of the earth might change came about through the efforts of geologists who found evidence of glaciation in the past, giving rise to the term “Ice Ages.” This idea was as controversial as today’s idea of global warming. People in the Alps were aware that glaciers were retreating; they knew this from reports by their ancestors.
No clear explanation came until Louis Agassiz took up the case. After some years of field study, he described Ice Ages in 1840. Even then, the matter was not resolved until 1875, when James Croll published an extensive analysis that not only proved previous ice ages when glaciers covered much of Europe, but provided an explanation of their cause. Huge changes in the earth’s temperature in the past implied the possibility of present-day changes taking place.
In the 1890s, American astronomer Samuel Langley attempted to measure the temperature of the moon’s surface by measuring the infrared light leaving the moon and arriving on earth. The Swedish physicist Svante Arrhenius used Langley’s data to estimate the atmospheric cooling or heating upon changes in carbon dioxide in the atmosphere. He was interested in exploring mechanisms that might result in another ice age. He calculated that another ice age would result if the carbon dioxide fell to one-half its value. Equally, he calculated a warming of 5-degrees if it doubled. Estimates that the carbon dioxide content of the atmosphere was increasing led him to predict a slight global warming that might take thousands of years.
Is Carbon Dioxide A Factor?
The matter remained in doubt during the first half of the 20th century. Methods of measurement were improved, but the absence of long-term studies made it difficult to distinguish between random fluctuation and a warming trend. Most scientists remained unconvinced. Charles Keeling, of the Scripps Institute of Oceanography, was the first person to make frequent regular measurements of the atmospheric carbon dioxide concentration. Beginning in 1958, he made continuous measurements at several locations, extending on to 2015. His measurements at Mauna Loa, Hawaii, show a clear increase.
Over each year the carbon dioxide level fluctuates above the average line in May and below the average line in late September. The average line, however, smoothly rose from 315-PPM (parts per million) to 400-PPM carbon dioxide today. The increase slightly accelerated with time and will reach a doubling before mid-century if the increase continues. Modern computers permitted much more accurate and extensive versions of Arrhenius’s calculations.
Computer Models Corroborate
By the 1970s three-dimensional computer climate models were predicting that a doubling of carbon dioxide would result in a 2-degrees C rise in global temperature (3.6-degrees F). This doubling now seems certain from the Keeling curve. By this century, climate study has become well-accepted science. Permanent research programs are being carried out at both poles. Data gathered from satellite observations gives continuous measurements of ice and snow loss at both poles and of increasing fluctuations of ocean temperatures.
The result is that almost every issue of the scientific journals comes out with one or more detailed research report supporting climate change and adding to our understanding of its effects. This includes this year’s Nov. 13 special issue of the journal Science, which is devoted to how climate change is transforming the oceans.
This article first appeared in the December 2, 2015 issue of the Rossmoor News authored by Wayne Lanier, Ph D.