In , the U. The Weather Bureau was planning to measure atmospheric CO 2 at remote locations to establish a baseline of CO 2 concentrations. Keeling had proposed to both Wexler and Revelle that he could deploy a new analytical tool called an infrared gas analyzer to perform continuous measurements of CO 2 in air samples.
The Weather Bureau offered to support analyzers at locations in Hawaii and Antarctica, and a third aboard a research ship. Additional samples would be collected in glass flasks at remote locations and onboard research aircraft and returned to Scripps for analysis.
Keeling moved to La Jolla in August of He immediately began the difficult task of preparing the equipment and protocol and hiring staff needed to implement the CO 2 program, which was scheduled to begin the following July. The first of the remote flask samples was collected at the South Pole in early and sent back to Scripps for analysis, providing the earliest data from the program.
A second analyzer was prepared for installation aboard a Scripps research ship, set to launch in the fall of Sampling by U. Air Force aircraft was the next priority. The observatory is located on the remote north slope of the Mauna Loa volcano, one of several volcanoes on the Island of Hawaii commonly known as the Big Island , and it is an ideal location for collecting pristine air far from human influences.
Weather Bureau employees were responsible for the difficult work of obtaining measurements and maintaining the instrument, and they relayed data to Keeling in California for further analysis. The first reading from Mauna Loa, dated March 29, , measured the atmospheric CO 2 concentration at ppm.
Daily averages were recorded until power failures interrupted the equipment between May and July. These data from the first three months showed a progressive increase in CO 2 concentrations. When testing resumed in July, a decrease was registered. Additional equipment failures resulted in lapses in the records for September and October. By November, CO 2 levels showed a new low, only to increase in the following months. When a full year of measurements was completed in , a pattern emerged that began to make sense.
In the winter when plants lose their foliage, carbon stored within plant tissues and soils is released to the atmosphere, increasing CO 2 concentrations.
Keeling reported his initial findings in the geophysics journal Tellus in , describing the seasonal pattern of CO 2 variations. Given what Keeling and other scientists knew about the effect of CO 2 as a greenhouse gas, there were strong reasons to continue the monitoring program, uninterrupted. For each succeeding year of the record, the average annual CO 2 level rose. A clear picture of how fossil fuel emissions, the greenhouse effect and climate change are connected began to come into focus.
As humans exploited fossil fuels such as coal, oil and natural gas starting in large quantities during the Industrial Revolution , they released the carbon stored therein into the atmosphere as CO 2. Using these data, Keeling was able to compare the amount of CO 2 accumulating in the atmosphere against estimates of the amount of CO 2 being released by burning fossil fuels. Knowing the airborne fraction is necessary not only for scientists who look at the present and past to describe the impacts humans have had on the atmosphere, but also for those who look ahead.
Carbon, 14 C, with two extra neutrons, makes up only a trace amount. The isotopes 12 C and 13 C are stable, meaning they are conserved over time, while 14 C is unique among the three for being unstable. This isotope, also called radiocarbon, is created in nature when cosmic rays act upon nitrogen atoms in the atmosphere atomic tests have also contributed some 14 C.
The less 14 C an object has, the older it must be. In contrast, the amount of 12 C and 13 C remains unchanged after many thousands of years.
Therefore, modern sources of CO 2 such as living organisms have about the same amount of 14 C as the atmosphere, whereas ancient sources like fossil fuels have none left. Authorities realized that this new Sign up now to learn about This Day in History straight from your inbox. In one of the most sensational trials in American history, Julius and Ethel Rosenberg are convicted of espionage for their role in passing atomic secrets to the Soviets during and after World War II. The husband and wife were later sentenced to death and were executed in Grant move against the Confederate trenches around Petersburg.
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