He received a Ph.D. in applied physics from Harvard University in 1988 for developing a novel technique for the accurate measurement of atmospheric oxygen.
[6][7] By October 25, 1986, Keeling had developed a working prototype, a stainless steel box about seven feet tall, with a glass front.
[8][9] The instrument Keeling developed was able to measure oxygen at a far more precise level than anything previously created, detecting differences of a few molecules per million.
[8] In a "landmark study" in 1996, Keeling demonstrated that land and ocean carbon sinks could be compared by examining the partial pressures of atmospheric oxygen and CO2.
Although the land is releasing millions of tons of CO2 as a result of deforestation, thawing of permafrost, and other global warming-related phenomena, plants are growing faster and taking up more CO2 in response.
[17] With Stephens and others, Keeling hypothesizes about oceanographic processes that may have stabilized and destabilized the oceans over time, in particular about possible thermostatic effects of Antarctic ice.