Charles David Keeling, a 1948 graduate of the Department of Chemistry at the University of Illinois, was renowned for making the extremely precise measurements of carbon dioxide (CO₂) that clearly indicated that the atmospheric concentrations were increasing, leading to the recognition that human activities could have a very significant impact on the earth’s climate system. After receiving his PhD in chemistry from Northwestern in 1954, Dr. Keeling spent most of his career at the Scripps Institution of Oceanography until his death in 2005.

As the first to confirm the accumulation of atmospheric CO₂, he produced a data set now known widely as the Keeling Curve. Prior to these investigations, it was commonly held that the oceans would readily absorb any excess CO₂ from the atmosphere produced by the burning of fossil fuels and other industrial activities. To quote Charles Kennel, former Scripps Director, these “are the single most important environmental data set taken in the 20th century. Dave Keeling was living proof that a scientist could, by sticking close to his bench, change the world.”

He also constructed one of the first models of the carbon cycle into which future man-made CO₂ can be introduced to predict concentration levels in the air and water well into the next century. His first few years of measurements also demonstrated the now well-known seasonal cycle in atmospheric CO₂ due to the “breathing” of the biosphere.

Dr. Keeling had many other major accomplishments in his rich scientific career. These include a capability for detecting the isotopic composition of respired air, and measurement techniques for accurately measuring carbon dioxide in seawater. His exacting seawater measurement techniques formed a benchmark for major ocean measurement programs.

Dr. Keeling was the author of over 100 research articles and the recipient of many awards. Keeling received the 1981 Second Half Century Award of the American Meteorology Society for his fundamental and far-reaching work on the measurement of atmospheric carbon dioxide. He was elected a Fellow of the American Academy of Arts and Sciences in 1986. In 1991, he received the Maurice Ewing Medal of the American Geophysical Union, and in 1993, received the Blue Planet Prize from the Science Council of Japan and the Asahi Foundation. In 1994 he was elected a member of the National Academy of Sciences. In 1997, Keeling was honored at a White House ceremony by then-Vice President Al Gore with a special achievement award “for forty years of outstanding scientific research associated with monitoring atmospheric carbon dioxide in connection with the Mauna Loa Observatory.” In 2002, President George W. Bush selected Keeling to receive the National Medal of Science, the nation’s highest award for lifetime achievement in scientific research. In 2005, Keeling received the Tyler Prize for Environmental Achievement, generally considered to be the world’s most distinguished award in environmental science.