DAVE KEELING was one of the world’s leading authorities on climate change. His far-reaching and undisputed findings are now cited by scientists and most world leaders in support of efforts to mitigate global warming.
In 1958 Keeling began to monitor closely the concentration of carbon dioxide in the atmosphere. His results, plotted on a graph, yield what is known as the “Keeling curve”. It shows that each year the proportion of CO2 in the air rises by about one part in a million — except in the past few years, when it has been rising about 1.5ppm, and by an unprecedented 2ppm in each of the past two years.
When Keeling started out, the scientific consensus was that atmospheric CO2 concentrations would remain fairly static because any extra CO2 released by the burning of fossil fuels would be absorbed by plants and the oceans.
This has proved not to be the case. Keeling established that since the Industrial Revolution there has been a steady increase. While today the level is 380 parts of CO2 per million, when he started taking samples, only half a century ago, the level was 315ppm. Ice cores taken at the poles have shown that the pre-industrial level was around 280ppm — that is an increase of around 35 per cent over the past 300 years, and the level of CO2 in the atmosphere is the highest for about 400,000 years.
This is the chief cause of the “greenhouse effect” — the extra CO2 in the atmosphere, along with other gases, notably methane, traps the sun’s heat ��� which is already thought to be wreaking havoc with the world’s weather.
Advertisement
Keeling also noted from his detailed record of the natural daily and seasonal fluctations in atmospheric CO2 that spring in the northern hemisphere is now starting about a week earlier than in the 1950s.
Charles David Keeling — Dave to his friends, and C. D. Keeling in academic contexts — was born in Scranton, Pennsylvania, in 1928. He studied chemistry at the University of Illinois and took his PhD in chemistry at Northwestern University in 1954.
A year later, while working as a geochemist at California Institute, Pasadena, he took on a project which allowed him to indulge in his fondness for hiking. In order to test the theory that the amount of CO2 dissolved in fresh water is always in balance with the air above it, he spent a summer with his wife and newborn son sleeping beneath the stars in remote areas of California and taking regular air samples. It became apparent that for an accurate understanding of the atmosphere, he needed reliable readings of “background” CO2 — unaffected by local variations due, for example, to the abundance of plants in a certain area.
In 1956 Keeling joined the Scripps Institution of Oceanography in San Diego, recruited by its director, Roger Revelle, one of the first scientists to be concerned about the greenhouse effect. With his backing, Keeling began accurate, continuous sampling of atmospheric CO2 at a US weather station on Mauna Loa, a dormant volcano in Hawaii. At 11,000ft, the station was isolated enough to yield consistent readings for the northern hemisphere.
Keeling’s findings, though unwelcome in certain quarters and initially criticised as banal, have never been seriously disputed. Aware of their momentous implications for developed and developing economies alike, Keeling was always careful not to jeopardise his work with rash claims or premature assertions. He resisted making explicit the connection between his research findings and global warming until the beginning of the 1990s, by when his results had irrefutably shown that the increase in atmospheric CO2 was the result of human activity.
Advertisement
Keeling’s work earned numerous awards, including the National Medal of Science. This, the US’s highest honour for scientific research, was presented to Keeling in 2002 by President Bush — one of the few world leaders to reject the finding that global warming is due to human activity.
Keeling’s other passion was music. He was an accomplished pianist and at one time he had considered playing professionally. Keeling is survived by his wife, a daughter and four sons, one of whom devised the first tech- nique to measure atmospheric oxygen concentrations accurately.
Advertisement
David Keeling, climate scientist, was born on April 20, 1928. He died on June 20, 2005, aged 77.