June 23, 2005
Charles D. Keeling, 77, Who Raised Global Warming Issue, Dies
By KENNETH CHANG
Dr. Charles D. Keeling, who set off current concerns of global warming through measurements beginning in the 1950's that showed steadily rising amounts of carbon dioxide in the air, died Monday at his home in Montana. He was 77.
The cause was a heart attack after a short hike, said the Scripps Institution of Oceanography in San Diego, where Dr. Keeling had long worked.
Carbon dioxide, which traps heat in the atmosphere, is one of the greenhouse gases. But when Dr. Keeling began his work, most scientists did not think that emissions from cars and factories could have a measurable effect on the earth's climate, assuming that nearly all the carbon dioxide would be absorbed by plants or the oceans.
In 1955, Dr. Keeling camped out at Big Sur State Park in California, collecting samples of air in flasks to measure their carbon dioxide content. Three years later, he lugged the instrument for measuring carbon dioxide to a weather station, two miles up, on Mauna Loa in Hawaii.
Carbon dioxide levels rise and fall over the course of a day, and his first measurement at Mauna Loa showed an average concentration of 315 parts per million. His measurements also showed that carbon dioxide levels rise and fall with the seasons, following the ebb and flow of vegetation in the Northern Hemisphere.
But his measurements also showed that carbon dioxide levels were rising year after year. That upward trend of carbon dioxide, known as the Keeling Curve, has now reached nearly 380 parts per million and is continuing to rise.
Dr. Keeling's work to establish long-term monitoring of carbon dioxide concentrations in a way that provided a running global average was simple in concept but profound in its impact, according to many climate experts.
"It became clear very quickly that his measured CO2 increase was proportional to fossil fuel emissions and that humans were the source of the change," said Dr. James E. Hansen, director of NASA's Goddard Institute for Space Studies in New York. "He altered our perspectives about the degree to which the earth can absorb the human assault."
The current debate over global warming centers on how much warming the increased carbon dioxide will generate, but few have disputed Dr. Keeling's underlying carbon dioxide data.
"I don't think I'm aware of any controversy about Dave's measurements, and that's really kind of remarkable," said Dr. Walter Munk, an oceanographer and colleague of Dr. Keeling at Scripps for three decades. "Dave was a stickler for every detail in connection with his experimental work."
A small gap in the carbon dioxide data from February through April 1964 tells of Dr. Keeling's tenacity in fighting for his experiment.
"His government funding sources told him in effect that 'You have shown that atmospheric carbon dioxide is increasing, now find some other interesting science to do,' " said Dr. F. Sherwood Rowland, a professor of chemistry at University of California, Irvine. "He fought to continue his measurement series, with support from many other scientists, and was back taking data in May of 1964."
Born in Scranton, Pa., Charles David Keeling received his bachelor's degree in chemistry from the University of Illinois in 1948 and his doctorate in chemistry from Northwestern University in 1954.
The director of Scripps then, Roger Revelle, was among the first to become concerned about the possible warming effects of carbon dioxide and recruited Dr. Keeling, who had already begun his measurements of carbon dioxide at Big Sur, to Scripps in 1956.
More recently, in 1996, Dr. Keeling and colleagues showed that seasonal swings of carbon dioxide levels in the Northern Hemisphere were becoming larger, possibly a sign that the growing season is beginning earlier because of global warming.
Dr. Keeling was elected to the National Academy of Sciences in 1994 and received the National Medal of Science in 2002.
Dr. Keeling is survived by his wife, Louise; four sons, Andrew, of Zurich; Ralph, of San Diego who followed in also doing atmospheric research at Scripps; Eric, of Missoula, Mont.; and Paul of Vancouver, British Columbia; a daughter, Emily, of Boulder, Colo.; and six grandchildren.
Andrew C. Revkin contributed reporting for this article.Copyright 2005 The New York Times Company