Ahead of the Curve
Charles Keeling’s groundbreaking work at Mauna Loa.
Enter the Big Island’s then newly built Mauna Loa Observatory. At more than 11,000 feet above sea level, in the middle of the Pacific, its air is among the cleanest on Earth. (Although nearby Kilauea generates a large amount of CO2, it doesn’t affect the curve’s measurements. Data is obtained at night, when the down slope winds bring air from higher elevations.) Keeling and his team didn’t know it at the time, but their measurements at Mauna Loa would provide the first evidence of rapidly increasing greenhouse gases in the atmosphere due to the burning of fossil fuels.
Their data set, which became known as the “Keeling Curve,” shows a clear and steady increase in CO2 levels starting from its first measurement in 1958, at about 315 parts per million (ppm), to its February 2008 measurement, around 386 ppm.
“I think [Charles] was somewhat stunned to discover the consistency of the rise from year to year,” says Ralph Keeling, Charles’ son and a climate scientist at the Scripps Institution of Oceanography at the University of California San Diego, where his father also worked. “He recognized that there was something special about what he was seeing— evidence that the whole planet was changing, and changing because of humans.”
Carbon dioxide levels dip in the spring and summer growing seasons, when there are more plants to take in CO2 from the atmosphere.
Charles Keeling continued to monitor Mauna Loa’s measurements until his death in 2005, and Ralph continues his work today. “The challenge to humanity right now is to bend the curve,” Ralph says. “It keeps going up, and faster. Whether we succeed in slowing global warming will be measured by this curve.”