Graphs don't often seize the public's attention. But the Keeling Curve is one that did.
It's hard to imagine today's discussions about climate change without the iconic chart. For more than half a century, scientists at the Scripps Institution of Oceanography in La Jolla have used it to plot the rise of carbon dioxide in Earth's atmosphere. But with funding increasingly hard to come by, the project's future is uncertain.
Scripps researcher Charles David Keeling launched the Keeling Curve in 1958 and kept it alive by applying for grant renewals every few years. Today, his son Ralph Keeling has expanded the project to include oxygen measurements and other data points.
But the younger Keeling still writes the same grant proposals and collects the same atmospheric carbon dioxide measurements at Mauna Loa in Hawaii. He says the data collected there offered some of the first evidence that human activity was contributing to global warming: "It started the research agenda back in the 1960s by showing that something big was really happening."
But lately, funding for the Keeling Curve has been sloping downward. The National Science Foundation withdrew support a few years ago, and Keeling has had to cut staff.
"Things have never been this dire before," he told Nature earlier this week.
Keeling has considered finding a home for the project in a government agency, but the National Oceanic and Atmospheric Administration (NOAA) already conducts similar measurements. Keeling says it's important to have two independent projects doing the same work, though. That way they can play as checks on each other. Whether funding comes from the private or public sector, Keeling hopes to find a more permanent source of revenue for what he considers crucial ongoing work.
"With the Earth kind of like a sick patient, as soon as you think you might have a cure, you don't stop looking at the health of the patient," Keeling said. "And at this point we don't even have a cure."
Earlier this year, the Keeling Curve hit 400 parts per million, a milestone marking the highest level of atmospheric carbon dioxide for millions for years.
