In 1958, climatologist Charles David Keeling set up a monitoring station on summit of Mauna Loa, the second highest of the Big Island of Hawai‘i's two volcanoes, because it accessed some of the cleanest, most pollution-free air on Earth. Twice a day since, the Mauna Loa Observatory (MLO) has recorded the levels of atmospheric CO2 at the summit.
At first, the data seemed inconclusive; CO2 went up and down seasonally. But over time, the general upward trend was irrefutable, and the "Keeling Curve" has since become the single most compelling piece of evidence tying human industry to climate change. Al Gore used it in An Inconvenient Truth to persuade audiences that the burning of fossil fuels is indeed implicated in the warming of the planet. Despite the seasonal fluctuations, over the 41 years since the MLO first collected data, the curve has steadily and inexorably risen. Now, it's at a million-year high.
From today's Honolulu Star-Bulletin:
The readings at this 2-mile-high station show a troubling upward curve as the world counts down to crucial climate talks: Global-warming gases are building in the atmosphere at record levels from emissions that match scientists' worst-case scenarios.
Carbon dioxide concentrations this fall are hovering at around 385 parts per million, on their way to a near-certain record high above 390 in the first half of next year, at the annual peak.
"For the past million years we've never seen 390," said physicist John Barnes, the observatory director. "You have to wonder what that's going to do."
One leading atmospheric scientist, Stephen Schneider, sees "coin-flip odds for serious outcomes for our planet."
The "coin-flip odds" he means could be a 4.3 to 11.5 degree F increase by the end of the century.
It would "probably be at 390 (ppm) next year at Mauna Loa," said Fred T. Mackenzie, a professor emeritus of oceanography at the University of Hawaii at Manoa. That would represent almost a 40-percent increase in carbon dioxide density in the atmosphere since before the industrial age and extensive use of fossil fuels.
Schneider, a Stanford University climatologist, said the world faces a huge risk.
"I think meters of sea-level rise are virtually inevitable unless we can stop this. But I'm not such an optimist," he told journalists on a fellowship program with the Honolulu-based East-West Center. "The main message is we're in risk management. We do not know the science well enough to know exactly what the temperature is at when a tipping point will occur."