The world’s longest continuous monitoring of carbon dioxide concentrations in the atmosphere. And from a place ideally situated for providing data not “contaminated” by other influences (car traffic, power plant emissions, etc.), but rather offering a pristine global perspective.

Climate experts will recognize that as pretty clearly referring to the Mauna Loa, Hawaii, carbon dioxide monitoring pioneered in the fifties by the Scripps Institution’s Charles David Keeling. And leading to the iconic “Keeling curve” showing increasing CO2 atmospheric concentrations.

That and more are the focus of a new 20-minute exchange featuring Ralph Keeling, currently heading Scripps’ CO2 monitoring work (and son of the now-deceased Charles David Keeling), and scientist Britton Stephens, of the National Center for Atmospheric Research’s Earth Observing Laboratory, in Boulder, Co.

Passing 400 PPM ‘Forever’ … and No Slow Down in Sight

In their discussion, Keeling explains how “we will cross above and below [the 400 ppm CO2 global concentration] a number of times as we rise slowly to a point where we’re above it forever.” This year we’ll almost certainly see the first monthly averages over 400 ppm, Keeling adds. The Mauna Loa data is showing that “we’re shooting right through” the 400 ppm figure, with “no slowing down in sight.”

Mauna Loa Observatory, home of the iconic ‘Keeling Curve.’

Keeling says that the globe could well exceed 450 ppm “in a matter of decades.” He adds that the 400 ppm figure is “a psychological and not a physical threshold. People keep track of round numbers and they remember them.” Keeling goes on to say that society could perhaps slow the rise so it doesn’t go much above 500 ppm, up from about 280 ppm in the nineteenth century prior to the widespread combustion of fossil fuels and releases of carbon dioxide into the atmosphere.

Keeping concentrations below 450 ppm “is already out of reach at this point just because there is so much inertia,” Keeling said. Society is “not in a position to reverse the trend any time soon” because we haven’t really exercised the ‘control knob’” — fossil fuel combustion and releases of CO2.

Pointing to NCAR’s similar but independent CO2 atmospheric monitoring work, NCAR’s Stephens explained the merits of having numerous monitoring efforts under way. He pointed specifically to “a lot of really good arguments in terms of redundancy.”

“No one scrutinizes these data as closely as the people who actually collect the information and notice things no one else notices,” he said. “We need a lot of people scrutinizing the data, looking at the data day in and day out.” Stephens said science and society overall would suffer unless “we avoid devolving into a situation where we have maybe a group of data providers who are doing it as cheaply as they can, and then a group of data users.”

Both scientists pointed to constant and recurring challenges in adequately funding long-term climate research such as they undertake, and Keeling pointed to some recent successes with crowd-sourcing, which he said helped “put us on the radar screen of a lot of people” and raised “not insignificant” financial support.

Acknowledging the perennial funding support challenges, Stephens said he fears federal agency funders’ frequent emphasis on “short-term hypothesis-driven funding efforts” could lead to human resources challenges over the next 20 years as long-term researchers effect a “changing of the guard” to a possibly shrinking pool of young scientists apprehensive about long-term research funding prospects.

The March 19 exchange is the third in an ongoing Yale Forum series moderated by freelance science writer Bruce Lieberman. Details on the upcoming one, scheduled for mid-May, will be announced on this site and also at the Yale Forum’s “30onClimate” site.