Declaring Independence

The nexus of global climate change and energy was brought home to me in ways large and small over the past couple of weeks:

◾ Charles D. Keeling, who discovered that the concentration of CO₂ in Earth's atmosphere is rising inexorably, passed away at age 77.
◾ Crude oil prices climbed above $60 per barrel for the first time.
◾ The lead article in the Sunday New York Times travel section was titled "The Race to Alaska Before It Melts."

Although I was C&EN's West Coast bureau head from 1981 to 1994 and covered some aspects of atmospheric chemistry for the magazine, I never met Keeling, an atmospheric chemist at Scripps Institution of Oceanography in La Jolla, Calif. Keeling is one of those rare scientists whose work led to an eponymous cultural artifact, the "Keeling curve."

Starting in the mid-1950s, Keeling began measuring CO₂ concentrations in pristine atmospheres, first at Big Sur in California and then at the weather station on Mauna Loa in Hawaii. Keeling continued his measurements for more than 40 years. He observed that the CO₂ concentration in the late 1950s was around 315 ppm and that atmospheric CO₂ varied with the seasons. Over the next several years, however, he noticed something else: Each year's level was slightly higher than the previous year's.

The Keeling curve is a reasonably linear sawtooth plot that traces the rise in CO₂ concentration from 315 ppm in the late '50s to about 380 ppm at the turn of the century. I listened to an appreciation of Keeling on NPR while I was driving home from work a few days after he died. F. Sherwood Rowland, the University of California, Irvine, atmospheric chemist and Nobel Laureate whose work revealed another of humanity's impacts on the atmosphere--chlorofluorocarbons' ability to deplete stratospheric ozone--said of Keeling that, when he began his work, few people thought it was important to measure a quantity like atmospheric CO₂ over time. You measured it a few times to confirm the accuracy of your measurement, and you were through with it. Keeling's work suggested that "maybe the thing you were measuring wasn't constant," Rowland said, "and that what was important was the change."

Thanks to Keeling, we know that burning fossil fuels is leading to an increase in atmospheric CO₂. How sure are we that this increase has any significant impact on climate? Global warming skeptics insist we don't know the answer to this question. The fact is that's just not true. That Earth's atmosphere acts like the glass of a greenhouse was first proposed by Fourier in the early 19th century.

In 1896, Svante Arrhenius published a paper titled "On the Influence of Carbonic Acid in the Air upon the Temperature of the Ground" in which he presented detailed calculations on the effect of increased and decreased atmospheric CO₂ on temperature as a function of latitude. Arrhenius speculated that a sharp decline in atmospheric CO₂ might have been responsible for the onset of ice ages and speculated further that burning fossil fuels might be preventing the onset of another ice age.

In fact, as soon as Keeling showed that atmospheric CO₂ was rising, all of the scientific knowledge was in hand to realize that humanity faces a serious problem. Global warming skeptics yammer endlessly about the uncertainty of computer models that attempt to quantify the potential effects on global climate of rising atmospheric CO₂, but that's a straw man to deflect our attention from the certainty that we face a problem.

Look, the oil business is a good one to be in. Oil companies are very profitable these days and would like to remain profitable. That's their right, just as it is the right of cigarette companies to make handsome profits selling cigarettes. But the cigarette companies maintained for a very long time that smoking was not a health hazard. After a while, we stopped paying attention to them because the evidence so strongly contradicted them.

The same is true of oil company global warming skeptics and their paid supporters. This being Independence Day in the U.S., it seems fitting that we declare our intention to free ourselves again--first, from our slavish dependence on fossil fuels and second, from the cant regarding global climate change.

Thanks for reading.