Climate Change 101

Trio of articles re-cover some global warming basics

A little more than a year ago, there was a feeling among many editors and reporters that the climate-change story had, in a sense, progressed since the release of the Intergovernmental Panel on Climate Change’s (IPCC) watershed Fourth Assessment Report in 2007.

Following the release of that report, coverage of climate science soared, with innumerable articles laying out the basics of the greenhouse effect, the carbon cycle, and how scientists know the Earth is warming at an unusual pace and why human industry is most likely responsible. Appropriately, articles quickly moved on to stories about the politics and economics associated with addressing the problem. To a large extent, the climate story became the energy story.

Then came the unauthorized release of a large cache of controversial e-mails from prominent scientists in the United Kingdom and United States, the failure of the Copenhagen climate summit, the revelation of minor errors in the IPCC’s 2007 report, and the failure of climate legislation in Congress. As my colleague Cristine Russell recently pointed out, “It’s been a challenging time for the climate change story on just about every front.”

The adversity is causing some journalists to revisit the basics of climate science in a very satisfying way, however. Two articles on Wednesday offered great refreshers on why scientists know two very important things: that atmospheric carbon dioxide is rising and that global temperature is rising. As the Knight Science Journalism Tracker observed, the long features “provide a serious, handy, collective guide to the yin and yang of observational climatology’s primary jobs these days - explaining and measuring global warming.”

The New York Times’s Justin Gillis was responsible for the piece about measuring the steady increase in atmospheric carbon dioxide. In essence, it is a profile of the scientist Charles D. Keeling, who died in 2005, how he learned to measure the concentration of CO2 in the air, and how he charted its rise along with the help of his son, Ralph, who carries on his work. As the Tracker’s Charlie Petit pointed out, it’s a story that “has been told many times,” but the front-page treatment, followed by a double-truck after the jump, was a high-profile way to reintroduce readers to the famous (among scientists, at least) Keeling Curve. Moreover, Gillis also weaves in the parallel story of the so far fruitless efforts to restrict global greenhouse-gas emissions, bringing readers right up to the recent United Nations summit in CancĂșn.

The smart decision to ground the explanatory science in current events was also on display in the article about why scientists know worldwide temperatures are rising, which was written for Climate Central by Tom Yulsman, co-director of the University of Colorado’s Center for Environmental Journalism. The piece starts with a newsy discrepancy: NASA’s Goddard Institute for Space Studies (GISS) recently announced that November was the warmest November on record, while the National Climatic Data Center said it was the second warmest November. From there it provides an excellent explanation of three primary groups that track surface temperatures, their methods, how they handle gaps and biases in their data, and, most importantly, why the groups’ datasets are in close agreement, despite the fact they’re not identical.

Side-by-side, Gillis and Yulsman’s articles explain the two most fundamental phenomena underlying global warming - rising carbon dioxide and rising temperatures. Neither piece really discusses the bridge in the relationship - temperature’s “sensitivity” to increasing carbon dioxide. Thankfully, Gillis got to write this follow-up post on the Times’s Green blog.

Pennsylvania State University climatologist Richard B. Alley, whom Gillis quoted in his article, seems to have the prompted the post. In his article, Gillis presented “one of the canonical projections of climate science”—that the average surface temperature of the earth is likely to increase by five or six degrees Fahrenheit, with a doubling of carbon dioxide in the atmosphere—and contrasted that with a prediction from skeptics, who say that the increase is likely to be less than two degrees. Apparently, Alley got in touch with Gillis to say:

[He] gets annoyed by the way this contrast is often presented in news accounts. The higher estimate is often put forward as a worst case, he pointed out, while the skeptic number is presented as the best case.

In fact, as Dr. Alley reminds anyone who will listen, and as he recently told a Congressional committee, the estimate of 5 or 6 degrees is actually mildly optimistic. Computer programs used to forecast future climate show it as the most likely outcome from a doubling of carbon dioxide, but those programs also show substantial probabilities that the warming will be much greater.

The true worst case from doubled carbon dioxide is closer to 18 or 20 degrees of warming, Dr. Alley said — an addition of heat so radical that it would render the planet unrecognizable to its present-day inhabitants.

Gillis then goes on to give a brief description of some of the challenges of accurately determining “climate sensitivity,” explaining that “scientists are simultaneously trying to project the earth’s response to a given future level of carbon dioxide, and to project how high the carbon dioxide will actually go before emissions are brought under control.”

Gillis’s front-pager was the second installment in a new climate series, “Temperature Rising,” that the Times launched on November 13. As the paper’s environment editor, Erica Goode, recently explained to CJR, the series will “focus on the central arguments in the climate debate and examine the evidence for global warming and its consequences.”

[Update, 1/4: In an e-mail responding to questions about the usefulness of this sort of back-to-basics journalism, Yulsman said he has been struck by the disconnect between scientists’ concern about climate change and the public’s general apathy.

“Can explanatory science journalism targeted at non-experts help?” he wrote. “I doubt it’s going to elevate the issue on the list of public priorities. But my hope is that the Climate Central piece that I wrote, and the more extensive, narrative-driven, and more broadly distributed CO2 story by Justin Gillis, are now out there, waiting to be picked up by people who are confused but curious as authoritative sources of information when the climate change wars heat up again. In the age of Web 2.0, when there is so much conflicting information floating around out there, much of it completely without merit, my hope is that good, old fashioned journalistic verification can win out, one small post at a time, little by little by little.”]

Taken together, Gillis and Yulsman’s articles, plus the follow-up post from Gillis, are an exemplary contribution to what will hopefully be an even wider effort to revisit some of the basic scientific context undergirding the ongoing efforts to curb planet-warming greenhouse gas emissions.

Curtis Brainard writes on science and environment reporting. Follow him on Twitter @cbrainard. Tags: , ,