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Observations

Observations

Opinion, arguments & analyses from the editors of Scientific American

A 2.4-degree C rise by 2020? Probably not

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earthClimate change is happening faster than scientists' predicted. Meltdowns in Greenland and Antarctica are well ahead of climate science projections and overall warming continues to accelerate—we have just endured the hottest year and hottest decade on record. About the only thing that isn't happening faster than expected is increasing concentrations of CO2 and other greenhouse gases in the atmosphere, still steadily ticking upwards by roughly two parts per million (ppm) per year.


Now, a new study from the Argentina-based Fundacion Ecologica Universal suggests that if the world continues to burn fossil fuels and emit CO2 at its present pace, atmospheric concentrations will reach 490 ppm by 2020—up from roughly 390 ppm today. Extrapolating that directly into heat, the study suggests global average temperatures would rise by 1.4 degrees Celsius in the next nine years alone—more than six times faster than present warming. The researchers move on then to their real concern: the impact of all the heat on food crops (not good), hence the study's title: "The Food Gap." (pdf)


The only problem is that increasing concentrations of CO2 don't translate instantaneously into warming. In fact, greenhouse gases take time to trap the sun's heat and warm the globe—the main reason we have built up a store of trouble for the future with more than a century of greenhouse gas emissions. In fact, the average temperature of the planet for the next several millennia will likely be determined this century by those of us living today and how much fossil fuel burning and deforestation, among other things, we choose to engage in.


Our content partner Climatewire reported on this study, including caveats from climate scientists not associated with it questioning its assumptions and noting the timing problem. We posted the Climatewire story on Wednesday morning, then took it offline Wednesday evening after we learned about the study's significant criticism and republished it Thursday with an explanatory editor's note. Climate scientists and climate contrarians alike are denouncing the study for its aggressive assumptions about the potential pace of climate change as well as its impacts on agriculture and hunger. Climate experts such as NASA GISS's Gavin Schmidt have called the kind of warming the study suggests impossible. And Eurekalert, the science news clearinghouse of the American Association for the Advancement of Science (AAAS), went so far as to retract a press release touting the study, calling it "erroneous" for "report[ing] a rate of global warming inconsistent with other respected sources of information regarding global climate change."


That is as it should be, part of the process of science correcting itself. Scientific American continues to monitor and clarify that critical process.

The views expressed are those of the author and are not necessarily those of Scientific American.

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