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From “Nuclear Winter” to “Carbon Summer”


When Al Gore received the 2007 Nobel Peace Prize for his efforts to raise awareness about man-made climate change, his acceptance speech featured a new word, or rather a new sense of an old word, that Oxford lexicographers have been watching closely: carbon, in the sense of “carbon dioxide or other gaseous carbon compounds released into the atmosphere.” As I wrote back in July, this extended sense of carbon can be found in all sorts of novel lexical compounds: carbon-neutral (2006 New Oxford American Dictionary Word of the Year), carbon footprint, carbon tax, carbon trading, and so forth. In his speech, Gore introduced another compound into the mix: carbon summer.

“More than two decades ago, scientists calculated that nuclear war could throw so much debris and smoke into the air that it would block life-giving sunlight from our atmosphere, causing a ‘nuclear winter,’” Gore said. “Now science is warning us that if we do not quickly reduce the global warming pollution that is trapping so much of the heat our planet normally radiates back out of the atmosphere, we are in danger of creating a permanent ‘carbon summer.’”

Nuclear winter, the model for carbon summer, was introduced into public discourse in 1983, when a team of scientists including Richard Turco and Carl Sagan published a landmark article in the journal Science. The earliest citation in the Oxford English Dictionary is actually a newspaper column by Sagan from a couple of months earlier, previewing the team’s findings. Sagan described scenarios of nuclear war involving detonations from 100 to 5000 megatons. Even the 100-megaton scenario, Sagan wrote, “would ignite thousands of fires, and the smoke from these fires alone would be enough to generate an epoch of cold and dark almost as severe as in the 5000 megaton case.” This “epoch of cold and dark” was dubbed nuclear winter by Turco’s team. Though the research findings were the subject of much dispute about the mixing of science and politics, nuclear winter remained a potent image throughout the US-Soviet standoff of the 1980s.

The public acceptance of the nuclear winter concept more than twenty years ago now helps to shape the discussion of climate change, with the equivalent scenario of carbon summer suggested by scientists investigating possible “tipping points” for a massive, irreversible global meltdown. Gore was not, in fact, the first to come up with the expression carbon summer. It turned up in a June 29, 1988 hearing held by the U.S. House Committee on Science, Space, and Technology on “Technologies for Remediating Global Warming.” During the hearing, Dr. Erik Storm of the Lawrence Livermore National Laboratory made the exact same parallel to nuclear winter: “I think that the discussion and possibility of a nuclear winter truly raised the concern of the effects of nuclear war to a global concern. I personally believe that that was a significant factor in the discussion that has led to the first real nuclear arms reduction.” Dr. Storm continued, “I’d like to hope that the prospect and discussion of what one might call ‘carbon summer’ will also stimulate action, action on a very broad international level.”

There was evidently not much media attention paid to the testimony of Dr. Storm (quite an appropriate name for a climate change expert, by the way). Gore’s high-profile speech in Oslo, on the other hand, has a vastly greater chance of popularizing carbon summer as an environmental buzzword. By now we’re much more used to hearing carbon used in various combining forms related to the emission of greenhouse gases. In his Nobel speech, Gore used carbon in two other such contexts. First, he suggested that “the innovators who will … invent an engine that’s carbon-negative may live in Lagos or Mumbai or Montevideo.” Carbon-negative goes carbon-neutral one better, implying that a fuel source can “sequester” more carbon dioxide than it releases into the atmosphere (for instance, with biofuels that transfer carbon dioxide back into the soil). Later in the speech, Gore stressed that “we need to put a price on carbon – with a CO2 tax that is then rebated back to the people, progressively.” Here carbon is understood as shorthand for the pollution of the atmosphere with carbon dioxide, which could be curtailed by the implementation of a tax on major polluters.

Regardless of whether one agrees with Gore’s stance on climate change and how to ameliorate it, it’s clear that carbon “really has taken on a new meaning,” as Shorter Oxford English Dictionary editor Angus Stevenson recently told The Guardian. Gore might be a trendsetter in this semantic expansion, but it will take the rest of us carbon-based life forms to set the path for the future of carbon.

ben.jpgBen Zimmer is an editor at Oxford University Press and a true word junkie. Once a week he surfaces from his dictionaries to write this column. Check out his “words of the week” on our main page (center column) or by clicking here

Recent Comments

  1. Nelson Fincher

    You wrote, “…nuclear winter remained a potent image throughout the US-Soviet standoff of the 1980s.”

    Would the impact(if not the sense itself) of the phrase “US-Soviet standoff” be affected in any way if it were reversed (“Soviet-US standoff”)?

  2. Michael Ejercito

    Could not a nuclear winter be used to offset a carbon summer?

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