Following the explosive growth in the use of coal for industrial processes, in which the UK from the late 1800s to the mid-1900s was memorably darkened with soot, the public became aware of "pollution". Black carbon, nitrides, sulfides, heavy metals, volatile organic compounds, chloro / fluorocarbons, pesticides, toxic waste, and spent nuclear fuel were on the list of industrial products that would become "pollution" if not handled properly... and it was quite often that they were not handled properly.

Now, the expression "carbon pollution" is being put into headlines by the Sierra Club, the Environmental Defense Fund, Harvard University, and even the Associated Press (via MarketWatch). None of these sources are talking about black carbon, hydrocarbons, or CFCs: "carbon pollution" means carbon dioxide.

Is it true that carbon dioxide is pollution?

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    Excess carbon dioxide is pollution. Some carbon dioxide is essential.
    – DavePhD
    Jan 22, 2019 at 15:56
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    This is off-topic as it boils down to deciding on the definition of a specific word, "pollution" in this case. This is not the type of question that works well here. Jan 22, 2019 at 16:54
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    @elliotsvensson Skeptics is about determining the validity of falsifiable claims, not deciding on definitions. Perhaps you could ask on ELU?
    – Tashus
    Jan 22, 2019 at 18:01
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    @elliotsvensson To explain it another way: so what? If you defined the word "pollution" narrowly to mean "soot," that would only affect language, not the impact of carbon dioxide on the environment. That's why this question is not appropriate here. Jan 22, 2019 at 21:33
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    @elliotsvensson it wasn't the same question. They were asked whether CO2 is a pollutant under the definition "The term “air pollutant” means any air pollution agent or combination of such agents, including any physical, chemical, biological, radioactive (including source material, special nuclear material, and byproduct material) substance or matter which is emitted into or otherwise enters the ambient air" law.cornell.edu/uscode/text/42/7602
    – DavePhD
    Jan 23, 2019 at 1:28

1 Answer 1


According to "The Modification of Planet Earth by Man," Gordon J. F. MacDonald, Technology Review, Oct/Nov. 1969, pp. 27-35 (official link):

There are at least six ways in which man's activities could perturb the atmospheric heat balance and thus the climate in a significant way. These are: 1. increasing the carbon dioxide content of the atmosphere by burning fossil fuels, 2. decreasing atmospheric transparency...

Of these, carbon dioxide pollution has long been recognized as potentially affecting worldwide climate.

Also, in the November 1967 US National Bureau of Standards 1967 fiscal year report it is stated at page 77:

... determine the amount of CO2 pollution in the atmosphere. For simultaneous data collection and monitoring of carbon dioxide pollution levels at widely separated geographic locations, samples must be taken continuously or at intervals over a long period of time and measurements of concentration..

So for at least 50 years, excess carbon dioxide in the atmosphere has been considered a form of pollution.

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