I am looking to calculate the CO2 emission of an average male human while arguing/debating.

It is my understanding that the amount of CO2 emitted will be based on the respiratory rate of any given human over a period of time. According to this seemingly well-researched post an average adult human is estimated to produce between 700 and 900g of CO2 per day based on food intake (former estimate) and breaths per day at 16 breaths per minute (latter estimate).

This is a helpful start, but in my case I am interested in humans actively debating/conversing, would conversing result in more breaths per minute and added exertion and CO2 emission, or would it be negligible?

Is this even measurable?


I think you've misunderstood the CO2 issue. The problem with greenhouse gases, the way in which they present a threat to the very existence of human civilisations, is because we are adding C/CO2 to the carbon cycle.

Growing food, eating food, metabolising food, exhaling CO2, is wholly within the carbon cycle: that is, it does not in itself add extra C/CO2 to the cycle. Some food production does add C/CO2 to the carbon cycle: fossil-fuel uses in the food supply chain, or greenhouse gas emissions from land-use changes or from livestock.

Furthermore, not only is CO2 exhaled by living creatures irrelevant to the greenhouse gas problem, but you also may have misunderstood human metabolism. Conversing uses negligible additional amounts of energy relative to standing there saying nothing, so the additional exhalation of CO2 is miniscule.

  • I'd argue that growing food is not completely within the carbon cycle, depending on the type of food you're talking about. Especially meat adds not only CO2 but also methane to the atmosphere, increasing the amount of CO2-equivalents. – Erik Dec 6 '18 at 9:24

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