A critique of a recent research paper wherein the authors argue that AI generated content is more environmentally friendly than human writing or art
When I began teaching organic chemistry, I watched whatever open course lectures I could find for guidance and inspiration. The lecture series that had the most profound effect on my approach to science education was Professor McBride’s Freshman Organic Chemistry series from Yale’s open courses. The thing that stuck with me the most from the lectures was his suggestion that when thinking scientifically, one’s first question should be ‘How do you know?”, and the second should be “Compared to what?”
“Compared to what?” is the question that came to mind when I recently stumbled across a study that claims that generating writing and images using artificial intelligence is hundreds to thousands of times more carbon efficient than having a human write or paint the same amount of content. The article, titled The carbon emissions of writing and illustrating are lower for AI than for humans1, offers a comparative analysis of the carbon emissions created by popular AI systems such as Midjourney or ChatGPT versus the carbon cost of a human doing the same task. They factor in things like the cost of training the AI (a one-time event) and then find the carbon cost per page of text or image. And this is compared to the averaged yearly carbon footprint of a human divided by the time it would typically take a human author or artist to produce a similar result (one hour per page of writing, for example). A human, just by existing in society, produces somewhere between roughly 100 to 1000 times more carbon dioxide in an hour than ChatGPT produces in the short time it takes to generate a page. Therefore, having AI do the writing is 100 to 1000 times more energy efficient than doing it ourselves.
It was at this point that I realized that I could dismiss this paper’s conclusion out of hand. Not because I found any flaw in how they got their numbers, but because their conclusion contains an implication that renders it absurd. Let’s assume that they are correctly accounting for all the energy costs of AI generation versus the average carbon cost of a living person. Their conclusion, that “AI has a substantially lower carbon footprint than humans engaged in the same task” is then technically true, but what is it supposed to demonstrate? The fatal flaw in their reasoning is that they are comparing the very existence of the human writer to the operational cost of the AI as if the former will go away if we choose the latter.
There are several obvious problems with this framing. First of all, AI doesn’t prompt itself, so a human’s carbon footprint ought to be involved in the generation as well. The authors, to their credit, recognized and even calculated an estimate of the carbon produced simply due to human prompt writing, but they conspicuously failed to add this to the cost of AI generation. Had they done so, AI generation would have still been more efficient, but an order of magnitude less so (roughly 10 to 100 times more efficient rather than 100 to 1000 times more efficient). Putting this aside, however, the claim that it is more efficient to have writing or art produced by AI than by a human creator falls apart when we consider what efficiency means.
The Oxford dictionary defines efficient as: “(especially of a system or machine) achieving maximum productivity with minimum wasted [emphasis added] effort or expense.” Other definitions similarly focus on the avoidance of waste as central to the definition of efficiency. The authors explicitly argue that their results imply that AI generation is more efficient than human creative work when they argue: “In sum, due to its substantially lower impact than humans at at least two important tasks, AI can play an important role in various sectors of society without, at present, running afoul of problematic carbon emissions. While the carbon footprint of AI is nontrivial, the footprint of humans doing the same work is far greater, and should not be discounted in the assessment of AI.”
This is the crux of it. If we are comparing two modes of production and deciding which is more efficient, the comparison only makes sense if we have a choice of one or the other, not both. That’s the way you avoid waste. But the waste we would need to avoidfor AI to be more efficient isn’t extra human labor, it’s an extra human, existing! If the people are still alive and doing other things, they are going to be producing more or less the exact same amount of carbon dioxide. Therefore, the carbon footprint of AI, as modest as it may be compared to that of human beings, is still an additional cost. Presumably the authors are not suggesting that human writers and artists are to be terminated to make way for the machines. So all of their research and analysis results in a moot point (don’t worry, though, the authors disclose that they used AI to help them write the paper, so hopefully not too much of their labor was wasted).
Another way to illustrate the central fallacy here is to point out that, in a effort to show the full range of the carbon cost of human labor, the authors used both the calculated carbon footprints of a person from the US and India to show a range of per capita carbon impact, from high to low, respectively. ChatGPT is calculated to be 130 times more carbon efficient at writing than a resident of India, and 1100 times more efficient than a US based writer. But this shows the absurdity of using carbon footprints for comparison. People in the US have a higher average carbon footprint than people in India for reasons that have nothing at all to do with the work of writing or illustration. Imagine for a moment that all writers in the US gave up their trade and all of the professional writing was outsourced to India. Assuming the former writers go on living (and making a living), it would be foolish to expect this reshuffling alone to reduce carbon emissions, let alone by a factor of ten. Our carbon footprint is higher in the US because we drive and fly more and consume more electricity as a country. And now our AI data centers have pushed it even higher.
This paper is a classic case of flying too close to the sun, because the data they present does support some less dramatic claims (again, I’m assuming their numbers are sound for the sake of argument, as this is not my field of expertise). For instance, they compared the carbon generated by a laptop or desktop computer for the hour it would take a human writer to produce a page of writing and found that AI uses significantly less energy, mostly due to producing the content faster. This is a real potential efficiency gain, though much more modest in its magnitude than AI versus a living US resident. But for the efficiency gain to be realized, the prompter would need to shut down their computer immediately after prompting and go touch grass or something for an hour. Unfortunately, the premise of AI is that it will make us all more productive, which will often mean that the hour freed up from writing will just be used to prompt even more, compounding productivity. Or just as likely, the human writer will spend the liberated hour aimlessly scrolling social media.
The authors make no effort to hide their pro AI bias, and they advocate for AI adoption throughout the paper. In fact, they present their paper, which they disclose was written in the first draft by AI, as a piece of praxis. Should their conclusion hold, after all, using AI to write one’s research manuscripts instead of writing it oneself is another way to go green. It almost becomes a moral imperative (“Oh, you still write yourself? Guess someone doesn’t care about the climate.”) But their conclusion does not hold. The authors, as people living in society, produced the same carbon footprint they would have produced without AI. No carbon waste was avoided there. And they may have saved some computer usage by drafting the manuscript with AI, but by their own admission they edited and revised the manuscript quite extensively. Presumably on their computers. And I humbly suggest that if they had taken the hours saved by AI and used them to think this whole thing through a little more, they might have retooled their argument before putting it out into the world. But by giving the pro AI crowd a peer reviewed research paper to bandy around as a faulty argument against the environmental concerns around AI, they caused many people like me to dedicate considerable kilowatt-hours to pointing out the glaring error in their reasoning. Unintended consequences are the order of the day in the AI age.
(Like everything on this blog, this article was written entirely without the use of AI. Any flaws in the reasoning are attributable to me alone.)
- Tomlinson, B., Black, R.W., Patterson, D.J. et al. The carbon emissions of writing and illustrating are lower for AI than for humans. Sci Rep 14, 3732 (2024). https://doi.org/10.1038/s41598-024-54271-x











