It’s been a hot minute since I checked in on the W3C’s web sustainability work. I briefly joined the working group before other events interfered with my professional life. Given that big tech has thrown their sustainability goals out the window, I want to do what little I can in my little corner of the internet. So I went back down the sustainability rabbit hole to see if I can estimate what this website emits and how I can make improvements.
I got to a place where I could calculate this site’s emissions at an average of 0.11g CO2e per page. But that doesn’t tell the whole story, because my photo galleries pages are a lot heavier (more and bigger images). The pages under /photography are 0.15g CO2e on average, but the “heaviest” is 1.454g CO2e.
So, I want to go through how do we get to those numbers, because there are a couple different sites to check that don’t tell you a whole lot. I also want to how to reason about them, how to make sense across a site and particular pages.
What’s in a number?
W3C’s Sustainable Web Interest Group has a description of the version 4 methodology for calculating the average emissions per page view.
Very briefly, they’re using known values for operating energy consumption for data centers, network, and user devices, and deriving energy consumption from the production of the data centers, network, and user device hardware as a portion of global hardware manufacturing. Those numbers for (operational and “embodied” energy consumption) are then amortized across the total data transferred across the internet, and converted to emissions using a “grid intensity” factor.
The data for operational energy consumption comes from 2022 for data centers and networks (IEA 2022) and 2023 for user devices 2020 (Malmodin 2023). The data for embodied energy consumption comes from 2020 (Andrae 2020). Total data transfer across the internet is as of 2022 (ITU 2024). Grid intensity comes from 2022 (Ember 2022).
If these dates for those values made you go “Wait!” in this 2026, give me a minute, I’ll get there.
Generally, this is pretty tidy — it’s hard extrapolate a useful measurement from, for example, me vising a website on my phone when I charged on a sunny day (with a mostly solar energy mix). By taking top-line numbers for operation and production energy and grid emissions, and then amortizing them over total internet data transfer, you get a relatively straight-forward estimate.
Or you would have in 2022 or so.
The dates matter
All of those top-line numbers would be… highly complicated by the generative “AI” bubble.
You might arrive here from a search page that automatically generated an LLM response whether you wanted or needed one. You might be using a browser that’s downloading gigabytes to your device without your consent or knowledge. You might even not have arrived here directly at all, you may have asked a chatbot a question and it navigated here and scraped the content on its own in the process of answering.
The Data center power consumption story is even more complex. While we can choose green data centers and/or hosting providers, we can’t separate whether their consumption is going to serve data to humans, to chatbot in response to a human, or to an AI crawler adding the data to training data. And we’d need top-line consumption numbers that separate out those green providers’ data centers with data centers that are outrageous (in some cases illegally) dirty.
Thinking about traffic, the total data transferred across the internet has both soared and been taken over by AI (Cloudflare said 57.4% of all web traffic back in June).
But it doesn’t stop there! We don’t just accept that all this traffic, climate cost, and consumption of websites is worthwhile. Defenses against the generative AI crawling, scraping, exist, and have their own climate costs. Cloudflare’s Labyrinth, for example, adds links that are intended to send generative AI crawlers through an endless maze of links to stop them from scraping or crawling a website that doesn’t want to be.
The data that’s starting to emerge backs all of this up, with generative AI projected to increase CO2 emissions by up to ~5% of 2024 global energy emissions, and drive an increase in the carbon intensity of everything they touch. There are some attempts to come to grips with this impact, such as Watershed’s AI emissions framework, trying to understand and measure generative AI emissions. This work could lead to a place where we can start untangling all of this.
Wow, that’s bleak
If this feels bleak, it is, and it’s where the tech industry’s relentless push for something that people generally don’t seem to want.
I have a lot of thoughts about generative AI that don’t fit neatly into this particular essay, which was inspired by the question “how sustainable is my website?” You probably have a sense of what those are (though maybe not to strength of that feeling).
My website is for humans, by a human. I don’t expect it to be used by machines, and I do what I can to make that difficult. I am, by nature of serving public content on the internet and being a human who uses technologies that have (somewhere in their supply chain) use or enable use of generative AI, implicated.
A digression into theory
A quick detour into theory, because I am using the word “implicated” specifically to refer to the concept of an implicated subject from Michael Rothberg. To be an implicated subject is to inhabit or benefit from systems of harm that we do not directly control or contribute to, and may even be harmed by them ourselves, while being implicated by them in the harm of others. But implication is not individual culpability, we are responsible for our own actions, even if those actions are constrained by the systems of harm.
So how do we act? Donna Haraway implores us to “stay with the trouble”, recognize that our responsibility is also response-ability (a capacity to respond), and that it is a continuous, collaborative making-with rather than making-for, with the kin we find occupying the same space, in different positions of implication. To paraphrase Joel Olson, we bring our biography, abilities, and commitments, to those of others staying with the same “trouble”.
And we’re back
That’s all the theory for now. I genuinely value sustainability, as do others within the web sustainability and small web movements. This makes us kin with, among others, those fighting pollution from AI data centers. What I can do is to ensure that my public presence on the internet is as sustainable as possible.
For my little site, the values as gram of CO2e has been useful as a relative value and to discover what I can reasonably target for optimization. I doubt the realism of the absolute numbers in 2026, but I do know that going from an average of 0.70g CO2e to 0.11g is a meaningful difference.