Explained / What AI costs the planet

8 minute read

Is using AI bad for the environment?

The short answer

AI uses real electricity and real water, and demand is growing quickly. But most of the per-question figures circulating are unreliable, including the flattering ones and the alarming ones. The honest position is that the direction is clear, the individual numbers mostly are not, and your personal chatbot use is a very small part of it.

Two different costs, often muddled together

Training a model is a large, one-off expenditure of energy. It happens once, takes months, and is the figure usually quoted in headlines.

Answering your question is a tiny cost by comparison — but it happens billions of times a day. Over a model's life, serving it generally uses far more energy in total than training it did.

Water enters because data centres are cooled, and some cooling evaporates fresh water. How much depends enormously on the site, the local climate and the cooling design, which is exactly why single global figures are so unsatisfying.

BEEP / THE MYTH-BUSTER

I have seen my own energy use described as trivial and as catastrophic in the same week, both with a confident number attached. Somebody is wrong, and it might be everybody.

Why the numbers you have seen are shaky

Providers publish very little. Most public per-query figures are estimates built on assumptions about hardware, model size and utilisation that the estimator could not verify.

The variables are enormous. A short answer from a small model and a long answer from a large reasoning model can differ by orders of magnitude, so any single average hides more than it reveals.

Location matters as much as technology. The same query on a grid running on wind has a fraction of the carbon of one on a grid burning coal. A global average silently blends the two.

Comparisons to everyday things — a kettle, a mile driven, a web search — are almost always doing this blending, and usually in whichever direction supports the article.

What is actually known

Data centre electricity demand is rising, and AI is a significant part of that rise. That much is well established by energy agencies, and it is the part worth taking seriously.

It is also true that the growth is concentrated in a small number of very large operators, several of which buy substantial renewable capacity. Both of those facts are true at once, which is why the argument never resolves.

What does not hold up is the idea that an individual asking a chatbot a few questions a day is making a meaningful difference either way.

Where the impact actually sits

Large
Training frontier models; running them at global scale; building the data centres.
Moderate
Heavy automated use — agents, bulk processing, anything looping unattended.
Very small
One person asking questions, drafting and summarising during a normal day.

The shape of where the energy goes, not a measurement. Credible per-query figures are not publicly available.

What to actually do

  • Use a smaller model when a smaller model will do. This is the one lever with a real effect.
  • Do not run reasoning models or agents on jobs that do not need them.
  • Treat any confident per-question figure, in either direction, as an estimate with wide error bars.
  • Ask providers for disclosure. Individual restraint matters less than published numbers.

The honest summary

The direction of travel is real and worth watching. The individual guilt is largely misplaced, and the precise numbers are not currently knowable from outside the companies.

Anyone giving you a confident figure for the footprint of a single question is telling you more about their argument than about the world.

ORBIT / THE NAVIGATOR

This is the section where I would like to give you a tidy number and cannot. Nobody outside those companies can. That is the finding, not a failure to research it.

See it for yourself

Reading about it only gets you so far. This one is written to show you the thing described above, rather than describe it again.

Try asking

What actually uses the energy when I send you a message? Then tell me which parts of that answer are measured and which are estimates.

Then paste it into whichever assistant you use — ChatGPT, Claude, Gemini or Copilot. Not sure which? Meet them all.

If you remember nothing else

  • Training is a big one-off cost; serving answers is small but happens constantly.
  • Public per-query figures are estimates with very wide error bars.
  • Where the data centre is matters as much as what the model is.
  • Data centre demand is genuinely rising, and AI is a real part of that.
  • Choosing a smaller model is the one individual choice that measurably helps.

Where this came from

Anything here that turns out to be wrong is worth telling us about. Figures that move — prices, sizes, energy use — are kept in the registry with their dates, rather than written into the prose where they would quietly go stale.

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