People keep citing water/energy use to me and I remain unconvinced. The single best thing you can do for the planet is to have one less kid. A distant #2 and #3 are avoiding cars and flights: https://iopscience.iop.org/article/10.1088/1748-9326/aa7541
A recent estimate says using Claude Code is similar to running a dishwasher: https://simonwillison.net/2026/Jan/20/electricity-use-of-ai-coding-agents/
If you are a vegan monk who never drives and also hates LLMs, good for you: you have my respect and admiration. But I don't think this is what's motivating most people's arguments.