The Carbon Line Item Nobody Puts in the AI Feature Spec
Open any AI feature review and you will hear the same three numbers debated: latency, token cost, and accuracy. Someone pulls up the p95 chart, someone else does the math on cost-per-thousand-requests, and a third person argues the eval score is good enough to ship. Nobody mentions energy. Nobody mentions carbon. And because nobody mentions it, the environmental footprint of the feature still gets decided — implicitly, by whoever wins the argument about the dollar figure.
That is the quiet problem with AI sustainability. It is not that teams choose a high-carbon design on purpose. It is that they never choose at all. The footprint is a side effect of a cost decision, and cost only loosely tracks carbon. A routing rule that looks like a clean win on the spend dashboard can quietly double emissions, and no one in the room would know, because the number that would have told them was never on a dashboard.
This post treats energy and carbon as what they actually are: a measurable, ownable property of an AI system, on the same footing as latency and cost. Not a corporate-values footnote. A line item.
