When the Forecast Changes, So Does the Argument
A government emissions estimate revised upward by a factor of 100 does not merely update a spreadsheet — it retroactively changes the basis on which policy was debated. The UK's 123 million metric ton projection for AI data center emissions through 2035 arrived in documents accompanying a Compute Roadmap, without a press conference or a formal correction notice. Campaigners who had been pressing ministers using the earlier figure now must restate every argument they made; the institutional record does not rewind with them. The practical consequence is that the UK's AI expansion plans are now being evaluated against an environmental cost that is structurally larger than anyone in the debate had been using. Regulators citing the old number are already wrong, and the companies that were comfortable being compared to it have lost that cover.