Microsoft and other US tech companies successfully lobbied the EU to hide the environmental toll of their datacentres, an investigation has found, with demands to block a database of green metrics from public view written almost word for word into EU rules.

The secrecy provision, which the European Commission added to its proposal almost verbatim after industry lobbying in 2024, hinders scrutiny of the pollution that individual datacentres emit. It leaves researchers with just national-level summaries of their energy footprints.

The rise of AI chatbots has spurred a boom in the construction of chip-filled warehouses with a hunger for power that is being met, in part, by burning fossil gas. Legal scholars warn the blanket confidentiality clause may fall foul of EU transparency rules and the Aarhus convention on public access to environmental information.

“In two decades, I cannot recall a comparable case,” said Prof Jerzy Jendrośka, who spent 19 years on the body overseeing the convention and teaches environmental law at the University of Opole in Poland. “This clearly seems not to be in line with the convention.”