He decided to track down its source. That 5 to 10 percent number, Joshi found, was drawn from a paper published by Google and BCG, a consulting group, which in turn drew from a 2021 analysis by BCG, which simply cited the company’s “experience with clients” as a basis for estimating massive emissions reductions from AI—a source Joshi called “flimsy.” The analysis was published a year before the introduction of ChatGPT kicked off a race to build out the energy-intensive infrastructure that, tech companies claim, is needed to power the AI revolution.