A new tracker from climate communications firm Climate Power ranks eight AI companies on data center emissions, finding that Amazon, Google, and Microsoft are forcing double-digit emissions increases, while Elon Musk’s xAI has the most potential to cause new pollution. The Data Center Air Pollution Tracker evaluates planned and operational data centers using grid pollution metrics from the Environmental Protection Agency, the United Nations, The Financial Times, and The Guardian. Companies were rated from 1 to 100 based on behind-the-meter natural gas generator use and local grid electricity mix, where a grid producing 200 pounds of carbon dioxide per megawatt-hour (CO2/MWh) was cleanest and 1,000 lbs. CO2/MWh the least clean. Amazon scored 68 (716 lbs. CO2/MWh), followed by Microsoft at 64 (757 lbs. CO2/MWh), Google and Meta at 61 (857 and 802 lbs. CO2/MWh respectively), Anthropic at 59, Open AI at 56, Oracle at 51, and xAI at 6. xAI’s Colossus data center in Memphis uses smog-producing gas turbines that are largely unregulated. Scores were current as of July 24.