Project POLARIS: The Arctic AI Infrastructure Initiative — A National Strategy for Energy-Secure, Water-Responsible, and Resilient Artificial Intelligence Infrastructure

America's AI build-out is running into three walls: electricity, cooling, and water. Data centers already use about 4 percent of U.S. electricity and could use up to 12 percent by 2028, and most new campuses are being built in water-stressed regions where evaporative cooling consumes millions of cubic meters of freshwater a year. Project POLARIS proposes building the next generation of AI campuses on cold northern coastlines, designed as integrated energy systems: small modular reactors and hydropower supply carbon-free electricity; the ocean's deep, cold water absorbs waste heat through sealed closed-loop heat exchangers, consuming no freshwater; and before reaching the ocean, that heat warms homes, greenhouses, and fish farms. Every component operates commercially today - deep-water district cooling in Toronto since 2004, fjord-cooled data centers in Norway, Arctic renewable data centers in Iceland, small modular reactors under construction in North America. The paper develops the reference architecture and thermal-electrical balances for a 500 MW campus, proposes a U.S.-Denmark-Greenland flagship demonstration aligned with the three governments' active 2026 economic discussions, and a domestic companion track under the U.S. Department of Energy's AI-infrastructure-on-federal-lands program. The recommended first step is a joint feasibility study and twelve months of oceanographic data at candidate sites.