The writer is global systems and policy manager at the Climate and Community Institute and research manager at Transition Security Project

In the summer, the Pentagon announced plans to purchase nearly 7,500 tonnes of cobalt, reviving stockpiling at a scale not seen since the cold war. Amid an influx of new funding authorised by the Trump administration’s One Big Beautiful Bill Act, the solicitation for cobalt is a part of a wider push by the military to expand its reserves of critical minerals.

Since July, the US defence department has pursued contracts to stockpile a growing list of critical minerals which it says are used to manufacture virtually every weapons system it deploys, from unmanned aerial vehicles and fighter jets to an emerging arsenal of military technologies such as AI-driven autonomous warfare platforms.