Tech optimists' crush of the decade is surely 3D printing. It has been heralded as disruptive, democratizing, and revolutionary for its non-discriminatory ability to make almost anything: dresses, guns, even houses. The process—also known as "additive manufacturing"—is still expensive and slow, confined to boutique objets d'art or lab-driven medical prototyping. But scaled up, and put in the hands of ordinary consumers via plummeting prices, 3D printing has the potential to slash energy and material costs. Climate Desk asks: can 3D printing be deployed in the ongoing battle against climate change?