<p>Carbon-negative materials are increasingly central to credible net-zero strategies; however, their climate benefits depend on transparent life-cycle boundaries, realistic end-of-life scenarios and carbon storage. Bamboo is a fast-growing lignocellulosic resource that combines high biomass productivity with the ability to sequester atmospheric carbon in long-lived materials. Beyond its rapid growth, bamboo exhibits a hierarchical structure extending from molecular composition to cell-wall ultrastructure and tissue organization that influences transport, reactivity, mechanical performance and carbon retention. In this Review, we position bamboo as a multiscale materials platform in which chemical functionality, structural organization and processing pathways can be deliberately engineered to tailor performance and service lifetime. We examine how bond-selective chemistry, controlled hydration and structural modification strategies enable the conversion of bamboo into materials across multiple dimensional scales, including structural composites, functional laminates, fibre-based systems and nanoscale building blocks. We further discuss how process intensity, product durability and cascade utilization influence the extent to which these materials provide net climate benefits. By linking molecular design, hierarchical structure and life-cycle carbon accounting, we establish a framework connecting accessibility, reactivity and carbon permanence in bamboo-derived materials. Finally, we highlight the remaining challenges in structural control, durability and end-of-life design that will need to be overcome for bamboo materials to deliver meaningful climate benefits.</p>