Datacenter expansion under generative AI is increasingly framed as compatible with sustainability because of efficiency gains, cleaner electricity procurement, and improved facility design. Yet these claims often do not show that absolute electricity, water, material, waste, and community-facing burdens are falling. This Perspective addresses that evidentiary gap. Rather than asking whether efficiency gains are real, we ask when such gains are being enlarged into claims of system-wide sustainability to justify continued expansion. We develop a rebound-informed diagnostic framework for evaluating AI and datacenter sustainability narratives across five tests: metric, boundary, reinvestment, burden shifting, and governance. Applied to major AI industry sustainability reporting, the framework shows that firms largely justify continued expansion through efficiency improvements and clean-energy procurement, rather than by demonstrating reductions in absolute resource use. Applied to plateau claims in the literature, we show that many claims establish local or relative improvements while leaving energy rebound, lifecycle burdens, and enforceable limits unresolved. We argue that these sustainable-growth narratives begin to function as greenwashing when they use efficiency improvements to claim sustainability even as absolute energy, water, material, and public health burdens continue to increase. We conclude by positioning digital sufficiency as a burden-of-proof framework for governance: those advocating further datacenter expansion must show that it reduces, rather than merely redistributes or defers, absolute burdens across the full system.

翻译：生成式AI驱动下的数据中心扩张，日益被描绘为可持续的，其理由在于效率提升、更清洁的电力采购以及设施设计的改进。然而，这些声明往往未能证明绝对的电、水、材料、废弃物及面向社区的环境负担正在下降。本《视角》文章旨在填补这一证据空白。我们不问效率提升是否真实，而是追问何时这些提升会被放大为全系统可持续性的主张，用以合理化持续扩张。我们构建了一个基于反弹效应的诊断框架，通过五项检验（度量、边界、再投资、负担转移和治理）来评估AI和数据中心可持续性叙事。将该框架应用于主流AI产业可持续性报告后发现，企业主要是通过效率改进和清洁能源采购来合理化持续扩张，而非通过展示绝对资源使用量的减少。将该框架应用于文献中的“平台期”论断则表明，许多论断确立了局部或相对改善，却未能解决能源反弹效应、生命周期负担以及可执行的限制问题。我们认为，当效率提升被用于宣称“可持续性”，而绝对能源、水、材料和公共健康负担仍在增加时，这些可持续增长叙事便开始发挥“漂绿”的作用。最后，我们将“数字充分性”定位为一种治理层面的举证责任框架：任何主张进一步扩建数据中心的人，都必须证明此举能够减少（而非仅仅转移或推迟）整个系统中的绝对负担。