The Impact of Digital Infrastructure Development on Urban Green Economic Growth—A Quasi-Natural Experiment Based on the “Broadband China” Strategy

在中国经济快速发展背景下，伴随工业化和城镇化的加速，资源过度消耗与环境退化问题严重，亟需向绿色低碳发展模式转型以保障可持续发展。该研究旨在探讨“宽带中国”政策作为数字基础设施建设的国家试点，如何影响并促进城市绿色经济发展，并解析其作用机制。基于此，在技术创新效应与产业升级效应的理论框架下，该研究运用渐进双重差分模型，对2007~2020年中国285个地级市的面板数据进行实证分析，考察数字基础设施建设对城市绿色全要素生产率的影响。研究发现：第一，数字基础设施对城市绿色经济发展具有显著的促进作用；第二，其作用机制主要通过提升技术创新能力和推动产业升级两个核心路径实现；第三，受区域禀赋差异影响，数字基础设施的赋能效应呈现出显著的空间异质性特征。Against the backdrop of China’s rapid economic growth, the acceleration of industrialization and urbanization has led to severe issues of resource overconsumption and environmental degradation, necessitating a transition to a green, low-carbon development model to ensure sustainable development. This study aims to explore how the “Broadband China” policy, as a national pilot for digital infrastructure construction, influences and promotes urban green economic development, and to dissect its mechanisms of action. Based on this, within the theoretical framework of technological innovation effects and industrial upgrading effects, this research employs a progressive difference-in-differences model to empirically analyze panel data from 285 prefecture-level cities in China from 2007 to 2020, examining the impact of digital infrastructure construction on urban green total factor productivity. The findings reveal: first, digital infrastructure significantly promotes urban green economic development; second, its mechanism of action primarily operates through enhancing technological innovation capabilities and driving industrial upgrading; third, influenced by regional endowment differences, the empowering effect of digital infrastructure exhibits significant spatial heterogeneity characteristics.