China’s Belt and Road Initiative (BRI) is the largest infrastructure scheme in our lifetime, bringing unprecedented geopolitical and economic shifts far larger than previous rising powers. Concerns about its environmental impacts are legitimate and threaten to thwart China’s ambitions, especially since there is little precedent for analysing and planning for environmental impacts of massive infrastructure development at the scale of BRI. In this paper, we review infrastructure development under BRI to characterise the nature and types of environmental impacts and demonstrate how social, economic and political factors can shape these impacts. We first address the ambiguity around how BRI is defined. Then we describe our interdisciplinary framework for considering the nature of its environmental impacts, showing how impacts interact and aggregate across multiple spatiotemporal scales creating cumulative impacts. We also propose a typology of BRI infrastructure, and describe how economic and socio-political drivers influence BRI infrastructure and the nature of its environmental impacts. Increasingly, environmental policies associated with BRI are being designed and implemented, although there are concerns about how these will translate effectively into practice. Planning and addressing environmental issues associated with the BRI is immensely complex and multi-scaled. Understanding BRI and its environment impacts is the first step for China and countries along the routes to ensure the assumed positive socio-economic impacts associated with BRI are sustainable.

Urban flooding has become a serious issue in most Chinese cities due to rapid urbanization and extreme weather, as evidenced by severe events in Beijing (2012), Ningbo (2013), Guangzhou (2015), Wuhan (2016), Shenzhen (2019), and Chongqing (2020). The Chinese “Sponge City Program” (SCP), initiated in 2013 and adopted by 30 pilot cities, is developing solutions to manage urban flood risk, purify stormwater, and provide water storage opportunities for future usage. Emerging challenges to the continued implementation of Sponge Cities include (1) uncertainty regarding future hydrological conditions related to climate change projections, which complicates urban planning and designing infrastructure that will be fit for purpose over its intended operating life, and (2) the competing priorities of stakeholders and their reluctance to make trade-offs, which obstruct future investment in the SCP. Nature-Based Solutions (NBS) is an umbrella concept that emerged from Europe, which encourages the holistic idea of considering wider options that combine “Blue–Green” practices with traditional engineering to deliver “integrated systems of Blue–Green–Grey infrastructure”. NBS includes interventions making use of natural processes and ecosystem services for functional purposes, and this could help to improve current pilot SCP practices. This manuscript reviews the development of the SCP, focusing on its construction and design aspects, and discusses how approaches using NBS could be included in the SCP to tackle not only urban water challenges but also a wide range of social and environmental challenges, including human health, pollution (via nutrients, metals, sediments, plastics, etc.), flood risk, and biodiversity.