Special Session: Going Deeper: Underground Space as a Strategic Pathway to Urban Climate Resilience

As the climate crisis accelerates, cities are grappling with the urgent need to adapt. Rising temperatures, extreme weather events, and mounting pressure on surface infrastructure demand bold, innovative solutions-solutions that are spatially efficient, climate-resilient, and future-focused. Yet, a critical asset remains underutilized in most urban resilience strategies: underground space. This session, led by ITACUS (ITA-AITES Committee on Underground Space), repositions the underground not as an afterthought in urban design, but as a strategic lever for climate action and improved quality of life. Grounded in our global work and engagement with planners, policymakers, and engineers across continents, we argue that underground space holds transformative potential for shaping resilient, livable cities. Whether through integrated underground master planning, dual-use infrastructure, or multi-functional spaces that offer thermal comfort, stormwater buffering, and transit connectivity, going underground presents immense opportunities. But harnessing these opportunities requires a shift in mindset-from reactive excavation to proactive policy. Our presentation will outline a vision and policy roadmap for embedding underground space into urban climate strategies. It will highlight best practices and early adopters from different geographies, showcasing how underground solutions are being used to: Mitigate urban heat through thermally regulated underground public spaces. Reduce flood risk via underground stormwater detention and storage systems. Enhance mobility through interconnected subterranean transit networks. Reclaim surface land for green space, increasing urban biodiversity and wellbeing. We will also explore how underground strategies intersect with equity, affordability, and social inclusion-ensuring underground development does not deepen existing divides but serves as a tool for shared urban futures. Importantly, we will reflect on the policy vacuum that often surrounds underground development and propose actionable strategies that national and local governments can adopt. This includes frameworks for underground spatial planning, community engagement models, and institutional collaboration mechanisms that place underground space on equal footing with surface and aerial planning. With Riyadh itself exploring subterranean developments and sustainability goals, this session is timely. We invite city leaders, planners, and policy influencers to join us in a forward-looking dialogue that challenges conventional notions of "urban space" and expands the vocabulary of resilience planning. Our goal is not just to go deeper-but to go smarter, more sustainably, and more inclusively, beneath the surface of today's cities.

This session explores underground space as a visionary, policy-driven pathway to urban climate resilience. It presents a strategic roadmap for integrating subterranean solutions into urban planning and climate action-unlocking benefits for mobility, flood control, thermal comfort, and surface greening while promoting inclusive and sustainable development.