Underground Climate Change: Threat and Opportunity Below Cities is an exploration of one of the most overlooked consequences of urbanization: the progressive and persistent warming of the subsurface beneath cities. Drawing on years of field observations, laboratory investigations, and large-scale numerical simulations conducted across emblematic urban centers, the book offers an accessible yet scientifically rigorous journey into how anthropogenic heat released from building basements, underground parking garages, tunnels, and other subterranean transportation systems, buried utilities, and heated ground surfaces accumulates beneath cities. In doing so, it reveals the profound implications of underground warming for infrastructure performance, public comfort, environmental health, and the energy dynamics of cities.The book brings together insights from architecture, history, the arts, civil engineering, environmental science, building science, urban planning, and energy research, advancing a vision of the underground as an active, evolving, and strategic component of the urban environment rather than a passive and inert supporting medium. At the same time, it reframes underground climate change not only as a hidden threat, but also as an opportunity to rethink how cities manage, store, and recover energy from the subsurface.Combining scientific insight, real-world case studies, and a compelling public-facing narrative, the book seeks to raise awareness among researchers, practitioners, policymakers, designers, and the broader public about a critical phenomenon that has remained out of sight and out of mind for far too long, while simultaneously highlighting its potential to foster more sustainable, resilient, and energy-conscious urban futures.