Nathan Phillips, a Boston University earth and environment professor working with HEET, argues that the shift away from fossil fuels has to reckon with its ecological costs, not just its carbon accounting. Drawn from MIT's IAP course on geothermal energy networks, this session looks at natural gas leaks in urban distribution systems as a land-climate interaction problem, tracing how leaking methane affects street trees, soil, and local ecosystems in cities like Boston. Phillips connects utility infrastructure decisions directly to measurable environmental harm, making the case that networked geothermal systems offer a way to retire leaky gas pipes rather than simply patch them. The talk is short and pointed, aimed at viewers already following the course's broader argument for geothermal district heating as an alternative to incremental gas-system repairs.