This chapter examines climate change. We have discovered that in the United States climate change has motivated many cities to create climate action plans, which has then led to crafting broader and more comprehensive sustainability plans. We consider how cities view the importance of climate change generally and discuss efforts at both climate mitigation and adaptation more specifically. We focus the chapter on adaptation efforts as these are less understood and studied. The chapter explores differences in how climate change is used as a rational or motivator for adaptation such as alternative stormwater management, urban greening, or public health initiatives. We first explore how cities are adapting the built environment. We then examine how cities are adapting natural systems to cope with such issues as the urban heat island, coastal erosion, and wildfires. Last we examine adaptation measures in human systems and human health by detailing efforts to deal with extreme heat.