People experience heritage at historic sites as landscapes that include both environmental and cultural meaning. Heritage as social action overcomes the dichotomies of nature versus culture and past versus present, which are obstacles to resiliency and sustainability in this era of rising sea levels. That insight is exemplified by a program addressing climate change on the Florida Gulf Coast. The program includes community conversations on climate change and initial steps at multiscalar research using techniques from archaeology, environmental studies, and biology. At the broadest scales, the approach reconstructs the distribution of coastal heritage locations from the decades preceding human-caused sea-level rise to the present. At finer levels of temporal and spatial resolution, research documents vegetation, marine invertebrates, and material changes. At the finest scales, studies of microorganisms that inhabit historic and archaeological sites are inventoried. Integrating those scales through community-based archaeology offers the social meanings for coastal heritage under threat of rising sea levels, both to motivate actions to preserve the past and to prepare the public for the coming landscape transformations as an avenue for community conversations.