Geological Investigations of the Neogene explores past warmer-than-modern climates of the mid-Miocene (about 14-17 million years ago) and Piacenzian (about 3 million years ago) to assess the potential environmental and economic impacts to population centers along the US Atlantic coast under different rates and magnitudes of changes related to warmer temperatures. Specifically, we look at past changes and rates of change in sea level, precipitation, ocean acidification, and storm activity and use climate, ecological, and coastal process modeling as guides to help determine how our infrastructure, fishing, shipping, agriculture, and tourism industries might be affected by modern warming. Rapid changes of the past provide valuable examples of ecological and shoreline behavior for coastal communities as they plan for the impacts of modern sea surface warming on coastal economies.