States and cities have long been leaders on clean energy and climate policy. Their work has informed development of federal policies including motor vehicle standards and the Clean Power Plan. With the election of President Trump and the increasingly severe impacts of climate change, subnational leadership has become even more important and urgent. In response, many states and cities have pledged to enact new policies to mitigate the effects of climate change and help communities adapt. This Article focuses on recent developments in subnational leadership on both climate mitigation and adaptation to demonstrate the breadth and depth of engagement by leading states and cities. It provides just some examples that illustrate how, despite the Trump Administration’s best efforts to dismantle federal environmental policies, many states and cities are fighting federal rollbacks and moving forward with their own policies to address climate change, promote a clean energy economy, and prepare for the consequences of a changing climate. Taken together, these efforts are important in keeping the United States within reach of the Paris Agreement targets. However, broader participation and meaningful federal action will be necessary to meet international commitments and avoid the most catastrophic consequences of climate change
