The next decade is critical for climate action. As sea levels rise, wildfires rage, and disasters increase in frequency and scale, it is clear that the U.S. must leverage an expanding menu of legal, policy, and technological tools to address climate change’s destabilizing effects. At present, we remain off-track to reduce our collective greenhouse gas (“GHG”) emissions and avoid irreversible, catastrophic harm. The emissions gap — the difference between the world’s current emissions trajectory and what we must emit to avoid climate change’s most severe consequences — continues to grow. Although President Biden and the 117th congressional leadership have pledged to combat the climate crisis, the Democrats’ narrow Senate majority will make passing comprehensive climate legislation difficult. In the face of likely legislative paralysis, a diverse group of activists, policymakers, and lawmakers have called on the president to declare climate change a national emergency. Is climate change, and its multifaceted impacts, an emergency that warrants using supplemental legal authorities? If so, what federal emergency authorities are available? And what are the normative stakes to democratic governance if a president declares a climate emergency? This Article addresses these questions and others, arguing that climate change is unlike any problem facing the nation and the world. As climate change destabilizes the physical environment, it will force us to look with fresh eyes at all the legal tools available to address climate mitigation, climate adaptation, and how we respond to climate impacts. As such, presidents must consider using all legal authorities, including the National Emergencies Act (“NEA”), to address climate change.