"Local governments are on the front lines of climate change-related impacts to local economies, human health, natural resources and built infrastructure," said Michael Burger, author of the brief and executive director of a climate center at Columbia Law School in New York.
The "Clean Power" plan is being challenged by two dozen states and several conservative organizations, which argue that the Environmental Protection Agency overstepped its legal authority in mandating reductions in carbon emissions from existing power plants.
The cities' motion contends that urban residents across the country are threatened by severe impacts of climate change, such as heat-related deaths, longer droughts, storms and coastal flooding and erosion.
Mayor Stephanie Rawlings-Blake said through a spokesman that cities have joined in the legal dispute because they have much at stake. As current head of the Conference of Mayors, Rawlings-Blake attended the global climate talks in Paris earlier this month.
"America's mayors have called on the nations of the world to act on climate change for over a decade, recognizing the threat that climate changes presents to our safety and security, regardless of where we live," she said.