Declaring a Climate Change Emergency: A Citizen’s Guide, Part I

Based on press reports, it now seems likely that President Joe Biden will soon declare climate change to be a national emergency. Would this be legal? Would it unlock important powers that could be used to fight climate change? My answers are: It would probably be legal, and it would unlock some significant powers. But an emergency declaration is not a magic wand that gives presidents a blank check. It would allow some constructive steps to be taken, but within limits.