President Obama announced Tuesday a permanent ban on offshore oil and gas drilling across wide swaths of the Arctic and the Atlantic Seaboard. Obama used an obscure 63-year-old law, in a move that incoming President Donald Trump may not be able to reverse. The announcement bans all future oil and gas leases for the Arctic’s Chukchi Sea, as well as the vast majority of the Beaufort Sea. Canadian Prime Minister Justin Trudeau also announced a ban on new offshore drilling in Canadian Arctic waters on Tuesday.