Prime Minister Justin Trudeau says the federal government is going to ban offshore oil and gas licensing in Arctic waters – and says the ban will be reviewed every five years.

The joint announcement with the U.S. also sees President Obama designating the bulk of American owned waters in the Arctic ocean – and certain areas of the Atlantic – as indefinately off limits to future oil and gas leasing.

The U.S. move helps put some finishing touches on Obama’s environmental legacy – while testing President-elect Donald Trump’s promise to unleash America’s untapped energy reserves.