The action represents a partnership between the United States and Canada "to build a strong Arctic economy, preserve a healthy Arctic ecosystem and protect our fragile Arctic waters, including designating the bulk of our Arctic water and certain areas in the Atlantic Ocean as indefinitely off limits to future oil and gas leasing," the White House said. Environmental groups said Mr. Obama’s use of the law meant the incoming administration of Republican president-elect Donald Trump could not simply reverse the action but would have to fight it in the courts. The move came in a joint announcement by Mr. Obama and Canadian Prime Minister Justin Trudeau to launch “actions ensuring a strong, sustainable and viable Arctic economy and ecosystem.”

Mr. Obama said in a statement on Tuesday the joint actions “reflect the scientific assessment that, even with the high safety standards that both our countries have put in place, the risks of an oil spill in this region are significant and our ability to clean up from a spill in the region’s harsh conditions is limited.”

Canada will designate all Arctic Canadian waters as indefinitely off limits to future offshore Arctic oil and gas licensing, to be reviewed every five years through a climate and marine science-based life-cycle assessment. Obama used a 1953 law that allows presidents to block the sale of new offshore drilling and mining rights and makes it difficult for their successors to reverse the decision. The statute says that “the president of the United States may, from time to time, withdraw from disposition any of the unleased lands of the outer Continental Shelf.”

A permanent ban would mark the culmination of a slow reversal by Obama’s administration, which had been considering opening a broad area of the Atlantic Coast to drilling, but then backed away from that idea. He said the statute says a president can withdraw waters from the country’s leasing plans and “it doesn’t say you can put back in.”

If Trump does issue an order reversing Obama’s proclamation, it would be up to environmental groups or others to challenge his actions in court. The underwater canyons protected by the president cover nearly 4 million acres across the Atlantic continental shelf break, "running from Heezen Canyon offshore New England to Norfolk Canyon offshore the Chesapeake Bay," according to a separate fact sheet. “By contrast, it would take decades to fully develop the production infrastructure necessary for any large-scale oil and gas leasing production in the region – at a time when we need to continue to move decisively away from fossil fuels.”

In 2015, just 0.1% of US federal offshore crude production came from the Arctic.
U.S. President Barack Obama and Canadian Prime Minister Justin Trudeau jointly ban offshore oil drilling in the Arctic Ocean and parts of the Atlantic coast.