Former U.S. Vice President Al Gore, who recently criticized President Barack Obama's environmental policies, joined him at a campaign stop at Joe Louis Arena in Detroit, Michigan on June 16, 2008. REUTERS

Former vice president and activist Al Gore lambasted President Barack Obama's environmental policy Thursday, particularly the decision to allow exploratory wells to be drilled in the Arctic, which he said was “insane." Gore called for a ban of all oil and gas in the region.

Gore's remarks came days before Royal Dutch Shell plans to begin work drilling in the oil-rich Chukchi Sea in the Arctic under an Obama administration decision. The region is the last unchartered territory for oil production, with more than 20 percent of the world’s undiscovered, recoverable oil and gas. But Gore said there are too many risks that come with offshore drilling.

“I think Arctic drilling is insane," Gore told the Guardian. "I think that countries around the world would be very well advised to put restrictions on drilling for oil in the Arctic ocean."

In April 2010, a Deepwater Horizon oil rig explosion about 42 miles off the coast of Louisiana led to one of the most disastrous spills in history. More than 3.19 million barrels had leaked into the Gulf of Mexico by the time the BP oil rig was capped months later in July. The disaster is considered to be the largest accidental marine oil spill in the world and the largest environmental tragedy in U.S. history.

“I think the Deepwater Horizon spill was warning enough," Gore said. "The conditions are so hostile for human activity there. I think it’s a mistake to drill for oil in the Arctic. I think that ought to be banned."

Obama's environmental policy has been at the top of his agenda during his second term. Obama has released a new initiative every week on his vision since January, according to the Guardian.

“I think he is doing essentially a very good job, but on the fossil fuel side I would certainly be happier if he was not allowing so much activity like the Arctic drilling permit and the large amounts of coal extracted from public lands," Gore said.

Gore has long been an environmental advocate. He won an Oscar for his "An Inconvenient Truth" documentary about climate change.