Arctic

A huge pack of floating ice along the northern Greenland coastline is breaking up and drifting apart into the Arctic Ocean — another consequence, scientists say, of global warming caused by the buildup of greenhouse gases in the atmosphere.

"We've never seen anything this large in terms of an opening north of Greenland," says polar scientist Ted Scambos of the National Snow and Ice Data Center, which collaborates with the National Oceanic and Atmospheric Administration.

A short drive north of Fairbanks, Alaska, there's a red shed stuck right up against a hillside. The shed looks unremarkable, except for the door. It looks like a door to a walk-in freezer, with thick insulation and a heavy latch. Whatever is behind that door needs to stay very cold.

"Are you ready to go inside?" asks Dr. Thomas Douglas, a geochemist at the U.S. Army Corps of Engineers.

The Arctic is a huge, icy cap on the planet that acts like a global air conditioner. But the air conditioner is breaking down, according to scientists who issued a grim "report card" on the Arctic on Tuesday.

They say the North Pole continues to warm at an alarming pace — twice the rate as the rest of the planet, on average. This year was the Arctic's second-warmest in at least 1,500 years, after 2016.

Sea ice in the Arctic has been melting at a record-breaking pace. Scientists blame a warming climate for most of that, but researchers have now teased out a natural cycle for how Arctic sea ice melts year-to-year.

Based on that cycle, they conclude that 30 percent to 50 percent of the melting is due to natural causes, while human-caused warming is responsible for the rest.

President Obama has indefinitely blocked offshore drilling in areas of the Atlantic Ocean and in Arctic waters, a move aimed at advancing environmental protection during his final days in office.

The Arctic protections are a joint partnership with Canada. "These actions, and Canada's parallel actions, protect a sensitive and unique ecosystem that is unlike any other region on earth," the White House said in a statement.