AdvertisementNatural Environmental Swings Cause Up To Half Of Arctic Sea Ice LossMarch 14, 2017Christopher JoycefacebookEmailA U.S. Coast Guard crew retrieves a canister dropped by parachute in the Arctic in 2011. Over the past four decades, researchers at the University of California, Santa Barbara, and several other universities have studied shifts in atmospheric circulation above the Arctic. (NASA/Kathryn Hansen)