It is home to a quarter of the planet's oil and natural gas reserves, yet humans have hardly touched these resources in the far north. But in a few days that could change dramatically if Shell receives approval to drill for oil in the Arctic. The company has invested $4bn to set up exploratory wells in the Chukchi Sea, north of the Bering Straits. Once permission is given by the US Bureau of Safety and Environmental Enforcement, - possibly in a few weeks - exploration will begin using wells in Arctic waters. And that will bring trouble. Environment campaigners say that drilling could have terrible effects on the waters and wildlife of the Arctic. "It took a vast effort to clean up the recent spill in the Gulf of Mexico," said John Sauven of Greenpeace. "There are no such resources to stop a spill in the Chukchi. The consequences could be devastating and very long lasting."