sea conservation and oil exploration. >> reporter: wooly socks. check. emergency radio. check. robotic arm, check. we're about to enter the frigid waters of the chukchie off the coast of alaska. it's one of the most remote places on earth. but these days, it's also a battleground. >> there you go. >> all right. >> reporter: under this sea there's thought to be nearly 30 billion barrels of oil. >> this is amazing already. >> reporter: and just a few miles from us, shell is gearing up to start drilling. they hope to strike it rich. and greenpeace hopes to stop them. it is a dangerous mission. just me and greenpeace marine biologist john hocevar. at about 200 feet down, the world outside our sub is teeming with life. looks like a crab. plankton, krill, a seabed blanketed with starfish. the whole floor is covered by them. and creatures scene from another world. whoa. it's huge. >> that's the biggest i've ever seen. >> reporter: but hocevar says drilling could spell catastrophe for this fragile ecosystem that sustains life up the food chain. >> you would be talking about millions and millions of dead organisms. >> reporter: the payoff stands to be enormou

those people out there are drilling down 1,500 feet into the sea floor of the chukchi sea.t's what shell has achieved so far this year. they need to drill down 8,000 feet in order to get into hydrocarbon zone. that's not going to happen this year because of major setbacks. the biggest set back, the arctic challenger, the clean-up barge shell wanted to use in order to be on hand here in case of a spill. they had problems with that, they couldn't get it qualified to come up here. and then they had ice flows come in when they did start work, and it slowed everything down. basically, this is a $5 billion dress rehearsal, but shell says next year they'll be able to find this exact hole where these individuals are doing this year and continue that work. and next year they say they won't be exploratory wells. they'll be drilling for oil. erin? >> and miguel, green peace, obviously, along with other environmental groups, say this could be terrible. that if there were to be a leak, it could be much, much worse than the deep water because of the ice. do they have a point? >> reporter