Hudreds of protesters blocked for many hours entrance to a sea port terminal in Seattle where Shell loaded up a drilling rig.

The rig is due to head to the waters off Alaska this summer after the company received the green light to drill in the Arctic Ocean. Protesters, however, warn of a potential environmental catastrophe.

The region is thought to contain 30 percent of the world's undiscovered natural gas reserves and around 13 percent of the world's undiscovered oil.

Why is Arctic drilling so controversial? Would it really harm the environment?

Presenter: Mike Hanna

Guests:

Rod Downie - manager of polar programmes at the World Wide Fund for Nature. 

Jessica Shadian - a specialist and author on Arctic governance.

Manouchehr Takin - an independent oil and energy consultant.

Source: Al Jazeera