Four Greenpeace volunteers have occupied a second oil exploration rig in Cromarty Firth, Scotland, as part of a campaign to stop dangerous climate change and protect marine life in the north east Atlantic. The occupation comes just days after two Greenpeace climbers occupied the Jack Bates exploration rig in the same area. Both rigs are due to begin drilling operations in the deep waters west of the Hebrides (the so called "Atlantic Frontier") which is Europe's most important habitat for whales and coral reefs.