Three Greenpeace campaigners halted a British Petroleum oil rig off the coast of Scotland on Sunday as it prepared to leave for the North Sea to drill oil wells.

Carrying enough provisions to last several days aboard the rig, the climate action advocates pulled up to the 27,000-ton vessel in small boats as it attempted to leave Cromarty Firth, bound for the Vorlich oil field where BP plans to access up to 30 million barrels of oil.

The campaigners unfurled a banner reading “Climate Emergency” after climbing the rig.

Despite recent studies from the world’s top climate scientists warning that governments must transition to renewable energy sources and end their dependence on fossil fuels to stem the effects of the climate crisis, the U.K.’s Oil and Gas Authority last week awarded 37 license areas to 30 companies.