Six activists from the environmental group Greenpeace boarded a coal carrier bound for South Korea on the outskirts of Australia's Great Barrier Reef Wednesday calling for an end to exports of the fuel:

The Guardian reports:

The activists boarded the ship from inflatable boats at sunrise and had previously been on board the Rainbow Warrior, Greenpeace's own purpose-built ship. They presented a letter to the captain explaining the action and have set up camp at the bow of the ship.

A spokesman for Greenpeace on the Rainbow Warrior said: "We are calling on the rest of Australia to take whatever action is possible to ensure that we do not double our coal exports. We cannot deal with the climate change that will result from that."

According to research commissioned by Greenpeace, Australia's coal export expansion is the second-largest of 14 proposed fossil fuel enterprises. "We cannot pretend Australia is playing its part to avoid dangerous climate change if these shipments continue," said Greenpeace senior climate campaigner Dr. Georgina Woods.

"Australia's coal exports are the nation's greatest contribution to climate change and plans are under way to roughly double the volume of coal we export," Greenpeace said in a statement.

"Yet every tonne of coal that is exported will return to us as climate change: bushfires, heatwaves and drought."

Ports on the Barrier Reef coast currently export 156 million tons of coal each year, and there are plans to expand that to 953 tons within the next decade. By 2020 an estimated 7,000 ships will traverse the reef every year, up from 5,000 in 2010.

"We have no idea how it's going to play out at this stage," said protester Emma Giles from on board the Panama-flagged ship.

"Either the coastguard will come and get us, or we end up in Korea."