Greenpeace activists Pierre Boutin, left, Frederic Bleau and Jean Philippe Leblanc at Camp 2 of Mount Logan earlier this month. (Greenpeace)

Three Quebec environmental activists have attempted to send world leaders a climate-change message from the top of Mount Logan, but the trio had to abort their plans due to safety concerns.

The three Greenpeace Canada activists had travelled to the Yukon's Kluane National Park and Reserve this month, hoping to unveil a large banner with the message 'G8/G20: Stop climate change' on the summit of Canada's tallest peak.

The expedition was timed to coincide with the G8 and G20 leaders' summits in Ontario this weekend. The G8 meeting begins Friday in Huntsville, Ont., followed by the G20 summit in Toronto.

"The idea was really to take that opportunity to send a message," Frederic Bleau, one of the activists and an experienced mountain climber, told CBC News on Wednesday.

Fell into crevasse

But after spending a week on the 5,959-metre Yukon mountain, complete with tough weather conditions, Bleau and fellow activists Pierre Boutin and Jean Philippe Leblanc had to turn back last week.

Bleau said Leblanc had fallen into a large crevasse that was covered in snow. Leblanc was pulled out of the crevasse unharmed, but he had lost his backpack, which included the group's camp stove.

"The expedition was finished at that point," Bleau said.

"The best thing to do when a situation like that happens is to go down as soon as you can."

Andrew Lawrence, a Parks Canada public safety specialist who spoke to the climbers by satellite phone before they turned back, said the crevasse was at an elevation of about 4,800 metres.

"It seems to be a bit of a common theme this year. There were a couple other groups that managed to tumble into a crevasse in the same area," Lawrence said.

"That can knock the steam out of a group, and they work their way down after that."

Helicopter delivered stove

A helicopter dropped off a new stove for the climbers, and they made it safely down the mountain from there, Bleau said.

Greenpeace Canada spokesman Alex Paterson said the trio did the right thing by turning back, but he acknowledged the irony of a helicopter coming to the aid of climate-change protesters.

"The reason we don't have alternatives though is because there is no political will," Paterson said.

"Leaders like the G8 and G20 leaders have not created the space for that low-carbon green economy and for new technologies to grow."

Paterson said Greenpeace will continue to try and draw attention to climate change as the G8 and G20 summits get underway.

Lawrence said a total of 49 people have tried to climb to the summit of Mount Logan so far this year, but only 15 have succeeded.