From ghostly voices on the ice to a moment when a handful of chocolate may have saved the expedition, last Thursday the three explorers with the Catlin Arctic Survey talked openly about their 73 days spent dragging sleds 434km across the sea ice towards the North Pole.

They were speaking at an event held to thank sponsors, including the Green Guardian project, at the team's operations centre in London.

Explorers Pen Hadow, Martin Hartley and Ann Daniels revealed that the failure of key equipment drove them all to the point of exhaustion in the early weeks.

The conditions when they arrived were so extreme that the team’s SPRITE, a pioneering radar to measure ice thickness, and a high tech onboard sledge computer were both disabled.

Both pieces of equipment had been tested down to -45oC but not to the -55oC they faced for the first few weeks.

At that time, it was so cold a cup of hot coffee thrown into the air would crystallize before it hit the ground.

A fault, not previously detected, also prevented initial use of a SeaCat probe which measures the water column beneath the floating sea ice.

An unperturbed Mr Hadow said at the time: “It’s never wise to imagine that either man or technology has the upper hand in the natural world.”

However, he insisted on Thursday that the failed equipment was not the pioneering technology being referred to in media reports.

“It wasn’t perfect but it was really good, in my humble opinion,” joked the expedition leader.

Despite the horrendous conditions, the equipment failures and photographer Martin Hartley getting frosbite, the team persevered and took 1,500 pains-taking ice drill measurements and 16,000 scientific observations, gathering unique data on the sea ice and pioneering a new way of judging ice thickness based on the depth of snow covering the ice sheet.

The average ice thickness in the region was found to be 1.774m, much thinner than expected.

Mr Hadow suggested this might be because the the ice is now melting both from the warmer air above and a warmer sea below.

The results have been submitted for archiving on the Polar Data Catalogue of Canadian Cryospheric Information Network, a database used by climate researchers that will feed into the vital United Nations Climate Change Conference in December.

“There was less volume of ice floating on the Arctic Ocean than expected, which may impact on how long we have ice cover up there,” said Mr Hadow.

“Scientists assumed the older, thicker ice would cover a larger area than it did.”

Peter Wadhams, head of the polar ocean physics group at the University of Cambridge, said the survey showed sea ice is now so thin almost all of it will disappear in the summer within a decade.

Ms Daniels, lead navigator on the expedition, said the results were crucial to secure its future for generations to come.

“This is for our children and children’s children. Who knows, it could one day disappear,” she said.

”I did this because I believe in the environment and about what we do in the world. I live this life.”

As a mother of four, it was hard leaving her family, although not the first time as she first went to the Arctic Ocean in 1997 and in 2000 she first trekked to the North Pole.

In 2002 she was one of two women to reach the North Pole and in 2005 she set off there again on a solo trek.

Describing the bond that has grown between the survey team, Ms Daniels said: "They are like my family, I miss them when they’re not here. Even if I didn’t see Pen for six months he’d still be very close to my heart.

“You get to know each other so intimately, it’s not something you can explain.”

To bankroll the expedition the team needed to raise about £2.2m, which they managed through a lot of good will, grants and dedicated fundraising, despite the challenging economic situation.

The interest in the expedition was phenomenal and the media coverage they received in dozens of countries round the world would have cost an estimated £25m if they paid for it.

Mr Hadow was not surprised and said: “It’s going to affect almost everybody, whether you are north, south, east or west of the globe.

“I believe the role of modern exploration is alive and well, you need to get down on your hands and knees and learn about it (the planet).

“We need to understand how it all works so we can manage our relationship with the natural system.

“We haven’t just found the information, we are actually going to ram it down the throats of the people that need to know, in the nicest possible way of course.”

Their motivation was clear throughout but the cold, frostbite, lack of clean clothes, delayed re-supplies and missing family made life on the ice incredibly tough.

Ms Daniels admitted to finding it “horrendous” at first as she fought for survival and she revealed strange experiences on the ice when she heard voices, like ghosts in the Arctic.

“For me it was like a playground and I could hear children’s voices,” she said. “When you listen to nature growling and grinding around you, you realise how insignificant you are.”

What spurred her on was a little encouraging word from her colleagues whenever she got so low that she forgot why she was there.

For photographer Mr Hartley it was always about getting the ice data each day but for Mr Hadow revealed it was the little gestures of support that kept him going.

On one key occasion in the early weeks, when he was exhausted after drilling for up to five hours at the end of a long day dragging a sled , Mr Hartley came up to him and said: “I thought you might want this.”

In his hand was the chocolate rations he had been saving for two days to give to Mr Hadow.

“He hadn’t been eating because he’d seen I needed some sort of lift,” said Mr Hadow. “It just spoke volumes. It’s takes huge human empathy and courage to make that sort of gesture. When someone does that in those circumstances it’s incredibly inspirational.”

The operations team now plan to get their heads together to see if they can come up with another expedition in a different eco-system, such as the rainforest.

There is even talk of trying to get somebody like BBC’s Tribe star Bruce Parry on board.

Until then, the focus will be on the results and the progress that can be made when they are presented at the United Nations Climate Change Conference in Copenhagen this December.

Howard Scott, managing director of Newsquest South London, decided the Green Guardian project should sponsor the expedition after hearing an inspirational speech by Mr Hadow at the South West London Green Guardian awards in November.

He said: “If you had a crowd of men and said ‘pick out the explorer’, you wouldn’t pick Pen because he is just a normal man doing something extraordinary.

“It will be interesting to see how the data and the work they have done are received. The education element of it is what sets it apart from other expeditions.

“Their work is vital and fundamental and I feel proud to be involved in it.”

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