0:00:07 > 0:00:10This is Antarctica,
0:00:10 > 0:00:15the last great wilderness.
0:00:15 > 0:00:23It's the coldest, windiest, driest and most isolated place on Earth,
0:00:23 > 0:00:27and it's home to the British Antarctic Survey's
0:00:27 > 0:00:29Halley Research Station.
0:00:29 > 0:00:33Here, cutting-edge science is making vital discoveries
0:00:33 > 0:00:38about how our lives are vulnerable to the sun's activities
0:00:38 > 0:00:41and threatened by man-made climate change.
0:00:43 > 0:00:49It's 27th of January, 2016, and we're at 75 degrees south.
0:00:49 > 0:00:52For the last couple of weeks, we've been on this ship behind me,
0:00:52 > 0:00:56the RRS Ernest Shackleton, crossing the Southern Ocean.
0:00:58 > 0:01:02We're making this journey to resupply the research station,
0:01:02 > 0:01:05but this is also something of a rescue mission.
0:01:07 > 0:01:11Although it appears to be on solid ground, Halley actually
0:01:11 > 0:01:17sits on a constantly-moving and cracking ice shelf -
0:01:17 > 0:01:20an ice shelf that's developed a chasm that threatens to
0:01:20 > 0:01:25cast the station adrift on a massive iceberg -
0:01:25 > 0:01:30and our cargo is part of the effort to stop that happening.
0:01:30 > 0:01:31I'm Peter Gibbs,
0:01:31 > 0:01:35and my job is working for the Met Office as a BBC weatherman
0:01:35 > 0:01:37but back in my younger days
0:01:37 > 0:01:41I worked as a meteorologist in Antarctica for over two years,
0:01:41 > 0:01:46and I never, ever thought I'd get the opportunity to return.
0:01:46 > 0:01:50'This is my journey to investigate the threat to Halley's future...'
0:01:52 > 0:01:54- OK, Hilmar, here we go, then.- Yeah.
0:01:54 > 0:01:57It's going over the edge that's the worst bit.
0:01:58 > 0:02:01'..and science at the end of the world.'
0:02:01 > 0:02:03It is just phenomenal.
0:02:06 > 0:02:09ICE CRACKS
0:02:17 > 0:02:20My journey starts at the southern tip of Africa.
0:02:22 > 0:02:26Here, the Royal Research Ship Ernest Shackleton is waiting for me.
0:02:30 > 0:02:33As I go below to find my cabin and stow my bags...
0:02:33 > 0:02:35FOGHORN HONKS
0:02:35 > 0:02:37..we're soon underway.
0:02:39 > 0:02:41We're heading out of Cape Town harbour -
0:02:41 > 0:02:45you can probably see Table Mountain in the background behind me -
0:02:45 > 0:02:49on our way to the frozen continent of Antarctica.
0:02:49 > 0:02:51Now, we're expecting it to take about two weeks.
0:02:51 > 0:02:54It's around about 3,000 miles.
0:02:54 > 0:02:55We'll be going at ten to 12 knots,
0:02:55 > 0:02:59so at just about a brisk cycling pace.
0:02:59 > 0:03:02We're also heading through some of the roughest seas in the world,
0:03:02 > 0:03:04so I'm a little bit nervous about that,
0:03:04 > 0:03:09but really, really excited to be heading for Antarctica.
0:03:38 > 0:03:40Well, it's the fourth day at sea.
0:03:40 > 0:03:44About 660 miles south, now, of Cape Town.
0:03:44 > 0:03:46The air temperature at the moment is ten degrees.
0:03:46 > 0:03:48I've got the extra layer on.
0:03:48 > 0:03:50The sea temperature's not much higher than that -
0:03:50 > 0:03:52around about 11 degrees -
0:03:52 > 0:03:56and you might notice we've got a big swell heading up from the south,
0:03:56 > 0:03:58the direction we're heading.
0:04:00 > 0:04:03The Ernest Shackleton has been making this long journey
0:04:03 > 0:04:08across the Southern Ocean to resupply Halley since 1999,
0:04:08 > 0:04:11but British scientific research goes back much further
0:04:11 > 0:04:14and has a surprising beginning.
0:04:14 > 0:04:17The modern-day British Antarctic Survey
0:04:17 > 0:04:20actually has its roots in a secret wartime mission from World War II,
0:04:20 > 0:04:22which was based up here on the peninsula
0:04:22 > 0:04:26at Port Lockroy and Deception Island.
0:04:26 > 0:04:28The idea of the operation was to protect
0:04:28 > 0:04:29the waters around Antarctica,
0:04:29 > 0:04:32particularly towards the Drake Passage towards South America,
0:04:32 > 0:04:34from Nazi submarines.
0:04:34 > 0:04:38But, even though the men based there were far from the bullets and bombs
0:04:38 > 0:04:42of World War II, it certainly wasn't an easy posting -
0:04:42 > 0:04:46Spartan living conditions, thousands of miles from home
0:04:46 > 0:04:48and tremendous isolation.
0:04:52 > 0:04:57But, in the event, it turned into more of a scientific expedition.
0:04:57 > 0:05:01The men set up a weather station, one of the first on Antarctica,
0:05:01 > 0:05:05and it provided viable data that's still used today
0:05:05 > 0:05:07to assess climate change.
0:05:10 > 0:05:14After the war, territorial claims led to 12 nations signing
0:05:14 > 0:05:18the Antarctic Treaty, and this untouched landscape became a home
0:05:18 > 0:05:21purely for scientific exploration.
0:05:22 > 0:05:24For the British Antarctic Survey,
0:05:24 > 0:05:28this meant a research station on the Brunt Ice Shelf.
0:05:31 > 0:05:34And that's our destination - Halley Research Station.
0:05:34 > 0:05:36The original building's long gone.
0:05:36 > 0:05:39Even the buildings I lived in have long since drifted off,
0:05:39 > 0:05:42entombed in the ice of an iceberg.
0:05:42 > 0:05:45We've still got a long way to go - the best part of a week.
0:05:45 > 0:05:48In fact, we are not even on the edge of this map yet.
0:06:05 > 0:06:09Various incarnations of the Halley Research Station have endured
0:06:09 > 0:06:15some of the most hostile conditions found on Earth for over 60 years.
0:06:17 > 0:06:20The weather here is extreme.
0:06:20 > 0:06:24Temperatures drop to over minus 50 Celsius,
0:06:24 > 0:06:27winds can reach almost 150km an hour,
0:06:27 > 0:06:31reducing visibility to just a few metres...
0:06:35 > 0:06:41..and, for over three months every winter, the sun never rises.
0:06:48 > 0:06:53Antarctica is also about as remote a place as you can find on Earth...
0:06:59 > 0:07:02..but it's this remoteness that allows experiments to be
0:07:02 > 0:07:07performed at Halley that simply can't be done anywhere else.
0:07:24 > 0:07:26Well, this is the real deal now -
0:07:26 > 0:07:31a huge iceberg that probably broke off the continent decades ago.
0:07:31 > 0:07:32The point is, though,
0:07:32 > 0:07:35if we were here in this spot at the end of winter, there would be
0:07:35 > 0:07:41several hundred miles of continuous sea ice between us and the coast.
0:07:41 > 0:07:44That's why it's impossible to get into Halley
0:07:44 > 0:07:46for a good nine months of the year.
0:07:49 > 0:07:51Back to the UK, now, and that frosty start in the south.
0:07:51 > 0:07:53It's not going to last too long, though.
0:07:53 > 0:07:54The sunshine, once it comes up,
0:07:54 > 0:07:56clearing the frost fairly quickly, I think.
0:07:56 > 0:07:58Further north, though, a bit of a different story...
0:07:58 > 0:08:02'I've been waving my arms in front of weather charts for,
0:08:02 > 0:08:04'well, 20-odd years now,'
0:08:04 > 0:08:05but straight from university
0:08:05 > 0:08:08I actually applied to the British Antarctic Survey.
0:08:08 > 0:08:11I was taken on to be sent down as the weatherman
0:08:11 > 0:08:15to their Halley Research Station, down in Antarctica,
0:08:15 > 0:08:17but it was for two years.
0:08:17 > 0:08:19That was standard back in those days.
0:08:19 > 0:08:22This is a bit of a roughie-toughie shot,
0:08:22 > 0:08:24but behind there you can see there's a pretty young man who is
0:08:24 > 0:08:28just still getting to grips with the enormity of what he's...
0:08:28 > 0:08:31he's actually taken on.
0:08:31 > 0:08:36Once a month, we'd have a 200-word telex message in and out,
0:08:36 > 0:08:38erm, but, to be honest, after a few months,
0:08:38 > 0:08:42I was struggling to find very much to put into those 200-word messages.
0:08:42 > 0:08:45And, essentially, for eight to nine months of the year,
0:08:45 > 0:08:48there is no way to get anybody in or out
0:08:48 > 0:08:51but, you know, I absolutely loved it. I really took to it.
0:08:51 > 0:08:55Even after two years, when the ship came to actually take me away,
0:08:55 > 0:08:58I... I didn't want to go.
0:08:58 > 0:09:00I really didn't want to go.
0:09:00 > 0:09:01Erm...
0:09:01 > 0:09:04I had such an attachment to the place that
0:09:04 > 0:09:06I really didn't want to leave it,
0:09:06 > 0:09:12so to have the chance to actually go back is...is a big thing.
0:09:17 > 0:09:2035 years on and e-mail has replaced telex,
0:09:20 > 0:09:23but Halley is still as isolated as ever.
0:09:26 > 0:09:28It's so far from civilisation,
0:09:28 > 0:09:31it may as well be on another planet...
0:09:35 > 0:09:40..and everyone posted there still needs to be utterly self-reliant.
0:09:43 > 0:09:45I'm Jess. I'm the winter station leader
0:09:45 > 0:09:49and I am in charge of making sure the station runs smoothly
0:09:49 > 0:09:53over the winter, when we're down to a team of just 13 of us.
0:09:53 > 0:09:57We don't have help, so all our emergency planning is
0:09:57 > 0:10:01based on people on the station sorting themselves out.
0:10:01 > 0:10:04We have to be prepared for any circumstances,
0:10:04 > 0:10:08so, in an event like a fire, we have all our emergency supplies
0:10:08 > 0:10:12elsewhere on station - in containers, in other buildings.
0:10:14 > 0:10:17With outside help possibly months away,
0:10:17 > 0:10:21the station has supplies to survive for almost 300 days.
0:10:23 > 0:10:27Food allowances are calculated based on military rations,
0:10:27 > 0:10:30and we add the polar allowance to that, which adds for the more...
0:10:30 > 0:10:33more calories because of the colder weather.
0:10:33 > 0:10:35We have a lot of stores -
0:10:35 > 0:10:411,500kg of tinned tomatoes and nearly 900kg of beef.
0:10:41 > 0:10:43We never want to run out of food.
0:10:43 > 0:10:46It's often said that the chef is one of the most important
0:10:46 > 0:10:48people on the station.
0:10:48 > 0:10:52My name is Victoria Stone and I'm the winter chef.
0:10:52 > 0:10:55I'll be here, then, until 2017.
0:10:55 > 0:10:58It is that kind of a world, you don't have to worry about things.
0:10:58 > 0:11:02I mean, I haven't been out here long but I absolutely love it.
0:11:02 > 0:11:05I think food is really important, working at Halley, because it's...
0:11:05 > 0:11:08You're working in severe conditions.
0:11:08 > 0:11:11You're away from friends and family and, you know,
0:11:11 > 0:11:14that's the one thing that you look forward to,
0:11:14 > 0:11:15and everyone talks about it -
0:11:15 > 0:11:18what we're having for lunch, what's for evening dinner and...
0:11:18 > 0:11:23So it's a very big responsibility, but I'm quite happy with that, so...
0:11:36 > 0:11:39ICE SNAPS AND BOAT RUMBLES
0:11:39 > 0:11:40Even in summer,
0:11:40 > 0:11:45sailing through the Southern Ocean to get to Halley is a challenge.
0:11:45 > 0:11:48BOAT RUMBLES
0:11:50 > 0:11:54Well, we finally hit the edge of the Weddell Sea pack ice last night,
0:11:54 > 0:11:55and I mean hit.
0:11:55 > 0:11:58There was an almighty bang as we struck the first floe,
0:11:58 > 0:12:00and I was startled awake.
0:12:00 > 0:12:04The sound when you're actually inside the ship is just remarkable.
0:12:04 > 0:12:06It's almost like you're inside a war zone,
0:12:06 > 0:12:07and this is what the ship's
0:12:07 > 0:12:08designed to... BOAT THUDS
0:12:08 > 0:12:11do, power through ice.
0:12:11 > 0:12:13I'll tell you what,
0:12:13 > 0:12:16it's still a bit nerve-racking until you actually get used to it.
0:12:21 > 0:12:23As we crunch through the ice,
0:12:23 > 0:12:26the captain offers me the chance of a lifetime -
0:12:26 > 0:12:30something I'd secretly been hoping to do -
0:12:30 > 0:12:33drive his 1,800-tonne ship.
0:12:33 > 0:12:35Are you sure about this, John?
0:12:35 > 0:12:37Yeah.
0:12:37 > 0:12:41At the moment we've got 83% pitch, which is basically your power,
0:12:41 > 0:12:45which is giving us about ten knots, but it will build up,
0:12:45 > 0:12:47cos we're in a patch of open water here.
0:12:47 > 0:12:53So, just be careful what you hit at that sort of speed.
0:12:53 > 0:12:54- Yes, I will.- But the...
0:12:54 > 0:12:57It's a strange sort of feeling of power and terror, actually.
0:12:57 > 0:12:59So, if you... You take that.
0:12:59 > 0:13:02You've got some nice... nice new ice coming up, here,
0:13:02 > 0:13:04and just aim for the crack
0:13:04 > 0:13:06- and she'll follow it along. - PETER CHUCKLES
0:13:09 > 0:13:11- It's rather like a... - That incredible -
0:13:11 > 0:13:16the speed that crack's actually formed, right across the whole floe.
0:13:16 > 0:13:17There's a good covering of snow
0:13:17 > 0:13:21- on most of these floes, as well.- Oh. BOAT THUDS
0:13:21 > 0:13:22So that'll be...
0:13:22 > 0:13:24It's probably the best part of a metre thick,
0:13:24 > 0:13:26with the snow on the top.
0:13:26 > 0:13:28- It's certainly slowed us down a bit.- Yes.
0:13:30 > 0:13:32- And are we OK to hit this bit of ice coming up?- Yup.
0:13:32 > 0:13:34You might want to just drop your pitch...
0:13:34 > 0:13:37- Drop your power a bit there. - Slow down a touch...- Yeah.
0:13:37 > 0:13:40..so we don't give people downstairs a shock.
0:13:43 > 0:13:46I'm Jamie Shaw. I'm chief engineer on the Ernest Shackleton.
0:13:46 > 0:13:49I've been here for nearly seven years.
0:13:49 > 0:13:53We're a reinforced general cargo ship, built in Norway,
0:13:53 > 0:13:56and the ice belt, which is the part that does the actual icebreaking,
0:13:56 > 0:13:59if you like, is... the steel's about that thick,
0:13:59 > 0:14:02so Norwegians build very good ships.
0:14:02 > 0:14:06Generally speaking, the bridge, they try and find the cracks,
0:14:06 > 0:14:09sort of, between the ice, but the bridge enjoy it.
0:14:09 > 0:14:15We actually go straight for it and, literally, bash our way through it.
0:14:15 > 0:14:17It's good fun for the first few hours
0:14:17 > 0:14:20but, when you're doing it for days on end and you're trying to sleep,
0:14:20 > 0:14:23it's not quite so much fun.
0:14:23 > 0:14:25You can sometimes tell who's driving, as well,
0:14:25 > 0:14:27so some of the younger ones are...
0:14:27 > 0:14:30They're definitely there with the throttles, going for it,
0:14:30 > 0:14:33and you think, "Oh, here we go." You know, bang, crash, you know?
0:14:33 > 0:14:36But maybe us older people would maybe go round a little bit.
0:14:38 > 0:14:40Now, we're coming up to a floe that's
0:14:40 > 0:14:41a good few hundred metres across.
0:14:41 > 0:14:44- Are we going to get through this? - Erm, you...
0:14:44 > 0:14:45What you... What you look for...
0:14:45 > 0:14:47You're going to say I'm being a bit ambitious.
0:14:47 > 0:14:50THEY LAUGH
0:14:51 > 0:14:56My piloting skills have the local penguins fleeing in terror
0:14:56 > 0:14:58but I'm not stopping for anything.
0:15:01 > 0:15:04I have to say, this is fantastic fun.
0:15:04 > 0:15:08I can see why you keep coming back down here, John.
0:15:08 > 0:15:12It is. We spend our whole careers at sea, trying to avoid other things...
0:15:12 > 0:15:17- Yeah.- ..and this is our one chance to hit everything in sight.
0:15:17 > 0:15:20ICE CRACKS
0:15:20 > 0:15:22BOAT CLANGS
0:15:27 > 0:15:33Breaking through sea ice is an unforgettable experience,
0:15:33 > 0:15:39like exploring another universe in a spaceship,
0:15:39 > 0:15:43but we're still a world away from our destination.
0:15:46 > 0:15:49Even through the Halley Research Station appears to be
0:15:49 > 0:15:52built on solid ground, it isn't.
0:15:52 > 0:15:58Its home is the Brunt Ice Shelf - a seemingly endless frozen sea -
0:15:58 > 0:16:01and, for the research station, this is a problem.
0:16:09 > 0:16:12The ice shelves that surround Antarctica are glaciers that
0:16:12 > 0:16:15have flowed down from the continent's landmass.
0:16:18 > 0:16:21Hundreds of metres thick, they crack as they spread
0:16:21 > 0:16:25like a stiff honey across the sea's surface.
0:16:31 > 0:16:34I'm Hilmar Gudmundsson. I am a glaciologist.
0:16:34 > 0:16:36I think glaciers are really cool.
0:16:37 > 0:16:40So, ice shelves grow with time,
0:16:40 > 0:16:42as more and more ice is being added,
0:16:42 > 0:16:45and typically they then lose mass
0:16:45 > 0:16:47through an event that they call calving,
0:16:47 > 0:16:51which is basically the breaking off of a chunk of the ice shelf,
0:16:51 > 0:16:54which breaks away and then floats as a tabular iceberg.
0:16:54 > 0:16:59This is a natural process, which you always expect.
0:16:59 > 0:17:00It's certainly happened in the past.
0:17:00 > 0:17:02It happens with other ice shelves as well
0:17:02 > 0:17:05and certainly will happen again and again in the future.
0:17:05 > 0:17:09On Brunt Ice Shelf, we have a particular situation right now,
0:17:09 > 0:17:11which is that there's a crack that has formed.
0:17:11 > 0:17:14It was formed at least 30 years ago,
0:17:14 > 0:17:18but recently it has started to grow again.
0:17:18 > 0:17:22Now, if this crack were to continue to grow at the same rate
0:17:22 > 0:17:25as it has over the last few years, in the same direction,
0:17:25 > 0:17:29then eventually it will cut across the whole ice shelf.
0:17:30 > 0:17:35We know there was a huge calving event between 1915 and 1956,
0:17:35 > 0:17:39when the coastline of the ice shelf dramatically changed,
0:17:39 > 0:17:45and now the ice shelf has almost extended to its 1915 profile,
0:17:45 > 0:17:49so another major calving event is due.
0:17:50 > 0:17:54If that happens, then the research station itself will be
0:17:54 > 0:18:00cast adrift into the Southern Ocean on a huge tabular iceberg.
0:18:15 > 0:18:16Well, here it is.
0:18:16 > 0:18:20That glistening white line in the distance
0:18:20 > 0:18:23are the icy ramparts of the Caird Coast -
0:18:23 > 0:18:25the continent of Antarctica.
0:18:25 > 0:18:30A coast first spotted and named by Shackleton just over 100 years ago,
0:18:30 > 0:18:34before he got trapped in the ice just further down the coast here,
0:18:34 > 0:18:38and first spotted by me 36 years ago
0:18:38 > 0:18:40and, I have to say, there's...
0:18:40 > 0:18:43There's a bit of that young man certainly coming back
0:18:43 > 0:18:47as I stand here at the moment.
0:18:47 > 0:18:48It's pretty emotional.
0:18:48 > 0:18:51It's... It feels like coming home.
0:18:54 > 0:18:59My first sight of the ice shelf brings back a flood of memories.
0:18:59 > 0:19:03It's a bleak, beautiful place -
0:19:03 > 0:19:06an alien world, right here on planet Earth.
0:19:11 > 0:19:13And it's a treacherous landscape -
0:19:13 > 0:19:18at any moment, at the water's edge, a section could collapse.
0:19:23 > 0:19:24But it's highest through here...
0:19:24 > 0:19:26'But we have a job to do,
0:19:26 > 0:19:29'delivering supplies for the research station'
0:19:29 > 0:19:33and, with no docks, like everything else in Antarctica,
0:19:33 > 0:19:35you make what you need yourself.
0:19:40 > 0:19:43So, Captain Harper creates a berth
0:19:43 > 0:19:46by running the ship alongside the ice.
0:19:46 > 0:19:49If the shelf doesn't collapse, so the theory goes,
0:19:49 > 0:19:51it's safe to go ashore.
0:19:54 > 0:19:57Violent southern ocean storms could drive the Shackleton
0:19:57 > 0:20:00off the ice shelf, so, as the weather closes in,
0:20:00 > 0:20:03the rest of our day is spent securing the ship.
0:20:05 > 0:20:09This means all hands, including me, go to work
0:20:09 > 0:20:13digging four massive anchors deep into the ice.
0:20:22 > 0:20:26ENGINE HUMS
0:20:26 > 0:20:28The sun has come out to greet us
0:20:28 > 0:20:30for the last leg of our journey.
0:20:41 > 0:20:46The 30km snowcat ride across the blindingly white ice shelf
0:20:46 > 0:20:53seems endless but, after two weeks at sea waiting for this moment,
0:20:53 > 0:20:54I'm not disappointed.
0:20:58 > 0:20:59Well, there it is.
0:20:59 > 0:21:02I mean, I've seen pictures, but when you see it for real
0:21:02 > 0:21:05it's just an incredible building.
0:21:05 > 0:21:07I mean, it's like something out of The Martian
0:21:07 > 0:21:10or 2001: A Space Odyssey.
0:21:11 > 0:21:13Time to get inside.
0:21:16 > 0:21:20'Built in 2012, the Halley Research Station consists of
0:21:20 > 0:21:24'eight huge modules and, just like a moon-base,
0:21:24 > 0:21:27'they have everything needed to maintain life
0:21:27 > 0:21:28'in a hostile environment.'
0:21:30 > 0:21:32All right, I'm going to take you through from one end,
0:21:32 > 0:21:34right through to the other.
0:21:34 > 0:21:37So, we're starting in the quiet room, which doubles up as a library,
0:21:37 > 0:21:39and we move out of there
0:21:39 > 0:21:43into the first part of the accommodation block.
0:21:43 > 0:21:45- Now, we're into a sort of admin area.- Hello.
0:21:45 > 0:21:49We've got the communications room on the left.
0:21:49 > 0:21:54We've got the equipment here, on the right, in case of fire,
0:21:54 > 0:21:57and a board up here where you have to tag in and tag out -
0:21:57 > 0:22:00safety, a very big concern here at the moment.
0:22:00 > 0:22:02Surgery over on the right.
0:22:02 > 0:22:08Now, we're moving through into the main dining room and lounge area.
0:22:08 > 0:22:11So, this is the real, sort of, hub of the station
0:22:11 > 0:22:13far off to the left here.
0:22:13 > 0:22:16Oh, and along the wall on this corridor
0:22:16 > 0:22:18that we're just coming past,
0:22:18 > 0:22:21all the pictures of past winterers,
0:22:21 > 0:22:26starting from 1956, right through to the present day.
0:22:26 > 0:22:31'And, of course, there's me and the rest of the guys in 1981,
0:22:31 > 0:22:34'and you'll notice, back then, no women.'
0:22:36 > 0:22:38OK, let's move on. We're going through.
0:22:38 > 0:22:40Now, you'll start to hear a bit of a hum.
0:22:40 > 0:22:42We're moving through the sort of plant area.
0:22:42 > 0:22:44So, things like the... the generators.
0:22:44 > 0:22:46And now, a big, deep breath.
0:22:46 > 0:22:51We're going outside, through these heavy, airlock-type doors.
0:22:51 > 0:22:55STRONG WIND BLOWS
0:22:55 > 0:22:57WIND CONTINUES
0:23:03 > 0:23:06And now we're on into the main science area,
0:23:06 > 0:23:09so, the labs either side,
0:23:09 > 0:23:12and now we're going to go up the stairs to
0:23:12 > 0:23:15the best view in Halley,
0:23:15 > 0:23:20which is the Met Office observation deck,
0:23:20 > 0:23:26where you get a panoramic view of the Brunt Ice Shelf.
0:23:32 > 0:23:36This ice shelf is just a small part of Antarctica.
0:23:39 > 0:23:43It's a vast continent, almost twice the size of Australia.
0:23:48 > 0:23:56It contains 70% of the world's fresh water,
0:23:56 > 0:24:03trapped in an ice sheet that's up to 5km thick
0:24:03 > 0:24:05and, because of this,
0:24:05 > 0:24:10Antarctica is a huge influence on global weather patterns,
0:24:10 > 0:24:14so monitoring what goes on here is critical.
0:24:20 > 0:24:24For 60 years, Halley has delivered a continuous stream of weather data
0:24:24 > 0:24:29for scientists around the world to use in climate models,
0:24:29 > 0:24:34so every single morning sees the launch of a weather balloon.
0:24:34 > 0:24:36Amy, one of the disadvantages of this job,
0:24:36 > 0:24:38is that you've got to get up before
0:24:38 > 0:24:40most of the people on the station, isn't it?
0:24:40 > 0:24:43It's only during summer, though.
0:24:43 > 0:24:47In winter, we launch at 10.30.
0:24:47 > 0:24:49That's a bit more civilised.
0:24:51 > 0:24:55'Civilised perhaps, but when I did this job in the early 1980s,
0:24:55 > 0:24:57'this was a tricky operation.'
0:24:57 > 0:25:01- So, Amy, this is just a one-person job now, yes?- Yes, it is.
0:25:01 > 0:25:03Cos when I was here
0:25:03 > 0:25:07it needed four people to actually do a balloon ascent every day.
0:25:07 > 0:25:09Wow.
0:25:09 > 0:25:11Cos you had... You had to track it by radar,
0:25:11 > 0:25:15so there were two people sitting in the radar,
0:25:15 > 0:25:18tracking the balloon and sending the measurements back to
0:25:18 > 0:25:20the Met Office, where there was two people sitting,
0:25:20 > 0:25:23plotting it out on a map,
0:25:23 > 0:25:26working out the winds from that using a calculator,
0:25:26 > 0:25:30coding it all up and then sending it off by telex.
0:25:30 > 0:25:35'40 research stations, dotted across this vast wilderness,
0:25:35 > 0:25:39'provide all the data for the whole of Antarctica's weather patterns.'
0:25:39 > 0:25:42Because there are so few measurement stations in Antarctica,
0:25:42 > 0:25:46every single measurement from every station counts, and we get
0:25:46 > 0:25:50- a call from the Met Office if we start to miss more than one.- Really?
0:25:50 > 0:25:52- Yes.- Oh, well, that's good because, of course,
0:25:52 > 0:25:54you have to have that spread of data,
0:25:54 > 0:25:56otherwise the models don't work as well.
0:25:58 > 0:26:02'Each weather balloon is filled with helium to lift it high into the
0:26:02 > 0:26:07'atmosphere, and it carries a little white box called a radiosonde.'
0:26:10 > 0:26:13So, this measures pressure, temperature and relative humidity,
0:26:13 > 0:26:15and it's also got a GPS in it.
0:26:15 > 0:26:17And the key thing is that it's giving us a profile
0:26:17 > 0:26:19through the atmosphere.
0:26:19 > 0:26:21And you're getting these things up to what sort of height?
0:26:21 > 0:26:25So, we're interested at the height of about 10km,
0:26:25 > 0:26:28but they continue on up to about 25-30km.
0:26:28 > 0:26:31But they get to a huge size, don't they, before they actually burst?
0:26:31 > 0:26:33Yeah, about the size of a double-decker bus.
0:26:33 > 0:26:35It's hard to believe when you see this thing here.
0:26:35 > 0:26:37OK, well, I suppose it's getting towards time to release.
0:26:37 > 0:26:39Would you like to launch it?
0:26:39 > 0:26:40I'd love to. Thank you.
0:26:40 > 0:26:43Yeah, that'd be... That'd be a real privilege, thank you.
0:26:45 > 0:26:47- OK.- When you're ready.
0:26:47 > 0:26:50Three, two, one, and go.
0:27:00 > 0:27:02Well, that launch was pretty straightforward this morning
0:27:02 > 0:27:04but then it's the middle of summer here,
0:27:04 > 0:27:07the temperature a fairly balmy minus 8.
0:27:07 > 0:27:10Imagine doing that in the middle of winter.
0:27:10 > 0:27:13Three and a half months of darkness here at Halley,
0:27:13 > 0:27:16temperatures down as low as minus 56 Celsius,
0:27:16 > 0:27:19and often severe wind-chill, as well.
0:27:21 > 0:27:25And it's that severe winter weather that creates a mass of
0:27:25 > 0:27:29heavy, dense, cold air across the Antarctic continent, that actually
0:27:29 > 0:27:32isolates the atmosphere from the circulation around it.
0:27:32 > 0:27:34You get these winds whipping around the cold air.
0:27:34 > 0:27:38It's what we meteorologists call the Antarctic polar vortex,
0:27:38 > 0:27:41and that weather feature was instrumental in creating
0:27:41 > 0:27:46a deadly threat to every living thing on the planet.
0:27:46 > 0:27:49Back in the early '80s, when I was last here,
0:27:49 > 0:27:54Halley was at the centre of a global environmental news story,
0:27:54 > 0:27:59all about a frightening man-made hole high in the stratosphere.
0:28:01 > 0:28:03An aerosol can -
0:28:03 > 0:28:06the argument goes that sprays are destroying
0:28:06 > 0:28:09a vital part of the Earth's atmosphere.
0:28:09 > 0:28:14There's a two-mile-thick layer of a gas called ozone just here,
0:28:14 > 0:28:16about ten miles above the Earth.
0:28:20 > 0:28:24Ozone matters because it does one crucial thing -
0:28:24 > 0:28:26it shields all life on the Earth's surface
0:28:26 > 0:28:29from the sun's harmful radiation.
0:28:30 > 0:28:33Scientists at Halley discovered that each spring,
0:28:33 > 0:28:38as the sun reappeared, ozone levels above here dropped dramatically.
0:28:38 > 0:28:41They were so surprised that they went back and checked
0:28:41 > 0:28:43and rechecked their results.
0:28:43 > 0:28:46In fact, what they'd found was a hole in the ozone layer
0:28:46 > 0:28:48the size of Antarctica,
0:28:48 > 0:28:52and this is the machine that discovered the ozone hole.
0:28:52 > 0:28:54This is the Dobson spectrophotometer.
0:28:58 > 0:29:00This actual instrument was here -
0:29:00 > 0:29:03it was the one we used when I was here back in the 1980s -
0:29:03 > 0:29:05but it was invented back in the 1920s
0:29:05 > 0:29:08by Oxford scientist GMB Dobson,
0:29:08 > 0:29:11basically in his garden shed,
0:29:11 > 0:29:14but, even now, almost 100 years later,
0:29:14 > 0:29:17it's still the gold standard for ozone measurement.
0:29:17 > 0:29:19MACHINE HUMS
0:29:19 > 0:29:23Essentially what it's telling us is how much harmful UV radiation
0:29:23 > 0:29:25gets down to the Earth's surface.
0:29:27 > 0:29:30What the spectrophotometer detected in the '80s was
0:29:30 > 0:29:35the effect of man-made gases, used in spray cans and fridges,
0:29:35 > 0:29:39trapped within Antarctica's polar vortex.
0:29:40 > 0:29:44In winter, the cold air circulating high above the continent
0:29:44 > 0:29:49forms stratospheric ice clouds, containing these gases
0:29:49 > 0:29:52and, when the spring sun returns, they act as a catalyst,
0:29:52 > 0:29:54destroying ozone.
0:29:56 > 0:30:00Ozone has been measured daily here at Halley since the mid-1950s,
0:30:00 > 0:30:04but it was the change in levels during the '70s and '80s that led
0:30:04 > 0:30:08scientists to realise that it was being destroyed in the stratosphere.
0:30:08 > 0:30:13That then led onto the signing of the Montreal Protocol in 1987
0:30:13 > 0:30:17to ban ozone-destroying chemicals like CFCs.
0:30:17 > 0:30:19It was an unprecedented feat of
0:30:19 > 0:30:22international cooperation. MACHINE HUMS
0:30:22 > 0:30:25Measurements are still being taken on a daily basis
0:30:25 > 0:30:28and what they show is that it will take at least to
0:30:28 > 0:30:33the end of the century for levels to return to near normal,
0:30:33 > 0:30:36so it seems as if the rot has stopped.
0:30:43 > 0:30:46Studying the atmosphere at Halley is critical.
0:30:46 > 0:30:51Antarctica is a huge, ice-covered continent, surrounded by ocean,
0:30:51 > 0:30:54and when that ocean freezes during the winter,
0:30:54 > 0:30:59for as much as 1,000 miles, it doubles the area of ice.
0:30:59 > 0:31:06That yearly heartbeat is a huge influence on the planet's climate,
0:31:06 > 0:31:10and also, the Southern Oceans are a big player in absorbing carbon
0:31:10 > 0:31:11from the atmosphere.
0:31:11 > 0:31:14The endless storms that circulate around the periphery
0:31:14 > 0:31:19of Antarctica drive a global conveyor belt of oceanic heat.
0:31:19 > 0:31:22While this place may be out of sight for most of us,
0:31:22 > 0:31:26what happens here in Antarctica affects us all.
0:31:31 > 0:31:36But, today, the very existence of this unique research facility
0:31:36 > 0:31:37is threatened.
0:31:37 > 0:31:41A huge crack across the Brunt Ice Shelf is expanding,
0:31:41 > 0:31:44and it may cause the research station to float off
0:31:44 > 0:31:47into the Southern Ocean.
0:31:47 > 0:31:50For glaciologist Hilmar Gudmundsson,
0:31:50 > 0:31:54it's like watching geology in fast forward,
0:31:54 > 0:31:57so this faultline is constantly monitored,
0:31:57 > 0:32:01and there really is only one way to get a closer look.
0:32:02 > 0:32:09The last time I abseiled was 35 years ago, so I'm a little nervous.
0:32:09 > 0:32:11- OK, Hilmar. Here we go, then.- Yeah.
0:32:11 > 0:32:15It's going over the edge that's the worst bit for me.
0:32:15 > 0:32:18It's quite a long way down, isn't it?
0:32:18 > 0:32:21I've been looking at this crack from satellite images,
0:32:21 > 0:32:24and now being within it is just great.
0:32:24 > 0:32:28This is a feature which has been here for ages.
0:32:28 > 0:32:30Just phenomenal.
0:32:32 > 0:32:36'When low cloud and snow reflect and diffuse the sunlight,
0:32:36 > 0:32:40'the full extent of the chasm is difficult to see,
0:32:40 > 0:32:43'but when the sun comes out, it's a different story.'
0:32:48 > 0:32:52This is, as you can see, a fairly large crack.
0:32:52 > 0:32:55It's a chasm, that's what they call it. Chasm 1, in fact.
0:32:55 > 0:32:58Yeah, chasm, chasm sounds about right from where I'm sitting.
0:32:58 > 0:33:03- Across, I would say this is maybe 80...80m at least...- Yeah.
0:33:03 > 0:33:08..and the whole thing is getting wider as we speak,
0:33:08 > 0:33:11by about 15cm every day.
0:33:11 > 0:33:12- Every day?- Every day.
0:33:12 > 0:33:1815cm from this edge here to the other one over there,
0:33:18 > 0:33:20and it's been going like a clock
0:33:20 > 0:33:22ever since we started to measure this, which is...
0:33:22 > 0:33:24which was early 2015.
0:33:24 > 0:33:26And, Hilmar, the bottom of the chasm, there,
0:33:26 > 0:33:29looks very different to the ice round about.
0:33:29 > 0:33:31This is very blue, very white...
0:33:31 > 0:33:33- It's much darker down in the bottom, there.- Yeah.
0:33:33 > 0:33:37Yeah, I suspect down there we're literally at sea level.
0:33:37 > 0:33:40It is the colour of the ocean which is causing this slight tint.
0:33:42 > 0:33:44'Hilmar is keen to investigate
0:33:44 > 0:33:47'whether we are actually at sea level,
0:33:47 > 0:33:51'and that means going right to the very bottom of the chasm.'
0:33:51 > 0:33:54Ooh!
0:33:54 > 0:33:55That's better.
0:33:55 > 0:33:58'It's a huge relief getting down,
0:33:58 > 0:34:00'but we don't take off our safety lines.
0:34:00 > 0:34:03'With the freezing Southern Ocean just beneath our feet,
0:34:03 > 0:34:05'we're treading very carefully.'
0:34:05 > 0:34:07..poke in there, so let's have a look.
0:34:07 > 0:34:09Matt, are you happy with us going down here?
0:34:09 > 0:34:13- If you follow the trail we've made previously, that'd be good.- OK.
0:34:18 > 0:34:22- Are you OK?- Yeah, it's fine. LAUGHTER
0:34:22 > 0:34:25- OK, he's safe. - I nearly got my foot wet.
0:34:25 > 0:34:31- Fantastic.- OK, I'll follow - maybe not quite as elegantly as you did.
0:34:31 > 0:34:33A slightly different way, yeah.
0:34:36 > 0:34:38And that is going...
0:34:41 > 0:34:44- It's salty.- It's salty? - It's salty!- It really is? Oh.
0:34:44 > 0:34:46I wasn't expecting this.
0:34:46 > 0:34:47Is that a first for you?
0:34:47 > 0:34:50Yeah, yeah, I thought we had, maybe, one or two metres here
0:34:50 > 0:34:51of solid ice on top.
0:34:51 > 0:34:54So we're on this huge, floating mass of ice,
0:34:54 > 0:34:57which is 150m thick.
0:34:57 > 0:35:02We've had a journey up from the coast of three hours in the snowcat.
0:35:02 > 0:35:04We've come an hour and a half in from the base,
0:35:04 > 0:35:06across this featureless snow plain,
0:35:06 > 0:35:08to this massive, great chasm,
0:35:08 > 0:35:10and you get down to the bottom of it,
0:35:10 > 0:35:13and you actually find seawater in there. It's really...
0:35:13 > 0:35:16It feels like you're in the belly of the ice shelf,
0:35:16 > 0:35:19and it just brings it home how sort of precarious
0:35:19 > 0:35:21this whole landscape actually is.
0:35:21 > 0:35:24I guess, because it's always breaking up, it's growing,
0:35:24 > 0:35:28it's widening by about 15cm a day,
0:35:28 > 0:35:31the sea ice formation just can't keep up with it.
0:35:31 > 0:35:36This rapid expansion of the chasm may prevent sea ice from forming,
0:35:36 > 0:35:38but it's not the width that's the threat to
0:35:38 > 0:35:42the Halley Research Station - it's the length.
0:35:43 > 0:35:45At the same time that this gets wider,
0:35:45 > 0:35:50it also gets longer by about 1.7km a year.
0:35:52 > 0:35:56So, if it kept on going at that rate, in that direction,
0:35:56 > 0:35:58eventually it's going to reach the sea at the other side of
0:35:58 > 0:36:02- the ice shelf, and you've got a massive iceberg.- Yes.
0:36:02 > 0:36:04And, of course, the problem here is,
0:36:04 > 0:36:09Halley, the station, is on that developing iceberg.
0:36:09 > 0:36:10Yes.
0:36:16 > 0:36:18ENGINE HUMS
0:36:18 > 0:36:23Keeping Halley operational on this particular ice shelf is critical,
0:36:23 > 0:36:25not just for monitoring the weather.
0:36:25 > 0:36:3060 years ago, it was sited here, along with numerous aerials,
0:36:30 > 0:36:34to investigate the interactions between the Earth and the sun.
0:36:38 > 0:36:40My name's Richard Horne.
0:36:40 > 0:36:42I work at the British Antarctic Survey
0:36:42 > 0:36:45and I lead the Space, Weather and Atmosphere team.
0:36:45 > 0:36:48Halley is our window into space - that's what we call it -
0:36:48 > 0:36:51and I just feel like the luckiest person on Earth, really.
0:36:55 > 0:36:59Each winter at Halley, there's a dazzling display of light -
0:36:59 > 0:37:02the aurora australis.
0:37:02 > 0:37:05"Curtains waving" is one of the best descriptions,
0:37:05 > 0:37:08actually given by the early Norsemen, many, many years ago.
0:37:09 > 0:37:11But, when I see the aurora,
0:37:11 > 0:37:14I also think of huge electrical currents
0:37:14 > 0:37:20which are coming down from space, crashing through the atmosphere.
0:37:20 > 0:37:23The electrons are being accelerated across the Earth's magnetic field
0:37:23 > 0:37:26and then exciting the molecules in the atmosphere,
0:37:26 > 0:37:28and then they give off the light that we see.
0:37:28 > 0:37:31That's really what the aurora is about.
0:37:35 > 0:37:39The aurora are only possible at the North and South Poles
0:37:39 > 0:37:42because of the shape of the Earth's magnetic field
0:37:42 > 0:37:45and, by monitoring what goes on above our heads,
0:37:45 > 0:37:48Halley's location gives scientists the opportunity to
0:37:48 > 0:37:53protect our modern world from the sun's destructive activity.
0:37:56 > 0:37:58This is the Maggy Tunnel.
0:37:58 > 0:38:02It's called that because it houses the magnetometer,
0:38:02 > 0:38:04which needs a constant temperature
0:38:04 > 0:38:06and, buried ten metres down here in the ice shelf,
0:38:06 > 0:38:10the temperature never really varies from minus 15 year round.
0:38:10 > 0:38:15This thing is measuring fluctuations in the Earth's magnetic field.
0:38:17 > 0:38:20The flow of the planet's molten iron core is what creates
0:38:20 > 0:38:22the Earth's magnetic field.
0:38:22 > 0:38:25Field lines stretch out into space -
0:38:25 > 0:38:2860,000km facing the sun
0:38:28 > 0:38:34and trailing away some 400,000km on the dark side of the Earth.
0:38:38 > 0:38:42These field lines can't be seen, but we do witness the aurora
0:38:42 > 0:38:46when they are disrupted by the sun's coronal mass ejections.
0:38:54 > 0:38:57A coronal mass ejection emits billions of tonnes of
0:38:57 > 0:39:01charged particles and when they come towards the Earth
0:39:01 > 0:39:04they see the Earth's magnetic field as a barrier,
0:39:04 > 0:39:07but it has the potential of ripping open the outer layers
0:39:07 > 0:39:10of the Earth's magnetic field, drawing the field
0:39:10 > 0:39:15across the polar caps and extending the magnetic field into the tail.
0:39:15 > 0:39:18The magnetic field lines on the dark side of the Earth, suddenly,
0:39:18 > 0:39:21violently, they snap back into place.
0:39:21 > 0:39:25The analogy is an earthquake in space, if you like,
0:39:25 > 0:39:30and that whole process really is the start of a large, geomagnetic storm,
0:39:30 > 0:39:34and the manifestation of that is the aurora that you
0:39:34 > 0:39:36see in the polar regions.
0:39:39 > 0:39:42But Halley isn't just under the auroral zone...
0:39:44 > 0:39:49..it also sits within a unique glitch in the Earth's magnetic field,
0:39:49 > 0:39:53called the South Atlantic anomaly,
0:39:53 > 0:39:57and for scientists it's a window into space that allows them
0:39:57 > 0:40:02to study the radio waves thrown out by those coronal mass ejections.
0:40:04 > 0:40:07Our research has shown that those radio waves
0:40:07 > 0:40:11can accelerate charged particles up to very, very high energies
0:40:11 > 0:40:12and damage the spacecraft.
0:40:12 > 0:40:14We call them killer electrons.
0:40:17 > 0:40:20Killer electrons become trapped in magnetic fields
0:40:20 > 0:40:24wrapped around the Earth called the Van Allen radiation belts.
0:40:28 > 0:40:32And during a magnetic storm caused by a coronal mass ejection
0:40:32 > 0:40:37they can increase 10,000-fold in as little as two minutes.
0:40:38 > 0:40:41The problem is that over half of all satellites
0:40:41 > 0:40:44pass through the Van Allen belts as they orbit the Earth.
0:40:47 > 0:40:51The charged particles can penetrate the outer skin of a spacecraft
0:40:51 > 0:40:55and then they get buried into circuit boards, insulators,
0:40:55 > 0:40:58cables, and that charge can then build up.
0:41:00 > 0:41:03If it builds up to a very high level,
0:41:03 > 0:41:04it can cause electrostatic discharge.
0:41:07 > 0:41:09The analogy, really, is a lightning bolt.
0:41:11 > 0:41:14And they have been related to the loss of a spacecraft,
0:41:14 > 0:41:18the total satellite loss, costing 250 million.
0:41:18 > 0:41:20That's a lot of money.
0:41:20 > 0:41:22And you think that there are something like
0:41:22 > 0:41:251,200 satellites on orbit in total.
0:41:30 > 0:41:32The space weather research done here
0:41:32 > 0:41:36is attempting to forecast the impact of geomagnetic storms
0:41:36 > 0:41:39because of the damage they can do.
0:41:40 > 0:41:42We need to know what
0:41:42 > 0:41:46the largest level of the radiation can be in a severe storm
0:41:46 > 0:41:50because we can then give that information to the designers
0:41:50 > 0:41:55and they can then design against that to help protect the spacecraft.
0:42:01 > 0:42:04Whilst the impact of the sun on the Earth
0:42:04 > 0:42:09is measured by the aerials and radar installations OUTSIDE Halley,
0:42:09 > 0:42:14inside, other experiments are looking other much further field.
0:42:14 > 0:42:17In the depths of winter it's permanently dark,
0:42:17 > 0:42:20with temperatures that are hostile to any living creature
0:42:20 > 0:42:24and with little physical contact with the outside world,
0:42:24 > 0:42:29it's the nearest thing we have here on Earth to surviving in space.
0:42:33 > 0:42:34For the station's medic,
0:42:34 > 0:42:39these extreme conditions are a gift to do some interplanetary research
0:42:39 > 0:42:43because she is allowed to use its winter inhabitants
0:42:43 > 0:42:45as guinea-pig astronauts.
0:42:45 > 0:42:48I hear the winterers have a name for you, is that right?
0:42:48 > 0:42:51That is right, Peter, I see you are well informed.
0:42:51 > 0:42:53Well, since they call me Madame Whiplash,
0:42:53 > 0:42:55why don't you take a seat and find out why?
0:42:55 > 0:42:57LAUGHING: OK, let's try it!
0:42:58 > 0:43:01'I'm quite relieved to find Nathalie's leather chair
0:43:01 > 0:43:04'is simply the seat for her Soyuz docking simulator!'
0:43:05 > 0:43:08- RADIO:- 'We are at the range of 55 metres,
0:43:08 > 0:43:10'everything is nominal,
0:43:10 > 0:43:13'crosshairs are aligned with the target.'
0:43:13 > 0:43:17In December 2015, en route to the International Space Station,
0:43:17 > 0:43:20Tim Peake and his crew encountered a problem.
0:43:22 > 0:43:26In his launch the automatic system failed
0:43:26 > 0:43:30and so the Russian pilot had to dock it manually
0:43:30 > 0:43:33and it's exactly the procedure that we're going to do here.
0:43:33 > 0:43:36- So, were the staff here saying, "I could have done that!"- Yes!
0:43:36 > 0:43:38They were all saying it!
0:43:38 > 0:43:41- Fantastic!- Piece of cake.
0:43:42 > 0:43:45Of course, Tim's mission docked successfully.
0:43:45 > 0:43:48It's going to be interesting to see how I get on.
0:43:52 > 0:43:54You want to move in as fast as possible
0:43:54 > 0:43:56because time is one of the critical items,
0:43:56 > 0:44:01but your closing velocity can never exceed your distance divided by 200.
0:44:01 > 0:44:03And the computer does that, right?
0:44:03 > 0:44:05No, you have to do that.
0:44:05 > 0:44:07THEY LAUGH
0:44:07 > 0:44:08So I've got to do mental arithmetic
0:44:08 > 0:44:12and control two joysticks at the same time?
0:44:12 > 0:44:15Well, YOU wanted to be an astronaut!
0:44:15 > 0:44:18Do you know, I did once, but I'm not quite so sure now!
0:44:21 > 0:44:25- So, you are 35 metres away now.- OK.
0:44:25 > 0:44:29So, let's further correct that negative drift that has reappeared.
0:44:29 > 0:44:32Oh, yes. I'm getting nervous now!
0:44:32 > 0:44:34I can feel my heart going!
0:44:34 > 0:44:38So, what are you actually testing with this system?
0:44:38 > 0:44:39Well, as you will see
0:44:39 > 0:44:43when you will be perfectly proficient in this task,
0:44:43 > 0:44:47is that once you reach a standardised level of performance,
0:44:47 > 0:44:51if you don't practise it for a while, you forget it.
0:44:51 > 0:44:54And this is a major problem for exploration space flight
0:44:54 > 0:44:56because it...
0:44:56 > 0:45:01if we train a pilot and we send him or her to Mars,
0:45:01 > 0:45:05this really long journey, we expect them to be on top of their game
0:45:05 > 0:45:08when they arrive and so the question here is,
0:45:08 > 0:45:10what is the frequency of training you need
0:45:10 > 0:45:14to actually keep a certain level of proficiency up?
0:45:14 > 0:45:18So, we have a group of winterers who train frequently
0:45:18 > 0:45:21and a group of winterers who train infrequently
0:45:21 > 0:45:26and it is to quantify the rate of skill degradation in both groups.
0:45:26 > 0:45:29And it's the isolation, it's the winter darkness,
0:45:29 > 0:45:32sort of simulating what you would experience
0:45:32 > 0:45:34during a long-duration space flight?
0:45:34 > 0:45:38Well, it's not simulating, it IS long and dark.
0:45:38 > 0:45:39Yes, that's true.
0:45:39 > 0:45:41And there is no escape.
0:45:41 > 0:45:46And for ethical reasons, this is something we can't simulate.
0:45:46 > 0:45:49Even if in the middle of winter you say,
0:45:49 > 0:45:52"No, no, no, no, I've changed my mind, I really want out now,"
0:45:52 > 0:45:54- you can't. - You have to just deal with it?
0:45:54 > 0:45:56Yeah, indeed.
0:45:56 > 0:45:58Getting very close now, five metres.
0:45:58 > 0:46:00I'm now trying to...
0:46:01 > 0:46:03..look at two screens at once
0:46:03 > 0:46:06with crosses going in different directions.
0:46:06 > 0:46:09And brake, brake, brake because you are going to overshoot.
0:46:09 > 0:46:11Yep.
0:46:11 > 0:46:12Two metres.
0:46:14 > 0:46:16SIMULATOR WHIRS
0:46:18 > 0:46:21'Pictures show capture and hard dock.'
0:46:21 > 0:46:25PETER LAUGHS We're in! Fantastic!
0:46:25 > 0:46:28- Well done!- I'm exhausted!
0:46:28 > 0:46:30Tim Peake is going to start getting very worried.
0:46:30 > 0:46:31NATHALIE LAUGHS
0:46:34 > 0:46:38Arguably, back here on Earth, Halley's most important work
0:46:38 > 0:46:41is to look out for signs of climate change.
0:46:41 > 0:46:42Neil, this snow surface actually
0:46:42 > 0:46:44is almost perfect, isn't it, for skiing?
0:46:44 > 0:46:47Yeah, it's absolutely great, it's lovely and soft.
0:46:47 > 0:46:51And it's this snow, within Halley's clean-air sector,
0:46:51 > 0:46:54that we've come to take a closer look at.
0:46:58 > 0:47:01This is not the easiest, with big boots on, is it?
0:47:01 > 0:47:03No, definitely not.
0:47:05 > 0:47:07The prevailing wind arriving here
0:47:07 > 0:47:11blows over 2,000 miles of an untouched continent,
0:47:11 > 0:47:14making it the purest air in the world.
0:47:15 > 0:47:18So, when it's trapped by the snow falling here,
0:47:18 > 0:47:22isolating pollutants created by human activity is made a lot easier.
0:47:25 > 0:47:29And operations at Halley mean that purity is guaranteed.
0:47:29 > 0:47:31There's no vehicles that come down here.
0:47:31 > 0:47:35People... The only way to get into this area
0:47:35 > 0:47:37is to either walk or to ski.
0:47:37 > 0:47:39Right, suit on, what's next?
0:47:39 > 0:47:41First of all, we need a hole and that will take some time.
0:47:41 > 0:47:44Right, well, that's going to warm us up.
0:47:45 > 0:47:47We are wearing these fetching overalls
0:47:47 > 0:47:50to prevent us contaminating the snow samples.
0:47:53 > 0:47:54I'm suffering for science!
0:47:56 > 0:47:58Because the air here is so pure,
0:47:58 > 0:48:02chemicals trapped in the snow reveal historic climate change.
0:48:05 > 0:48:06Well, snow sampling gives us
0:48:06 > 0:48:09a present-day understanding of the atmosphere
0:48:09 > 0:48:11as compared to ice cores,
0:48:11 > 0:48:15which provide an atmospheric reference to the past.
0:48:18 > 0:48:19If we can link these two together,
0:48:19 > 0:48:22we can provide a better understanding
0:48:22 > 0:48:25of what the atmosphere will be like in the future
0:48:25 > 0:48:28and the effects that will have on our climate.
0:48:28 > 0:48:33Millennium-old ice cores only contain natural pollutants
0:48:33 > 0:48:35from forest fires and volcanic eruptions.
0:48:35 > 0:48:40The snow samples contain everything man-made in the modern world.
0:48:41 > 0:48:44So comparing the two can help determine
0:48:44 > 0:48:49the impact those pollutant levels may have on the climate.
0:48:49 > 0:48:51But that's not the whole story.
0:48:58 > 0:49:02Another kilometre further away is the Clean Air Lab.
0:49:02 > 0:49:05The monitoring equipment here is so sensitive
0:49:05 > 0:49:09it can detect forest fires and volcanic eruptions
0:49:09 > 0:49:11as far away as South America or Africa.
0:49:14 > 0:49:16I'm breathing the cleanest air on the planet!
0:49:16 > 0:49:18- I like that!- Yeah.
0:49:18 > 0:49:23The Clean Air Lab is searching for evidence of global warming,
0:49:23 > 0:49:27in particular the greenhouse gases CO2 and methane.
0:49:30 > 0:49:32So, here we've got the sample pipe.
0:49:32 > 0:49:34The air comes in, a small off-take is taken
0:49:34 > 0:49:37and goes into the instrument
0:49:37 > 0:49:41and that's where we measure the air outside, the clean air outside.
0:49:41 > 0:49:44And these are the real-time values that we're seeing
0:49:44 > 0:49:47of what actually are all greenhouse gases.
0:49:47 > 0:49:51Yes, as we know, CO2 is one of the main greenhouse gases at the moment.
0:49:51 > 0:49:55As you can see, it's about 398 parts per million.
0:49:55 > 0:49:57Now, I've been an atmospheric chemist
0:49:57 > 0:49:58probably for the past 16 years.
0:49:58 > 0:50:02When I first started, it was around 375,
0:50:02 > 0:50:07so it's probably increased by nearly 10% or thereabouts...
0:50:07 > 0:50:09- In that time?- Yes.
0:50:09 > 0:50:12How can we be sure that those levels that you're seeing increasing
0:50:12 > 0:50:14are actually coming from human activity?
0:50:14 > 0:50:18Well, the only other way you could get a large amount of CO2
0:50:18 > 0:50:21into the atmosphere is probably through volcano eruptions
0:50:21 > 0:50:24and we know there hasn't really been any large volcanic eruptions
0:50:24 > 0:50:29in the last...150 years, so we can categorically say
0:50:29 > 0:50:32that it's more than likely come from fossil burning.
0:50:32 > 0:50:35Although volcanoes erupt all the time,
0:50:35 > 0:50:38there have been no major events for over a century
0:50:38 > 0:50:43and the present concentration of atmospheric CO2, carbon dioxide,
0:50:43 > 0:50:48is higher than it has been for almost 1,000,000 years.
0:50:48 > 0:50:50But for atmospheric chemists,
0:50:50 > 0:50:53CO2 is also an indicator of what could happen
0:50:53 > 0:51:00with a far more dangerous greenhouse gas - CH4 or methane.
0:51:00 > 0:51:02And as you can see here, the level of methane
0:51:02 > 0:51:07is less than two parts per million, so it's a lot less than CO2.
0:51:07 > 0:51:10But we know that we are putting more CO2 into the atmosphere,
0:51:10 > 0:51:12so we are heating up the atmosphere.
0:51:12 > 0:51:14As the atmosphere starts to warm up,
0:51:14 > 0:51:17the oceans will start to warm up and as the oceans start to warm up,
0:51:17 > 0:51:19more CO2 will come off the oceans
0:51:19 > 0:51:22and then you get sort of a runaway effect,
0:51:22 > 0:51:23so if this keeps rising
0:51:23 > 0:51:27then there's a chance that that permafrost is going to start to melt
0:51:27 > 0:51:30and with that, we are going to get the release of methane.
0:51:30 > 0:51:33The permafrost of the Northern Hemisphere
0:51:33 > 0:51:35across Russia and North America
0:51:35 > 0:51:40holds vast amounts of methane within its frozen soil
0:51:40 > 0:51:44and this gas is an even bigger threat than CO2.
0:51:47 > 0:51:50Methane, even though it's a lot smaller in concentration,
0:51:50 > 0:51:54is 20 times more potent as a greenhouse gas than CO2,
0:51:54 > 0:51:57so methane in the future could well be the one.
0:51:59 > 0:52:01For Neil, the danger is clear.
0:52:01 > 0:52:03He thinks that rising CO2 levels
0:52:03 > 0:52:08could cause the release of more methane into the atmosphere
0:52:08 > 0:52:10and that this gas is likely to have
0:52:10 > 0:52:13a far greater impact on global warming.
0:52:14 > 0:52:15But even today,
0:52:15 > 0:52:19the current levels of these greenhouse gases are being felt.
0:52:21 > 0:52:23Long-term measurements have found
0:52:23 > 0:52:26that temperatures across the Antarctic Peninsula
0:52:26 > 0:52:30have risen by over 3 degrees Celsius over the last 60 years.
0:52:30 > 0:52:32That's more than ten times the global average.
0:52:32 > 0:52:37Over the next century, greenhouse gases will drive further warming
0:52:37 > 0:52:40across Antarctica and its surrounding seas.
0:52:40 > 0:52:45The work being done at Halley is vital.
0:52:45 > 0:52:46We need to understand those processes
0:52:46 > 0:52:50to be able to predict the impact of that future warming.
0:53:02 > 0:53:06But Halley has to cope in this hostile environment
0:53:06 > 0:53:09and each year it's a challenge to survive.
0:53:10 > 0:53:13Well, Mike, thanks for letting me into the cab.
0:53:13 > 0:53:16- Is this your normal job? - It's my first season in Antarctica.
0:53:16 > 0:53:20I'm normally a farmer back at home, up in East Yorkshire.
0:53:20 > 0:53:21It's a similar flat landscape,
0:53:21 > 0:53:23but obviously a very different colour.
0:53:23 > 0:53:25You're not going to grow much here either, are you?
0:53:25 > 0:53:28No, I don't think it would be very easy to get a crop of spuds off...
0:53:28 > 0:53:30- They wouldn't do too well around here, I reckon.- No.
0:53:32 > 0:53:35Although it may look flat and unchanging,
0:53:35 > 0:53:38each winter huge snowdrifts accumulate
0:53:38 > 0:53:40around the research station.
0:53:43 > 0:53:45And each summer they need to be shifted.
0:53:51 > 0:53:55What we're doing at the moment is we're pushing the wind tails,
0:53:55 > 0:53:59which is the snow from the winter, away from the modules,
0:53:59 > 0:54:02so we are having to move about 1.5 metres of snow away
0:54:02 > 0:54:04and flattening the site out.
0:54:04 > 0:54:06And this is really the machine for doing it, isn't it?
0:54:06 > 0:54:08Yeah, this is about 450 horsepower
0:54:08 > 0:54:11and it's great at moving huge quantities of snow.
0:54:14 > 0:54:17The station I was in back in the early '80s
0:54:17 > 0:54:19had been there for nearly ten years when I got here,
0:54:19 > 0:54:21but it was designed to be buried,
0:54:21 > 0:54:25so it was like living in a submarine under the ice
0:54:25 > 0:54:27- in these huts, in metal tubes.- Yeah.
0:54:27 > 0:54:29You were about 50 feet down.
0:54:30 > 0:54:32Halley III finally succumbed,
0:54:32 > 0:54:35entombed and crushed by the mounting snow.
0:54:35 > 0:54:40It was abandoned a year after I left in 1983,
0:54:40 > 0:54:43but amazingly, finally reappeared years later
0:54:43 > 0:54:45at the edge of the ice shelf.
0:54:47 > 0:54:52Holding back nature in Antarctica is virtually impossible,
0:54:52 > 0:54:56but this is something Halley's designers have thought about.
0:54:56 > 0:54:58This station is designed to be jacked up every year,
0:54:58 > 0:55:01so that's what we've been doing the past couple of weeks,
0:55:01 > 0:55:04is involved in raising the station by two metres.
0:55:15 > 0:55:17Sitting on massive hydraulic jacks
0:55:17 > 0:55:22means Halley now keeps itself happily above the snow's surface.
0:55:25 > 0:55:29However, there is still the threat of the chasm.
0:55:29 > 0:55:32As it lengthens, the greater the chance that
0:55:32 > 0:55:36the research station finds itself floating into the Southern Ocean.
0:55:39 > 0:55:43But there's another unusual feature in Halley's design,
0:55:43 > 0:55:46the first of its kind, which will help it survive.
0:55:46 > 0:55:50At the bottom of its hydraulic legs are huge skis...
0:55:52 > 0:55:55..so each module will be detached from its neighbour
0:55:55 > 0:55:57then dragged to a new site
0:55:57 > 0:56:01in the same way it was brought here four years ago.
0:56:02 > 0:56:08After extensive surveys, a new location has been found 20km away,
0:56:08 > 0:56:11safely on the other side of the chasm.
0:56:16 > 0:56:20And there, Halley can continue its work.
0:56:25 > 0:56:28Before we head home, at the edge of the ice shelf
0:56:28 > 0:56:31all the ship's cargo is finally unloaded.
0:56:31 > 0:56:34These big, red shipping containers we brought down on the Shackleton
0:56:34 > 0:56:37contain living accommodation - kitchen, bedrooms,
0:56:37 > 0:56:41bathrooms, working spaces - and they are going to be used
0:56:41 > 0:56:44to build a temporary camp for the team up at Halley VI.
0:56:44 > 0:56:46So it's all hands on deck at the moment,
0:56:46 > 0:56:49the container is being craned out over the ice
0:56:49 > 0:56:51onto these heavy-duty sledges
0:56:51 > 0:56:55that will then be dragged all the way up to Halley VI.
0:56:58 > 0:57:00Once the temporary accommodation is set up,
0:57:00 > 0:57:03then Halley can be moved out of danger.
0:57:19 > 0:57:24After an all-too-brief nine days on the ice shelf, I'm heading for home.
0:57:24 > 0:57:27It's a bittersweet farewell
0:57:27 > 0:57:31to somewhere I'm unlikely to ever see again.
0:57:33 > 0:57:35I wasn't sure what it would be like,
0:57:35 > 0:57:38coming back here after all these years.
0:57:38 > 0:57:41What I found is a landscape that is completely unchanged,
0:57:41 > 0:57:45but an operation that is on a different scale
0:57:45 > 0:57:47to what I experienced back in the early '80s.
0:57:47 > 0:57:49It feels much more professional.
0:57:49 > 0:57:52The science is bigger, there's more experiments,
0:57:52 > 0:57:55and yet this place has such a huge influence
0:57:55 > 0:57:58on the planet's weather and climate,
0:57:58 > 0:58:01which is why the work done here at Halley is so vital.
0:58:06 > 0:58:09I thoroughly enjoyed my time back on the ice.
0:58:09 > 0:58:11I was worried what it was going to be like leaving.
0:58:11 > 0:58:14To be honest, I thought I'd probably just fall apart,
0:58:14 > 0:58:19but actually, I don't know, it feels like I've come full circle, it's...
0:58:19 > 0:58:22it's feeling like the end of a journey
0:58:22 > 0:58:24that I started half a lifetime ago.