:00:00. > :00:23.This is Antarctica, the last, great wilderness. It's the coldest,
:00:24. > :00:31.windiest, driest and most isolated place on earth. And it's home to the
:00:32. > :00:36.British Antarctic survey's Halley research station. Here, cutting-edge
:00:37. > :00:43.science is making vital discoveries about how our lives are vulnerable
:00:44. > :00:51.to the sun's activities and threatened by man-made climate
:00:52. > :00:55.change. It's January 27, 2016, and we're at 75 degrees south. For the
:00:56. > :00:59.last couple of weeks, we've been on this ship behind me, the RRS earnest
:01:00. > :01:07.Shackleton, crossing the Sothern Ocean. We're making this journey to
:01:08. > :01:17.resupply the research station, but this is also something of a rescue
:01:18. > :01:24.mission. Although it appears to be on solid ground, Hally sits on a
:01:25. > :01:28.constantly moving and cracking ice shelf, which has a chasm that
:01:29. > :01:31.threatens to cast the station adrift on a massive iceberg. Our cargo is
:01:32. > :01:37.part of the effort to stop that happening. I'm Peter Gibbs, my job
:01:38. > :01:43.is working for the Met Office as a BBC weatherman, but back in my
:01:44. > :01:47.younger days, I worked as a meteorologist in Antarctica for over
:01:48. > :01:53.two years. I never, ever thought I'd get the opportunity to return. This
:01:54. > :01:59.is my journey to investigate the threat to Halley's future. Here we
:02:00. > :02:05.go then. It's going over the edge that's the worst bit. And science at
:02:06. > :02:28.the end of the world. It's just phenomenal.
:02:29. > :02:35.This is the real deal now, a huge iceberg that probably broke off the
:02:36. > :02:39.continent decades ago. The point is, though, if we were here in this spot
:02:40. > :02:44.at the end of winter, there would be several hundred miles of continuous
:02:45. > :02:51.sea ice between us and the coast. That's why it's impossible to get
:02:52. > :02:54.into Halley for a good nine months of the year. Back to the UK now and
:02:55. > :02:59.that frosty start in the south, it's not going to last too long. The
:03:00. > :03:05.sunshine, once it comes up, clearing the frost fairly quickly.
:03:06. > :03:09.I've been waving my arms in front of weather charts for 20-odd years now.
:03:10. > :03:14.But straight from university, I actually applied to the British
:03:15. > :03:18.Antarctic survey. I was taken on to be sent down as the weatherman to
:03:19. > :03:22.their Halley research station in Antarctica. It was for two years
:03:23. > :03:26.that. Was standard in those days. This is a bit of a roughy, toughy
:03:27. > :03:30.shot, but behind there, you can see there's a pretty young man, who is
:03:31. > :03:38.still getting to grips with the enormity of what he's actually taken
:03:39. > :03:42.on. Once a month, we'd have a 200-word telex message in and out.
:03:43. > :03:46.To be honest, after a few months, I was struggling find very much to put
:03:47. > :03:51.into those 200-word messages. Essentially, for eight, nine months
:03:52. > :03:55.of the year, there is no way to get anybody in or out. But I absolutely
:03:56. > :03:59.lovered it. I really took to it. -- loved it. I really took to it. Even
:04:00. > :04:06.after two years, when the ship came to take me away, I didn't want to
:04:07. > :04:09.go. I really didn't want to go. I had such an attachment to the place,
:04:10. > :04:21.that I really didn't want to leave it, so to have the chance to
:04:22. > :04:27.actually go back is a big thing. 35 years on, and e-mail has replaced
:04:28. > :04:34.telex, but Halley is still as isolated as ever. So far from
:04:35. > :04:44.civilisation it may as well be on another planet. And everyone posted
:04:45. > :04:50.there still needs to be utterly self-reliant. I'm Jess. I'm the
:04:51. > :04:54.winter station leader. I am in charge of making sure the station
:04:55. > :05:00.runs smoothly over the winter, when we're down to a team of just 13 of
:05:01. > :05:03.us. We don't have help, so all our emergency planning is based on
:05:04. > :05:10.people on station sorting themselves out. We have to be prepared for any
:05:11. > :05:15.circumstances, so in the event like a fire, we have our emergency
:05:16. > :05:20.supplies elsewhere on station, in containers, in other buildings. With
:05:21. > :05:28.outside help possibly months away, the station has supplies to survive
:05:29. > :05:32.for almost 300 days. Food allowances are calculated based on military
:05:33. > :05:35.rations. We add the polar allowance to that, which adds for the more
:05:36. > :05:42.calories because of the colder weather. We have a lot of stores,
:05:43. > :05:47.1500 kilograms of tinned tomatoes. Nearly 900 kilograms of beef. We
:05:48. > :05:50.never want to run out of food. It's often said that the chef is one of
:05:51. > :05:59.the most important people on station.
:06:00. > :06:11.This ice shelf is just a small part of Antarctica. It's a vast
:06:12. > :06:24.continent, almost twice the size of Australia. It contains 70% of the
:06:25. > :06:32.world's fresh water. Trapped in an ice sheet that's up to five
:06:33. > :06:38.kilometres thick. And because of this, Antarctica is a huge influence
:06:39. > :06:45.on global weather patterns. So monitoring what goes on here is
:06:46. > :06:52.critical. Back in the early 80s, when I was last here, Halley was at
:06:53. > :06:58.the centre of a global environmental news story all about a frightening
:06:59. > :07:04.man-made hull high in the stratosphere. An aerosol can, the
:07:05. > :07:08.argument goes that sprays are destroying a vital part of the
:07:09. > :07:13.earth's atmosphere. There's a two-mile thick layer of a gas called
:07:14. > :07:21.ozone just here, about ten miles above the earth. Ozone matters
:07:22. > :07:27.because it does one crucial thing - it shields all life on the earth's
:07:28. > :07:33.surface from the sun's harmful radiation. Scientists at Halley
:07:34. > :07:38.discovered that each spring, as the sun re-appeared, ozone levels above
:07:39. > :07:41.here dropped dramatically. They were so surprised they went back and
:07:42. > :07:47.checked and rechecked their results. In fact what they found was a hole
:07:48. > :07:58.in the ozone layer the size of Antarctica. This is the machine that
:07:59. > :08:04.discovered the ozone hole, this is the Dobson spectramanometer. This
:08:05. > :08:11.was here in the 1980s, but it was invented in the 1920s by GMB Dobson,
:08:12. > :08:17.basically in his garden shed. Even now almost 100 years later, it's the
:08:18. > :08:21.gold standard for ozone measurement. Essentially what it's telling us is
:08:22. > :08:30.how much harmful UV radiation gets down to the earth's surface. What it
:08:31. > :08:36.detected in the 80s was the effect of man-made gases, used in spray
:08:37. > :08:41.cans and fridges, trapped within Antarctica's polar vortex. In
:08:42. > :08:46.winter, the cold air circulating high above the continent forms
:08:47. > :08:53.stratospheric ice clouds containing these gases. When the spring sun
:08:54. > :08:57.returns, they act as a catalyst, destroying ozone. Ozone has been
:08:58. > :09:02.measured daily here at Halley since the mid-1950s. It was the change in
:09:03. > :09:05.levels in the 70s and 80s that led scientists to realise that it was
:09:06. > :09:13.being destroyed in the stratosphere. That then led on to the signing of
:09:14. > :09:18.the Montreal protocol in 1987 to ban ozone destroying chemicals like
:09:19. > :09:22.CFCs. It was an unprecedented feat of international cooperation.
:09:23. > :09:26.Measurements are still being taken on a daily basis, what they show is
:09:27. > :09:32.that it will take at least to the end of the century for levels to
:09:33. > :09:41.return to near normal. So it seems as if the rot has stopped.
:09:42. > :09:49.Studying the atmosphere at Halley is critical. Antarctica is a huge
:09:50. > :09:54.ice-covered continent surrounded by ocean and when that ocean freezes
:09:55. > :10:01.during the winter, for as much as a thousand miles, it doubles the area
:10:02. > :10:09.of ice. That yearly heart beat is a huge influence on the planet's
:10:10. > :10:16.climate. Also the Sothern Oceans are a big player. The endless storms
:10:17. > :10:20.that circulate around the periphery of Antarctica drive a conveyor belt
:10:21. > :10:24.of oceanic heat. While this place might be out of sight for most of
:10:25. > :10:33.us, what happens here affects us all. Keeping Halley operational on
:10:34. > :10:38.this particular ice shelf is critical, not just for monitoring
:10:39. > :10:43.the weather. 60 years ago, it was cited here ah, long with numerous --
:10:44. > :10:48.along with numerous aerials to investigate the interactions between
:10:49. > :10:52.the earth and the sun. I'm Richard. I work at the British Antarctic
:10:53. > :10:56.survey and I lead the space weather and atmosphere team. Halley is our
:10:57. > :11:02.window on space, that's what we call it. I feel like the luckiest person
:11:03. > :11:10.on earth really. Each winter at Halley, there's a dazzling display
:11:11. > :11:14.of light, the Aurora australis. The Aurora are only possible at the
:11:15. > :11:20.north and south poles because of the shape of the earth's magnetic fields
:11:21. > :11:22.and by monitoring what goes on above our heads, Halley's location gives
:11:23. > :11:29.us the opportunity to protect our modern world from the sun's
:11:30. > :11:34.destructive activity. The flow of the planet's molten iron core is
:11:35. > :11:40.what creates the earth's magnetic field. Field lines stretch out into
:11:41. > :11:44.space, 60,000 kilometres facing the sun and trailing away some 400,000
:11:45. > :11:51.kilometres on the dark side of the earth
:11:52. > :12:01.These field lines can't be seen, but we do witness the Aurora when
:12:02. > :12:09.they're disrupted by the sun's coronal mass ejections.
:12:10. > :12:15.It emits billions of tonnes of charged particles and when they come
:12:16. > :12:19.to the earth they see the earth's magnetic field as a barrier. But it
:12:20. > :12:24.has a potential of ripping open the outer layers of the earth's magnetic
:12:25. > :12:28.field, drawing the field across the polar caps and extending the
:12:29. > :12:34.magnetic field into the tail. The magnetic field lines on the dark
:12:35. > :12:41.side of the earth are suddenly violently snapped back into place.
:12:42. > :12:45.It's an earthquake in space, if you like. That process is the start of a
:12:46. > :12:52.large geometic storm and the manifestation of that is that the
:12:53. > :12:57.Aurora you see in the polar regions. But Halley isn't just under this
:12:58. > :13:03.zone. It also sits within a unique glitch
:13:04. > :13:10.in the earth's magnetic field called the south Atlantic anomaly.
:13:11. > :13:16.And for scientists it's a window into space that allows them to study
:13:17. > :13:21.radio waves thrown out by those coronal mass ejikss. Our research
:13:22. > :13:25.has shown those radio waves can accelerate charged particles up to
:13:26. > :13:34.very high energies and damage the sprayscraft. We call them killer
:13:35. > :13:39.electrons. They become trapped in magnetic fields wrapped around the
:13:40. > :13:45.earth called the van Allen radiation belts.
:13:46. > :13:49.And during a magnetic storm caused by a coronal mass ejection they can
:13:50. > :13:55.increase 10,000-fold in as little as two minutes.
:13:56. > :14:00.The problem is that over half of all satellites pass through these belts
:14:01. > :14:05.as they orbit the earth. The charged particles can penetrate
:14:06. > :14:11.the outer skin of a spacecraft and then they get buried into circuit
:14:12. > :14:20.boards, insulators, cables and that charge can then build up. If it
:14:21. > :14:24.builds up to a very high level it can cause electrostatic discharge.
:14:25. > :14:29.It's like a lightning bolt. They have been related to the loss of a
:14:30. > :14:36.spacecraft, the total satellite loss, costing $250 million. That's a
:14:37. > :14:40.lot of money. You think that there is something like 120 satellites on
:14:41. > :14:49.orbit in total. The space weather research done here
:14:50. > :14:54.is attempting to forecast the impact of geo mag yettic storms because of
:14:55. > :14:59.the damage they can do. We need to know what the largest level of the
:15:00. > :15:04.radiation can be in a severe storm because we can then give that
:15:05. > :15:15.information to the designers and they can then design against that to
:15:16. > :15:20.help protect the spacecraft. Arguably back here on earth Halley's
:15:21. > :15:24.most important work is to look out for signs of climate change.
:15:25. > :15:29.Neil, this snow surface is almost perfect for skiing. Yeah, it's
:15:30. > :15:32.absolutely great. It's lovely and sot -- lovely and soft. It's this
:15:33. > :15:38.snow within the clean air sector that we have come to take a closer
:15:39. > :15:47.look at. This is not the easiest with big
:15:48. > :15:53.boots on, is it? No, definitely not. The prevailing wind arriving here
:15:54. > :15:57.blows over 2,000 miles of an untouched continent, making it the
:15:58. > :16:01.purest air in the world. When it's trapped by the snow falling here
:16:02. > :16:08.isolating pollutants created by human activity is made a lot easier.
:16:09. > :16:12.Operations at Halley mean that purity is guaranteed.
:16:13. > :16:18.There is no vehicles coming down here. The only way to get into this
:16:19. > :16:23.area is to walk or ski. Right the suit is on. What's next? First of
:16:24. > :16:28.all, we need a hole and that will take sometime. That will warm us up.
:16:29. > :16:33.We are wearing these fetching overalls to prevent us contaminating
:16:34. > :16:40.the snow samples. I am suffering for science!
:16:41. > :16:47.Because the air here is so pure chemicals trapped in the snow reveal
:16:48. > :16:53.historic climate change. Snow sampling gives us a present day
:16:54. > :16:58.understanding of the atmosphere as compared to ice cores which provide
:16:59. > :17:03.an atmospheric reference to the past. If we can link these two
:17:04. > :17:06.together we can provide a better understanding of what the atmosphere
:17:07. > :17:13.will be like in the future and the effects that will have on our
:17:14. > :17:20.climate. Millennium old ice cores only contain natural pollutants from
:17:21. > :17:25.forest fires. The snow sachls contain everything manmade in the
:17:26. > :17:28.modern world. So comparing the two can help determine the impact those
:17:29. > :17:40.pollutant levels may have on the climate.
:17:41. > :17:44.But that's not the whole story. Another kilometre further away is
:17:45. > :17:49.the clean air lab. The air monitoring equipment here is so
:17:50. > :17:55.sensitive it can detect forest fires and volcanic eruptions as far away
:17:56. > :18:00.as south America or Africa. Breathing the cleanest air on the
:18:01. > :18:08.planet, I like that. The clean air lab is searching for evidence of
:18:09. > :18:15.global warming. In particular, the greenhouse gases CO2 and methane.
:18:16. > :18:19.Here we have the sample pipe, the air comes in, it goes into the
:18:20. > :18:23.instrument and that's where we measure the air outside, the clean
:18:24. > :18:28.air outside. These are the real-time values we are seeing of what
:18:29. > :18:38.actually are all greenhouse gases? Yes, as we know CO2 is one of the
:18:39. > :18:47.main gases at the moment. It's about 390 per million. When I first
:18:48. > :18:50.started it was around 375. It's probably increased by nearly 10% or
:18:51. > :18:55.thereabouts. How can you be sure those levels that you are seeing
:18:56. > :19:05.increasing are coming from human activity? The only way you can get a
:19:06. > :19:09.large amount into the atmosphere is through volcano eruptions and there
:19:10. > :19:17.hasn't been any large in the last 150 years. We can say it's more than
:19:18. > :19:20.likely coming from fossil burns. Although volcanoes erupt all the
:19:21. > :19:26.time there have been no major events for over a century and the present
:19:27. > :19:33.concentration of atmospheric CO2 is higher than it has been for almost a
:19:34. > :19:39.million years. But for atmospheric chemists it's also an indicator of
:19:40. > :19:47.what can happen with a far more dangerous greenhouse gas, CH4, or
:19:48. > :19:53.methamne. As you can see it's a lot less than CO22. We know that we are
:19:54. > :19:59.putting more CO2 into the atmosphere. As the atmosphere warms
:20:00. > :20:06.up the owings will warm up and as they warm up more CO26789 will come
:20:07. > :20:09.off the oceans. If this reaps rising there is a chance that frost will
:20:10. > :20:15.start to melt and with that we will get the release of methane. The
:20:16. > :20:20.frost off the northern hemisphere across Russia and North America
:20:21. > :20:29.holds vast amounts of methane within its frozen soil. This gas is an even
:20:30. > :20:35.bigger threat than CO2. Methane even though it's smaller in
:20:36. > :20:41.concentration, is 20 times more potent. In the future it could well
:20:42. > :20:48.be the one. For Neil the danger is clear. He thinks that rising CO2
:20:49. > :20:53.levels could cause the release of more methane into the atmosphere and
:20:54. > :21:00.this gas is likely to have a far greater impact on global warming.
:21:01. > :21:06.But even today the current levels of these greenhouse gases are being
:21:07. > :21:09.felt. Long-term measurements have found temperatures across the
:21:10. > :21:14.Antarctic have risen by over three degrees over the last 60 years, more
:21:15. > :21:20.than ten times the global average. Over the next century greenhouse
:21:21. > :21:24.gases will drive further warming across Antarctic and the surrounding
:21:25. > :21:29.seas. The work being done at Halley is vital. We need to understand
:21:30. > :21:49.those processes to predict the impact of that future warming.
:21:50. > :21:58.After an all too brief nine days on the ice shelf I am heading for home.
:21:59. > :22:03.It's a bittersweet farewell to somewhere I am unlikely to ever see
:22:04. > :22:07.again. I wasn't sure what it was going to
:22:08. > :22:12.be like coming back here after all these years. What I found is a
:22:13. > :22:15.landscape that's completely unchanged but an operation that's on
:22:16. > :22:19.a different scale to what I experienced back in the early 80s.
:22:20. > :22:24.It feels much more professional. The size is bigger, there is more
:22:25. > :22:27.experiments. And yet this place has such a huge influence on the
:22:28. > :22:35.planet's weather and climate which is why the work done here at Halley
:22:36. > :22:39.is so vital. I thoroughly enjoyed my time back on
:22:40. > :22:44.the ice. I was worried what it was going to be like leaving, to be
:22:45. > :22:48.honest I thought I would probably fall apart. But actually, I don't
:22:49. > :22:54.know, it feels like I have come full circle. It's feeling like the end of
:22:55. > :23:35.a journey that I started half a lifetime ago.
:23:36. > :23:36.Hello. We have had lovely spells of sunshine