:00:34. > :00:36.between 18-60. Now it is time for Our World. British scientists are
:00:36. > :00:39.in ing dramatic and potentially dangerous changes to
:00:39. > :00:43.the west Antarctic ice shelf. There is a strange and mysterious place
:00:43. > :00:47.at the edge of our planet which most of us will never see. 1.5
:00:47. > :00:50.times the size of the United States, it holds just ice. Now one of
:00:50. > :00:53.Antarctica's greatest glaciers has begun to race into the ocean,
:00:53. > :00:57.putting more ice into the sea than any other in the world. Nobody
:00:57. > :01:07.knows what the consequences for the world's oceans will be. Just one
:01:07. > :01:43.
:01:43. > :01:47.thing is certain: If you want It is brass monkeys out there! You
:01:47. > :01:50.would think that after six trips to this icy continent, I would be used
:01:50. > :01:54.to the cold but it is impossible to grow complacent about any aspect of
:01:54. > :01:57.Antarctica. For 20 years, I have been reporting on how it has
:01:57. > :02:00.changed. The seas around the Antarctic Peninsula have changed
:02:00. > :02:07.almost beyond recognition, and climate change is also having a
:02:07. > :02:17.dramatic effect. I am talking to scientists both here and in the UK
:02:17. > :02:27.
:02:27. > :02:30.about something they are reporting as a major global concern: The
:02:30. > :02:34.oddly named Pine Island Glacier is one of the world's largest rivers
:02:34. > :02:37.of ice and it has almost doubled its speed in the last 30 years. Its
:02:37. > :02:40.behaviour has left scientists confused and concerned. The ice
:02:40. > :02:50.here is melting faster than just about anyone thought possible. We
:02:50. > :02:54.
:02:54. > :03:04.have front-row seats here. The story begins here on the Antarctic
:03:04. > :03:05.
:03:05. > :03:09.Peninsula. Until the 1800s, Antarctica was nothing more than a
:03:09. > :03:14.myth and even when we discovered it was real, it retained a mythic
:03:14. > :03:24.status. We thought of it as the last great wilderness, untouched,
:03:24. > :03:37.
:03:38. > :03:47.unchanging. We were wrong. This man is an aero-geophysicist. In 1997 he
:03:48. > :03:49.
:03:49. > :03:52.was working on a vast expanse of floating ice called the Larsen B.
:03:52. > :03:56.Each ice shelf has its own character but this one has rifts
:03:56. > :04:00.and it is likely it could go. years ago, we were sitting in a
:04:00. > :04:07.small boat off the Antarctic Peninsula when you said this could
:04:07. > :04:15.be the next glacier to go. How did you know? In hindsight I should
:04:15. > :04:19.have been more forthright. There were three of us on the plane and
:04:19. > :04:22.we could see the enormous rifts and the way it was open. After the
:04:22. > :04:29.flight we were chatting. We all felt melancholy because we knew it
:04:29. > :04:39.was going to go at some point. could see its number was up. Hugh
:04:39. > :04:43.
:04:43. > :04:47.was right. So that is the place where the glacier should begin but
:04:47. > :04:51.instead it is full of water and Larsen B is gone. It is an
:04:51. > :05:01.extraordinary sight. In 2002, it was plain to see in the satellite
:05:01. > :05:06.
:05:06. > :05:09.images. In March, there was heavy cloud and when it cleared the
:05:10. > :05:15.glacier had vanished. It had become tiny shards which would eventually
:05:15. > :05:22.float out to sea. Scientists stared at their computer monitors in
:05:22. > :05:26.astonishment. We knew that other ice shelves had disintegrated as
:05:26. > :05:29.well but in a piecemeal fashion. Pieces would fall off and then more
:05:29. > :05:39.bits but this one was very different. The whole ice shelf
:05:39. > :06:01.
:06:01. > :06:04.literally disintegrated. A complete shock? Yes, it was not expected.
:06:04. > :06:08.soon as the weather permitted, scientists returned to the
:06:08. > :06:11.peninsula to try to work out why it had collapsed. It did not take them
:06:11. > :06:14.long. This is a meteorologist who tracks climate on the peninsula.
:06:14. > :06:24.She is watching as the climate behaves in an extraordinary way.
:06:24. > :06:30.
:06:30. > :06:33.Can you give me an overview of what has happened to temperatures?
:06:33. > :06:36.Antarctic Peninsula is one of the fastest warming places on the
:06:36. > :06:39.planet. Temperatures have risen by three degrees in 50 years, which is
:06:39. > :06:42.about ten times the global average. Scientists concluded that warming
:06:42. > :06:47.air was responsible for the glacier's demise. Climate change
:06:47. > :06:57.had claimed its first high-profile Antarctic victim. After the
:06:57. > :07:08.
:07:08. > :07:14.collapse of Larsen B, the focus was on the ice and who works on it. A
:07:14. > :07:18.world-leading glaciologist remembers the time very well.
:07:18. > :07:21.the biggest thing we have seen for many decades - an ice shelf that we
:07:21. > :07:31.thought was permanent suddenly collapsing in a short period. It
:07:31. > :07:40.was enormously important. This is the main research station of the
:07:40. > :07:46.British Antarctic Survey. Scientists and support staff stay
:07:46. > :07:56.here for stretches of up to 18 months at a time. One of their aims
:07:56. > :07:59.
:07:59. > :08:02.is to track every move that the ice makes. Some people take a little
:08:02. > :08:05.persuading, like this climate change scientist. I studied
:08:05. > :08:15.oceanography and wanted to work in the tropics, somewhere warm.
:08:15. > :08:15.
:08:15. > :08:24.Somewhere along the line I was diverted to the polar region. It is
:08:24. > :08:30.incredible! This is something many people can only dream about. A
:08:30. > :08:39.glacier is always on the move. Glaciers are always moving towards
:08:39. > :08:46.the sea. You can really see that in this fissure which has opened up.
:08:46. > :08:56.You can walk around and see that it is moving. Why are the icicles at
:08:56. > :08:57.
:08:57. > :09:02.right angles here? The larger ones have formed over many years. They
:09:02. > :09:06.are dripping down vertically but the ice itself is moving. When it
:09:06. > :09:16.is quiet, you can hear cracks and creaks and groans. That is another
:09:16. > :09:20.indication that it is moving and really quite fast. Movement is one
:09:20. > :09:30.of the basic principles of ice. As snow falls across the continent, it
:09:30. > :09:35.
:09:35. > :09:38.is slowly compressed into giant frozen rivers. Gravity and fresh
:09:38. > :09:41.snowfall force these glaciers to float towards the sea. There they
:09:41. > :09:51.edge out in vast floating platforms called ice shelves. Their tips
:09:51. > :10:01.
:10:01. > :10:06.break into icebergs and float away to sea. Until the collapse of
:10:06. > :10:10.Larsen B, scientists had thought that this happened very slowly.
:10:10. > :10:13.They had a theory that an ice shelf was like a cork in a bottle,
:10:13. > :10:23.holding back a glacier. If you take away the cork, the glacier just
:10:23. > :10:39.
:10:39. > :10:43.hotly-contested but then the Larsen B broke away and melted. Now we
:10:43. > :10:53.know that the ice shelf restrains the glacier behind it. If you take
:10:53. > :10:59.
:10:59. > :11:06.away the ice shelf, the glacier will speed up. It was like pulling
:11:06. > :11:10.a cork from a bottle. The ice shelf has stabilised the glaciers. When
:11:10. > :11:20.it was gone, the glaciers sped up. They are still retreating at this
:11:20. > :11:23.
:11:23. > :11:33.moment. An ice shelf floats and has no effect on sea levels, unlike the
:11:33. > :11:37.
:11:37. > :11:41.glaciers behind them. In just six months, the glaciers dropped in
:11:41. > :11:45.height by as much as 1.5 times the size of these peaks. Remove an ice
:11:45. > :11:48.shelf and the glaciers behind will race to the seas. Ice can be swift
:11:48. > :11:58.and volatile. It made them afraid of what would happen if rising
:11:58. > :12:02.temperatures spread. The Antarctic Peninsula is a vast formation of
:12:02. > :12:06.ice but it is dwarfed by the West Antarctic ice sheet further south.
:12:06. > :12:10.Here the air is not warming nearly as fast, so scientists thought the
:12:10. > :12:20.ice shelves were safe at least until now. Then something happened
:12:20. > :12:23.which made them change their mind. 800 miles from the nearest British
:12:23. > :12:32.base, Pine Island glacier has been tracked by satellite since the
:12:32. > :12:36.1990s and it is acting up. It is one of the largest ice streams on
:12:36. > :12:43.the planet - a large river on ice that drains the West Antarctic ice
:12:43. > :12:53.shelf. It is changing very quickly. It was melting more than 100 times
:12:53. > :12:57.faster than they had expected. Scientists did not know why and had
:12:57. > :13:06.to go there to find out. Less than one thousandth of 1% of the world's
:13:06. > :13:15.population has ever been to Antarctica. Science here still
:13:15. > :13:18.pushes the limits of polar exploration. To get to this ice
:13:18. > :13:22.shelf from the nearest base, scientists had to cross 800 miles
:13:22. > :13:32.of the most inhospitable terrain on earth. It is a place so remote that
:13:32. > :13:33.
:13:33. > :13:37.more people have landed on the moon. Conditions here are so tough that
:13:37. > :13:40.only one scientist has walked on a forward floating edge of the
:13:40. > :13:50.glacier. He was an American from NASA. The pilot was so nervous that
:13:50. > :13:53.
:13:53. > :13:56.No one except a special robot. In January 2009, scientists sent a
:13:56. > :14:05.remote-controlled submarine into a place no man or machine had ever
:14:05. > :14:11.been before. In icy waters of the ice sheet its job was to collect
:14:11. > :14:20.data from below the glacier. Adrian Jenkins is the oceanographer who is
:14:20. > :14:27.in charge. This is a model of the submarine. It is seven metres long
:14:27. > :14:31.and a metre in diameter. This is sophisticated technology. It is
:14:31. > :14:38.amazing. It gives us an unprecedented view on the world
:14:38. > :14:41.underneath the ice shelves. Frozen sea ice normally covers the bay but
:14:41. > :14:50.a lucky break in the weather meant Adrian and the ship got within
:14:50. > :14:57.three miles of the ice shelf. wanted to get in and we would tents
:14:57. > :15:05.knowing this was the big moment. -- were tense. We were the first
:15:05. > :15:09.mission below the glacier and have no idea what would come back.
:15:09. > :15:13.the teams saw the data they were astonished. They thought the ice on
:15:13. > :15:20.the underside of the Pine Island glacier was an kits to a ridge but
:15:20. > :15:24.the Autosub had made its way 30 kilometres inland. The glacier had
:15:24. > :15:27.come unstuck and it was floating. It wasn't warming air that was
:15:27. > :15:31.causing it to melt, it was warming seas. Not just lapping against the
:15:31. > :15:38.ice but eating away at its underbelly. It changed the way we
:15:38. > :15:41.think about the system. It was jaw- dropping. What the submarine
:15:41. > :15:45.revealed was the latest piece of evidence suggesting the melting of
:15:45. > :15:55.the Pine Island glacier and the West Antarctic ice sheet may be the
:15:55. > :15:56.
:15:56. > :15:58.largest source of global sea level rise the century. In 2007,
:15:58. > :16:08.governments commissioned a report written by scientists which
:16:08. > :16:11.
:16:11. > :16:15.estimated future sea-level rises around the world. By 2100, these
:16:15. > :16:19.seas were unlikely to rise by more than 59 centimetres, they said. But
:16:19. > :16:22.they also admitted not enough was known to fully include the ice in
:16:23. > :16:32.west Antarctica and I think what is happening now makes that report
:16:33. > :16:34.
:16:34. > :16:41.obsolete. David Vaughan here, I have been looking at the figures.
:16:41. > :16:44.David will be a lead author of the next IPCC report. The predictions
:16:44. > :16:49.are predictions of climate change are out of date when they are
:16:49. > :16:55.published. We are working in the IPCC to begin the process of doing
:16:55. > :16:58.that, complete and consolidated estimates. I will not prejudge the
:16:58. > :17:02.outcome of that but everything we had seen coming out of the science
:17:02. > :17:10.suggests Antarctic could contribute more than was known at the time of
:17:10. > :17:14.the last report. The world's oceans could rise 30 centimetres. Great
:17:14. > :17:24.coastal cities could be swamped by five metres of water if the West
:17:24. > :17:24.
:17:24. > :17:30.Antarctic ice sheet follows it. events we have seen in Pine Island
:17:30. > :17:40.glacier make us more concerned than we were five or 10 years ago. More
:17:40. > :17:40.
:17:40. > :17:44.than a metre of sea-level rise is potentially with us by 2100.
:17:44. > :17:48.Certainly by 2150. It seems increasingly likely the future of
:17:48. > :17:51.these coastal cities will be shaped by a piece of ice at the end of the
:17:51. > :17:57.Earth. It is a future scientists are struggling to bring into
:17:57. > :18:01.clearer relief. Ed King is one of a handful of scientists who have made
:18:01. > :18:09.it to the glacier itself. Accompanied only by an assistant
:18:09. > :18:12.and a camera. We had all sorts of issues to do with getting cross
:18:12. > :18:20.country into Pine Island glacier from another glacier we were
:18:21. > :18:24.studying. It should have taken three days, it took us 11. The
:18:24. > :18:34.weather clamped in on us, we sat in the tent seven days straight with
:18:34. > :18:37.40-knot winds blowing past. Blizzard conditions. Things broke.
:18:38. > :18:44.By the time we finally got to Pine Island glacier there was quite a
:18:44. > :18:51.lot of fixing to do. Despite the extreme conditions, he has mapped
:18:51. > :18:56.the glacier bed using radio waves. The image of the bed we have
:18:56. > :19:01.created was eated was dar survey. It is the most detailed image of
:19:01. > :19:09.this glacier ever created. And we can see straight away from that
:19:09. > :19:16.there is melting going on down there. There is water being
:19:16. > :19:20.produced and ice melting right under our feet at the moment.
:19:20. > :19:28.pioneering results are his swansong. After 17 tough seasons on the ice
:19:28. > :19:38.he has decided this is his final trip. It is an extraordinary place,
:19:38. > :19:45.
:19:45. > :19:51.it has been a privilege to be able to work here. Sometimes you can
:19:51. > :20:01.recognise that the time has come for something to end. This is that
:20:01. > :20:11.time. I bid farewell to the situation in the Antarctic. And it
:20:11. > :20:31.
:20:31. > :20:39.feels quite hard. For generations scientists have suffered out on the
:20:39. > :20:43.ice, trying to unlock its secrets. Now, technology is lending a hand.
:20:43. > :20:50.This is the wonderful world of aerogeophysics. Nothing can remain
:20:50. > :20:55.hidden for long. We have four utility aircraft, they are work
:20:55. > :20:59.horses for the survey. This is special in that it has been
:21:00. > :21:06.equipped to do airport geophysics. There are cables down the wings to
:21:06. > :21:11.the antenna. It is hoped by scanning Pine Island this play will
:21:11. > :21:16.show what is happening deep inside the ice. -- plane. Where do you
:21:16. > :21:20.take it? When we get the equipment installed and do a test flight and
:21:20. > :21:27.if all goes well, off we go to Ireland and the idea is to survey
:21:27. > :21:30.the ice shelf, the plug holding back Pine Island. -- Pine Island.
:21:30. > :21:36.Pine Island could answer the trillion dollar question about sea
:21:36. > :21:42.levels rising coming from the West Antarctic ice sheet. You're excited.
:21:42. > :21:45.Excited and worried. We want to a good job. It is a huge challenge. A
:21:45. > :21:49.huge challenge we have everything right because it is a one-shot
:21:49. > :21:59.chance. We have limited time and weather window and we must get it
:21:59. > :22:27.
:22:27. > :22:30.I have been have been e as a TV correspondent since the mid-1990s.
:22:30. > :22:34.It is interesting to reflect that back then it was thought the sort
:22:34. > :22:38.of changes we're seeing here would not happen until the time of my
:22:38. > :22:40.grandchildren or long after that. And yet it is happening now and it
:22:40. > :22:43.is happening much faster than thought possible. Scientists
:22:43. > :22:46.working here say the rapid changes on the peninsular are being driven
:22:46. > :22:50.by human activity. But they have not drawn any definite conclusions
:22:50. > :22:57.about Pine Island for one simple reason. They just don't think they
:22:57. > :23:02.have observed enough. Yet. We have seen dramatic changes but they are
:23:02. > :23:11.for a short time period. They have only been monitoring what is going
:23:11. > :23:14.on since the satellite era, the late 1970s. In terms of a time
:23:14. > :23:19.period to understand the changes, 30 years is very difficult to get
:23:19. > :23:24.any statistical significance. next step is to look at ice drilled
:23:24. > :23:27.from deep down in the ice sheet to hope it will unlock the past.
:23:27. > :23:37.cores are a fantastic resource because they show an archive of the
:23:37. > :23:37.
:23:37. > :23:41.climate. The most interesting one is past temperatures. Liz Thomas
:23:41. > :23:45.has spent a season during ice cores at the edge of the West Antarctic.
:23:45. > :23:52.What we are interested in finding out is how the climate of the West
:23:52. > :23:56.Antarctica has been changing over the last 200 years. We are
:23:56. > :24:02.interested in the causes of whatever is happening. Is this part
:24:02. > :24:06.of a natural cycle? So, the climate has been changing many times over
:24:06. > :24:09.the past million years, so it is this part of natural change or is
:24:10. > :24:17.this something that is more recent effect like something like human
:24:17. > :24:20.induced warming and change. Everyone I spoke to about Pine
:24:20. > :24:25.Island says the same. At the moment they have more questions than
:24:25. > :24:32.answers. But there is one thing about which they are all in
:24:32. > :24:37.agreement. It is one of the biggest questions facing science. Science
:24:37. > :24:47.and society as well. Because there is potential for the changes we see
:24:47. > :24:48.
:24:48. > :24:51.to affect all this. Regardless of the cause of the changes, it is
:24:51. > :24:54.something, with regard to sea level rises, it will affect everyone.
:24:54. > :24:59.does concern me. People have said to me, these things have happened
:24:59. > :25:02.in the past, that is true and the sea level has been higher than at
:25:02. > :25:07.the moment but back then the humans there were around were few and
:25:07. > :25:11.minimal. But back then, the humans were few in number and were nomads.
:25:11. > :25:14.They could move away from rising sea levels. Now we have 7 billion
:25:14. > :25:19.people on the planet. That is a thought echoed by everyone who
:25:19. > :25:25.works down here. It has made me think about things in a different
:25:25. > :25:28.way. So, consider this. In a way it really doesn't matter whether you
:25:28. > :25:31.think the changes in Antarctica are natural phenomena or global warming