On Thin Ice Frozen Planet


On Thin Ice

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This white wilderness, this emptiness, is the North Pole.

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I'm standing in the middle of a frozen ocean.

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Beneath my feet and for over 500 miles in every direction,

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there are several metres of ice.

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But something significant is likely to happen here,

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at the North Pole, soon.

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Chances are that some time, within the next few decades,

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perhaps even as soon as 2020, there will be open water here

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for the first time in human recorded history.

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The Arctic and Antarctic are changing.

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Enormous masses of ice that have been frozen for thousands of years

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are breaking apart and melting away.

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Ice scientists are going to extremes to find out exactly

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what's going on.

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For them, these are exciting times.

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But the transformation that's being seen here will be felt

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far beyond the polar wilderness.

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In this programme,

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I'll be trying to understand what these changes mean, not just to the

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wildlife and people that live around the Poles, but for the whole planet.

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I'm starting my journey in the Arctic, the far north of our planet.

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It's still very cold outside by most people's standards,

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but the Arctic has been warming fast,

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twice as fast as the rest of our planet.

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My first mission is to find out what effect

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that's having on the animals.

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Although first, we have to find them.

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It's April in Svalbard.

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We are 1,000 miles north of the Arctic Circle,

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in search of the region's top predator.

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We need to travel away from the land and out over the frozen sea.

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There's some tracks right beneath us.

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Over there.

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I'm with a Norwegian team,

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which is giving the polar bears of Svalbard their yearly health check.

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She's under us now.

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I'll come round for a clean shot.

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The team works together to give an anaesthetic injection

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from a dart gun without hurting the bear.

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It takes tremendous skill.

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Ah, you've got it.

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I'll just back off until she's asleep.

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Nobody likes to see a magnificent

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animal like a polar bear lolling about unconscious on the ice,

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but it's only by darting them

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in this way and keeping check on them

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year after year, that we can be sure we know

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what is happening to them and the population of polar bears as a whole.

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Over the last 30 years, many teams have been seeing

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the condition of their local bears deteriorate.

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Although not every bear is suffering.

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-How much?

-96, there.

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And 102 here, so that's 197, yeah.

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Is that good?

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It's not too bad, it's a bit above average.

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So she's a bear in a good condition for Svalbard.

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The trouble is that if this was underweight, she would be in trouble.

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Not only from her own point of view, but from the point of her cubs,

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because an underweight female gives birth to underweight cubs

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and underweight cubs have a great problem of surviving

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their difficult first year in these circumstances.

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It can be minus 40 degrees Centigrade when polar bear cubs emerge

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at the start of the Arctic spring,

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from their dens where they were born.

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This mother hasn't eaten for half a year.

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She and her cubs need to fatten up fast over the next few months and

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their chances of survival depend on what's happening beneath their feet.

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These polar bears aren't walking on land.

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They're roaming across the frozen surface of the sea.

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And the bear's food lives under the ice.

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Ringed seals are hunted by polar bears.

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In fact, in some parts, polar bears eat almost nothing else.

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So, it's very understandable that this mother ringed seal...

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..who's looking at me now, should be a little apprehensive.

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That pup of hers is only about three or four days old...

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..and the pup won't be able to swim for another two or three days.

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Seals have good reason to be nervous around their holes.

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They need the holes to breathe when the sea is frozen,

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but this makes them easy to find.

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Polar bears can sniff out seal holes, even if they're covered in snow.

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Spring is the best hunting season.

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This mother's found a food store under the snow

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that was probably made by an Arctic fox.

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It's a time of plenty now,

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but the bear family need to make the best of it

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because the good times are about to come to an end.

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As the weather warms,

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the ice beneath the bears' feet starts to break up and then melt.

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And as the ice dwindles, so do the bears' chances of a successful hunt.

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Most of the ice is lost over these shallow coastal waters,

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where most of the seals live.

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It's now summer and these bears have a choice - take their chances

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on the shrinking ice floes, or make for the safety of the land.

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It's a case of sink or swim.

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Bears have always gone hungry in the summer,

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but the length of time when there's enough ice for them

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to go hunting is getting shorter and shorter, across much of the Arctic.

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This is hitting cubs particularly hard,

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because they can't survive for as long without feeding as their mother.

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Cubs that were born underweight are at the greatest risk.

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This mother and her cubs may well not get another meal

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until the sea freezes again in winter.

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There's not much to eat on land and the fact is that the longer the cubs

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have to wait until the ice returns, the more likely they are to die.

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Longer summers with no ice are probably the main reason why

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many polar bear populations are dropping.

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To help monitor bears into the future, this female is being fitted

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with a radio collar to track her movements.

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It's an extraordinary sensation to be

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so close to such a powerful animal.

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With luck, carrying that collar,

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she will have more years to go yet...

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..and be telling us a great deal

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about herself and the rest

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of the race of polar bears, as they

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face this very uncertain future.

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The future of the ice cover on the sea isn't just

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an issue for the animals.

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It's a big concern for the people

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who live in the Arctic

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and travel across the ice every day.

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David Iqaqrialu is an Inuit from the village of Clyde River

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in the Canadian Far North.

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There are very few roads up here, so David and his community,

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like most Inuit people, have always travelled across the frozen sea.

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Dog sleds are the safest way to get around because the dogs feel

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thin ice underfoot and won't lead travellers into trouble.

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Old-timers, like David, know the ice is as well as we know

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the streets in our local neighbourhood.

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Every spring,

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cracks have always formed in the same places at the same time.

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It's going to be big very soon. After two weeks maybe...

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..it will be more open.

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But now, cracks are appearing where they never did before.

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So, David and his friend, Laimikie, have taken on a new job.

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They are using special GPS units to record the position

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of new cracks or weak ice.

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These findings will be used

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by locals for their own safety,

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but they're also being studied by ice scientists,

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who want to predict how the ice will change in years to come.

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THEY SPEAK THEIR NATIVE LANGUAGE

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The Inuit are keen to know what the future holds too

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because they've seen with their own eyes the changes

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that the scientists have seen from space.

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This satellite photo from 1980 shows the Arctic Ocean

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at the end of the summer, when ice cover is at its minimum.

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Since then, there's been a 30% drop in the area covered by ice.

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But these images can't tell us about changes to the most important factor,

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the thickness of the ice.

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Measuring thickness across the whole ocean

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was beyond scientists for many years,

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until help came from an unexpected source.

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The Arctic Ocean is of huge military importance, as it's the shortest

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route between North America and Russia.

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Since the late 1950s, British, US and Russian submarines

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have been patrolling the Arctic Ocean.

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But as well as looking out for enemy activity,

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they've also been measuring the thickness of the ice,

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critical when looking for a place to surface.

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When scientists got permission to look at the submarine crew's records,

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they discovered that the ice has been thinning fast.

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In fact, it's nearly halved in thickness since 1980.

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Across most of the Arctic Ocean,

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there are now just a couple of metres of ice.

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It's so thin that it could melt away almost entirely in the summertime,

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and that includes the ice at the North Pole.

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If current trends continue, then there will be

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open ocean here by summer's end,

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some time within the next few decades.

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So, the days of the Arctic Ocean being covered

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by a continuous sheet of ice seem to have passed.

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Whether or not that's a good or bad thing, of course,

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depends on your point of view.

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Nobody has had a better view of the changes to the Arctic Ocean

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than the people of Barrow, the most northerly town in Alaska.

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The people here have always survived by hunting on the frozen sea

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and they celebrate this at a festival every year.

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The blanket toss was once the best way to spot distant animals to hunt,

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as lifelong resident Lewis Brower explains.

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When we throw ourselves up into the blanket, you know,

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you get that much more of an 'Ahh' of seeing further and further out,

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so sometimes, you'll jump 15-20 feet in the air,

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and hopefully, you're being caught right back into the blanket.

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-I'm OK!

-THEY LAUGH

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But the old way of life is under threat.

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When Lewis was young, the sea stayed frozen to the horizon until July,

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and some ice remained off-shore all summer.

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But now, it's breaking up in June

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and melting away completely for two or three months.

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I used to go out on the ice all the time at this time of the year,

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but we can't do that any more, cos there's no more ice.

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Lewis can also see that the loss of sea ice is affecting

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the animals he hunts for a living.

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Since 2007, something very strange has been happening

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on this stretch of coastline, close to Barrow.

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Mother walruses, confused by the lack of ice, are crowding onto the land

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with their pups.

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This very tight crowding isn't normal

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and it's caused many youngsters to be crushed to death.

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Many Arctic animals are threatened by the changing conditions

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and that's also bad news for the traditional hunters.

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But the ice loss could be good news for some people.

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There are trillions of dollars' worth of oil

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and gas under the Arctic Ocean.

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But the only way to get to them,

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until now, has been by building expensive artificial islands,

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like this.

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But if the sea ice goes,

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it will be much easier to drill for the huge riches below.

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So, the countries that surround the Arctic are scrambling

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to stake their claims.

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This daring attempt by the Russians to claim the disputed seabed

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at the North Pole in 2007 caused fury among the competing countries

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and it's unlikely to be the last such dispute.

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The Arctic has never been so important

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and not just because of its resources.

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The North-West Passage,

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a legendary sea route around the north of Canada and Alaska, cleared

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of ice in the summer of 2007 for the first time since records began.

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This promises a much faster

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and cheaper shipping route between the Atlantic and Pacific Oceans.

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And some wildlife could benefit from an ice-free Arctic too.

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Bowhead whales are one of just a few whales that can live

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year-round in the Arctic because they have no dorsal fin.

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This means they can come up for air in small spaces

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and travel easily under the ice.

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Their unique body shape used to mean that the Arctic whales had

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the seas to themselves for most of the year.

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But now, some cousins from down south are moving in.

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Killer whales are now a much more common sight in the Arctic.

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Their tall fins make it difficult for them to travel under ice,

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but the longer summers mean they can travel much further north

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and make the most of the rich Arctic seas.

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For animals and people,

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it will be those that can adapt who will thrive in a changing Arctic.

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But the loss of sea ice isn't just an issue for the Arctic,

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because the state of the ice affects the climate of the whole planet.

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Because it's white, the ice reflects up to 90% of the Sun's energy.

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This is called the albedo effect and it's why

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we often see heat haze in the Arctic, even when the air feels cold.

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The frozen Arctic Ocean acts as a huge reflector,

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bouncing back the Sun's heat into space.

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Throughout history, that has helped to cool the planet,

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but when the ice melts, it's a different story.

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Because sea water is dark, it absorbs most of the Sun's heat.

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In the Arctic, this can trigger a chain reaction, as the warming

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water melts more ice, exposing more water to the Sun's heat.

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This cycle of warming, as huge areas start to absorb rather than

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reflect heat, is the main reason why the Arctic, a region the size

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of North America, is warming twice as fast as the rest of the Earth.

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So, melting sea ice is a big issue.

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But there's another kind of ice that could have an even more

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dramatic impact on our world.

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The ice that is found on land.

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This is fresh water ice,

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formed from thousands of years of accumulated snowfall.

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This is the front of a glacier, quite a small one, believe it or not.

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Glaciers are like rivers of frozen

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fresh water flowing across the surface of the land.

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This one, like most polar glaciers,

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is flowing down from a vast inland ice sheet.

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And it's what happens to those ice sheets

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that could radically alter the face of the planet.

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The Greenland ice sheet is by far the largest in the Arctic.

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It's two miles thick in places

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and six times the size of the United Kingdom.

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Every summer, some of the surface of the ice sheet melts,

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forming sapphire-blue lakes of melt water.

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More and more of these lakes have been forming

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as Greenland has warmed over the last 20 years.

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This lake has grown over several weeks and now it's overflowing,

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carving a deep channel through the ice.

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A network of channels criss-crosses the ice sheet,

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but many of them come to an abrupt end.

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Huge holes, like this, can open up quite suddenly,

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draining the melt water away.

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Alun Hubbard is a glaciologist, studying the enormous power

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of these waterfalls, which are known as moulins.

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We've got this amazing moulin going off here today.

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The water's overflowing from the lake, which is beginning to drain.

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Tonnes of water cascading down this pipe that is, effectively,

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plummeting to the depths of the ice sheet through

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over a kilometre of vertical ice.

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Alun is here to study where the melt water goes

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and what effect it has on the remaining ice.

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To do that, he needs to find a moulin that has recently run dry.

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Just a week ago, there was a three-mile long,

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ten-metre deep lake here.

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The weight of all that water cracked the ice beneath

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and the late drained in just a few hours with incredible force.

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Thousand-tonne ice boulders were tossed about like dice.

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Alun's team have found the hole down which the lake disappeared

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and they want to have a closer look.

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It's not a job for anyone with a fear of heights.

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As you can see, it's dry up here, but if you listen,

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you can hear the thunder of,

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there's a lot of water entering it at some depth.

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Alun wants to place a sensor deep into the moulin to discover

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how much water is flowing through the ice.

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As they drop, they travel back in time.

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30 metres down and they reach ice formed from snow that fell

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10,000 years ago, in the last Ice Age.

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When this lake drained and the plug got pulled and the whole lot

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flushed down through here, this ice sheet, it rose by a metre

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as that water accessed the bed and forced, jacked up the ice sheet.

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So, we know that the water

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in this whole plumbing cavity system, down here,

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we know that shoots straight through that ice

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and actually hits the bed of the ice sheet.

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We've hit the water, I can see the water now.

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Great. Nice work.

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This daring experiment is measuring how the water flowing under

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the ice sheet affects the speed with which the glaciers

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flow from it, down to the sea.

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The theory is that the water is acting as a lubricant.

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So, the more water there is, the faster the glacier flows.

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To the naked eye, glaciers don't appear to move at all.

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But move they do.

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These unique time-lapse images were captured over the last four years.

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Through long observations, we now know that Greenland's ice

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is flowing down to the sea twice as quickly as it was 20 years ago.

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The speed of the glaciers affects our sea levels

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because when they reach the water, they break apart into icebergs.

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Occasionally, a real mega-berg is born.

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This is the Store Glacier in May 2010.

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75 million tonnes of ice, that had been sitting on land

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for thousands of years, has broken away.

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Events like this have become increasingly common,

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as Greenland's glaciers flow faster into the sea.

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Every single one of these icebergs raises the sea level a small amount.

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Scientists monitoring the ice sheet predict that Greenland might add

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as much as a half metre to world sea levels by the end of the century,

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enough to swamp many of the world's low-lying islands.

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99% of the Arctic's fresh water ice is in Greenland.

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It's a staggeringly big ice sheet, but it's just a drop in the ocean

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compared to that at the southern end of our planet.

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In Antarctica, there is ten times more ice,

0:30:270:30:32

by far the largest concentration of ice on Earth.

0:30:320:30:35

Our exploration of the Antarctic only began

0:30:400:30:43

a little over 100 years ago.

0:30:430:30:45

The study of ice retreat here was unwittingly begun

0:30:510:30:55

on an expedition led by the great early explorer Ernest Shackleton.

0:30:550:30:59

In 1916, after their expedition boat was crushed and sunk by ice,

0:31:030:31:08

Shackleton and two companions set off to summon help in a tiny boat.

0:31:080:31:14

They sailed over 800 miles across the Southern Ocean

0:31:170:31:21

to the island of South Georgia, on the edge of the Antarctic.

0:31:210:31:24

Near starving and dressed in rags, the three men

0:31:280:31:32

walked across the ice sheet at the centre of the island, knowing there

0:31:320:31:35

was a whaling base on the opposite coast where they could summon help.

0:31:350:31:39

This team of Royal Marines is re-tracing the steps

0:31:470:31:51

of that journey in tribute to Shackleton and his men.

0:31:510:31:54

But for all their efforts, they can't exactly copy the great walk

0:31:560:32:01

because the ice is not as it was.

0:32:010:32:02

A number of South Georgia's glaciers

0:32:060:32:08

were photographed

0:32:080:32:10

by Shackleton's cameraman.

0:32:100:32:11

Frozen Planet saw a dramatic change

0:32:110:32:14

when they returned 94 years later.

0:32:140:32:17

Most of South Georgia's glaciers have shrunk since Shackleton's time

0:32:350:32:40

and most of that has happened

0:32:400:32:41

since I first went to the Antarctic 30 years ago.

0:32:410:32:44

I've been to South Georgia several times

0:32:460:32:49

and seen how greatly the glaciers there have changed.

0:32:490:32:52

This photograph of a glacier

0:32:560:32:58

reaching right down to the sea

0:32:580:33:00

was taken just six years

0:33:000:33:02

before I first visited in 1981.

0:33:020:33:05

Now, that glacier has retreated by 400 metres away from the beach.

0:33:060:33:11

Temperatures in South Georgia have risen sharply, but the Southern

0:33:160:33:21

Hemisphere's most dramatic warming has happened a little further south.

0:33:210:33:25

In recent years, stronger winds blowing over the Southern Ocean

0:33:270:33:31

have brought warmer air to the 800- mile-long finger of land that forms

0:33:310:33:35

the northern extremity of the Antarctic continent.

0:33:350:33:39

Here, on the Antarctic Peninsula, the changing wind patterns have driven

0:33:450:33:49

temperatures up by nearly three degrees Centigrade

0:33:490:33:53

over the last 50 years.

0:33:530:33:54

Ten times the average rate of the rest of the planet.

0:33:540:33:58

The rapid warming is having a big effect on the birdlife.

0:34:040:34:09

The Adelie penguin is the most southerly nesting of all penguins.

0:34:240:34:29

And like the polar bear up in the north,

0:34:320:34:35

their lives are dependent on the sea ice.

0:34:350:34:38

Adelies spend their whole lives near ice.

0:34:400:34:43

These birds have spent the winter feeding at the ice edge,

0:34:430:34:46

but now it's spring

0:34:460:34:48

and they've started a long trek over the frozen sea towards land.

0:34:480:34:53

They're heading for areas of exposed rock, where they gather

0:35:000:35:05

to breed, in colonies that can be over 100,000 strong.

0:35:050:35:09

But it seems that Adelies don't find the conditions

0:35:260:35:29

on the peninsula to their liking any more.

0:35:290:35:31

17 years ago, when I was last in the Antarctic, there were

0:35:330:35:38

large colonies of Adelie penguins all along the Antarctic Peninsula.

0:35:380:35:43

Now, warming temperatures have meant less sea ice

0:35:430:35:49

and Adelie penguin numbers are in decline.

0:35:490:35:52

Many colonies have been emptying fast.

0:36:010:36:04

It may be that penguins are starving,

0:36:080:36:10

or it may be that they're heading south to colder climes

0:36:100:36:14

where there's still plenty of ice on the sea.

0:36:140:36:17

But, as in the Arctic, while ice-loving animals are feeling

0:36:250:36:30

the heat, animals that like it a bit more cosy are moving in.

0:36:300:36:35

The bright orange beaks of Gentoo penguins are a much more common sight

0:36:430:36:46

on the peninsula these days.

0:36:460:36:49

I always used to know them as residents

0:36:490:36:51

of the slightly warmer islands north of the Antarctic.

0:36:510:36:55

But they've moved south in numbers.

0:36:550:36:57

There are thought to be ten times more Gentoos on the peninsula now

0:36:580:37:02

than just 30 years ago.

0:37:020:37:04

The peninsula has warmed a great deal,

0:37:130:37:16

but the same is not true further south.

0:37:160:37:18

The Antarctic continent is smothered by the world's greatest ice sheet.

0:37:230:37:28

One and half times the size of Australia

0:37:290:37:32

and up to three miles thick.

0:37:320:37:34

A staggering 75% of the Earth's fresh water is locked up in this ice.

0:37:370:37:42

Global sea levels would rise by some 60 metres if all this was to melt.

0:37:470:37:53

But what chance is there of that happening here in the coldest,

0:37:570:38:01

most hostile place on Earth?

0:38:010:38:03

The ice beneath me, up here on top of the ice cap, is so thick

0:38:080:38:13

that I am short of breath, simply because of the altitude.

0:38:130:38:18

This is midsummer

0:38:190:38:22

and the average temperature is some 20 degrees below freezing.

0:38:220:38:27

And I can tell you it feels much lower than that.

0:38:280:38:31

And even the worst predictions don't suggest

0:38:320:38:37

that the air is going to warm enough to melt the ice.

0:38:370:38:42

But now, scientists are asking a different question.

0:38:420:38:46

Could the speed at which the Antarctic ice flows off the land

0:38:470:38:52

be increased by a warmer ocean?

0:38:520:38:54

Where the ice sheet meets the sea,

0:38:550:38:58

scientists are going to extreme lengths to find out.

0:38:580:39:01

Firing!

0:39:010:39:02

Andy Smith works for the British Antarctic Survey.

0:39:140:39:17

What we have here is one kilogramme of pentolite explosive.

0:39:190:39:23

We're going to use this to generate a shockwave

0:39:230:39:26

and record the echoes that come back from underneath the ice.

0:39:260:39:29

Firing.

0:39:290:39:31

Andy is particularly interested in mapping

0:39:340:39:37

the underside of the ice around the coast.

0:39:370:39:39

Because here, it isn't resting on land.

0:39:410:39:44

It's floating on sea water, so if sea temperatures rise

0:39:440:39:48

just a little, it can be melted from below.

0:39:480:39:51

Around the coast of Antarctica,

0:39:530:39:56

the glaciers have flowed out across the sea to form immense masses

0:39:560:40:00

of floating fresh water ice, called ice shelves.

0:40:000:40:04

These freeze to the land around them, sticking fast and acting

0:40:080:40:12

like bathplugs, holding back the flow of the glaciers into the sea.

0:40:120:40:16

On the Antarctic Peninsula, a one-degree sea temperature rise

0:40:190:40:24

has helped to break apart seven major ice shelves in the last 30 years.

0:40:240:40:28

This is the Larsen B ice shelf,

0:40:300:40:32

three times the size of Greater London, breaking apart in 2002.

0:40:320:40:36

Afterwards, the glaciers it had been holding back

0:40:390:40:42

started flowing up to six times faster.

0:40:420:40:45

In 2008, a much larger ice shelf at the southern end

0:40:480:40:52

of the peninsula started to break up.

0:40:520:40:55

It's an enormous event that's never been filmed before.

0:40:560:40:59

Andy Smith is flying down the peninsula to study

0:41:020:41:04

this phenomenon first hand.

0:41:040:41:07

We're flying to a place called Wilkins Ice Shelf.

0:41:080:41:12

It's an ice shelf that, over the last couple of years,

0:41:120:41:15

has shown a very sudden and dramatic break-up.

0:41:150:41:19

The Wilkins Ice Shelf is a two-hour long flight south

0:41:210:41:24

from his research base, but Andy can start to see

0:41:240:41:28

the evidence of ice shelf break-up a long way before he gets there.

0:41:280:41:33

As we're heading further south,

0:41:330:41:34

we can see more and more icebergs in the ocean.

0:41:340:41:37

And most of the big ones will be ones

0:41:370:41:40

that have broken off the ice shelves in this area.

0:41:400:41:42

Once we cross the mountains, we should be able to see

0:41:480:41:50

Wilkins Ice Shelf and then it's not far then to the ice front, here,

0:41:500:41:54

where it's collapsing.

0:41:540:41:55

As Andy's team reaches their destination,

0:42:070:42:10

the scale of what's been happening soon becomes clear.

0:42:100:42:13

Here, for thousands of years, an area the size of Yorkshire

0:42:130:42:17

has been covered by a sheet of ice 200 metres thick.

0:42:170:42:20

But now, over half of that has broken apart.

0:42:250:42:28

Andy has been studying Antarctic ice for 25 years,

0:42:420:42:47

but even he is blown away by what he's seeing.

0:42:470:42:50

Now, that is pretty awesome. That is remarkable.

0:42:510:42:55

The edge of the ice shelf has just, kind of, disintegrated.

0:42:550:42:59

Some of the big pieces look like

0:42:590:43:02

they could be a mile or more in size.

0:43:020:43:04

It's almost like a, sort of, a slow motion explosion.

0:43:060:43:10

It all pushes outwards very quickly.

0:43:100:43:12

Every one of these huge icebergs will slowly drift out to sea.

0:43:200:43:25

To study how fast that happens, Andy needs to get closer to the action.

0:43:300:43:34

We're going to look around and see if we can find a place where

0:43:360:43:40

we can land. And if we can, we'll be able to put down an instrument

0:43:400:43:42

that will help us monitor the big icebergs that are breaking off

0:43:420:43:46

as the ice shelf breaks up.

0:43:460:43:47

Landing on an iceberg is another first for Andy's team.

0:43:550:43:59

This satellite transmitter will help to track the continued break-up

0:44:130:44:17

of this colossal ice shelf.

0:44:170:44:20

The remainder of the Wilkins looks set to break apart soon.

0:44:330:44:38

It's the latest ice shelf to disintegrate in a wave that's been

0:44:410:44:45

travelling southwards,

0:44:450:44:47

playing a major role in the loss of ice from the peninsula.

0:44:470:44:50

Next in line, and already weakening in places, are the ice shelves

0:44:510:44:57

that hold back Antarctica's gigantic continental ice sheet.

0:44:570:45:02

And it would only take a small corner of this to slide into the sea

0:45:030:45:07

to have major global consequences.

0:45:070:45:09

We've only started to see changes in the Arctic and Antarctic recently.

0:45:120:45:17

So, it's hard to predict exactly what impact these changes will have.

0:45:170:45:21

But we can see for ourselves that these places are changing

0:45:210:45:25

and on a scale that is hard to ignore.

0:45:250:45:28

The Poles, North and South, may seem very remote,

0:45:310:45:36

but what is happening here is likely to have a greater effect upon us

0:45:360:45:40

than any other aspect of global warming.

0:45:400:45:44

If the Arctic sea ice continues to disappear,

0:45:440:45:48

it will drive up the planet's temperature more quickly.

0:45:480:45:53

And the melting ice sheets could contribute to a sea level rise

0:45:530:45:55

of a metre, enough to threaten the homes of millions of people

0:45:550:46:00

around the world's coasts by the end of the century.

0:46:000:46:03

We've seen that the animals are already adapting to these changes,

0:46:040:46:09

but can WE respond to what is happening now to the frozen planet?

0:46:090:46:16

The increasing unpredictability of the ice was a big issue

0:46:530:46:57

for the Frozen Planet team, who spent three years working on top of it.

0:46:570:47:02

Whether on sea, land, lake or river,

0:47:090:47:12

the state of the ice was the first concern for most filming crews.

0:47:120:47:17

Unexpected break-ups left many a cameraman in need of a swift rescue.

0:47:220:47:28

Sometimes, help came by boat, and sometimes by air.

0:47:280:47:31

I had a chance to see the changing ice conditions for myself,

0:47:380:47:42

when I visited the North Pole.

0:47:420:47:44

I flew with the team to a temporary camp that is set up every year in

0:47:470:47:51

the centre of the frozen Arctic Ocean to support expeditions to the Pole.

0:47:510:47:55

I had never visited the North Pole before,

0:48:000:48:04

so this was a great highlight for me.

0:48:040:48:06

But it was hard going in temperatures of minus 40,

0:48:070:48:10

so as soon as filming finished, we flew south.

0:48:100:48:12

Little did we know that we had made it out just in time.

0:48:150:48:18

We got back from the Pole camp last night and I've just bumped into

0:48:200:48:24

the Russian Commander, who's just heard from the camp.

0:48:240:48:28

And the news is that a little crack, which I'd seen in the ice

0:48:280:48:33

between our tent and the airstrip, which was no more than an inch

0:48:330:48:39

or so wide, has, overnight, widened to 20 metres.

0:48:390:48:43

Temporary break-ups, caused by stormy weather

0:48:430:48:47

and strong winds, have happened before, but they've been getting

0:48:470:48:50

more and more frequent over recent years as the ice has got weaker.

0:48:500:48:54

It was only swift action by the staff that prevented

0:48:590:49:02

a lot of valuable equipment going in the drink.

0:49:020:49:05

The biggest concern was that the ice airstrip might break apart,

0:49:120:49:16

but, luckily, it held and everyone was able to evacuate

0:49:160:49:19

when the weather improved.

0:49:190:49:21

The Frozen Planet team's clearest demonstration of the power

0:49:250:49:29

and unpredictability of breaking ice

0:49:290:49:32

came when they went to film the melting of a frozen Canadian river.

0:49:320:49:36

Producer Mark Linfield

0:49:360:49:38

and researcher Matt Swarbrick have travelled to the far North of Canada.

0:49:380:49:42

Matt, when was the last time we saw a car?

0:49:420:49:44

I don't know, about three hours ago.

0:49:440:49:46

They've driven through the vast Northwest Territory on a mission

0:49:480:49:52

to film the moment when this frozen waterfall breaks apart.

0:49:520:49:55

The break-up, when the frozen river above the waterfall thaws

0:49:590:50:03

and masses of water start to flow again, can be a spectacular event.

0:50:030:50:07

But predicting exactly when it's going to break

0:50:070:50:10

is the big challenge, if Mark and Matt want to get the best shots.

0:50:100:50:14

And they're not the only ones who want to know.

0:50:160:50:19

When the waterfall breaks, it can flood the town of Hay River,

0:50:190:50:23

just downstream, with millions of tonnes of water and ice.

0:50:230:50:28

Mark is taking advice from scientist Fay Hicks,

0:50:280:50:31

who studies the break-up of Canada's frozen rivers.

0:50:310:50:35

What happens is, you get ice jams form upstream and they start to dam

0:50:350:50:38

up the water and it builds

0:50:380:50:39

and builds and builds, and that can let go,

0:50:390:50:41

and that's a much bigger wave of water, you know,

0:50:410:50:44

than just the normal flow.

0:50:440:50:46

So, it just depends upon how dramatically it unfolds.

0:50:460:50:49

Every spring, Fay travels to Northern Canada

0:50:500:50:53

to study the way that breaking ice can jam rivers.

0:50:530:50:56

The spring break-up is of great significance to the people of the far north.

0:51:050:51:09

When the upper reaches of these rivers melt, huge amounts of water can build up

0:51:100:51:14

behind dams of ice.

0:51:140:51:16

When these dams burst, a surge of ice and water

0:51:160:51:19

can cause devastation to settlements along the banks.

0:51:190:51:23

Ground-penetrating radar provides information about the thickness of the ice,

0:51:250:51:29

crucial to the study of the break-up.

0:51:290:51:32

But predicting the date of the big day is notoriously hard.

0:51:320:51:38

Fay has warned the team that events could unfold very quickly

0:51:380:51:41

if conditions continue to warm.

0:51:410:51:43

The crew start to prepare. The waterfall appears to be waking.

0:51:470:51:52

There's a lot of work to do if they're to cover the break-up with as many cameras as possible.

0:51:540:51:59

The weather continues to warm, but nothing happens.

0:52:060:52:09

Far upstream, there's been a snowstorm, which is slowing down the break-up.

0:52:130:52:18

The team waits and waits and waits.

0:52:200:52:23

Mark is concerned that the crew have to return home soon, so

0:52:270:52:30

he heads into town to get the advice

0:52:300:52:32

of long-term resident Red McBrian.

0:52:320:52:35

We just have to live with it and take whatever evasive action we can.

0:52:350:52:41

Red has had 50 years of witnessing the power of the river.

0:52:410:52:45

Well, we're hoping that she may break up in two or three days.

0:52:450:52:49

Oh, no, no, no, that's too soon. Oh, no, no.

0:52:490:52:53

Boys, you're looking at seven or eight days

0:52:530:52:57

before she breaks of any significance.

0:52:570:53:02

And if she breaks, she can jam and hold up. She can be...

0:53:020:53:08

She'd be down here probably around the 5th or 6th May.

0:53:090:53:13

The snowstorm has derailed the team's plans,

0:53:150:53:19

and another week goes by before the river starts to move.

0:53:190:53:22

Finally, it seems that things might be happening.

0:53:340:53:37

We've just heard some cracks from upstream,

0:53:370:53:39

so, if we're lucky, we might get some action.

0:53:390:53:43

-Seven o'clock, which gives us two hours of light.

-Two hours.

0:53:430:53:47

If it happens at night, we're going to miss the whole thing.

0:53:470:53:51

Sure enough, the town is put on red alert

0:53:520:53:55

that the river is about to break in the middle of the night.

0:53:550:53:59

They've just called a full evacuation of the Eye Inn,

0:53:590:54:02

where we're staying, and if we don't move now, we're all going to be

0:54:020:54:05

underwater and possibly get trapped here for a few days.

0:54:050:54:08

The team have to move out and get up to the waterfall,

0:54:090:54:11

hoping that it doesn't break before it's light enough to film.

0:54:110:54:16

Luckily, the sun is up before the main event begins.

0:54:210:54:24

That is a serious amount of ice coming around the corner.

0:54:240:54:28

After weeks of waiting, the sleeping giant of a river,

0:54:390:54:43

we thought nothing was go to happen and suddenly, look at this!

0:54:430:54:47

This is what we're here for. Unbelievable.

0:54:490:54:52

-Absolutely unbelievable. Holy

-BLEEP!

0:54:520:54:55

The team is used to handling multiple cameras,

0:54:590:55:01

but they don't usually have to dodge ten-tonne ice floes at the same time.

0:55:010:55:05

As you can see, it's racing over at unbelievable speed.

0:55:090:55:11

The power, I just, if you were here to feel this, it's a deep rumbling

0:55:110:55:15

sound of the river, I can feel it up through my feet.

0:55:150:55:19

The power, I just can't imagine. That could crush a house in no time.

0:55:190:55:24

The team takes to the air to witness the destruction that's unleashed.

0:55:240:55:28

Huge ice blocks are pushed downstream on the wave of water

0:55:280:55:32

released by the breaking waterfall.

0:55:320:55:34

This could devastate the town.

0:55:380:55:40

But, this year, the residents are lucky.

0:55:440:55:48

There was no serious flooding,

0:55:510:55:53

as the ice blocks didn't badly jam the river near to the town.

0:55:530:55:58

As for the date of the break-up, 6th May,

0:55:580:56:01

Red is right on the nose.

0:56:010:56:05

I don't use any of these here gauges and mechanical assistance,

0:56:060:56:11

I just go by what I see on the river as I walk it down.

0:56:110:56:16

And I say I walk it down, back and forth every day on the river to see

0:56:160:56:21

what's happening, and from that, I gauge when it's going to hit here

0:56:210:56:26

and what the situation is going to be like when it does get here.

0:56:260:56:30

You know, when it went this morning,

0:56:300:56:31

I said to my students, "Guess what the date is?"

0:56:310:56:34

Red told us it was the 6th May and we were, you know, I'm not

0:56:340:56:36

surprised, because we've been here a couple of times and that's happened.

0:56:360:56:39

Ten days, two weeks out and he just looks around and goes "5th May."

0:56:390:56:42

How does he know that?

0:56:420:56:45

It's incredible.

0:56:450:56:46

It's because he just has lived on this river

0:56:460:56:48

and lived this break-up for 50 years.

0:56:480:56:52

Ice scientists are improving the accuracy of their predictions

0:56:530:56:57

all the time, but in the meantime,

0:56:570:56:59

the people of Hay River have a remarkable guardian.

0:56:590:57:03

Red, you were completely right this year. Are you right every year?

0:57:030:57:07

No, I'm...

0:57:070:57:09

I miss the odd one. Yes, 1985, I missed it.

0:57:090:57:15

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