1 00:00:30,720 --> 00:00:32,519 This white wilderness, 2 00:00:32,600 --> 00:00:35,839 this emptiness, is the North Pole. 3 00:00:36,560 --> 00:00:40,879 I'm standing in the middle of a frozen ocean. 4 00:00:41,520 --> 00:00:46,839 Beneath my feet, and for over 500 miles in every direction, 5 00:00:46,920 --> 00:00:49,079 there are several meters of ice. 6 00:00:50,400 --> 00:00:53,719 But something significant is likely to happen here 7 00:00:53,800 --> 00:00:55,959 at the North Pole soon. 8 00:00:56,880 --> 00:01:01,159 Chances are that sometime within the next few decades, 9 00:01:01,240 --> 00:01:04,079 perhaps even as soon as 2020, 10 00:01:04,680 --> 00:01:06,959 there will be open water here 11 00:01:07,040 --> 00:01:10,479 for the first time in human recorded history. 12 00:01:12,840 --> 00:01:15,959 The Arctic and Antarctic are changing. 13 00:01:16,360 --> 00:01:17,919 Enormous masses of ice 14 00:01:18,000 --> 00:01:20,399 that have been frozen for thousands of years 15 00:01:20,480 --> 00:01:22,999 are breaking apart and melting away. 16 00:01:36,680 --> 00:01:42,279 Ice scientists are going to extremes to find out exactly what's going on. 17 00:01:42,560 --> 00:01:45,719 For them, these are exciting times, 18 00:01:46,080 --> 00:01:48,559 but the transformation that's being seen here 19 00:01:48,640 --> 00:01:52,119 will be felt far beyond the polar wilderness. 20 00:01:58,120 --> 00:02:01,239 In this program, I'll be trying to understand 21 00:02:01,320 --> 00:02:05,359 what these changes mean, not just to the wildlife and people 22 00:02:05,440 --> 00:02:08,879 that live around the Poles, but for the whole planet. 23 00:02:20,840 --> 00:02:25,319 I'm starting my journey in the Arctic, the far north of our planet. 24 00:02:29,400 --> 00:02:32,679 It's still very cold outside by most people's standards, 25 00:02:32,760 --> 00:02:38,199 but the Arctic has been warming fast, twice as fast as the rest of our planet. 26 00:02:39,480 --> 00:02:44,439 My first mission is to find out what effect that's having on the animals. 27 00:02:44,520 --> 00:02:47,119 Although first, we have to find them. 28 00:02:47,760 --> 00:02:50,039 It's April in Svalbard. 29 00:02:50,360 --> 00:02:53,959 We are a thousand miles north of the Arctic Circle 30 00:02:54,280 --> 00:02:57,159 in search of the region's top predator. 31 00:03:05,440 --> 00:03:10,079 We need to travel away from the land and out over the frozen sea. 32 00:03:17,840 --> 00:03:20,719 There are some tracks right beneath us. 33 00:03:26,840 --> 00:03:28,199 Over there! 34 00:03:31,040 --> 00:03:32,999 I'm with a Norwegian team 35 00:03:33,080 --> 00:03:37,679 which is giving the polar bears of Svalbard their yearly health check. 36 00:03:40,760 --> 00:03:44,679 - She's under us now. - I'll come round for a clean shot. 37 00:03:51,080 --> 00:03:54,279 The team works together to give an anesthetic injection 38 00:03:54,360 --> 00:03:57,719 from a dart gun without hurting the bear. 39 00:03:58,720 --> 00:04:00,639 It takes tremendous skill. 40 00:04:05,400 --> 00:04:06,919 Ah, you got it! 41 00:04:12,120 --> 00:04:15,079 I’ll just back off until she's asleep. 42 00:04:24,520 --> 00:04:28,719 Nobody likes to see a magnificent animal like a polar bear 43 00:04:28,800 --> 00:04:31,719 lolling about unconscious on the ice, 44 00:04:31,800 --> 00:04:34,799 but it's only by darting them in this way 45 00:04:34,880 --> 00:04:37,639 and keeping check on them year after year, 46 00:04:37,720 --> 00:04:40,599 that we can be sure we know what is happening to them 47 00:04:40,680 --> 00:04:43,039 and the population of polar bears as a whole. 48 00:04:44,400 --> 00:04:47,639 Over the last 30 years, many teams have been seeing 49 00:04:47,720 --> 00:04:50,759 the condition of their local bears deteriorate. 50 00:04:51,920 --> 00:04:54,559 Although not every bear is suffering. 51 00:05:03,520 --> 00:05:06,679 - How much? Ninety-six there, 52 00:05:07,720 --> 00:05:11,639 and 102 here, so that's 197, yeah. 53 00:05:11,720 --> 00:05:15,159 - Is that good? - It's not too bad. 54 00:05:15,240 --> 00:05:17,119 It's a bit above average. 55 00:05:17,200 --> 00:05:20,159 So she's a bear in a good condition for Svalbard today. 56 00:05:20,240 --> 00:05:21,759 The trouble is 57 00:05:22,560 --> 00:05:26,919 that if this was underweight, she would be in trouble, 58 00:05:27,000 --> 00:05:30,919 not only from her own point of view but from the point of view of her cubs, 59 00:05:31,000 --> 00:05:35,079 because an underweight female gives birth to underweight cubs, 60 00:05:35,160 --> 00:05:37,999 and underweight cubs have a great problem 61 00:05:38,080 --> 00:05:42,519 of surviving their difficult first year in these circumstances. 62 00:05:44,560 --> 00:05:49,279 It can be -40 degrees centigrade when polar bear cubs emerge 63 00:05:49,360 --> 00:05:53,519 at the start of the Arctic spring from their dens where they were born. 64 00:06:05,920 --> 00:06:08,799 This mother hasn't eaten for half a year. 65 00:06:11,040 --> 00:06:14,959 She and her cubs need to fatten up fast over the next few months 66 00:06:15,040 --> 00:06:19,639 and their chances of survival depend on what's happening beneath their feet. 67 00:06:23,480 --> 00:06:26,559 These polar bears aren't walking on land, 68 00:06:26,640 --> 00:06:29,999 they're roaming across the frozen surface of the sea. 69 00:06:33,800 --> 00:06:37,319 And the bears' food lives under the ice. 70 00:06:49,840 --> 00:06:53,799 Ringed seals are hunted by polar bears. 71 00:06:55,120 --> 00:07:00,559 In fact, in some parts, polar bears eat almost nothing else. 72 00:07:01,280 --> 00:07:06,359 So it's very understandable that this mother ringed seal, 73 00:07:07,960 --> 00:07:09,919 who's looking at me now, 74 00:07:10,720 --> 00:07:13,039 should be a little apprehensive. 75 00:07:15,320 --> 00:07:19,559 That pup of hers is only about three or four days old, 76 00:07:21,560 --> 00:07:26,439 and the pup won't be able to swim for another two or three days. 77 00:07:28,640 --> 00:07:32,759 Seals have good reason to be nervous around their holes. 78 00:07:32,840 --> 00:07:36,159 They need the holes to breathe when the sea is frozen, 79 00:07:36,240 --> 00:07:38,639 but this makes them easy to find. 80 00:07:41,160 --> 00:07:45,679 Polar bears can sniff out seal holes even if they're covered in snow. 81 00:07:52,160 --> 00:07:54,599 Spring is the best hunting season. 82 00:07:57,400 --> 00:08:00,039 This mother's found a food store under the snow 83 00:08:00,120 --> 00:08:02,919 that was probably made by an Arctic fox. 84 00:08:05,200 --> 00:08:06,719 It's a time of plenty now, 85 00:08:06,800 --> 00:08:09,279 but the bear family need to make the best of it 86 00:08:09,360 --> 00:08:12,639 because the good times are about to come to an end. 87 00:08:18,000 --> 00:08:21,279 As the weather warms, the ice beneath the bears' feet 88 00:08:21,360 --> 00:08:24,279 starts to break up and then melt. 89 00:08:24,360 --> 00:08:26,079 And as the ice dwindles, 90 00:08:26,160 --> 00:08:29,239 so do the bears' chances of a successful hunt. 91 00:08:33,520 --> 00:08:37,039 Most of the ice is lost over the shallow coastal waters 92 00:08:37,120 --> 00:08:39,319 where most of the seals live. 93 00:08:44,520 --> 00:08:47,719 It's now summer and these bears have a choice. 94 00:08:47,800 --> 00:08:50,319 Take their chances on the shrinking ice floes 95 00:08:50,400 --> 00:08:52,879 or make for the safety of the land. 96 00:08:57,960 --> 00:09:00,759 It's a case of sink or swim. 97 00:09:07,880 --> 00:09:10,479 Bears have always gone hungry in the summer, 98 00:09:10,560 --> 00:09:13,719 but the length of time when there's enough ice for them to go hunting 99 00:09:13,800 --> 00:09:17,279 is getting shorter and shorter across much of the Arctic. 100 00:09:20,800 --> 00:09:23,999 This is hitting cubs particularly hard 101 00:09:24,080 --> 00:09:28,399 because they can't survive for as long without feeding as their mother. 102 00:09:30,280 --> 00:09:34,039 Cubs that were born underweight are at the greatest risk. 103 00:09:43,920 --> 00:09:47,319 This mother and her cubs may well not get another meal 104 00:09:47,400 --> 00:09:50,039 until the sea freezes again in winter. 105 00:09:51,440 --> 00:09:53,439 There's not much to eat on land, 106 00:09:53,520 --> 00:09:57,639 and the fact is that the longer the cubs have to wait until the ice returns, 107 00:09:57,720 --> 00:10:00,039 the more likely they are to die. 108 00:10:03,040 --> 00:10:06,759 Longer summers with no ice are probably the main reason 109 00:10:06,840 --> 00:10:10,199 why many polar bear populations are dropping. 110 00:10:18,520 --> 00:10:20,559 To help monitor bears into the future, 111 00:10:20,640 --> 00:10:23,399 this female is being fitted with a radio collar 112 00:10:23,480 --> 00:10:25,399 to track her movements. 113 00:10:29,440 --> 00:10:31,399 It's an extraordinary sensation 114 00:10:31,480 --> 00:10:34,839 to be so close to such a powerful animal. 115 00:10:35,600 --> 00:10:38,359 With luck, carrying that collar, 116 00:10:38,440 --> 00:10:41,279 she will have more years to go yet, 117 00:10:42,240 --> 00:10:45,959 and be telling us a great deal about herself 118 00:10:46,360 --> 00:10:52,719 and the rest of the race of polar bears as they face this very uncertain future. 119 00:11:00,120 --> 00:11:04,559 The future of the ice cover on the sea isn't just an issue for the animals. 120 00:11:05,480 --> 00:11:08,559 It's a big concern for the people who live in the Arctic 121 00:11:08,640 --> 00:11:10,839 and travel across the ice every day. 122 00:11:19,640 --> 00:11:23,959 David Iqaqrialu is an Inuit from the village of Clyde River 123 00:11:24,040 --> 00:11:25,479 in the Canadian Far North. 124 00:11:32,000 --> 00:11:33,719 There are very few roads up here, 125 00:11:33,800 --> 00:11:37,079 so David and his community, like most Inuit people, 126 00:11:37,160 --> 00:11:40,199 have always travelled across the frozen sea. 127 00:11:42,480 --> 00:11:45,079 Dog sleds are the safest way to get around 128 00:11:45,160 --> 00:11:50,319 because the dogs feel thin ice underfoot and won't lead travelers into trouble. 129 00:11:52,800 --> 00:11:55,999 Old-timers like David know the ice as well as we know the streets 130 00:11:56,080 --> 00:11:58,159 in our local neighborhood. 131 00:12:02,240 --> 00:12:06,999 Every spring, cracks have always formed in the same places at the same time. 132 00:12:08,640 --> 00:12:13,079 It's going to be big very soon, after two weeks maybe, 133 00:12:14,600 --> 00:12:16,559 it will be more open. 134 00:12:18,320 --> 00:12:21,959 But now, cracks are appearing where they never did before, 135 00:12:22,040 --> 00:12:26,239 so David and his friend Laimikie have taken on a new job. 136 00:12:28,080 --> 00:12:30,599 They are using special GPS units 137 00:12:30,680 --> 00:12:34,279 to record the position of new cracks or weak ice. 138 00:12:36,960 --> 00:12:40,239 These findings will be used by locals for their own safety 139 00:12:40,320 --> 00:12:43,079 but they're also being studied by ice scientists 140 00:12:43,160 --> 00:12:45,639 who want to predict how the ice will change 141 00:12:45,720 --> 00:12:47,359 in years to come. 142 00:12:55,600 --> 00:12:58,439 The Inuit are keen to know what the future holds, too, 143 00:12:58,520 --> 00:13:00,799 because they've seen with their own eyes 144 00:13:00,880 --> 00:13:04,239 the changes that the scientists have seen from space. 145 00:13:06,000 --> 00:13:08,479 This satellite photo from 1980 146 00:13:08,560 --> 00:13:11,079 shows the Arctic Ocean at the end of summer 147 00:13:11,160 --> 00:13:13,559 when ice cover is at its minimum. 148 00:13:13,640 --> 00:13:18,799 Since then, there's been a 30% drop in the area covered by ice. 149 00:13:21,040 --> 00:13:25,719 But these images can't tell us about changes to the most important factor, 150 00:13:26,720 --> 00:13:28,719 the thickness of the ice. 151 00:13:32,120 --> 00:13:34,519 Measuring thickness across the whole ocean 152 00:13:34,600 --> 00:13:37,239 was beyond scientists for many years, 153 00:13:37,320 --> 00:13:41,119 until help came from an unexpected source. 154 00:13:57,880 --> 00:14:01,479 The Arctic Ocean is of huge military importance, 155 00:14:01,560 --> 00:14:05,319 as it's the shortest route between North America and Russia. 156 00:14:11,160 --> 00:14:15,439 Since the late 1950s, British, US and Russian submarines 157 00:14:15,520 --> 00:14:18,159 have been patrolling the Arctic Ocean. 158 00:14:21,080 --> 00:14:23,999 But as well as looking out for enemy activity, 159 00:14:24,080 --> 00:14:26,799 they've also been measuring the thickness of the ice, 160 00:14:26,880 --> 00:14:29,359 critical when looking for a place to surface. 161 00:14:33,080 --> 00:14:36,839 When scientists got permission to look at the submarine crews' records, 162 00:14:36,920 --> 00:14:39,879 they discovered that the ice has been thinning fast. 163 00:14:39,960 --> 00:14:43,919 In fact, it's nearly halved in thickness since 1980. 164 00:14:48,360 --> 00:14:50,119 Across most of the Arctic Ocean, 165 00:14:50,200 --> 00:14:53,239 there are now just a couple of meters of ice. 166 00:14:57,640 --> 00:15:01,839 It's so thin that it could melt away almost entirely in the summertime 167 00:15:01,920 --> 00:15:04,799 and that includes the ice at the North Pole. 168 00:15:05,920 --> 00:15:07,639 If current trends continue, 169 00:15:07,720 --> 00:15:10,719 then there will be open ocean here by summer's end 170 00:15:10,800 --> 00:15:13,399 sometime within the next few decades. 171 00:15:16,440 --> 00:15:18,359 So, the days of the Arctic Ocean 172 00:15:18,440 --> 00:15:22,319 being covered by a continuous sheet of ice seem to be past. 173 00:15:23,000 --> 00:15:25,279 Whether or not that's a good or bad thing, 174 00:15:25,360 --> 00:15:28,079 of course, depends on your point of view. 175 00:15:31,640 --> 00:15:34,719 Nobody has had a better view of the changes to the Arctic Ocean 176 00:15:34,800 --> 00:15:38,759 than the people of Barrow, the most northerly town in Alaska. 177 00:15:39,200 --> 00:15:43,199 The people here have always survived by hunting on the frozen sea 178 00:15:43,280 --> 00:15:46,439 and they celebrate this at a festival every year. 179 00:15:48,160 --> 00:15:52,079 The blanket toss was once the best way to spot distant animals to hunt, 180 00:15:52,160 --> 00:15:55,199 as lifelong resident Lewis Brewer explains. 181 00:15:56,080 --> 00:15:58,559 When we throw ourselves up into the blanket, you know, 182 00:15:58,640 --> 00:16:02,479 you get that much more of an "Ah!" of seeing further and further out. 183 00:16:02,560 --> 00:16:05,879 So, sometimes you’ll jump 15, 20 feet in the air 184 00:16:05,960 --> 00:16:09,799 and hopefully you're being caught right back into the blanket. 185 00:16:11,000 --> 00:16:12,039 I'm okay! 186 00:16:15,120 --> 00:16:17,519 But the old way of life is under threat. 187 00:16:17,600 --> 00:16:22,239 When Lewis was young, the sea stayed frozen to the horizon until July 188 00:16:22,320 --> 00:16:25,199 and some ice remained off-shore all summer, 189 00:16:25,280 --> 00:16:27,599 but now, it's breaking up in June 190 00:16:27,680 --> 00:16:30,999 and melting away completely for two or three months. 191 00:16:31,800 --> 00:16:35,519 I used to go out on the ice all the time this time of the year. 192 00:16:35,600 --> 00:16:40,759 But we can't do that any more because there's no more ice. 193 00:16:42,560 --> 00:16:45,639 Lewis can also see that the loss of sea-ice 194 00:16:45,720 --> 00:16:48,759 is affecting the animals he hunts for a living. 195 00:16:49,840 --> 00:16:53,519 Since 2007, something very strange has been happening 196 00:16:53,600 --> 00:16:56,559 on this stretch of coastline close to Barrow. 197 00:17:00,480 --> 00:17:03,559 Mother walruses, confused by the lack of ice, 198 00:17:03,640 --> 00:17:06,479 are crowding onto the land with their pups. 199 00:17:07,800 --> 00:17:10,119 This very tight crowding isn't normal 200 00:17:10,200 --> 00:17:13,679 and it's caused many youngsters to be crushed to death. 201 00:17:16,200 --> 00:17:19,919 Many Arctic animals are threatened by the changing conditions 202 00:17:20,000 --> 00:17:23,359 and that's also bad news for the traditional hunters. 203 00:17:23,840 --> 00:17:27,159 But the ice loss could be good news for some people. 204 00:17:32,320 --> 00:17:36,759 There are trillions of dollars' worth of oil and gas under the Arctic Ocean, 205 00:17:36,840 --> 00:17:39,519 but the only way to get to them until now 206 00:17:39,600 --> 00:17:43,519 has been by building expensive artificial islands like this. 207 00:17:44,320 --> 00:17:45,959 But if the sea ice goes, 208 00:17:46,040 --> 00:17:49,839 it will be much easier to drill for the huge riches below. 209 00:17:49,920 --> 00:17:52,039 So the countries that surround the Arctic 210 00:17:52,120 --> 00:17:54,719 are scrambling to stake their claims. 211 00:18:05,760 --> 00:18:08,119 This daring attempt by the Russians 212 00:18:08,200 --> 00:18:12,719 to claim the disputed seabed at the North Pole in 2007 213 00:18:12,800 --> 00:18:15,599 caused fury among the competing countries 214 00:18:15,680 --> 00:18:18,679 and it's unlikely to be the last such dispute. 215 00:18:20,800 --> 00:18:25,839 The Arctic has never been so important, and not just because of its resources. 216 00:18:28,880 --> 00:18:30,239 The Northwest Passage, 217 00:18:30,320 --> 00:18:33,759 a legendary sea route around the north of Canada and Alaska, 218 00:18:33,840 --> 00:18:39,239 cleared of ice in the summer of 2007 for the first time since records began. 219 00:18:40,120 --> 00:18:43,679 This promises a much faster and cheaper shipping route 220 00:18:43,760 --> 00:18:46,519 between the Atlantic and Pacific Oceans. 221 00:18:50,480 --> 00:18:54,479 And some wildlife could benefit from an ice-free Arctic, too. 222 00:18:59,640 --> 00:19:02,399 Bowhead whales are one of just a few whales 223 00:19:02,480 --> 00:19:06,799 that can live year-round in the Arctic because they have no dorsal fin. 224 00:19:08,840 --> 00:19:11,679 This means they can come up for air in small spaces 225 00:19:11,760 --> 00:19:14,079 and travel easily under the ice. 226 00:19:15,760 --> 00:19:18,039 Their unique body shape used to mean 227 00:19:18,120 --> 00:19:22,599 that the Arctic whales had the seas to themselves for most of the year, 228 00:19:22,680 --> 00:19:26,159 but now, some cousins from down south are moving in. 229 00:19:33,600 --> 00:19:36,799 Killer whales are now a much more common sight in the Arctic. 230 00:19:38,280 --> 00:19:41,719 Their tall fins make it difficult for them to travel under ice 231 00:19:41,800 --> 00:19:45,279 but the longer summers mean they can travel much farther north 232 00:19:45,360 --> 00:19:48,079 and make the most of the rich Arctic seas. 233 00:19:55,960 --> 00:19:57,679 For animals and people, 234 00:19:57,760 --> 00:20:01,999 it will be those who can adapt who will thrive in a changing Arctic. 235 00:20:10,800 --> 00:20:13,959 But the loss of sea-ice isn't just an issue for the Arctic, 236 00:20:14,040 --> 00:20:18,279 because the state of the ice affects the climate of the whole planet. 237 00:20:21,200 --> 00:20:26,079 Because it's white, the ice reflects up to 90% of the sun's energy. 238 00:20:26,560 --> 00:20:28,879 This is called the albedo effect, 239 00:20:28,960 --> 00:20:31,519 and it's why we often see heat haze in the Arctic, 240 00:20:31,600 --> 00:20:33,799 even when the air feels cold. 241 00:20:40,560 --> 00:20:44,439 The frozen Arctic Ocean acts as a huge reflector, 242 00:20:44,520 --> 00:20:47,679 bouncing back the sun's heat into space. 243 00:20:48,120 --> 00:20:51,799 Throughout history, that has helped to cool the planet, 244 00:20:51,880 --> 00:20:55,679 but when the ice melts, it's a different story. 245 00:21:00,960 --> 00:21:06,079 Because sea water is dark, it absorbs most of the sun's heat. 246 00:21:06,840 --> 00:21:09,879 In the Arctic, this can trigger a chain reaction 247 00:21:09,960 --> 00:21:15,199 as the warming water melts more ice, exposing more water to the sun's heat. 248 00:21:20,680 --> 00:21:21,999 This cycle of warming, 249 00:21:22,080 --> 00:21:25,599 as huge areas start to absorb rather than reflect heat, 250 00:21:25,680 --> 00:21:29,759 is the main reason why the Arctic, a region the size of North America, 251 00:21:29,840 --> 00:21:33,119 is warming twice as fast as the rest of the Earth. 252 00:21:38,320 --> 00:21:42,479 So, melting sea-ice is a big issue, but there's another kind of ice 253 00:21:42,560 --> 00:21:45,719 that could have an even more dramatic impact on our world, 254 00:21:47,240 --> 00:21:49,799 the ice that is found on land. 255 00:21:52,240 --> 00:21:54,479 This is freshwater ice, 256 00:21:54,560 --> 00:21:58,039 formed from thousands of years of accumulated snowfall. 257 00:22:04,560 --> 00:22:07,479 This is the front of a glacier. 258 00:22:07,560 --> 00:22:10,279 Quite a small one, believe it or not. 259 00:22:10,360 --> 00:22:13,559 Glaciers are like rivers of frozen fresh water 260 00:22:13,640 --> 00:22:16,319 flowing across the surface of the land. 261 00:22:16,840 --> 00:22:19,999 This one, like most polar glaciers, 262 00:22:20,080 --> 00:22:23,719 is flowing down from a vast inland ice sheet, 263 00:22:24,560 --> 00:22:27,639 and it's what happens to those ice sheets 264 00:22:27,720 --> 00:22:30,839 that could radically alter the face of the planet. 265 00:22:32,440 --> 00:22:35,879 The Greenland ice sheet is by far the largest in the Arctic. 266 00:22:35,960 --> 00:22:38,319 It's two miles thick in places 267 00:22:38,400 --> 00:22:41,679 and six times the size of the United Kingdom. 268 00:22:48,600 --> 00:22:52,519 Every summer, some of the surface of the ice sheet melts, 269 00:22:52,600 --> 00:22:55,839 forming sapphire-blue lakes of melt water. 270 00:22:57,800 --> 00:23:00,119 More and more of these lakes have been forming 271 00:23:00,200 --> 00:23:03,559 as Greenland has warmed over the last 20 years. 272 00:23:05,200 --> 00:23:08,839 This lake has grown over several weeks, and now it's overflowing, 273 00:23:08,920 --> 00:23:11,599 carving a deep channel through the ice. 274 00:23:18,200 --> 00:23:21,599 A network of channels criss-crosses the ice sheet, 275 00:23:21,680 --> 00:23:24,799 but many of them come to an abrupt end. 276 00:23:35,680 --> 00:23:38,999 Huge holes like this can open up quite suddenly, 277 00:23:39,080 --> 00:23:41,279 draining the melt water away. 278 00:23:52,880 --> 00:23:55,239 Alun Hubbard is a glaciologist 279 00:23:55,320 --> 00:23:58,319 studying the enormous power of these waterfalls, 280 00:23:58,400 --> 00:24:00,319 which are known as moulins. 281 00:24:00,640 --> 00:24:04,799 We've got this amazing moulin going off here today. 282 00:24:05,480 --> 00:24:09,559 The water's overflowing from the lake, which is beginning to drain. 283 00:24:10,080 --> 00:24:13,559 Tons of water cascading down this pipe 284 00:24:13,640 --> 00:24:17,559 that is effectively plummeting to the depths of the ice sheet 285 00:24:17,640 --> 00:24:20,999 through over a kilometer of vertical ice. 286 00:24:28,520 --> 00:24:31,799 Alun is here to study where the melt water goes 287 00:24:31,880 --> 00:24:34,879 and what affect it has on the remaining ice. 288 00:24:34,960 --> 00:24:39,199 To do that, he needs to find a moulin that has recently run dry. 289 00:24:45,800 --> 00:24:50,839 Just a week ago, there was a three-mile long, 10-metre deep lake here. 290 00:24:52,040 --> 00:24:55,079 The weight of all that water cracked the ice beneath 291 00:24:55,160 --> 00:24:59,079 and the lake drained in just a few hours with incredible force. 292 00:25:04,400 --> 00:25:07,999 Thousand-ton ice boulders were tossed about like dice. 293 00:25:15,440 --> 00:25:18,919 Alun's team have found the hole down which the lake disappeared 294 00:25:19,000 --> 00:25:20,959 and they want to have a closer look. 295 00:25:21,040 --> 00:25:24,439 It's not job for anyone with a fear of heights. 296 00:25:31,000 --> 00:25:33,279 As you can see, it's dry up here, but if you listen, 297 00:25:33,360 --> 00:25:34,759 you can hear the thunder of... 298 00:25:34,840 --> 00:25:37,719 There's a lot of water entering it at some depth. 299 00:25:39,680 --> 00:25:43,079 Alun wants to place a sensor deep into the moulin 300 00:25:43,160 --> 00:25:46,599 to discover how much water is flowing through the ice. 301 00:25:52,320 --> 00:25:55,479 As they drop, they travel back in time. 302 00:25:57,280 --> 00:26:00,839 Thirty meters down and they reach ice formed from snow 303 00:26:00,920 --> 00:26:04,319 that fell 10,000 years ago, in the last ice age. 304 00:26:07,400 --> 00:26:11,519 When this lake drained and the plug got pulled, 305 00:26:11,600 --> 00:26:14,479 and the whole lot flushed down through here, 306 00:26:15,200 --> 00:26:18,119 this ice sheet, it rose by a meter 307 00:26:18,200 --> 00:26:22,679 as that water accessed the bed and force-jacked up the ice sheet. 308 00:26:22,760 --> 00:26:28,439 So, we know that the water in this whole plumbing cavity system down here, 309 00:26:28,520 --> 00:26:31,239 we know that shoots straight through the ice 310 00:26:31,320 --> 00:26:33,959 and actually hits the bed of the ice sheet. 311 00:26:34,440 --> 00:26:36,999 We've hit the water! I can see the water now. 312 00:26:37,080 --> 00:26:39,519 Great. Nice work! 313 00:26:42,400 --> 00:26:44,079 This daring experiment 314 00:26:44,160 --> 00:26:46,959 is measuring how the water flowing under the ice sheet 315 00:26:47,040 --> 00:26:51,359 affects the speed with which the glaciers flow from it down to the sea. 316 00:26:52,360 --> 00:26:55,519 The theory is that the water is acting as a lubricant, 317 00:26:55,600 --> 00:26:59,199 so the more water there is, the faster the glacier flows. 318 00:27:01,640 --> 00:27:05,359 To the naked eye, glaciers don't appear to move at all. 319 00:27:05,840 --> 00:27:07,479 But move they do. 320 00:27:09,520 --> 00:27:14,719 These unique time-lapse images were captured over the last four years. 321 00:27:25,320 --> 00:27:29,319 Through long observations, we now know that Greenland's ice 322 00:27:29,400 --> 00:27:34,559 is flowing down to the sea twice as quickly as it was 20 years ago. 323 00:27:35,960 --> 00:27:38,719 The speed of the glaciers affects our sea levels, 324 00:27:38,800 --> 00:27:43,199 because when they reach the water, they break apart into icebergs. 325 00:27:44,120 --> 00:27:47,279 Occasionally, a real mega-berg is born. 326 00:27:56,240 --> 00:27:59,959 This is the Store Glacier in May 2010. 327 00:28:55,680 --> 00:28:58,119 Seventy-five million tons of ice 328 00:28:58,200 --> 00:29:02,439 that had been sitting on land for thousands of years has broken away. 329 00:29:07,400 --> 00:29:10,399 Events like this have become increasingly common 330 00:29:10,480 --> 00:29:13,799 as Greenland's glaciers flow faster into the sea. 331 00:29:27,080 --> 00:29:31,919 Every single one of these icebergs raises the sea level a small amount. 332 00:29:33,440 --> 00:29:35,359 Scientists monitoring the ice sheet 333 00:29:35,440 --> 00:29:38,799 predict that Greenland might add as much as a half meter 334 00:29:38,880 --> 00:29:41,439 to world sea levels by the end of the century, 335 00:29:41,520 --> 00:29:45,359 enough to swamp many of the world's low-lying islands. 336 00:30:07,080 --> 00:30:11,999 99% of the Arctic's freshwater ice is in Greenland. 337 00:30:12,080 --> 00:30:16,479 It's a staggeringly big ice sheet but it's just a drop in the ocean 338 00:30:16,560 --> 00:30:19,959 compared to that at the southern end of our planet. 339 00:30:28,560 --> 00:30:32,799 In Antarctica, there is 10 times more ice, 340 00:30:32,880 --> 00:30:36,319 by far the largest concentration of ice on Earth. 341 00:30:41,560 --> 00:30:46,519 Our exploration of the Antarctic only began a little over 100 years ago. 342 00:30:52,320 --> 00:30:54,479 The study of ice retreat here 343 00:30:54,560 --> 00:30:58,639 was unwittingly begun on an expedition led by the great early explorer, 344 00:30:58,720 --> 00:31:00,399 Ernest Shackleton. 345 00:31:04,960 --> 00:31:10,039 In 1916, after their expedition boat was crushed and sunk by ice, 346 00:31:10,120 --> 00:31:15,519 Shackleton and two companions set off to summon help in a tiny boat. 347 00:31:18,720 --> 00:31:21,879 They sailed over 800 miles across the Southern Ocean 348 00:31:21,960 --> 00:31:26,199 to the island of South Georgia, on the edge of the Antarctic. 349 00:31:29,800 --> 00:31:32,319 Near starving and dressed in rags, 350 00:31:32,400 --> 00:31:35,959 the three men walked across the ice sheet at the center of the island 351 00:31:36,040 --> 00:31:38,839 knowing there was a whaling base on the opposite coast 352 00:31:38,920 --> 00:31:41,119 where they could summon help. 353 00:31:48,240 --> 00:31:52,919 This team of Royal Marines is re-tracing the steps of that journey 354 00:31:53,000 --> 00:31:55,599 in tribute to Shackleton and his men. 355 00:31:57,200 --> 00:32:01,079 But for all their efforts, they can't exactly copy the great walk 356 00:32:01,160 --> 00:32:03,559 because the ice is not as it was. 357 00:32:07,120 --> 00:32:09,439 A number of South Georgia's glaciers 358 00:32:09,520 --> 00:32:12,399 were photographed by Shackleton's cameraman. 359 00:32:12,720 --> 00:32:18,159 Frozen Planet saw a dramatic change when they returned 94 years later. 360 00:32:36,080 --> 00:32:38,919 Most of South Georgia's glaciers have shrunk 361 00:32:39,000 --> 00:32:40,959 since Shackleton's time, 362 00:32:41,040 --> 00:32:42,519 and most of that has happened 363 00:32:42,600 --> 00:32:45,759 since I first went to the Antarctic 30 years ago. 364 00:32:47,720 --> 00:32:49,839 I've been to South Georgia several times 365 00:32:49,920 --> 00:32:53,279 and seen how greatly the glaciers there have changed. 366 00:32:58,040 --> 00:33:01,439 This photograph of a glacier reaching right down to the sea 367 00:33:01,520 --> 00:33:06,479 was taken just six years before I first visited in 1981 . 368 00:33:07,600 --> 00:33:12,559 Now that glacier has retreated by 400 meters away from the beach. 369 00:33:18,240 --> 00:33:21,239 Temperatures in South Georgia have risen sharply, 370 00:33:21,320 --> 00:33:24,079 but the Southern Hemisphere's most dramatic warming 371 00:33:24,160 --> 00:33:26,679 has happened a little further south. 372 00:33:28,120 --> 00:33:31,839 In recent years, stronger winds blowing over the Southern Ocean 373 00:33:31,920 --> 00:33:35,759 have brought warmer air to the 800-mile-long finger of land 374 00:33:35,840 --> 00:33:39,639 that forms the northern extremity of the Antarctic continent. 375 00:33:46,120 --> 00:33:48,559 Here, on the Antarctic Peninsula, 376 00:33:48,640 --> 00:33:51,519 the changing wind patterns have driven temperatures up 377 00:33:51,600 --> 00:33:55,359 by nearly three degrees centigrade over the last 50 years, 378 00:33:55,440 --> 00:33:59,079 10 times the average rate of the rest of the planet. 379 00:34:05,600 --> 00:34:09,479 The rapid warming is having a big effect on the birdlife. 380 00:34:25,440 --> 00:34:30,319 The Adélie penguin is the most southerly nesting of all penguins. 381 00:34:32,920 --> 00:34:35,679 And like the polar bear, up in the north, 382 00:34:36,160 --> 00:34:39,399 their lives are dependent on the sea-ice. 383 00:34:41,040 --> 00:34:44,039 Adélies spend their whole lives near ice. 384 00:34:44,960 --> 00:34:48,039 These birds have spent the winter feeding at the ice edge 385 00:34:48,120 --> 00:34:51,159 but now it's spring and they've started a long trek 386 00:34:51,240 --> 00:34:53,759 over the frozen sea towards land. 387 00:35:02,480 --> 00:35:05,439 They're heading for areas of exposed rock, 388 00:35:05,520 --> 00:35:10,439 where they gather to breed in colonies that can be over 100,000 strong. 389 00:35:26,880 --> 00:35:30,679 But it seems that Adélies don't find the conditions on the Peninsula 390 00:35:30,760 --> 00:35:32,759 to their liking any more. 391 00:35:34,680 --> 00:35:38,239 Seventeen years ago, when I was last in the Antarctic, 392 00:35:38,320 --> 00:35:41,319 there were large colonies of Adélie penguins 393 00:35:41,400 --> 00:35:44,119 all along the Antarctic Peninsula. 394 00:35:44,760 --> 00:35:49,479 Now warming temperatures have meant less sea-ice 395 00:35:49,920 --> 00:35:52,959 and Adélie penguin numbers are in decline. 396 00:36:02,080 --> 00:36:04,719 Many colonies have been emptying fast. 397 00:36:09,200 --> 00:36:13,679 It may be that penguins are starving or it may be that they are heading south 398 00:36:13,760 --> 00:36:17,599 to colder climes, where there's still plenty of ice on the sea. 399 00:36:26,880 --> 00:36:28,559 But as in the Arctic, 400 00:36:28,640 --> 00:36:31,639 while ice-loving animals are feeling the heat, 401 00:36:31,720 --> 00:36:35,519 animals that like it a bit more cozy are moving in. 402 00:36:43,200 --> 00:36:46,039 The bright orange beaks of gentoo penguins 403 00:36:46,120 --> 00:36:49,719 are a much more common sight on the Peninsula these days. 404 00:36:50,360 --> 00:36:54,039 I always used to know them as residents of the slightly warmer islands 405 00:36:54,120 --> 00:36:57,839 north of the Antarctic, but they've moved south in numbers. 406 00:36:59,800 --> 00:37:03,439 There are thought to be 10 times more gentoos on the Peninsula now 407 00:37:03,520 --> 00:37:05,439 than just 30 years ago. 408 00:37:14,280 --> 00:37:19,959 The Peninsula has warmed a great deal but the same is not true further south. 409 00:37:24,640 --> 00:37:30,119 The Antarctic continent is smothered by the world's greatest ice sheet, 410 00:37:30,680 --> 00:37:35,719 one and a half times the size of Australia and up to three miles thick. 411 00:37:38,320 --> 00:37:43,719 A staggering 75% of the Earth's fresh water is locked up in this ice. 412 00:37:48,680 --> 00:37:54,199 Global sea levels would rise by some 60 meters if all this was to melt. 413 00:37:58,120 --> 00:38:00,799 But what chance is there of that happening here 414 00:38:00,880 --> 00:38:04,439 in the coldest, most hostile place on Earth? 415 00:38:10,040 --> 00:38:14,159 The ice beneath me up here on top of the icecap 416 00:38:14,240 --> 00:38:20,319 is so thick that I am short of breath, simply because of the altitude. 417 00:38:20,400 --> 00:38:23,159 This is mid-summer 418 00:38:23,240 --> 00:38:28,999 and the average temperature is some 20 degrees below freezing, 419 00:38:29,520 --> 00:38:32,839 and I can tell you it feels much lower than that. 420 00:38:33,680 --> 00:38:38,879 And even the worst predictions don't suggest that the air 421 00:38:38,960 --> 00:38:42,799 is going to warm enough to melt the ice. 422 00:38:43,160 --> 00:38:46,919 But now scientists are asking a different question. 423 00:38:48,920 --> 00:38:52,439 Could the speed at which the Antarctic ice flows off the land 424 00:38:52,520 --> 00:38:55,079 be increased by a warmer ocean? 425 00:38:56,680 --> 00:38:58,719 Where the ice sheet meets the sea, 426 00:38:58,800 --> 00:39:02,359 scientists are going to extreme lengths to find out. 427 00:39:02,440 --> 00:39:03,639 Firing! 428 00:39:15,200 --> 00:39:18,759 Andy Smith works for the British Antarctic Survey. 429 00:39:20,160 --> 00:39:23,799 What we have here is one kilogram of pentolite explosive. 430 00:39:23,880 --> 00:39:27,039 We're going to use this to generate a shockwave 431 00:39:27,120 --> 00:39:30,239 and record the echoes that come back from underneath the ice. 432 00:39:30,320 --> 00:39:31,519 Firing. 433 00:39:35,040 --> 00:39:37,039 Andy is particularly interested 434 00:39:37,120 --> 00:39:40,079 in mapping the underside of the ice around the coast, 435 00:39:41,800 --> 00:39:44,519 because here, it isn't resting on land, 436 00:39:45,240 --> 00:39:47,439 it's floating on seawater. 437 00:39:47,520 --> 00:39:50,319 So if sea temperatures rise just a little, 438 00:39:50,400 --> 00:39:52,559 it can be melted from below. 439 00:39:54,920 --> 00:39:56,839 Around the coast of Antarctica, 440 00:39:56,920 --> 00:39:59,239 the glaciers have flowed out across the sea 441 00:39:59,320 --> 00:40:02,839 to form immense masses of floating fresh water ice 442 00:40:02,920 --> 00:40:05,319 called ice shelves. 443 00:40:09,160 --> 00:40:14,399 These freeze to the land around them, sticking fast and acting like bathplugs, 444 00:40:14,480 --> 00:40:17,759 holding back the flow of the glaciers into the sea. 445 00:40:20,520 --> 00:40:24,439 On the Antarctic Peninsula, a one-degree sea temperature rise 446 00:40:24,520 --> 00:40:27,519 has helped to break apart seven major ice shelves 447 00:40:27,600 --> 00:40:29,399 in the last 30 years. 448 00:40:30,920 --> 00:40:33,359 This is the Larsen B Ice Shelf, 449 00:40:33,440 --> 00:40:38,119 three times the size of Greater London, breaking apart in 2002. 450 00:40:40,000 --> 00:40:42,839 Afterwards, the glaciers it had been holding back 451 00:40:42,920 --> 00:40:45,919 started flowing up to six times faster. 452 00:40:49,160 --> 00:40:52,279 In 2008, a much larger ice shelf 453 00:40:52,360 --> 00:40:55,959 at the southern end of the Peninsula started to break up. 454 00:40:57,040 --> 00:41:00,519 It's an enormous event that's never been filmed before. 455 00:41:03,160 --> 00:41:08,519 Andy Smith is flying down the Peninsula to study this phenomenon first-hand. 456 00:41:09,360 --> 00:41:12,759 We're flying to a place called Wilkins Ice Shelf. 457 00:41:13,480 --> 00:41:15,719 It's an ice shelf that over the last couple of years 458 00:41:15,800 --> 00:41:20,079 has shown a very sudden and dramatic break-up. 459 00:41:22,680 --> 00:41:26,079 The Wilkins Ice Shelf is a two-hour-long flight south 460 00:41:26,160 --> 00:41:27,879 from his research base, 461 00:41:27,960 --> 00:41:31,079 but Andy can start to see the evidence of ice shelf break-up 462 00:41:31,160 --> 00:41:33,479 a long way before he gets there. 463 00:41:34,120 --> 00:41:35,679 As we are heading further south, 464 00:41:35,760 --> 00:41:38,399 we can see more and more icebergs in the ocean, 465 00:41:38,480 --> 00:41:41,319 and most of the big ones will be ones that have broken off 466 00:41:41,400 --> 00:41:43,599 the ice shelves in this area. 467 00:41:49,240 --> 00:41:51,599 Once we cross the mountains, we should be able to see 468 00:41:51,680 --> 00:41:54,079 Wilkins Ice Shelf, and then it's not far then 469 00:41:54,160 --> 00:41:56,159 to the ice front here where it's collapsing. 470 00:42:08,440 --> 00:42:11,159 As Andy’s team reaches their destination, 471 00:42:11,240 --> 00:42:14,439 the scale of what's been happening soon becomes clear. 472 00:42:14,520 --> 00:42:17,999 Here, for thousands of years, an area the size of Yorkshire 473 00:42:18,080 --> 00:42:21,599 has been covered by a sheet of ice 200 meters thick. 474 00:42:26,480 --> 00:42:29,559 But now, over half of that has broken apart. 475 00:42:44,560 --> 00:42:48,439 Andy has been studying Antarctic ice for 25 years, 476 00:42:48,520 --> 00:42:51,559 but even he is blown away by what he's seeing. 477 00:42:52,480 --> 00:42:56,039 Now, that is pretty awesome! That is remarkable! 478 00:42:56,840 --> 00:43:00,839 The edge of the ice shelf has just kind of disintegrated, 479 00:43:00,920 --> 00:43:05,439 and some of the big pieces look like they could be a mile or more in size. 480 00:43:07,400 --> 00:43:10,839 It's almost like a sort of slow motion explosion. 481 00:43:10,920 --> 00:43:13,439 It all pushes outwards very quickly. 482 00:43:21,240 --> 00:43:23,639 Every one of these huge icebergs 483 00:43:23,720 --> 00:43:25,919 will slowly drift out to sea. 484 00:43:30,680 --> 00:43:35,639 To study how fast that happens, Andy needs to get closer to the action. 485 00:43:37,040 --> 00:43:40,799 We're going to look around and see if we can find a place where we can land, 486 00:43:40,880 --> 00:43:43,399 and if we can, we'll be able to put out an instrument 487 00:43:43,480 --> 00:43:46,639 that will help us monitor the big icebergs that are breaking off 488 00:43:46,720 --> 00:43:48,239 as the ice shelf breaks up. 489 00:43:56,920 --> 00:44:01,159 Landing on an iceberg is another first for Andy's team. 490 00:44:15,160 --> 00:44:19,759 This satellite transmitter will help to track the continued breakup 491 00:44:19,840 --> 00:44:21,639 of this colossal ice shelf. 492 00:44:34,400 --> 00:44:38,679 The remainder of the Wilkins looks set to break apart soon. 493 00:44:42,280 --> 00:44:44,879 It's the latest ice shelf to disintegrate 494 00:44:44,960 --> 00:44:47,679 in a wave that's been travelling southwards, 495 00:44:47,760 --> 00:44:51,439 playing a major role in the loss of ice from the Peninsula. 496 00:44:53,440 --> 00:44:56,759 Next in line, and already weakening in places, 497 00:44:56,840 --> 00:44:58,679 are the ice shelves that hold back 498 00:44:58,760 --> 00:45:02,399 Antarctica's gigantic continental ice sheet. 499 00:45:03,800 --> 00:45:07,919 And it would only take a small corner of this to slide into the sea 500 00:45:08,000 --> 00:45:10,679 to have major global consequences. 501 00:45:13,720 --> 00:45:18,239 We've only started to see changes in the Arctic and Antarctic recently, 502 00:45:18,320 --> 00:45:22,559 so it's hard to predict exactly what impact these changes will have, 503 00:45:22,640 --> 00:45:26,479 but we can see for ourselves that these places are changing 504 00:45:26,560 --> 00:45:29,239 and on a scale that is hard to ignore. 505 00:45:32,240 --> 00:45:36,279 The Poles, north and south, may seem very remote, 506 00:45:37,000 --> 00:45:42,319 but what is happening here is likely to have a greater effect upon us 507 00:45:42,400 --> 00:45:45,079 than any other aspect of global warming. 508 00:45:46,080 --> 00:45:49,199 If the Arctic sea-ice continues to disappear, 509 00:45:49,280 --> 00:45:52,839 it will drive up the planet's temperature more quickly 510 00:45:52,920 --> 00:45:56,359 and the melting ice sheets could contribute to a sea level rise 511 00:45:56,440 --> 00:45:59,439 of a meter, enough to threaten the homes 512 00:45:59,520 --> 00:46:02,439 of millions of people around the world's coasts 513 00:46:02,520 --> 00:46:04,559 by the end of the century. 514 00:46:05,840 --> 00:46:10,239 We've seen that the animals are already adapting to these changes. 515 00:46:10,880 --> 00:46:17,159 But can we respond to what is happening now to the frozen planet? 516 00:46:54,600 --> 00:46:57,479 The increasing unpredictability of the ice 517 00:46:57,560 --> 00:46:59,999 was a big issue for the Frozen Planet team, 518 00:47:00,080 --> 00:47:02,919 who spent three years working on top of it. 519 00:47:10,520 --> 00:47:13,399 Whether on sea, land, lake or river, 520 00:47:13,480 --> 00:47:15,679 the state of the ice was the first concern 521 00:47:15,760 --> 00:47:17,679 for most filming crews. 522 00:47:23,200 --> 00:47:28,279 Unexpected breakups left many a cameraman in need of a swift rescue. 523 00:47:28,360 --> 00:47:32,399 Sometimes help came by boat and sometimes by air. 524 00:47:39,280 --> 00:47:43,119 I had a chance to see the changing ice conditions for myself 525 00:47:43,200 --> 00:47:45,119 when I visited the North Pole. 526 00:47:47,960 --> 00:47:50,559 I flew with the team to a temporary camp 527 00:47:50,640 --> 00:47:54,639 that is set up every year in the center of the frozen Arctic Ocean 528 00:47:54,720 --> 00:47:57,159 to support expeditions to the Pole. 529 00:48:02,120 --> 00:48:04,479 I had never visited the North Pole before 530 00:48:04,560 --> 00:48:07,159 so this was a great highlight for me. 531 00:48:08,160 --> 00:48:11,119 But it was hard going in temperatures of -40, 532 00:48:11,200 --> 00:48:14,199 so as soon as filming finished, we flew south. 533 00:48:15,800 --> 00:48:19,439 Little did we know that we had made it out just in time. 534 00:48:21,360 --> 00:48:25,039 We got back from the Pole camp last night 535 00:48:25,120 --> 00:48:27,999 and I've just bumped into the Russian Commander 536 00:48:28,080 --> 00:48:30,399 who's just heard from the camp, 537 00:48:30,480 --> 00:48:34,199 and the news is that a little crack which I'd seen in the ice 538 00:48:34,280 --> 00:48:37,559 between our tent and the airstrip, 539 00:48:37,640 --> 00:48:40,559 which was no more than an inch or so wide, 540 00:48:40,640 --> 00:48:44,319 has, overnight, widened to 20 meters. 541 00:48:45,680 --> 00:48:49,199 Temporary breakups caused by stormy weather and strong winds 542 00:48:49,280 --> 00:48:50,479 have happened before, 543 00:48:50,600 --> 00:48:53,799 but they've been getting more and more frequent over recent years 544 00:48:53,880 --> 00:48:55,919 as the ice has got weaker. 545 00:49:00,000 --> 00:49:01,879 It was only swift action by the staff 546 00:49:01,960 --> 00:49:05,799 that prevented a lot of valuable equipment going in the drink. 547 00:49:13,160 --> 00:49:17,039 The biggest concern was that the ice airstrip might break apart, 548 00:49:17,120 --> 00:49:20,399 but luckily it held and everyone was able to evacuate 549 00:49:20,480 --> 00:49:22,519 when the weather improved. 550 00:49:26,960 --> 00:49:29,799 The Frozen Planet team's clearest demonstration 551 00:49:29,880 --> 00:49:32,879 of the power and unpredictability of breaking ice 552 00:49:32,960 --> 00:49:37,079 came when they went to film the melting of a frozen Canadian river. 553 00:49:37,480 --> 00:49:40,519 Producer Mark Linfield and researcher Matt Swarbrick 554 00:49:40,600 --> 00:49:43,159 have travelled to the Far North of Canada. 555 00:49:43,240 --> 00:49:44,999 Matt, when was the last time we saw a car? 556 00:49:45,600 --> 00:49:48,639 I don't know, about three hours ago? 557 00:49:49,840 --> 00:49:52,519 They've driven through the vast Northwest Territory 558 00:49:52,600 --> 00:49:56,759 on a mission to film the moment when this frozen waterfall breaks apart. 559 00:50:00,560 --> 00:50:03,999 The breakup when the frozen river above the waterfall thaws 560 00:50:04,080 --> 00:50:08,559 and masses of water start to flow again can be a spectacular event, 561 00:50:08,640 --> 00:50:12,639 but predicting exactly when it's going to break is the big challenge 562 00:50:12,720 --> 00:50:15,599 if Mark and Matt want to get the best shots. 563 00:50:18,440 --> 00:50:20,519 And they're not the only ones who want to know. 564 00:50:20,600 --> 00:50:23,919 When the waterfall breaks, it can flood the town of Hay River, 565 00:50:24,000 --> 00:50:27,719 just downstream, with millions of tons of water and ice. 566 00:50:28,920 --> 00:50:32,479 Mark is taking advice from the scientist Faye Hicks, 567 00:50:32,560 --> 00:50:35,839 who has the job of predicting when the ice will break. 568 00:50:35,920 --> 00:50:38,159 What happens is...is you get ice jams form upstream 569 00:50:38,240 --> 00:50:41,039 and they start to dam up the water and it builds and builds and builds, 570 00:50:41,120 --> 00:50:44,959 and that can let go and that's a much bigger wave of water, 571 00:50:45,040 --> 00:50:46,799 you know, than just the normal flow. 572 00:50:46,880 --> 00:50:49,799 So, it just depends upon how dramatically it unfolds. 573 00:50:51,240 --> 00:50:53,079 Faye takes her research helicopter 574 00:50:53,160 --> 00:50:56,439 to monitor the situation upstream of the waterfall. 575 00:51:06,040 --> 00:51:09,639 Just 10 miles upriver, the ice is starting to break. 576 00:51:11,840 --> 00:51:14,919 The locals are concerned because huge amounts of water 577 00:51:15,000 --> 00:51:17,479 can build up if these ice chunks dam the river 578 00:51:17,560 --> 00:51:20,519 and that can lead to devastating flooding in the town 579 00:51:20,600 --> 00:51:22,399 when the dams burst. 580 00:51:22,480 --> 00:51:24,799 Simon, it's moving through there now. 581 00:51:24,880 --> 00:51:26,359 Yeah, got you. I'm on your six. 582 00:51:26,480 --> 00:51:29,559 Using cameras and sonar to assess the state of the river, 583 00:51:29,640 --> 00:51:30,999 Faye makes her best guess 584 00:51:31,080 --> 00:51:33,999 of when this breakup will hit the waterfall just above the town. 585 00:51:34,080 --> 00:51:38,119 As of now, guys, I think we have about 48 hours to go. 586 00:51:39,360 --> 00:51:41,639 Faye’s prediction of the 24th of April 587 00:51:41,720 --> 00:51:43,959 is exciting news for the team. 588 00:51:46,680 --> 00:51:50,159 Upstream from here, it's already starting to melt, 589 00:51:50,240 --> 00:51:53,599 and Faye thinks that we may only have another one or two days 590 00:51:53,680 --> 00:51:55,799 before this whole thing goes, 591 00:51:55,880 --> 00:51:59,039 which is almost impossible to imagine looking at it now, 592 00:51:59,120 --> 00:52:00,559 but that's what she says. 593 00:52:01,720 --> 00:52:03,879 With the breakup seemingly imminent, 594 00:52:03,960 --> 00:52:06,959 the team set up their cameras in anticipation. 595 00:52:09,280 --> 00:52:12,919 Over the next 48 hours, the weather warms to well above freezing, 596 00:52:13,000 --> 00:52:14,599 but there's no sign of the breakup. 597 00:52:14,680 --> 00:52:17,839 The team waits and waits and waits. 598 00:52:27,840 --> 00:52:31,079 Mark is concerned that the crew have to return home soon, 599 00:52:31,160 --> 00:52:36,119 so he heads into town to get the advice of long-term resident Red McBrian. 600 00:52:37,320 --> 00:52:41,559 We just have to live with it and take whatever evasive action we can. 601 00:52:42,160 --> 00:52:46,119 Red has had 50 years of witnessing the power of the river. 602 00:52:46,200 --> 00:52:50,279 Well, we're hoping that she may break up in two or three days, even. 603 00:52:50,360 --> 00:52:53,119 - Oh, no. No, no, no. That's too soon. - You think it'll be longer? 604 00:52:53,200 --> 00:52:56,199 Oh, no, no. Boys, you're looking at... 605 00:52:56,800 --> 00:53:02,119 You're looking at seven or eight days before she breaks of any significancy. 606 00:53:02,840 --> 00:53:06,799 And if she breaks, she can jam and hold up. 607 00:53:08,000 --> 00:53:09,439 She can be... 608 00:53:10,000 --> 00:53:12,999 She'd be down here probably around the 5th or 6th of May. 609 00:53:13,080 --> 00:53:14,119 Right. 610 00:53:15,760 --> 00:53:19,919 The townspeople are on tenterhooks waiting for the big day, 611 00:53:20,000 --> 00:53:23,799 but another week goes by before anything starts to happen. 612 00:53:35,640 --> 00:53:38,199 Finally it seems that things might be happening. 613 00:53:38,280 --> 00:53:40,559 We've just heard some cracks from upstream, 614 00:53:40,640 --> 00:53:44,799 so if we're lucky, we might get some action. 615 00:53:44,880 --> 00:53:47,159 It's 7:00, which gives us two hours light. 616 00:53:47,240 --> 00:53:49,279 Two hours light. If it happens at night, 617 00:53:49,360 --> 00:53:51,759 we're going to miss the whole thing. 618 00:53:53,560 --> 00:53:56,199 Sure enough, the town is put on red alert 619 00:53:56,280 --> 00:54:00,039 that the river is about to break in the middle of the night. 620 00:54:01,360 --> 00:54:04,679 They've just called a full evacuation of the Eye Inn where we're staying, 621 00:54:04,760 --> 00:54:07,039 and if we don't move now, we're all going to be underwater 622 00:54:07,120 --> 00:54:09,039 and possibly get trapped here for a few days. 623 00:54:10,040 --> 00:54:13,159 The team have to move out and get up to the waterfall, 624 00:54:13,240 --> 00:54:16,679 hoping that it doesn't break before it's light enough to film. 625 00:54:22,000 --> 00:54:25,839 Luckily, the sun is up before the main event begins. 626 00:54:26,640 --> 00:54:29,279 That is a serious amount of ice coming around the corner. 627 00:54:40,440 --> 00:54:43,399 After weeks of waiting, 628 00:54:43,480 --> 00:54:46,239 the sleeping giant of a river, and we thought nothing was gonna happen, 629 00:54:46,320 --> 00:54:48,599 and suddenly, look at this! 630 00:54:49,320 --> 00:54:52,319 This is what we're here for. Unbelievable! 631 00:54:52,400 --> 00:54:54,599 Absolutely unbelievable! 632 00:54:55,520 --> 00:54:56,959 Holy ! 633 00:55:00,200 --> 00:55:02,839 The team is used to handling multiple cameras 634 00:55:02,920 --> 00:55:05,799 but they don't usually have to dodge 10-tonne ice floes 635 00:55:05,880 --> 00:55:07,519 at the same time. 636 00:55:09,200 --> 00:55:12,639 You can see it's racing over at unbelievable speed. 637 00:55:12,720 --> 00:55:14,399 The power... I just... 638 00:55:14,480 --> 00:55:18,039 If you were here to feel this, it's a deep rumbling sound of the river, 639 00:55:18,120 --> 00:55:19,999 I can feel it up through my feet. 640 00:55:20,080 --> 00:55:24,319 The power, I just can't imagine, that could crush a house in no time. 641 00:55:25,480 --> 00:55:27,039 The team takes to the air 642 00:55:27,120 --> 00:55:29,519 to witness the destruction that's unleashed, 643 00:55:29,600 --> 00:55:32,999 huge ice blocks are pushed downstream on the wave of water 644 00:55:33,080 --> 00:55:35,559 released by the breaking waterfall. 645 00:55:38,920 --> 00:55:40,799 This could devastate the town. 646 00:55:46,080 --> 00:55:49,199 But this year, the townspeople's luck is in. 647 00:55:49,280 --> 00:55:51,519 The town has escaped flooding. 648 00:55:56,040 --> 00:56:00,279 Crucially, the ice blocks did not dam the river, it's running free, 649 00:56:00,840 --> 00:56:04,159 and the date of the breakup, 6th of May. 650 00:56:04,240 --> 00:56:06,239 Red's got it right again. 651 00:56:07,640 --> 00:56:11,879 I don't use any of these here gauges and mechanical assistance. 652 00:56:11,960 --> 00:56:17,159 I just go by what I see on the river as I walk it down, 653 00:56:17,240 --> 00:56:21,639 and I say I walk it down, I back and forth every day on the river 654 00:56:21,720 --> 00:56:23,159 to see what's happening, 655 00:56:23,240 --> 00:56:27,239 and that from that I gauge when it's going to hit here 656 00:56:27,320 --> 00:56:30,719 and what the situation's going to be like when it does get here. 657 00:56:30,800 --> 00:56:32,399 You know, when it went this morning, 658 00:56:32,480 --> 00:56:35,119 I said to my students, "Guess what the date is?" 659 00:56:35,200 --> 00:56:37,119 Red told us it's the 6th of May, and we were... 660 00:56:37,200 --> 00:56:39,679 You know, I'm not surprised because we've been here a couple of times 661 00:56:39,760 --> 00:56:40,879 and that's happened. 662 00:56:40,960 --> 00:56:43,439 Ten days, two weeks out, he just looks around and goes, 663 00:56:43,520 --> 00:56:46,239 "5th of May," and we're like, "How does he know that?" 664 00:56:46,320 --> 00:56:49,519 It's incredible. It's because he just has lived on this river 665 00:56:49,600 --> 00:56:53,279 and lived this breakup for 50 years. 666 00:56:54,520 --> 00:56:56,119 Ice scientists are improving 667 00:56:56,200 --> 00:56:58,719 the accuracy of their predictions all the time, 668 00:56:58,800 --> 00:56:59,839 but in the meantime, 669 00:56:59,920 --> 00:57:03,199 the people of Hay River have a remarkable guardian. 670 00:57:04,040 --> 00:57:06,279 Red, you were completely right this year. 671 00:57:06,360 --> 00:57:08,079 Are you right every year? 672 00:57:08,160 --> 00:57:10,439 No, I miss... 673 00:57:10,520 --> 00:57:12,519 I miss the odd one. 674 00:57:13,120 --> 00:57:15,959 Yes. 1985, I missed it.