1 00:00:52,000 --> 00:00:53,480 David Attenborough: In this series, 2 00:00:53,600 --> 00:00:54,840 we have explored 3 00:00:54,960 --> 00:00:57,080 the earth's frozen frontiers. 4 00:01:15,160 --> 00:01:18,400 We have celebrated the astonishing variety 5 00:01:18,520 --> 00:01:20,880 of animals that are found there... 6 00:01:29,120 --> 00:01:30,120 And revealed 7 00:01:30,240 --> 00:01:32,040 the extraordinary ways 8 00:01:32,160 --> 00:01:34,320 by which they manage to survive. 9 00:01:46,560 --> 00:01:49,240 At a time when our icecaps are melting 10 00:01:49,360 --> 00:01:51,440 faster than ever before... 11 00:01:53,560 --> 00:01:54,680 We will meet 12 00:01:54,800 --> 00:01:57,640 the scientists and people who are dedicating their lives 13 00:01:57,760 --> 00:02:00,800 to protecting our frozen planet... 14 00:02:02,640 --> 00:02:04,720 And striving to turn things around 15 00:02:04,840 --> 00:02:07,520 while there is still time to do so. 16 00:02:07,640 --> 00:02:10,080 It won't be easy, but it's doable. 17 00:02:11,920 --> 00:02:15,360 It's crucial that we try to understand 18 00:02:15,480 --> 00:02:17,120 what the impact will be, 19 00:02:17,240 --> 00:02:21,200 not just for the wildlife and the people that live there, 20 00:02:21,320 --> 00:02:23,480 but for you and for me. 21 00:02:38,360 --> 00:02:42,080 We start our journey in the high arctic, 22 00:02:42,200 --> 00:02:46,080 and the vast frozen expanse of Greenland. 23 00:02:48,880 --> 00:02:53,160 This huge island is blanketed by the largest store of ice 24 00:02:53,280 --> 00:02:55,040 in the northern hemisphere. 25 00:02:58,120 --> 00:03:00,360 But now it's shrinking. 26 00:03:04,800 --> 00:03:08,040 Professor alun Hubbard is a glaciologist 27 00:03:08,160 --> 00:03:09,840 and he's spent over 30 years 28 00:03:09,960 --> 00:03:13,560 studying the movement of ice along Greenland's coastline. 29 00:03:15,520 --> 00:03:17,720 Alun: It is quite a beast of a glacier. 30 00:03:17,840 --> 00:03:20,400 It's just growling constantly. 31 00:03:22,320 --> 00:03:25,640 Thundenng". In the background. 32 00:03:27,160 --> 00:03:29,720 Ooh. There we go - bit of activity. 33 00:03:41,400 --> 00:03:43,520 Alun: Calving icebergs is a natural process, 34 00:03:43,640 --> 00:03:46,160 but what we've seen in the last 20 years is 35 00:03:46,280 --> 00:03:48,440 there's been much more melt, 36 00:03:48,560 --> 00:03:51,640 and much more ice calving off, 37 00:03:51,760 --> 00:03:53,720 producing huge icebergs... 38 00:03:57,000 --> 00:03:59,920 So it's quite an intimidating place 39 00:04:00,040 --> 00:04:01,080 to be hanging out. 40 00:04:10,600 --> 00:04:12,600 David: One thing in particular 41 00:04:12,720 --> 00:04:15,920 has caused this increase in melting and calving. 42 00:04:20,520 --> 00:04:25,560 We put this weather station here in 2010. 43 00:04:25,680 --> 00:04:29,840 And the hottest temperature was... 44 00:04:29,960 --> 00:04:31,240 Two days ago... 45 00:04:33,040 --> 00:04:37,080 At 22.37 degrees centigrade. 46 00:04:38,960 --> 00:04:42,680 That is very, very hot for Greenland. 47 00:04:48,280 --> 00:04:51,640 David: As the ice falls into the ocean, 48 00:04:51,760 --> 00:04:53,480 it raises sea levels globally. 49 00:04:57,120 --> 00:04:58,880 These are now rising 50 00:04:59,000 --> 00:05:01,720 by an average of four millimetres a year. 51 00:05:03,120 --> 00:05:08,640 A quarter of that comes from the Greenland ice sheet, 52 00:05:08,760 --> 00:05:13,760 and scientists fear that this figure could increase rapidly. 53 00:05:17,080 --> 00:05:21,040 To investigate, alun has travelled 70 miles inland 54 00:05:21,160 --> 00:05:22,920 to the top of the ice sheet, 55 00:05:23,040 --> 00:05:26,840 where the glaciers start their lives as compacted snow 56 00:05:26,960 --> 00:05:28,920 more than a mile thick. 57 00:05:33,320 --> 00:05:36,000 Here, the effects of a warming climate 58 00:05:36,120 --> 00:05:37,680 are only too clear. 59 00:05:39,240 --> 00:05:41,040 Alun: There are thousands 60 00:05:41,160 --> 00:05:43,360 of these beautiful azure-blue lakes 61 00:05:43,480 --> 00:05:46,080 littered across the surface of the ice sheet. 62 00:05:46,200 --> 00:05:50,120 David: The surface has always melted in the summer, 63 00:05:50,240 --> 00:05:51,880 but not on this scale... 64 00:05:54,440 --> 00:05:55,800 And alun wants to know 65 00:05:55,920 --> 00:05:58,600 what effect the increase in meltwater 66 00:05:58,720 --> 00:06:01,160 is having on the ice sheet as a whole. 67 00:06:03,360 --> 00:06:05,960 Alun: The sheer quantity of water... 68 00:06:09,040 --> 00:06:13,480 Shifting through this system is crazy! 69 00:06:17,200 --> 00:06:21,280 David: Powerful torrents of meltwater are boring shafts - 70 00:06:21,400 --> 00:06:23,480 known as moulins - into the ice sheet. 71 00:06:26,120 --> 00:06:28,200 Alun: This is nuts. 72 00:06:28,320 --> 00:06:30,840 This is a moulin actively being formed, 73 00:06:30,960 --> 00:06:32,520 a moulin in Genesis. 74 00:06:36,400 --> 00:06:38,720 As we speak, that water is finding 75 00:06:38,840 --> 00:06:41,520 the path of least resistance, 76 00:06:41,640 --> 00:06:47,240 sculpting this shaft that's going deep into the ice. 77 00:06:54,000 --> 00:06:56,160 And here it is, 78 00:06:56,280 --> 00:06:59,960 just toppling over a waterfall edge 79 00:07:00,080 --> 00:07:02,840 and dropping into the ice sheet. 80 00:07:06,000 --> 00:07:08,280 David: But where is all this meltwater is going? 81 00:07:08,400 --> 00:07:11,080 And what impact is it having 82 00:07:11,200 --> 00:07:13,720 on the structure of the ice sheet? 83 00:07:13,840 --> 00:07:15,520 To find out, 84 00:07:15,640 --> 00:07:19,240 alun decides to climb inside a dried-up moulin. 85 00:07:20,960 --> 00:07:24,920 Alun: I think I must be 15, 20 metres down here, 86 00:07:25,040 --> 00:07:28,040 but I'm going to go down a bit further. 87 00:07:29,800 --> 00:07:31,960 It's a very narrow shaft here. 88 00:07:33,040 --> 00:07:35,160 David: It's always been assumed that the meltwater 89 00:07:35,280 --> 00:07:38,480 drains straight down and out of the bottom of the ice sheet, 90 00:07:38,600 --> 00:07:41,760 but what alun discovers is very different. 91 00:07:41,880 --> 00:07:43,600 I can hear 92 00:07:43,720 --> 00:07:47,480 a big amount of water moving in this system, 93 00:07:47,600 --> 00:07:51,840 and the water's starting to spread sideways, laterally, 94 00:07:51,960 --> 00:07:54,600 so the drainage system is obviously complex. 95 00:07:54,720 --> 00:07:56,480 It's interlinked. 96 00:08:02,000 --> 00:08:05,720 David: These observations suggest that the meltwater 97 00:08:05,840 --> 00:08:07,920 is branching out in every direction, 98 00:08:08,040 --> 00:08:12,480 causing this once-rigid structure to destabilise. 99 00:08:15,120 --> 00:08:16,680 Whoa. 100 00:08:16,800 --> 00:08:18,000 It's a bit rotten. 101 00:08:18,120 --> 00:08:19,680 Everything's rotting here. 102 00:08:22,360 --> 00:08:25,120 David: The implications of this are frightening. 103 00:08:27,280 --> 00:08:30,760 Alun believes that as the ice sheet begins to thaw, 104 00:08:30,880 --> 00:08:34,400 it's sliding towards the ocean at a much faster rate. 105 00:08:38,480 --> 00:08:42,840 And he's now confirmed that using time-lapse photography. 106 00:08:46,360 --> 00:08:48,720 Alun: The ice at the front can be moving 107 00:08:48,840 --> 00:08:53,720 in excess of 20 metres a day, which is fast. 108 00:08:55,080 --> 00:08:59,280 That is a huge quantity of ice straight into the ocean. 109 00:09:00,680 --> 00:09:03,560 David: Some of Greenland's glaciers are moving 110 00:09:03,680 --> 00:09:07,040 three times faster today than they were 30 years ago. 111 00:09:08,280 --> 00:09:10,520 Alun: As the climate's warming, 112 00:09:10,640 --> 00:09:13,240 the rate at which this ice sheet flows 113 00:09:13,360 --> 00:09:14,960 is absolutely critical. 114 00:09:15,080 --> 00:09:16,720 80 whereas, at the moment, 115 00:09:16,840 --> 00:09:19,040 we're thinking this thing is going to take 116 00:09:19,160 --> 00:09:21,640 thousands of years to melt and disintegrate, 117 00:09:21,760 --> 00:09:25,720 if it does move faster and accelerate, 118 00:09:25,840 --> 00:09:27,720 it means centuries. 119 00:09:35,040 --> 00:09:37,880 That is a really contentious and very important question - 120 00:09:38,000 --> 00:09:40,920 because this ice sheet has enough water in it 121 00:09:41,040 --> 00:09:44,280 to raise global sea level by over seven metres, 122 00:09:44,400 --> 00:09:46,920 and that's a total disaster for humanity. 123 00:09:51,960 --> 00:09:53,720 David: Calculations predict 124 00:09:53,840 --> 00:09:55,920 that nearly half a billion people 125 00:09:56,040 --> 00:09:58,680 living in coastal communities around the world 126 00:09:58,800 --> 00:10:02,040 will be displaced by flooding by the end of the century. 127 00:10:03,360 --> 00:10:04,800 But if the Greenland ice sheet 128 00:10:04,920 --> 00:10:07,160 slips into the ocean more rapidly, 129 00:10:07,280 --> 00:10:09,160 this could all happen far sooner. 130 00:10:14,720 --> 00:10:18,800 Greenland isn't the only large body of ice in the arctic. 131 00:10:20,120 --> 00:10:22,920 In winter, the ocean here freezes over, 132 00:10:23,040 --> 00:10:24,480 creating a cover of ice 133 00:10:24,600 --> 00:10:27,560 larger than the entire United States. 134 00:10:30,800 --> 00:10:34,720 This sea ice has always got smaller in summer, 135 00:10:34,840 --> 00:10:38,680 but today it's rapidly disappearing. 136 00:10:41,240 --> 00:10:45,200 Hotter temperatures are melting it at an unprecedented rate... 137 00:10:47,640 --> 00:10:49,840 With worrying consequences 138 00:10:49,960 --> 00:10:52,640 for the wildlife that depends on it. 139 00:11:08,480 --> 00:11:11,400 For harp seals, the sea ice is an excellent place 140 00:11:11,520 --> 00:11:14,680 for giving birth out of the water. 141 00:11:19,280 --> 00:11:22,840 It provides the defenceless newborn pups 142 00:11:22,960 --> 00:11:26,080 with a safe space for their first six weeks, 143 00:11:26,200 --> 00:11:29,600 until they're big enough to swim proficiently. 144 00:11:37,600 --> 00:11:38,760 But with the sea ice 145 00:11:38,880 --> 00:11:41,240 disappearing increasingly fast... 146 00:11:42,880 --> 00:11:44,960 Will they be able to adapt? 147 00:11:49,840 --> 00:11:51,640 Radio: Coastguard 432. 148 00:11:51,760 --> 00:11:54,600 Coastguard radio. Coastguard 432. Check out. 149 00:11:56,680 --> 00:11:58,880 David: In Canada's Gulf of Saint Lawrence, 150 00:11:59,000 --> 00:12:02,760 a group of seal biologists are trying to find out. 151 00:12:04,720 --> 00:12:07,920 It's a pretty dangerous, pretty inhospitable place, 152 00:12:08,040 --> 00:12:09,736 but it's the perfect environment for these seals 153 00:12:09,760 --> 00:12:12,240 to spend the first few weeks of their lives. 154 00:12:12,360 --> 00:12:14,960 There's a group just down here to the right now. 155 00:12:16,800 --> 00:12:19,480 David: But the fragile sea ice is a challenging place 156 00:12:19,600 --> 00:12:21,680 in which to work. 157 00:12:24,640 --> 00:12:27,480 Here... let's go a little further out. 158 00:12:29,160 --> 00:12:31,840 David: To support a two-tonne helicopter, the ice must be 159 00:12:31,960 --> 00:12:33,440 at least 30 centimetres thick, 160 00:12:33,560 --> 00:12:38,760 and the only way to find out if that's so is with a drill. 161 00:12:49,520 --> 00:12:51,000 It's just not safe here. 162 00:12:58,680 --> 00:13:01,360 There's a couple just down here below us now. 163 00:13:06,840 --> 00:13:08,720 We've got a pretty short window here. 164 00:13:26,880 --> 00:13:29,520 David: The team are trying to discover 165 00:13:29,640 --> 00:13:32,720 where the seals go when they become independent. 166 00:13:34,800 --> 00:13:36,480 So, this is a juvenile harp seal. 167 00:13:36,600 --> 00:13:39,016 This is exactly what we've been out on the ice trying to find. 168 00:13:39,040 --> 00:13:40,120 Hey, little guy. 169 00:13:42,320 --> 00:13:44,280 They're absolutely beautiful. 170 00:13:45,800 --> 00:13:48,040 We'll be putting a satellite transmitter 171 00:13:48,160 --> 00:13:49,600 on the top of this animal's head, 172 00:13:49,720 --> 00:13:51,840 so that every time the animal comes to the surface, 173 00:13:51,960 --> 00:13:55,440 we can get a location estimate for where he is at sea. 174 00:13:58,240 --> 00:14:01,160 It won't harm them in any way, and, in return, 175 00:14:01,280 --> 00:14:04,080 the amount of information we get from them is invaluable. 176 00:14:08,480 --> 00:14:10,880 It'll be really interesting to see where these animals go 177 00:14:11,000 --> 00:14:13,120 as the ice starts to break up over the coming months. 178 00:14:15,000 --> 00:14:17,240 David: The results from the study so far 179 00:14:17,360 --> 00:14:18,840 do not look encouraging. 180 00:14:20,040 --> 00:14:22,680 Despite migrating huge distances, 181 00:14:22,800 --> 00:14:26,080 when the time comes to have pups of their own, 182 00:14:26,200 --> 00:14:29,040 harp seals almost always return to the area 183 00:14:29,160 --> 00:14:31,600 where they themselves were born. 184 00:14:35,440 --> 00:14:37,160 But as the sea ice shrinks, 185 00:14:37,280 --> 00:14:40,160 so does its suitability as a nursery. 186 00:14:43,640 --> 00:14:47,680 The problem really comes about if the only ice available 187 00:14:47,800 --> 00:14:50,440 in the traditional areas is very thin. 188 00:14:50,560 --> 00:14:52,640 They'll still use that ice and then you get 189 00:14:52,760 --> 00:14:54,440 an increased mortality. 190 00:14:58,200 --> 00:15:00,360 David: In short, the pups risk drowning 191 00:15:00,480 --> 00:15:02,560 if the ice isn't thick enough. 192 00:15:05,200 --> 00:15:07,080 And the bigger question is, 193 00:15:07,200 --> 00:15:09,880 will the ice continue to exist at all? 194 00:15:14,160 --> 00:15:16,680 In my lifetime, we've lost about two-thirds 195 00:15:16,800 --> 00:15:19,640 of the summer sea ice in the arctic. 196 00:15:23,280 --> 00:15:26,520 And it's likely that in the next 30 years 197 00:15:26,640 --> 00:15:30,680 we're going to end up with an ice-free arctic in the summer. 198 00:15:32,960 --> 00:15:35,400 I think one of the issues with climate change 199 00:15:35,520 --> 00:15:38,160 is that it's really difficult to see. 200 00:15:40,480 --> 00:15:43,960 But in the case of harp seals, it's really quite simple. 201 00:15:47,080 --> 00:15:49,160 If we lose the sea ice in the arctic, 202 00:15:49,280 --> 00:15:51,200 we lose the harp seals. 203 00:16:03,400 --> 00:16:07,320 For harp seals, their future, it has to be said, 204 00:16:07,440 --> 00:16:09,320 appears uncertain. 205 00:16:09,440 --> 00:16:12,600 But what about the most famous face of climate change - 206 00:16:12,720 --> 00:16:14,040 the polar bear? 207 00:16:25,320 --> 00:16:27,800 Can this keenly intelligent animal 208 00:16:27,920 --> 00:16:31,400 adapt to a rapidly changing world? 209 00:16:33,880 --> 00:16:37,560 As the summer sea ice melts away, 210 00:16:37,680 --> 00:16:41,920 many polar bears are forced to head for dry land. 211 00:16:50,240 --> 00:16:55,120 Some swim up to 400 miles to get there. 212 00:17:08,400 --> 00:17:11,800 This is wrangel, 213 00:17:11,920 --> 00:17:15,320 a remote island in arctic Russia. 214 00:17:46,880 --> 00:17:50,560 David: Without the sea ice, the hungry bears cannot hunt seals 215 00:17:50,680 --> 00:17:53,440 and feed on their calorie-rich flesh, 216 00:17:53,560 --> 00:17:58,640 but find other sources of food, including human food supplies. 217 00:18:20,360 --> 00:18:25,160 Each summer, gennadiy is joined by polar bear expert 218 00:18:25,280 --> 00:18:26,960 dr Eric regehr. 219 00:18:29,760 --> 00:18:31,600 - We need to cross that Ridge. - Ok. 220 00:18:35,560 --> 00:18:37,440 David: Eric wants to find out 221 00:18:37,560 --> 00:18:40,360 just how many bears are ending up here. 222 00:18:43,960 --> 00:18:45,760 Eric: In 20 years of studying polar bears, 223 00:18:45,880 --> 00:18:49,520 I've never been anywhere like wrangel island. 224 00:18:49,640 --> 00:18:53,280 The density of bears is unlike anything I've ever seen before. 225 00:18:53,400 --> 00:18:57,360 This past two years, we've seen about 500 bears. 226 00:18:57,480 --> 00:19:00,520 My sense is that's just a fraction of how many are here. 227 00:19:04,680 --> 00:19:08,400 David: But with so many hungry animals in one place... 228 00:19:10,120 --> 00:19:12,880 Is there enough food to go round? 229 00:19:19,840 --> 00:19:21,960 Gennadiy, if you can keep an eye out for us, please, 230 00:19:22,080 --> 00:19:23,600 like up on the hill 231 00:19:23,720 --> 00:19:25,640 or just wherever you've got a good view. 232 00:19:25,760 --> 00:19:27,080 All right, thank you. 233 00:19:30,320 --> 00:19:31,600 This is a hair trap. 234 00:19:31,720 --> 00:19:34,560 So, bears like anything that smells strong, 235 00:19:34,680 --> 00:19:36,840 and so this has a little bit of spoiled cheese, 236 00:19:36,960 --> 00:19:38,320 milk and fish in it. 237 00:19:41,040 --> 00:19:44,360 The goal here is to get a polar bear to come in 238 00:19:44,480 --> 00:19:47,240 and put its hand or its head inside this box, 239 00:19:47,360 --> 00:19:48,720 and when that happens, 240 00:19:48,840 --> 00:19:51,280 these little wire brushes will pull out a few pieces of hair 241 00:19:51,400 --> 00:19:53,600 that we can use for scientific analysis. 242 00:19:55,600 --> 00:19:58,320 You can learn a lot about polar bears 243 00:19:58,440 --> 00:20:00,360 just from a piece of their hair. 244 00:20:00,480 --> 00:20:03,400 We can figure out which individual it is, 245 00:20:03,520 --> 00:20:05,960 or you can get information on what they're eating. 246 00:20:08,320 --> 00:20:10,720 There we go - hair collected. 247 00:20:14,640 --> 00:20:18,040 David: Eric's molecular studies of the polar bear's hair 248 00:20:18,160 --> 00:20:20,280 show that the bears on wrangel 249 00:20:20,400 --> 00:20:23,320 appear to be finding enough food. 250 00:20:23,440 --> 00:20:26,640 But with more and more bears coming here, 251 00:20:26,760 --> 00:20:29,800 will there still be enough food to go round? 252 00:20:34,800 --> 00:20:37,720 One of the main things we expect to happen 253 00:20:37,840 --> 00:20:40,200 with sea ice loss is changes in the movements 254 00:20:40,320 --> 00:20:42,960 and the distribution of polar bears, so polar bears 255 00:20:43,080 --> 00:20:45,120 are going to appear in places they never were before 256 00:20:45,160 --> 00:20:47,441 and they're going to disappear from places that they were. 257 00:20:54,480 --> 00:20:57,720 David: Some coastal towns in Siberia 258 00:20:57,840 --> 00:21:01,320 have been overrun with up to 50 bears at a time. 259 00:21:08,400 --> 00:21:11,360 They are desperate to eat whatever they can. 260 00:21:13,360 --> 00:21:16,880 And in the city of norilsk, 261 00:21:17,000 --> 00:21:18,600 one female was found 262 00:21:18,720 --> 00:21:21,680 an incredible 250 miles away from the coast. 263 00:21:27,480 --> 00:21:32,080 Lost and starving, she was eventually rescued. 264 00:21:34,280 --> 00:21:37,200 But many are not so lucky. 265 00:21:40,200 --> 00:21:42,600 They are intelligent animals, but there's simply 266 00:21:42,720 --> 00:21:45,360 no food on land that can compare to the seals 267 00:21:45,480 --> 00:21:47,760 that the bears eat on the sea ice. 268 00:22:01,800 --> 00:22:06,720 A future without polar bears would be very sad, 269 00:22:06,840 --> 00:22:10,400 but the sea ice is not just essential for animals. 270 00:22:11,640 --> 00:22:14,400 It's a lifeline for many of the four million people 271 00:22:14,520 --> 00:22:17,440 who call the arctic their home. 272 00:22:35,880 --> 00:22:39,320 David: Aleqatsiaq peary lives in qaanaaq 273 00:22:39,440 --> 00:22:40,920 on Greenland's west coast, 274 00:22:41,040 --> 00:22:44,360 the most northerly inuit town in the world. 275 00:22:48,000 --> 00:22:52,640 For centuries, life here has depended on the sea ice. 276 00:23:13,720 --> 00:23:15,160 Not only are dog sleds 277 00:23:15,280 --> 00:23:17,720 a way to reach neighbouring communities, 278 00:23:17,840 --> 00:23:20,360 which can be over 100 miles away, 279 00:23:20,480 --> 00:23:23,920 but, in a land where no crops can grow, 280 00:23:24,040 --> 00:23:28,000 travelling over the sea ice is a vital route to food, 281 00:23:28,120 --> 00:23:29,760 fur and livelihood. 282 00:24:05,560 --> 00:24:08,200 But the dwindling of the sea ice is making this way of life 283 00:24:08,320 --> 00:24:13,040 not only difficult, but increasingly dangerous. 284 00:25:03,240 --> 00:25:06,120 Today, they must turn back. 285 00:25:27,760 --> 00:25:31,000 For qaanaaq's 650 residents, 286 00:25:31,120 --> 00:25:36,600 the loss of sea ice is the loss of an entire way of life, 287 00:25:36,720 --> 00:25:40,040 and it is creating an uncertain future. 288 00:26:11,440 --> 00:26:13,800 And there's a reason 289 00:26:13,920 --> 00:26:15,880 for this accelerating rate of change. 290 00:26:19,680 --> 00:26:22,280 In the last 30 years, 291 00:26:22,400 --> 00:26:25,880 over 14 trillion tonnes of ice 292 00:26:26,000 --> 00:26:28,280 have been lost from the arctic, 293 00:26:28,400 --> 00:26:30,560 creating a vicious cycle 294 00:26:30,680 --> 00:26:33,240 of ever-increasing temperatures. 295 00:26:35,360 --> 00:26:36,480 Normally, 296 00:26:36,600 --> 00:26:40,400 large areas of snow and ice would act as a mirror, 297 00:26:40,520 --> 00:26:46,760 reflecting up to 85% of the sun's rays back into space. 298 00:26:46,880 --> 00:26:49,240 But as the ice melts, 299 00:26:49,360 --> 00:26:52,640 the great white mirror is being replaced 300 00:26:52,760 --> 00:26:55,200 by the darkness of the ice-free ocean. 301 00:26:58,560 --> 00:27:01,240 The dark ocean absorbs the sun's rays, 302 00:27:01,360 --> 00:27:04,480 so causing even more ice to melt, 303 00:27:04,600 --> 00:27:09,520 creating a feedback loop that contributes to further warming. 304 00:27:12,880 --> 00:27:14,360 Because of this, 305 00:27:14,480 --> 00:27:18,040 the arctic is now warming more than twice as fast 306 00:27:18,160 --> 00:27:20,360 as the earth as a whole. 307 00:27:24,080 --> 00:27:26,840 That has far-reaching consequences, 308 00:27:26,960 --> 00:27:29,080 not just for the arctic ocean, 309 00:27:29,200 --> 00:27:33,120 but for the vast frozen lands that surround it - 310 00:27:33,240 --> 00:27:35,120 the tundra. 311 00:27:39,600 --> 00:27:42,440 In summer, the open tundra provides refuge 312 00:27:42,560 --> 00:27:45,080 for great concentrations of life. 313 00:27:54,960 --> 00:27:57,680 But today, its thick surface soil 314 00:27:57,800 --> 00:28:00,560 that has been deeply frozen for thousands of years 315 00:28:00,680 --> 00:28:02,080 is thawing... 316 00:28:03,800 --> 00:28:07,360 And the pooling water is creating millions of new lakes. 317 00:28:13,200 --> 00:28:14,840 Katy: Here in Alaska, 318 00:28:14,960 --> 00:28:19,080 we've seen a 40% increase in the lake area since the '80s. 319 00:28:21,360 --> 00:28:23,800 David: Professor Katy Walter Anthony 320 00:28:23,920 --> 00:28:26,880 has worked across Alaska and Siberia 321 00:28:27,000 --> 00:28:28,720 studying their lakes. 322 00:28:28,840 --> 00:28:32,640 She is interested not so much in the lakes themselves 323 00:28:32,760 --> 00:28:36,120 but in what is seeping out of them. 324 00:28:36,240 --> 00:28:39,360 We are seeing a bright spot in the satellite image 325 00:28:39,480 --> 00:28:42,000 that we suspect is gas bubbling. 326 00:28:45,640 --> 00:28:48,640 To identify the gas in these bubbles, 327 00:28:48,760 --> 00:28:50,960 Katy must collect some of it. 328 00:28:53,160 --> 00:28:57,400 I'm surrounded by tiny bubbles that are rising. 329 00:28:58,920 --> 00:29:01,520 Methane appears to be the dominant gas. 330 00:29:04,400 --> 00:29:07,240 David: Methane is produced by the decaying remains 331 00:29:07,360 --> 00:29:09,040 of prehistoric plants and animals. 332 00:29:10,320 --> 00:29:13,480 As the frozen soil beneath the lake starts to thaw, 333 00:29:13,600 --> 00:29:17,920 it releases stores of this potent greenhouse gas, 334 00:29:18,040 --> 00:29:22,160 which is up to 30 times more effective than carbon dioxide 335 00:29:22,280 --> 00:29:25,040 when it comes to trapping heat in the atmosphere 336 00:29:25,160 --> 00:29:27,800 and accelerating global warming. 337 00:29:29,440 --> 00:29:32,640 Katy: 45 parts per million are these tiny bubbles. 338 00:29:32,760 --> 00:29:34,320 It's rising higher and higher. 339 00:29:34,440 --> 00:29:36,760 Now it's going above 70. 340 00:29:38,680 --> 00:29:41,120 This is a huge amount of methane. 341 00:29:41,240 --> 00:29:43,560 It could be a mega seep. 342 00:29:47,560 --> 00:29:50,080 Katy: We are discovering more and more 343 00:29:50,200 --> 00:29:51,960 of these methane mega seeps, so streaming out 344 00:29:52,080 --> 00:29:53,640 and entering into the atmosphere. 345 00:30:00,480 --> 00:30:03,840 David: Methane can be seen escaping from lakes... 346 00:30:07,960 --> 00:30:10,600 But it also rises from the land 347 00:30:10,720 --> 00:30:13,400 wherever the frozen soil, known as the permafrost, 348 00:30:13,520 --> 00:30:15,960 begins to thaw. 349 00:30:22,680 --> 00:30:26,560 And the arctic tundra is thawing 350 00:30:26,680 --> 00:30:28,400 and collapsing 351 00:30:28,520 --> 00:30:31,440 at an unprecedented rate. 352 00:30:33,480 --> 00:30:36,400 Katy: It's concerning because permafrost, 353 00:30:36,520 --> 00:30:40,480 or frozen ground, occupies about a quarter 354 00:30:40,600 --> 00:30:43,600 of the northern hemisphere land surface. 355 00:30:45,280 --> 00:30:48,040 As permafrost thaws, if even a small fraction 356 00:30:48,160 --> 00:30:50,720 of that trapped methane escapes”. 357 00:30:52,200 --> 00:30:55,040 It will accelerate climate warming... 358 00:30:56,560 --> 00:30:58,600 And you cannot reverse it. 359 00:31:04,560 --> 00:31:07,000 David: It's clear that in the arctic, 360 00:31:07,120 --> 00:31:09,760 changes to permafrost on the land 361 00:31:09,880 --> 00:31:12,440 and floating ice on the sea 362 00:31:12,560 --> 00:31:14,760 will have far-reaching consequences 363 00:31:14,880 --> 00:31:17,960 to the planet as a whole. 364 00:31:19,600 --> 00:31:22,400 And there is nowhere better to see the extent 365 00:31:22,520 --> 00:31:24,200 of these global changes... 366 00:31:26,480 --> 00:31:28,080 Than from space. 367 00:31:30,960 --> 00:31:33,360 Woman: All of my life, I've thought about 368 00:31:33,480 --> 00:31:34,920 how this would feel - 369 00:31:35,040 --> 00:31:39,240 to gaze back on the planet with my own eyes. 370 00:31:39,360 --> 00:31:42,240 David: NASA scientist Jessica meir 371 00:31:42,360 --> 00:31:44,880 has spent six months in orbit. 372 00:31:45,000 --> 00:31:48,000 Jessica: From the space station, you have the planet 373 00:31:48,120 --> 00:31:50,080 spinning beneath you, 374 00:31:50,200 --> 00:31:54,520 and you're passing over it at 17, 500mph. 375 00:31:54,640 --> 00:31:59,120 And we are going around the entire planet every 90 minutes. 376 00:31:59,240 --> 00:32:03,400 So you can begin to see larger-scale phenomenon 377 00:32:03,520 --> 00:32:07,360 in ways that you just can't experience on the ground. 378 00:32:07,480 --> 00:32:12,760 And we can see the change in these systems over time. 379 00:32:12,880 --> 00:32:15,080 We cannot deny that we are having 380 00:32:15,200 --> 00:32:17,640 an incredible effect on the fate of our planet, 381 00:32:17,760 --> 00:32:22,480 and the effect that we have as humans on our planet. 382 00:32:22,600 --> 00:32:27,280 Right there, actually, I'm looking down at several fires. 383 00:32:27,400 --> 00:32:30,800 I'm not sure where those are. 384 00:32:30,920 --> 00:32:33,440 Let's take a quick peek. 385 00:32:37,040 --> 00:32:39,000 So, right now we're flying over Europe 386 00:32:39,120 --> 00:32:42,120 and I can see some fires over in that direction. 387 00:32:43,680 --> 00:32:45,160 And that is, of course, 388 00:32:45,280 --> 00:32:48,560 something that we have to contend more and more with, 389 00:32:48,680 --> 00:32:50,840 as our climate changes. 390 00:32:53,120 --> 00:32:54,880 David: As the arctic warms, 391 00:32:55,000 --> 00:32:57,720 wildfires are not only getting more intense, 392 00:32:57,840 --> 00:32:59,000 but they're breaking out 393 00:32:59,120 --> 00:33:01,480 in parts of the northern hemisphere 394 00:33:01,600 --> 00:33:03,680 where they have never occurred before. 395 00:33:16,240 --> 00:33:19,480 Some scientists believe that unusually warm air 396 00:33:19,600 --> 00:33:21,040 rising in the arctic 397 00:33:21,160 --> 00:33:24,160 is disturbing high-altitude wind currents, 398 00:33:24,280 --> 00:33:25,920 like the polar jet stream. 399 00:33:27,760 --> 00:33:29,240 Once disturbed, 400 00:33:29,360 --> 00:33:32,320 the jet stream produces hotter and drier conditions 401 00:33:32,440 --> 00:33:34,080 much further south. 402 00:33:37,240 --> 00:33:41,080 All of these factors that contribute to wildfires - 403 00:33:41,200 --> 00:33:43,240 the temperature, the soil moisture, 404 00:33:43,360 --> 00:33:46,080 the presence of trees and shrubs and other fuel - 405 00:33:46,200 --> 00:33:49,760 have either strong direct or indirect ties 406 00:33:49,880 --> 00:33:51,520 to climate change. 407 00:33:53,240 --> 00:33:54,840 David: A warming arctic 408 00:33:54,960 --> 00:33:58,320 may not only be responsible for the outbreak of wildfires... 409 00:34:02,640 --> 00:34:05,600 But it may also be leading to extreme weather conditions 410 00:34:05,720 --> 00:34:08,640 across the whole of the northern hemisphere. 411 00:34:12,280 --> 00:34:14,680 I've always cared so much about the environment 412 00:34:14,800 --> 00:34:17,680 and known that we all need to do our part in protecting it, 413 00:34:17,800 --> 00:34:21,800 but after seeing this view with my own eyes, 414 00:34:21,920 --> 00:34:25,240 after seeing all of those ecosystems from up here, 415 00:34:25,360 --> 00:34:27,720 it really makes it resonate even more loudly. 416 00:34:37,600 --> 00:34:39,400 David: Outside the arctic, 417 00:34:39,520 --> 00:34:42,440 there's another frozen realm 418 00:34:42,560 --> 00:34:45,600 that stretches across the world's continents - 419 00:34:45,720 --> 00:34:47,800 our high mountains... 420 00:35:04,480 --> 00:35:07,840 Home to an extraordinary array of species. 421 00:35:31,960 --> 00:35:34,480 But here, too, there's a problem. 422 00:35:40,440 --> 00:35:44,040 Across the world, mountain glaciers which have existed 423 00:35:44,160 --> 00:35:46,320 for tens of thousands of years 424 00:35:46,440 --> 00:35:49,040 are shrinking and vanishing. 425 00:35:59,480 --> 00:36:00,960 By the end of this century, 426 00:36:01,080 --> 00:36:04,480 some ranges may have no ice remaining at all, 427 00:36:04,600 --> 00:36:09,320 and this will affect not just animals, but people too. 428 00:36:15,320 --> 00:36:17,840 Hamish: Ice loss from the mountain glaciers 429 00:36:17,960 --> 00:36:21,080 from the great ranges of the world 430 00:36:21,200 --> 00:36:24,800 have a huge consequence for the populations downstream, 431 00:36:24,920 --> 00:36:28,200 and that consequence is their water supply. 432 00:36:31,440 --> 00:36:33,760 Davi d: Glaciers in the himalayas 433 00:36:33,880 --> 00:36:37,680 are the source of ten of the largest rivers in Asia, 434 00:36:37,800 --> 00:36:40,680 which together provide reliable fresh water 435 00:36:40,800 --> 00:36:43,800 for around a billion people downstream. 436 00:36:45,320 --> 00:36:47,240 If the glaciers disappear, 437 00:36:47,360 --> 00:36:50,520 so too will the water they supply. 438 00:36:53,120 --> 00:36:55,800 Hamish: We know that these glaciers are losing 439 00:36:55,920 --> 00:36:58,560 about half a metre of ice a year. 440 00:36:58,680 --> 00:37:01,560 What we don't know is how much ice is left. 441 00:37:03,120 --> 00:37:06,080 So if we know how many metres of ice are left, 442 00:37:06,200 --> 00:37:07,960 we can work out how long they'll last, 443 00:37:08,080 --> 00:37:12,080 how long this water supply will keep going. 444 00:37:13,080 --> 00:37:17,600 David: Dr Hamish pritchard is part of a team of scientists 445 00:37:17,720 --> 00:37:19,640 who have devised a new instrument 446 00:37:19,760 --> 00:37:22,760 to measure one of the largest himalayan glaciers. 447 00:37:24,240 --> 00:37:27,680 What we're putting together here is a long frame structure, 448 00:37:27,800 --> 00:37:31,400 and it's designed to hang underneath a helicopter. 449 00:37:31,520 --> 00:37:34,080 We're going to put a radar on it, 450 00:37:34,200 --> 00:37:37,200 and the radar will send out the radio waves 451 00:37:37,320 --> 00:37:38,960 and then they'll bounce back 452 00:37:39,080 --> 00:37:40,920 off the bottom of the glacier 453 00:37:41,040 --> 00:37:43,880 and we'll be able to measure how thick the ice is. 454 00:37:45,160 --> 00:37:47,680 David: Once his team know how thick the ice is, 455 00:37:47,800 --> 00:37:51,080 they can start to work out how long it will last. 456 00:37:54,120 --> 00:37:56,240 Yeah, it's a nervous moment. We're just waiting 457 00:37:56,360 --> 00:37:58,040 for it to get lifted up for the first time. 458 00:37:58,160 --> 00:38:00,600 We're hoping it's going to be nice, steady, stable, 459 00:38:00,720 --> 00:38:02,200 a nice easy liftoff. 460 00:38:02,320 --> 00:38:04,120 But we're about to find out. 461 00:38:10,400 --> 00:38:12,040 Radio: Line is clear. 462 00:38:19,280 --> 00:38:20,960 Line is lifting. 463 00:38:33,560 --> 00:38:36,760 Hi, it's Hamish here. How is it flying? 464 00:38:36,880 --> 00:38:38,936 Radio: Yeah, when the wind picks up, it's a little... 465 00:38:38,960 --> 00:38:42,200 A little more squirrel/y, but no problems otherwise. 466 00:38:42,320 --> 00:38:44,920 Yeah, you might want to gain a little bit of height there. 467 00:38:45,040 --> 00:38:46,200 Yeah, no problem. 468 00:38:48,800 --> 00:38:51,360 Yeah, we'll fly out and then head towards Everest. 469 00:39:02,840 --> 00:39:05,200 David: After hours of scanning, 470 00:39:05,320 --> 00:39:07,520 the projection for this particular glacier 471 00:39:07,640 --> 00:39:09,240 is finally revealed. 472 00:39:13,440 --> 00:39:14,960 Yep, that's pretty nice and clear. 473 00:39:15,080 --> 00:39:17,000 I can see exactly how thick that ice is. 474 00:39:17,120 --> 00:39:18,680 That's about 150 metres. 475 00:39:21,920 --> 00:39:24,920 So, at the current rate of melting, 476 00:39:25,040 --> 00:39:28,120 this section would last maybe 200 to 300 years. 477 00:39:28,240 --> 00:39:31,080 But we know that the melt rates are increasing. 478 00:39:34,480 --> 00:39:36,840 And this is one of the biggest glaciers, 479 00:39:36,960 --> 00:39:38,816 so there are many, many glaciers which are much smaller 480 00:39:38,840 --> 00:39:40,480 than this, much thinner ice... 481 00:39:41,600 --> 00:39:42,840 And they're going to be 482 00:39:42,960 --> 00:39:45,520 disappearing much, much earlier than that. 483 00:39:49,680 --> 00:39:53,160 David: Water is already scarce in parts of Asia 484 00:39:53,280 --> 00:39:56,760 and as glacial water supplies dry up, 485 00:39:56,880 --> 00:39:59,560 there will be even less to go round. 486 00:40:02,880 --> 00:40:05,760 Hamish: So what happens if these glaciers disappear... 487 00:40:07,800 --> 00:40:10,320 Is that in dry summers the rivers dry up... 488 00:40:12,760 --> 00:40:14,840 Tensions rise... 489 00:40:14,960 --> 00:40:16,680 Especially between nations 490 00:40:16,800 --> 00:40:18,560 that share water across borders... 491 00:40:22,480 --> 00:40:25,360 So one of the big risks of losing this ice 492 00:40:25,480 --> 00:40:28,160 is that it raises the risk of conflict. 493 00:40:30,840 --> 00:40:33,240 And that's a frightening prospect. 494 00:40:34,960 --> 00:40:36,480 I have a one-year—old son. 495 00:40:36,600 --> 00:40:39,720 Children born at the same time as him will see this happen. 496 00:40:44,560 --> 00:40:48,120 We need to act now to turn those trajectories round. 497 00:40:56,840 --> 00:41:00,080 There's no doubt that large tracts 498 00:41:00,200 --> 00:41:04,480 of our frozen wilderness are undergoing dramatic changes. 499 00:41:04,600 --> 00:41:09,880 But what about the largest body of ice of all - Antarctica? 500 00:41:13,640 --> 00:41:16,440 We have already seen how, even here, 501 00:41:16,560 --> 00:41:19,520 animals living around the fringes 502 00:41:19,640 --> 00:41:22,680 are starting to be affected by climate change - 503 00:41:22,800 --> 00:41:25,240 including chinstrap penguins. 504 00:41:34,600 --> 00:41:37,320 But for another penguin, the adelie, 505 00:41:37,440 --> 00:41:40,240 the consequences are even more extreme. 506 00:41:48,840 --> 00:41:53,760 Man: I arrived here for the first time in 1974. 507 00:41:58,560 --> 00:42:03,640 This part of the world was just incomprehensibly wild. 508 00:42:06,320 --> 00:42:08,840 It was filled with life. 509 00:42:12,600 --> 00:42:16,960 Antarctica absolutely captured me. 510 00:42:22,240 --> 00:42:24,120 David: Professor bill Fraser 511 00:42:24,240 --> 00:42:27,400 has dedicated his entire 45-year career 512 00:42:27,520 --> 00:42:29,920 to studying the adélie penguin. 513 00:42:32,400 --> 00:42:37,040 Bill: What really fascinated me was the incredible hardiness 514 00:42:37,160 --> 00:42:39,040 of these penguins - 515 00:42:39,160 --> 00:42:42,800 feisty, determined, 516 00:42:42,920 --> 00:42:44,560 beautiful little animal. 517 00:42:51,080 --> 00:42:53,720 But this environment is changing. 518 00:42:56,080 --> 00:42:58,800 In the last 45 years, 519 00:42:58,920 --> 00:43:01,960 the tremendous warming that has occurred 520 00:43:02,080 --> 00:43:04,440 has had an incredible impact. 521 00:43:04,560 --> 00:43:07,480 The changes have been very rapid, 522 00:43:07,600 --> 00:43:10,360 more rapid than anyone anticipated. 523 00:43:19,360 --> 00:43:22,800 David: Bill has witnessed first-hand how these changes 524 00:43:22,920 --> 00:43:26,320 have affected one of the largest colonies of adelies 525 00:43:26,440 --> 00:43:29,240 on the western side of the antarctic peninsula. 526 00:43:30,920 --> 00:43:37,240 Bill: Four decades ago, this area contained 20,000 adults. 527 00:43:37,360 --> 00:43:38,760 Currently, we only have 528 00:43:38,880 --> 00:43:41,960 somewhere in the order of 400 breeding pairs. 529 00:43:43,720 --> 00:43:45,440 One of the issues 530 00:43:45,560 --> 00:43:48,800 that adélies are clearly experiencing right now 531 00:43:48,920 --> 00:43:50,880 is just the increase in rainfall. 532 00:43:53,320 --> 00:43:58,560 Adélies are a creature of the high antarctic. 533 00:43:58,680 --> 00:44:02,960 They evolved in a dry, cold polar system. 534 00:44:03,080 --> 00:44:07,520 They simply cannot tolerate being continuously wet. 535 00:44:12,560 --> 00:44:14,560 The chicks are soaking. 536 00:44:16,840 --> 00:44:19,880 The rain is penetrating their down, 537 00:44:20,000 --> 00:44:24,440 breaking down their ability to insulate themselves. 538 00:44:26,400 --> 00:44:28,440 That's why you see they're shivering - 539 00:44:28,560 --> 00:44:31,000 because they're just trying to maintain 540 00:44:31,120 --> 00:44:33,480 their body temperature, and they can't. 541 00:44:35,760 --> 00:44:37,240 It's sad. 542 00:44:50,200 --> 00:44:53,160 This tiny chick at this point 543 00:44:53,280 --> 00:44:56,400 has zero chances of surviving. 544 00:44:58,520 --> 00:45:01,280 They can't even react to the presence of a predator. 545 00:45:13,440 --> 00:45:15,280 We are standing, 546 00:45:15,400 --> 00:45:17,480 looking at climate change 547 00:45:17,600 --> 00:45:21,640 actually killing off these adélie penguins 548 00:45:21,760 --> 00:45:23,480 one at a time. 549 00:45:42,840 --> 00:45:45,680 David: Before he leaves Antarctica for the last time, 550 00:45:45,800 --> 00:45:50,400 bill is visiting an island that was once an adélie paradise. 551 00:45:53,920 --> 00:45:57,000 When we used to walk onto this island, 552 00:45:57,120 --> 00:46:00,320 you could immediately hear the adélies. 553 00:46:01,480 --> 00:46:03,080 They were everywhere. 554 00:46:05,640 --> 00:46:09,400 In 1974, the populations here 555 00:46:09,520 --> 00:46:13,560 were somewhere in the order of 1,000 breeding pairs. 556 00:46:13,680 --> 00:46:17,520 All that remains are these little pebbles 557 00:46:17,640 --> 00:46:21,040 scattered throughout the area, 558 00:46:21,160 --> 00:46:24,040 stones that were used in former nest sites. 559 00:46:25,720 --> 00:46:28,880 The pebbles are still visible, they're very abundant, 560 00:46:29,000 --> 00:46:31,680 but, uh, the birds are gone. 561 00:46:34,600 --> 00:46:36,880 This is where we recorded 562 00:46:37,000 --> 00:46:41,120 the first island-wide extinction of adélie penguins. 563 00:46:42,840 --> 00:46:49,440 And now the silence that exists here is pretty overbearing. 564 00:46:51,640 --> 00:46:52,640 Hold it. 565 00:47:10,240 --> 00:47:12,040 There's no... 566 00:47:12,160 --> 00:47:14,840 There's no words that can... 567 00:47:14,960 --> 00:47:19,120 Really describe what I'm feeling at the moment. 568 00:47:26,280 --> 00:47:28,480 Bill: We're working with canaries in the coalmine. 569 00:47:30,280 --> 00:47:33,200 Adélie penguins are, without a doubt, 570 00:47:33,320 --> 00:47:36,400 indicator species that are telling us 571 00:47:36,520 --> 00:47:38,240 that the globe is changing, 572 00:47:38,360 --> 00:47:40,720 the globe is getting warmer. 573 00:47:40,840 --> 00:47:42,600 It's happening. 574 00:47:42,720 --> 00:47:44,920 And we need to do something about it. 575 00:47:53,320 --> 00:47:56,240 David: The disappearance of adélie penguins 576 00:47:56,360 --> 00:47:58,160 along the antarctic peninsula 577 00:47:58,280 --> 00:48:02,120 is just one example of how record warming temperatures 578 00:48:02,240 --> 00:48:04,840 are affecting life here. 579 00:48:07,640 --> 00:48:10,160 But warming temperatures are also affecting 580 00:48:10,280 --> 00:48:12,360 the very coastline itself... 581 00:48:13,680 --> 00:48:18,240 With serious implications for global sea levels. 582 00:48:23,120 --> 00:48:25,720 Man: Across the glaciological community, 583 00:48:25,840 --> 00:48:29,200 we've identified that sea-level rise from Antarctica 584 00:48:29,320 --> 00:48:31,320 is the most pressing question 585 00:48:31,440 --> 00:48:33,520 for the next 50 to 100 years. 586 00:48:34,920 --> 00:48:37,840 And we as a collaborative group 587 00:48:37,960 --> 00:48:40,040 have come together to try and understand it, 588 00:48:40,160 --> 00:48:41,440 and governments 589 00:48:41,560 --> 00:48:43,560 have come together to try and understand it, 590 00:48:43,680 --> 00:48:46,480 because it's important. 591 00:48:47,960 --> 00:48:50,360 David: Professor sridhar anandakrishnan 592 00:48:50,480 --> 00:48:52,320 has been working in the polar regions 593 00:48:52,440 --> 00:48:54,800 for over three decades. 594 00:48:56,160 --> 00:48:59,000 He's part of a team of scientists undertaking 595 00:48:59,120 --> 00:49:01,400 the largest antarctic expedition 596 00:49:01,520 --> 00:49:03,320 for more than 70 years. 597 00:49:05,720 --> 00:49:09,520 Their destination is a remote part of western Antarctica 598 00:49:09,640 --> 00:49:12,240 called the thwaites ice shelf. 599 00:49:15,560 --> 00:49:19,160 Sridhar: Without getting out on the ice, you can't measure 600 00:49:19,280 --> 00:49:21,200 things underneath the ice. 601 00:49:22,320 --> 00:49:23,480 Radio: And take-off. 602 00:49:25,400 --> 00:49:29,400 Sridhar: Those kinds of things can't be done from space. 603 00:49:29,520 --> 00:49:31,480 They can't be done by drones 604 00:49:31,600 --> 00:49:33,080 or aircraft flying over it. 605 00:49:33,200 --> 00:49:37,120 You actually have to go and put your instruments on the ice. 606 00:49:43,960 --> 00:49:46,800 David: The interior of Antarctica is covered 607 00:49:46,920 --> 00:49:48,720 in a giant sheet of ice... 608 00:49:51,160 --> 00:49:52,880 Which for millennia 609 00:49:53,000 --> 00:49:56,080 has been slowly flowing to the coast. 610 00:50:00,520 --> 00:50:03,120 But because it's so cold here, 611 00:50:03,240 --> 00:50:05,720 rather than calve into the sea, 612 00:50:05,840 --> 00:50:09,320 the ice continues to flow out into the ocean, 613 00:50:09,440 --> 00:50:13,440 forming a floating platform known as an ice shelf. 614 00:50:19,120 --> 00:50:24,240 As an ice shelf grows, it begins to act as a dam, 615 00:50:24,360 --> 00:50:27,040 preventing more of the ice sheet behind it 616 00:50:27,160 --> 00:50:28,960 from slipping into the sea. 617 00:50:30,800 --> 00:50:33,520 And the thwaites ice shelf 618 00:50:33,640 --> 00:50:35,760 holds back a body of ice 619 00:50:35,880 --> 00:50:37,880 the size of Florida. 620 00:50:40,240 --> 00:50:42,760 But scientists are concerned 621 00:50:42,880 --> 00:50:45,720 that the ice shelf itself is now at risk of melting. 622 00:50:47,480 --> 00:50:50,680 We're going down through 600 metres of ice. 623 00:50:50,800 --> 00:50:52,640 Once we drill the hole, 624 00:50:52,760 --> 00:50:55,920 I'm going to put the explosive charge down. 625 00:50:59,200 --> 00:51:01,640 David: Small seismic surveys... 626 00:51:01,760 --> 00:51:03,480 Ok. Firing the hole. 627 00:51:05,400 --> 00:51:08,160 Help establish exactly where to sink 628 00:51:08,280 --> 00:51:10,520 their robotic underwater probe, 629 00:51:10,640 --> 00:51:13,560 which the team hope will record the temperature 630 00:51:13,680 --> 00:51:17,800 of the seawater directly beneath the ice shelf. 631 00:51:17,920 --> 00:51:19,880 Ok, Andy, ready to descend. 632 00:51:20,000 --> 00:51:22,360 Radio: Try to go a little slower. 633 00:51:23,960 --> 00:51:25,640 Coming up on 75 metres. 634 00:51:25,760 --> 00:51:27,200 75 metres now. 635 00:51:36,120 --> 00:51:37,720 425 metres. 636 00:51:40,000 --> 00:51:42,640 We've arrived at the ice-ocean interface. 637 00:51:45,640 --> 00:51:49,240 David: Early results are not encouraging. 638 00:51:49,360 --> 00:51:51,640 Have we noticed a huge change in the temperature? 639 00:51:51,760 --> 00:51:55,320 Er, yeah. It is warm water. 640 00:51:55,440 --> 00:51:57,920 Can you see it melt? Like, what is going on there? 641 00:52:01,160 --> 00:52:03,120 David: Because of climate change, 642 00:52:03,240 --> 00:52:06,000 warmer seas directly beneath the ice shelf 643 00:52:06,120 --> 00:52:08,120 are melting it from below... 644 00:52:10,320 --> 00:52:12,200 So it's no longer a question 645 00:52:12,320 --> 00:52:14,520 of if this giant dam will disappear, 646 00:52:14,640 --> 00:52:16,360 but when. 647 00:52:18,720 --> 00:52:20,400 When the vast ice sheet behind it 648 00:52:20,520 --> 00:52:22,520 spills into the ocean, 649 00:52:22,640 --> 00:52:25,600 it could have catastrophic consequences 650 00:52:25,720 --> 00:52:29,280 for global sea levels over the coming centuries. 651 00:52:33,440 --> 00:52:36,800 Sridhar: The amount of water that Antarctica contains 652 00:52:36,920 --> 00:52:39,480 that could go into the ocean is so huge. 653 00:52:42,880 --> 00:52:45,560 This is a global problem. 654 00:52:45,680 --> 00:52:48,680 The oceans are all connected together, 655 00:52:48,800 --> 00:52:53,520 so as soon as a glacier puts water into the ocean, 656 00:52:53,640 --> 00:52:55,520 it rises all over the world. 657 00:52:59,160 --> 00:53:01,520 Da vid: If sea levels rise as predicted, 658 00:53:01,640 --> 00:53:03,640 by the year 2050, 659 00:53:03,760 --> 00:53:09,040 150 million people could be displaced from coastal areas. 660 00:53:13,760 --> 00:53:15,280 And by 2070, 661 00:53:15,400 --> 00:53:20,560 cities, including Miami, New York, Shanghai and Mumbai, 662 00:53:20,680 --> 00:53:24,520 will be at risk of serious flooding. 663 00:53:27,760 --> 00:53:30,720 Sridhar: How much water will Antarctica contribute 664 00:53:30,840 --> 00:53:32,520 to sea-level rise? 665 00:53:32,640 --> 00:53:34,560 The biggest wildcard in all of that 666 00:53:34,680 --> 00:53:39,000 is how we as humans affect climate. 667 00:54:03,840 --> 00:54:09,920 Recently, at cop26, 120 nations came together 668 00:54:10,040 --> 00:54:14,080 in an effort to limit global warming to 1.5 degrees. 669 00:54:17,360 --> 00:54:19,440 While a 1.5-degree rise 670 00:54:19,560 --> 00:54:22,240 will still bring significant changes with it, 671 00:54:22,360 --> 00:54:24,000 to stand any chance 672 00:54:24,120 --> 00:54:26,160 of saving what remains of our frozen planet, 673 00:54:26,280 --> 00:54:27,720 and saving ourselves 674 00:54:27,840 --> 00:54:31,960 from the devastating consequences of its loss, 675 00:54:32,080 --> 00:54:35,720 we must stick to this commitment, and honour it, 676 00:54:35,840 --> 00:54:38,520 no matter how challenging it might be. 677 00:54:39,760 --> 00:54:42,680 James: We know that climate change is happening. 678 00:54:42,800 --> 00:54:46,360 We know that the main driver of climate change 679 00:54:46,480 --> 00:54:49,400 is human activities, it's human emissions. 680 00:54:50,800 --> 00:54:53,520 Jessica: As a whole human species, 681 00:54:53,640 --> 00:54:55,576 we are not recognising the impact that we're having 682 00:54:55,600 --> 00:54:57,560 and the fact that we do need to do something. 683 00:54:58,840 --> 00:55:01,120 Alun: But the important thing is that 684 00:55:01,240 --> 00:55:05,040 I believe all of these processes are reversible. 685 00:55:06,280 --> 00:55:08,280 Jessica: If everybody can make the effort 686 00:55:08,400 --> 00:55:09,560 of doing just one thing - 687 00:55:09,680 --> 00:55:11,840 reducing their carbon footprint. 688 00:55:11,960 --> 00:55:13,320 Alun: Consume less, 689 00:55:13,440 --> 00:55:15,680 think about what we need, what we really want. 690 00:55:15,800 --> 00:55:19,640 Think more sensibly about the journeys we take, 691 00:55:19,760 --> 00:55:23,160 about the food we eat, how that's produced. 692 00:55:23,280 --> 00:55:25,880 Figure out a lifestyle that is sustainable. 693 00:55:29,720 --> 00:55:31,800 Sridhar: And we're right at the point 694 00:55:31,920 --> 00:55:37,600 where we can generate all the power that we need 695 00:55:37,720 --> 00:55:43,240 from renewable sources, like solar and wind. 696 00:55:44,480 --> 00:55:45,480 To do that, 697 00:55:45,600 --> 00:55:49,360 you need to really transform society as a whole. 698 00:55:51,200 --> 00:55:53,520 James: We can speak to our representatives to try 699 00:55:53,640 --> 00:55:55,120 and reconsider energy policies. 700 00:55:57,120 --> 00:55:59,720 If enough of us are educated 701 00:55:59,840 --> 00:56:04,320 about the effects of carbon in the atmosphere, 702 00:56:04,440 --> 00:56:08,640 even the most poorly educated politician will respond 703 00:56:08,760 --> 00:56:11,040 to what their citizenry wants. 704 00:56:12,800 --> 00:56:15,680 Hamish: The awareness and the concern is greater now 705 00:56:15,800 --> 00:56:18,880 than it ever has been, so that gives us some hope. 706 00:56:20,160 --> 00:56:24,040 It won't be easy, but it's doable. 707 00:56:25,080 --> 00:56:27,040 Aleqatsiaq: If you can do something about it, 708 00:56:27,160 --> 00:56:28,160 then do it... 709 00:56:30,040 --> 00:56:32,640 Instead of just thinking about it. 710 00:56:32,760 --> 00:56:35,320 If you can do something about it, then do it. 711 00:56:42,800 --> 00:56:44,560 David: We can do it. 712 00:56:45,680 --> 00:56:49,000 It's within our power to do it. 713 00:56:49,120 --> 00:56:51,760 We can do it. 714 00:56:53,120 --> 00:56:55,520 We must do it. 715 00:57:02,000 --> 00:57:05,840 Then there will be a future for the planet.