WEBVTT FILE 1 00:00:01.620 --> 00:00:05.620 Larsen: You guys got everything tied down back there? 2 00:00:05.620 --> 00:00:09.620 Truffer: Yep. Christoffersen: Yep. 3 00:00:09.620 --> 00:00:13.620 Larsen: We’re going through the lee of St. Elias, so there might be some turbulence. 4 00:00:13.620 --> 00:00:17.620 Christoffersen: Fasten Seat Belt sign on? 5 00:00:17.620 --> 00:00:21.620 Larsen: Well … who am I to tell you what to do? 6 00:00:21.620 --> 00:00:25.620 [aircraft engine noise, rising music] 7 00:00:25.620 --> 00:00:29.620 8 00:00:29.620 --> 00:00:33.620 [music builds] 9 00:00:33.620 --> 00:00:37.620 10 00:00:37.620 --> 00:00:41.620 11 00:00:41.620 --> 00:00:45.620 12 00:00:45.620 --> 00:00:49.620 [booming sound] 13 00:00:49.620 --> 00:00:53.620 14 00:00:53.620 --> 00:00:57.620 [theme music] 15 00:00:57.620 --> 00:01:01.620 16 00:01:01.620 --> 00:01:05.620 17 00:01:05.620 --> 00:01:09.620 18 00:01:09.620 --> 00:01:13.620 19 00:01:13.620 --> 00:01:17.620 Narrator: There are tens of thousands of glaciers in Alaska, 20 00:01:17.620 --> 00:01:21.620 some stunning cliffhangers, others wide glaciers that come down 21 00:01:21.620 --> 00:01:25.620 to meet the ocean tides. Some, like this one 22 00:01:25.620 --> 00:01:29.620 we flew over in August, are easily visible 23 00:01:29.620 --> 00:01:33.620 from low Earth orbit, and are mesmerizing 24 00:01:33.620 --> 00:01:37.620 from a thousand feet above, and have trees growing on top of their soil-laden boundaries. 25 00:01:37.620 --> 00:01:41.620 Those glaciers – although they represent only a fraction 26 00:01:41.620 --> 00:01:45.620 fraction of the world’s ice – are contributing much more than their share 27 00:01:45.620 --> 00:01:49.620 to sea level rise. 28 00:01:49.620 --> 00:01:53.620 Chris Larsen and his colleagues have repeatedly measured 29 00:01:53.620 --> 00:01:57.620 220 of them in a small single engine Otter. 30 00:01:57.620 --> 00:02:01.620 measuring their height with lasers and their depth with radar, 31 00:02:01.620 --> 00:02:05.620 and watching them change from season to season and year to year. 32 00:02:05.620 --> 00:02:09.620 But Alaskan glaciers 33 00:02:09.620 --> 00:02:13.620 are all so different we’re only just figuring out how they all behave. 34 00:02:13.620 --> 00:02:17.620 Data from flights like these, part of NASA’s Operation IceBridge, 35 00:02:17.620 --> 00:02:21.620 can help fill the gaps.Chris and radar specialist Martin Truffer 36 00:02:21.620 --> 00:02:25.620 are both from the University of Alaska Fairbanks, 37 00:02:25.620 --> 00:02:29.620 and both seasoned Alaskan pilots, but they rely 38 00:02:29.620 --> 00:02:33.620 on their good friend and legendary bush pilot Paul Claus 39 00:02:33.620 --> 00:02:37.620 and his 35,000 hours in the cockpit 40 00:02:37.620 --> 00:02:41.620 cockpit to fly the incredibly demanding flightlines the mission requires. 41 00:02:41.620 --> 00:02:45.620 And does it help you guys being pilots too? Chris: I would like to think so but 42 00:02:45.620 --> 00:02:49.620 but watching Paul fly and seeing what he does is kind of like trying to 43 00:02:49.620 --> 00:02:53.620 learn quantum mechanics in kindergarten. 44 00:02:53.620 --> 00:02:57.620 Truffer: you know, I can fly my airplane around, but just seeing what Paul does in this extremely 45 00:02:57.620 --> 00:03:01.620 challenging environment in the mountains 46 00:03:01.620 --> 00:03:05.620 while trying to follow the specific flight line at a 47 00:03:05.620 --> 00:03:09.620 specific altitude above ground negotiating winds, 48 00:03:09.620 --> 00:03:13.620 topography, maybe occasional low-level clouds 49 00:03:13.620 --> 00:03:17.620 that you have to get around – just managing all that 50 00:03:17.620 --> 00:03:21.620 that is just several levels above 51 00:03:21.620 --> 00:03:25.620 what I could do as a pilot. 52 00:03:25.620 --> 00:03:29.620 Claus: Well, I think the first time I came here to this park I was probably four years old 53 00:03:29.620 --> 00:03:33.620 with my father. I’ve been blessed to be able to fly 54 00:03:33.620 --> 00:03:37.620 fly in lots of places in the world, all over the place actually, almost every continent. 55 00:03:37.620 --> 00:03:41.620 I guess I’m always looking for some place that might be better 56 00:03:41.620 --> 00:03:45.620 than this, but I haven’t found it. [laughs] 57 00:03:45.620 --> 00:03:49.620 Narrator:Paul’s plane is about 60 years old and the first single engine Otter 58 00:03:49.620 --> 00:03:53.620 ever retrofitted with a 1000 horsepower engine, 59 00:03:53.620 --> 00:03:57.620 which make takeoffs feel effortless and gives Paul the ability 60 00:03:57.620 --> 00:04:01.620 to negotiate wild terrain.
Which he certainly did during the first 61 00:04:01.620 --> 00:04:05.620 first two incredible science flights of this campaign, and with sunny skies 62 00:04:05.620 --> 00:04:09.620 and relatively calm air, we covered three vastly different pieces of ice. 63 00:04:09.620 --> 00:04:13.620 While Paul fueled up 64 00:04:13.620 --> 00:04:17.620 the plane Chris gave us a preview of today’s science and scenery. 65 00:04:17.620 --> 00:04:21.620 Larsen: So it has one of the greatest coastal 66 00:04:21.620 --> 00:04:25.620 reliefs anywhere in the world. So between 67 00:04:25.620 --> 00:04:29.620 the ocean and the summit of Mt. St. Elias, which is 18,008 feet high, 68 00:04:29.620 --> 00:04:33.620 it’s less than 10 miles. There’s a stupendous amount of mountain 69 00:04:33.620 --> 00:04:37.620 right off the ocean. It’s hard to beat it anywhere in the world. 70 00:04:37.620 --> 00:04:41.620 It might be the prettiest for me. It’s absolutely stunning. 71 00:04:41.620 --> 00:04:45.620 From here in McCarthy we’ll cross one of the bigger 72 00:04:45.620 --> 00:04:49.620 precipitation gradients in Alaska too. Here it’s about 73 00:04:49.620 --> 00:04:53.620 10 inches of precipitation a year and we’ll go over to an area where it’s on the order 74 00:04:53.620 --> 00:04:57.620 of 200 inches per year. So from one of the driest parts of Alaska 75 00:04:57.620 --> 00:05:01.620 to one of the wettest parts of Alaska in about 45 minutes, flight time. 76 00:05:01.620 --> 00:05:05.620 [aircraft engine noise, music] 77 00:05:05.620 --> 00:05:09.620 Truffer: Whoa that’s pretty good. Larsen: That’s awesome. 78 00:05:09.620 --> 00:05:13.620 Do you want to do Tyndall next? Claus: Sure, whatever you want. 79 00:05:13.620 --> 00:05:17.620 Larsen: If the winds are calm now might as well grab it. [laughs] 80 00:05:17.620 --> 00:05:21.620 Narrator: First, we came to the rugged landscape 81 00:05:21.620 --> 00:05:25.620 of Icy Bay, which not that long ago wasn’t a bay at all – 82 00:05:25.620 --> 00:05:29.620 it was filled with ice. Tidewater glaciers in this region 83 00:05:29.620 --> 00:05:33.620 can make dramatic advances and retreats as they feed on high rates 84 00:05:33.620 --> 00:05:37.620 of snowfall and then retreat as they’re melted by warm ocean waters. 85 00:05:37.620 --> 00:05:41.620 Like the Tyndall glacier seen here, most of these glaciers 86 00:05:41.620 --> 00:05:45.620 retreated dramatically over the last hundred years, but nearby 87 00:05:45.620 --> 00:05:49.620 Yahtse Glacier, after years of retreat, is currently the most rapidly 88 00:05:49.620 --> 00:05:53.620 advancing glacier in Alaska.Overall though, 89 00:05:53.620 --> 00:05:57.620 the IceBridge Alaska surveys, from the Denali region in the north, 90 00:05:57.620 --> 00:06:01.620 to the Juneau Icefield in the Southeast, have documented pretty substantial 91 00:06:01.620 --> 00:06:05.620 thinning of glacial ice. Areas seen here 92 00:06:05.620 --> 00:06:09.620 here in orange and red show between about 10 and 15 feet 93 00:06:09.620 --> 00:06:13.620 of thinning per year. Larsen: 1,200 94 00:06:13.620 --> 00:06:17.620 Truffer: That’s a nice waterfall up there from that hanging ice. 95 00:06:17.620 --> 00:06:21.620 Larsen: When we very first started profiling this Paul 96 00:06:21.620 --> 00:06:25.620 this gravel fan and the one in the valley next to it didn’t exist. 97 00:06:25.620 --> 00:06:29.620 Claus: Yeah, I was gonna say. Look at all the good landing spots here. 98 00:06:29.620 --> 00:06:33.620 There was no place to land here before. Larsen: No, it was deep water. 99 00:06:33.620 --> 00:06:37.620 Narrator:After covering several of Icy Bay’s glaciers, 100 00:06:37.620 --> 00:06:41.620 given that it was time for lunch, just like that, we landed 101 00:06:41.620 --> 00:06:45.620 in this unforgettable spot. [waterfall noise] 102 00:06:45.620 --> 00:06:49.620 103 00:06:49.620 --> 00:06:53.620 104 00:06:53.620 --> 00:06:57.620 [engine noise taking off] 105 00:06:57.620 --> 00:07:01.620 Flying eastward, leaving Icy Bay behind, 106 00:07:01.620 --> 00:07:05.620 we came to the mighty Malaspina, one of the Earth’s 107 00:07:05.620 --> 00:07:09.620 great examples of a “Piedmont” glacier, that spills out like pancake 108 00:07:09.620 --> 00:07:13.620 batter onto a broad plane as it approaches the sea. 109 00:07:13.620 --> 00:07:17.620 It surges at uneven intervals, creating dramatic patterns 110 00:07:17.620 --> 00:07:21.620 on its surface as it distorts the moraines of rock and soil 111 00:07:21.620 --> 00:07:25.620 borne along by the glacier. The Malaspina 112 00:07:25.620 --> 00:07:29.620 is less dynamic than the Yahtse and is only melting 113 00:07:29.620 --> 00:07:33.620 at about the average rate for Alaska. But that could change quickly. 114 00:07:33.620 --> 00:07:37.620 Larsen:Has the potential for being one of the bigger geographic evolutions in Alaska 115 00:07:37.620 --> 00:07:41.620 Certainly, my son will be able to witness 116 00:07:41.620 --> 00:07:45.620 some big geography changes there … There’s potential for it being connected 117 00:07:45.620 --> 00:07:49.620 with the ocean through some narrow lagoons, estuaries, 118 00:07:49.620 --> 00:07:53.620 which would take a little bit of coastal erosion, but it’s not too hard 119 00:07:53.620 --> 00:07:57.620 to imagine that this – where the Malaspina Glacier 120 00:07:57.620 --> 00:08:01.620 is now could become a large bay. 121 00:08:01.620 --> 00:08:05.620 Narrator:The data that Martin’s radar provides could reveal how vulnerable the Malaspina is 122 00:08:05.620 --> 00:08:09.620 to melting by the nearby ocean. Here we see the 123 00:08:09.620 --> 00:08:13.620 radar returns from the surface of the glacier, and here is something that Chris’s lasers 124 00:08:13.620 --> 00:08:17.620 can’t see – the rocky bed of the glacier, giving us both 125 00:08:17.620 --> 00:08:21.620 clues as to what’s happening under the ice, as well as a 126 00:08:21.620 --> 00:08:25.620 measurement of its thickness. 127 00:08:25.620 --> 00:08:29.620 Finally, we came to the Yakutat ice field, 300 square miles of absolutely 128 00:08:29.620 --> 00:08:33.620 doomed ice perched high in the mountains. 129 00:08:33.620 --> 00:08:37.620 Researchers even debate how this ice field came to be at all, 130 00:08:37.620 --> 00:08:41.620 Since in its current configuration, it’s hard to imagine how 131 00:08:41.620 --> 00:08:45.620 it could capture enough snow to form glacial ice. 132 00:08:45.620 --> 00:08:49.620 And so even if the Arctic weren’t warming faster than the rest 133 00:08:49.620 --> 00:08:53.620 of the planet, this area would be likely to melt within a century or two. 134 00:08:53.620 --> 00:08:57.620 But with many other glaciers, 135 00:08:57.620 --> 00:09:01.620 , it’s easier to see the connection between a warming planet and ice loss. 136 00:09:01.620 --> 00:09:05.620 Thanks to data from IceBridge and other surveys, 137 00:09:05.620 --> 00:09:09.620 we now have a good estimate of the current rate of loss from Alaskan glaciers 138 00:09:09.620 --> 00:09:13.620 -- 75 gigatons a year. 139 00:09:13.620 --> 00:09:17.620 While airborne observations over Alaskan glaciers have 140 00:09:17.620 --> 00:09:21.000 provided a rich record of change in the area, those efforts 141 00:09:21.000 --> 00:09:25.620 are now augmented by NASA’s newest ice-measuring tool, ICESat-2. 142 00:09:25.620 --> 00:09:29.000 With six laser beamss of its own, 143 00:09:29.000 --> 00:09:33.620 and orbiting the Earth every 90 minutes, the satellite 144 00:09:33.620 --> 00:09:37.620 will carry on the record of Alaskan change. 145 00:09:37.620 --> 00:09:41.620 For their part, Chris and his team will continue to do their surveys for at least 146 00:09:41.620 --> 00:09:45.620 the next two years, helping to validate the ICESat-2 data, 147 00:09:45.620 --> 00:09:51.936 and make further detailed observations over the stunning glaciers of Alaska.