WEBVTT FILE 1 00:00:04.338 --> 00:00:05.205 >> MICHELLE: Hello and welcome to 2 00:00:05.205 --> 00:00:06.807 NASA Goddard Space Flight Center. 3 00:00:06.807 --> 00:00:07.774 Today we're going to talk about 4 00:00:07.774 --> 00:00:09.543 one of the most compelling issues of our day, 5 00:00:09.543 --> 00:00:10.677 sea level rise. 6 00:00:10.677 --> 00:00:12.813 And with me is Dr. Tom Wagner, 7 00:00:12.813 --> 00:00:15.816 the Program Scientist for the cryosphere at NASA headquarters. 8 00:00:15.816 --> 00:00:17.251 >> TOM WAGNER: And today, we're going to take you 9 00:00:17.251 --> 00:00:19.753 right behind the frontlines of sea level rise research, 10 00:00:19.753 --> 00:00:21.488 out into the field with the researchers, 11 00:00:21.488 --> 00:00:22.756 and here's what we're going to be talking about 12 00:00:22.756 --> 00:00:24.091 for the next hour. 13 00:00:24.091 --> 00:00:30.097 ♪[Music]♪ 14 00:01:33.727 --> 00:01:35.062 >> TOM WAGNER: So the big thing is this. 15 00:01:35.062 --> 00:01:37.831 Around the world, sea level is rising. 16 00:01:37.831 --> 00:01:40.367 It's going up by three millimeters a year. 17 00:01:40.367 --> 00:01:43.770 In the last 20 years it's gone up by three inches. 18 00:01:43.770 --> 00:01:46.840 And, we're trying to understand kind of why that is. 19 00:01:46.840 --> 00:01:49.076 But more importantly, we're trying to project out, 20 00:01:49.076 --> 00:01:51.878 you know, where it's going to be in the next hundred years. 21 00:01:51.878 --> 00:01:53.013 Like it or not, 22 00:01:53.013 --> 00:01:55.749 already the East Coast of the US is seeing flooding 23 00:01:55.749 --> 00:01:57.217 from sea level rise. 24 00:01:57.217 --> 00:01:58.685 It's things like the big storms 25 00:01:58.685 --> 00:02:01.288 that hit New York and New Jersey, Katrina. 26 00:02:01.288 --> 00:02:03.290 But even in places like the Kennedy Space Center, 27 00:02:03.290 --> 00:02:05.192 we're seeing tremendous amounts of erosion. 28 00:02:05.192 --> 00:02:07.427 They've gone as far as to make a map 29 00:02:07.427 --> 00:02:09.129 of areas that they are going to lose. 30 00:02:09.129 --> 00:02:11.865 The City of Miami is getting routine flooding. 31 00:02:11.865 --> 00:02:13.834 Now, you might say, 32 00:02:13.834 --> 00:02:17.437 "Well, you know, three inches in 20 years. what's the big deal?" 33 00:02:17.437 --> 00:02:20.307 We can probably deal with what we've already seen, right? 34 00:02:20.307 --> 00:02:22.509 But you know, the thing that we're worried about 35 00:02:22.509 --> 00:02:25.679 is that as you project out a hundred years, 36 00:02:25.679 --> 00:02:29.750 it could be more like three feet, four feet, five feet, 37 00:02:29.750 --> 00:02:32.452 and the way that society responds to that, 38 00:02:32.452 --> 00:02:34.955 the costs rise exponentially. 39 00:02:34.955 --> 00:02:35.856 >> MICHELLE: And one of the things 40 00:02:35.856 --> 00:02:37.991 we're going to talk a lot about today is ice, 41 00:02:37.991 --> 00:02:40.293 and talk to us about why ice is so important 42 00:02:40.293 --> 00:02:42.129 in the topic of sea level rise. 43 00:02:42.129 --> 00:02:43.630 >> TOM WAGNER: Yeah. So in general, 44 00:02:43.630 --> 00:02:45.832 the rise that we're seeing today comes from two places. 45 00:02:45.832 --> 00:02:47.901 One, as the ocean warms up, 46 00:02:47.901 --> 00:02:50.637 it expands just like hot air in a balloon. 47 00:02:50.637 --> 00:02:52.406 But also, two, the big ice sheets, 48 00:02:52.406 --> 00:02:55.308 the glaciers of Greenland and... of Greenland... 49 00:02:55.308 --> 00:02:57.477 the glaciers of Canada and Alaska, 50 00:02:57.477 --> 00:02:59.746 the big ice sheets of Greenland and Antarctica, 51 00:02:59.746 --> 00:03:02.249 they are waking up and spitting ice into the ocean 52 00:03:02.249 --> 00:03:04.017 and that's the other half of sea level rise. 53 00:03:04.017 --> 00:03:06.053 >> MICHELLE: And so, we're going to be bringing in Josh Willis 54 00:03:06.053 --> 00:03:07.654 from the Jet Propulsion Laboratory. 55 00:03:07.654 --> 00:03:09.256 And then we also have Vena Chu 56 00:03:09.256 --> 00:03:11.291 who is at the University of California, Berkeley. 57 00:03:11.291 --> 00:03:12.826 And I believe that's Larry Smith 58 00:03:12.826 --> 00:03:16.063 from the University of California, Los Angeles. 59 00:03:16.063 --> 00:03:19.599 >> JOSH WILLIS: Well, sea level has been rising pretty steadily 60 00:03:19.599 --> 00:03:23.236 in the last 23 years around the globe, 61 00:03:23.236 --> 00:03:26.606 and we've been measuring this with Satellite Altimeters 62 00:03:26.606 --> 00:03:30.610 with our colleagues in the French Space Agency, CNES, 63 00:03:30.610 --> 00:03:32.612 ever since 1992. 64 00:03:32.612 --> 00:03:35.382 And the net rate of sea level rise 65 00:03:35.382 --> 00:03:37.784 is about three millimeters per year, 66 00:03:37.784 --> 00:03:40.253 which works out to about an inch a decade. 67 00:03:40.253 --> 00:03:44.424 And, it's interesting because the rise isn't equal everywhere. 68 00:03:44.424 --> 00:03:48.628 In fact, in places like the West Coast of the United States, 69 00:03:48.628 --> 00:03:51.498 sea level has actually been falling very slightly, 70 00:03:51.498 --> 00:03:54.868 and this is because of the natural cycles in the ocean 71 00:03:54.868 --> 00:03:58.805 and the way the oceans and winds can push heat around 72 00:03:58.805 --> 00:04:00.474 and redistribute it across the planet. 73 00:04:00.474 --> 00:04:03.810 So sea level rise is actually not all that level. 74 00:04:03.810 --> 00:04:05.112 >> TOM WAGNER: Yeah, but Josh, like, 75 00:04:05.112 --> 00:04:06.980 but... overwhelmingly, right? 76 00:04:06.980 --> 00:04:09.082 The total amount of sea level rise that we've seen, 77 00:04:09.082 --> 00:04:11.551 say, in the 28th century versus the last 20 years, 78 00:04:11.551 --> 00:04:12.552 what's it like? 79 00:04:12.552 --> 00:04:14.287 >> JOSH WILLIS: Sea levels have increased. 80 00:04:14.287 --> 00:04:16.823 The rate of rise has increased incredibly 81 00:04:16.823 --> 00:04:19.493 in the last hundred years or so. 82 00:04:19.493 --> 00:04:21.061 In the early 1900s 83 00:04:21.061 --> 00:04:23.563 we were looking at about one millimeter per year. 84 00:04:23.563 --> 00:04:26.666 In the 1950s it was more like two millimeters per year, 85 00:04:26.666 --> 00:04:28.869 and now it's three millimeters per year. 86 00:04:28.869 --> 00:04:31.838 And, in fact, if you look back even farther, 87 00:04:31.838 --> 00:04:33.507 the last 2,000 years 88 00:04:33.507 --> 00:04:36.109 have had almost no sea level rise whatsoever. 89 00:04:36.109 --> 00:04:39.312 So we've pushed the Earth into a brand-new regime 90 00:04:39.312 --> 00:04:41.882 and sea level rise is now the norm. 91 00:04:41.882 --> 00:04:43.183 >> TOM WAGNER: Can you tell us a little bit, though? 92 00:04:43.183 --> 00:04:45.352 And I know Michelle was asking about this before we started. 93 00:04:45.352 --> 00:04:47.387 How do we actually get to those numbers? 94 00:04:47.387 --> 00:04:48.421 Like you were talking about, 95 00:04:48.421 --> 00:04:49.756 how do we know what sea level rise was 96 00:04:49.756 --> 00:04:51.792 in the 1800s or the 1700s? 97 00:04:51.792 --> 00:04:54.261 I mean today, you've pointed out we have this radar altimeters 98 00:04:54.261 --> 00:04:55.595 that measure the height of the ocean, 99 00:04:55.595 --> 00:04:57.130 but what are the other ways we know? 100 00:04:58.899 --> 00:05:00.801 >> JOSH WILLIS: Well, we've had tide gauge records 101 00:05:00.801 --> 00:05:02.469 for 150 years, 102 00:05:02.469 --> 00:05:04.204 in a few places, even longer. 103 00:05:04.204 --> 00:05:07.741 But in the last 2,000 years 104 00:05:07.741 --> 00:05:11.178 we've actually been keeping a record of sea level rise 105 00:05:11.178 --> 00:05:14.881 in the sediments in places like North Carolina. 106 00:05:14.881 --> 00:05:16.917 There's a salt marsh there 107 00:05:16.917 --> 00:05:20.954 and it turns out that the land there is steadily sinking, 108 00:05:20.954 --> 00:05:22.422 just very slightly. 109 00:05:22.422 --> 00:05:24.624 And as the water creeps up the land, 110 00:05:24.624 --> 00:05:26.293 it leaves behind a record 111 00:05:26.293 --> 00:05:29.496 in the form of tiny little bugs and critters, 112 00:05:29.496 --> 00:05:32.232 uh, that die and live in the sediment. 113 00:05:32.232 --> 00:05:34.601 So, uh, people drilling sediment cores 114 00:05:34.601 --> 00:05:37.070 have actually been able to reconstruct 115 00:05:37.070 --> 00:05:41.107 a very accurate sea level record for the last 2,000 years. 116 00:05:41.107 --> 00:05:45.946 And, what it shows is not much until the last 150, 117 00:05:45.946 --> 00:05:48.148 and that's when sea level rise really took off 118 00:05:48.148 --> 00:05:51.618 and we began to see the rates we have today. 119 00:05:51.618 --> 00:05:52.452 >> MICHELLE: Now, one of the things 120 00:05:52.452 --> 00:05:53.453 I think people aren't aware of 121 00:05:53.453 --> 00:05:55.622 is just how many resources NASA has 122 00:05:55.622 --> 00:05:57.591 to study what's changing on the Earth. 123 00:05:57.591 --> 00:05:58.491 Uh, I think that right now 124 00:05:58.491 --> 00:06:00.427 there are actually about 19 different space crafts 125 00:06:00.427 --> 00:06:01.528 that are orbiting the Earth 126 00:06:01.528 --> 00:06:02.529 taking readings from everything 127 00:06:02.529 --> 00:06:04.731 about the oceans, the land, and the atmosphere. 128 00:06:04.731 --> 00:06:06.766 What are some of the missions that you specifically work with 129 00:06:06.766 --> 00:06:08.668 and... and what are some of the data that you take? 130 00:06:10.770 --> 00:06:12.873 >> JOSH WILLIS: Well, the best mission of all those 131 00:06:12.873 --> 00:06:15.942 is the Jason Missions, in my humble opinion, 132 00:06:15.942 --> 00:06:17.777 because those are the ones that I work on. 133 00:06:17.777 --> 00:06:19.846 But, uh, I think, uh there's... 134 00:06:19.846 --> 00:06:21.781 as you say, there is a whole bunch of missions. 135 00:06:21.781 --> 00:06:23.149 The Jason Missions 136 00:06:23.149 --> 00:06:25.719 measures sea level directly from space, 137 00:06:25.719 --> 00:06:27.087 uh, missions like GRACE 138 00:06:27.087 --> 00:06:30.991 actually weigh the continents and the oceans. 139 00:06:30.991 --> 00:06:32.692 >> MICHELLE: Yeah, that's really excellent stuff, 140 00:06:32.692 --> 00:06:34.361 you know, and the GRACE Mission that you mentioned 141 00:06:34.361 --> 00:06:36.763 is one of the things that I find really compelling 142 00:06:36.763 --> 00:06:38.365 that, in fact, there's so much water 143 00:06:38.365 --> 00:06:39.666 melting off these glaciers, 144 00:06:39.666 --> 00:06:42.202 it's actually changing the gravity field of the Earth. 145 00:06:42.202 --> 00:06:43.270 I mean, could you tell us a little bit about 146 00:06:43.270 --> 00:06:46.172 how GRACE works and how that measurement is made? 147 00:06:46.172 --> 00:06:47.474 >> JOSH WILLIS: Yeah, GRACE is really fun. 148 00:06:47.474 --> 00:06:50.677 Uh, in fact, um, it's made of two satellites. 149 00:06:50.677 --> 00:06:52.779 Uh, they are named Tom and Jerry 150 00:06:52.779 --> 00:06:54.814 and they chase each other around, 151 00:06:54.814 --> 00:06:57.651 and whenever the first one goes over something heavy, 152 00:06:57.651 --> 00:07:01.187 the pull of gravity causes it to speed up just slightly. 153 00:07:01.187 --> 00:07:03.290 And the two satellites actually measure 154 00:07:03.290 --> 00:07:05.091 the distance between each other 155 00:07:05.091 --> 00:07:08.361 and you can use that information to infer the mass 156 00:07:08.361 --> 00:07:10.530 of the thing you're flying over. 157 00:07:10.530 --> 00:07:12.265 >> TOM WAGNER: Hey, Josh! I got a question yesterday 158 00:07:12.265 --> 00:07:13.433 from a reporter. 159 00:07:13.433 --> 00:07:14.934 Can you just talk a little bit about, 160 00:07:14.934 --> 00:07:18.371 okay, look, the radar altimetry, the record we get 161 00:07:18.371 --> 00:07:20.173 and how we see things like tide gauge, 162 00:07:20.173 --> 00:07:22.776 how do they work and how does that all come together? 163 00:07:22.776 --> 00:07:24.177 >> JOSH WILLIS: Yeah, well, uh, 164 00:07:24.177 --> 00:07:27.447 so the satellites that measure sea level are really amazing. 165 00:07:27.447 --> 00:07:28.682 They're 800 miles up 166 00:07:28.682 --> 00:07:31.751 and they can measure the level of the ocean 167 00:07:31.751 --> 00:07:35.422 in a... in about a six-mile footprint 168 00:07:35.422 --> 00:07:38.458 with an accuracy of just one inch or better. 169 00:07:38.458 --> 00:07:40.660 >> JOSH WILLIS: So it's an incredibly accurate 170 00:07:40.660 --> 00:07:41.828 piece of equipment. 171 00:07:41.828 --> 00:07:45.231 Um it measures the entire planet once every ten days. 172 00:07:45.231 --> 00:07:47.400 And by averaging all of that data together, 173 00:07:47.400 --> 00:07:48.768 we can actually, 174 00:07:48.768 --> 00:07:51.404 uh, get an estimate of the total level of the ocean, 175 00:07:51.404 --> 00:07:53.073 the total volume of the ocean, 176 00:07:53.073 --> 00:07:55.642 with an accuracy of about half a centimeter, 177 00:07:55.642 --> 00:07:57.544 so it's really tiny. 178 00:07:57.544 --> 00:08:01.648 And they're really incredibly, accurate at these missions. 179 00:08:01.648 --> 00:08:02.849 In fact, 180 00:08:02.849 --> 00:08:07.320 we've often compared them with tide gauges. 181 00:08:07.320 --> 00:08:08.955 So in a few key locations, 182 00:08:08.955 --> 00:08:09.956 we have tide gauges 183 00:08:09.956 --> 00:08:13.960 that have been running for the entire 23-year long record 184 00:08:13.960 --> 00:08:17.797 and they've allowed us to help, tie together 185 00:08:17.797 --> 00:08:19.866 one satellite after another. 186 00:08:19.866 --> 00:08:22.936 We've also been lucky enough to have each satellite survive 187 00:08:22.936 --> 00:08:24.571 until the next one was launched. 188 00:08:24.571 --> 00:08:27.474 So beginning with TOPEX/Poseidon in 1992, 189 00:08:27.474 --> 00:08:30.610 uh, and then continuing with Jason-1 in 2001 190 00:08:30.610 --> 00:08:32.612 and Jason-2 in 2008, 191 00:08:32.612 --> 00:08:34.748 and we're hopeful to launch Jason-3 192 00:08:34.748 --> 00:08:38.084 sometime in the next six months, something like that. 193 00:08:38.084 --> 00:08:41.654 Uh, and so, we're really excited 194 00:08:41.654 --> 00:08:43.757 about our record of sea level rise 195 00:08:43.757 --> 00:08:47.327 because, uh, it's one of the most accurate means we have 196 00:08:47.327 --> 00:08:48.395 for charting, 197 00:08:48.395 --> 00:08:51.698 how humans are changing the overall climate, 198 00:08:51.698 --> 00:08:53.199 on the planet. 199 00:08:53.199 --> 00:08:54.200 >> JOSH WILLIS: Because if you think about it, 200 00:08:54.200 --> 00:08:56.469 the Earth is two-thirds ocean. 201 00:08:56.469 --> 00:08:57.804 >> TOM WAGNER: Great! Hey, thank you very much 202 00:08:57.804 --> 00:08:59.873 and I know we're going to have you back later in the show. 203 00:08:59.873 --> 00:09:01.007 But coming up next, Michelle, 204 00:09:01.007 --> 00:09:02.776 I think we have a video? 205 00:09:02.776 --> 00:09:03.576 >> MICHELLE: Well, yes. In fact, 206 00:09:03.576 --> 00:09:04.778 we're going to be speaking to a scientist 207 00:09:04.778 --> 00:09:05.812 that actually does research 208 00:09:05.812 --> 00:09:07.847 sponsored by the NSF in Greenland. 209 00:09:07.847 --> 00:09:09.315 So if we can roll the video about 210 00:09:09.315 --> 00:09:12.152 Mike Bevis and his work, please! 211 00:09:12.152 --> 00:09:13.620 >> MIKE BEVIS: Yeah, this is the... 212 00:09:13.620 --> 00:09:17.757 this is the champion, uh, glacier of Greenland. 213 00:09:17.757 --> 00:09:19.058 This is Jakobshavn, 214 00:09:19.058 --> 00:09:23.129 so this is the one that's losing the most mass. 215 00:09:23.129 --> 00:09:26.366 It's losing so much mass you can see it in space, 216 00:09:26.366 --> 00:09:28.435 they can see gravity change. 217 00:09:28.435 --> 00:09:31.371 The loss of the mass is causing gravity to change. 218 00:09:32.772 --> 00:09:34.474 Yeah, we've got instruments all over the place 219 00:09:34.474 --> 00:09:36.443 but this is going to be one of our most important ones. 220 00:09:36.443 --> 00:09:39.546 There's the antenna, and it's bolted to the rock. 221 00:09:39.546 --> 00:09:43.116 So this ice is the... is the weight 222 00:09:43.116 --> 00:09:45.685 holding the elastic Earth down. 223 00:09:45.685 --> 00:09:49.055 As that weight is released by the loss of ice, 224 00:09:49.055 --> 00:09:51.891 the ground is rising, that antenna is rising. 225 00:09:51.891 --> 00:09:53.159 >> UNIDENTIFIED SPEAKER: And you can measure that? 226 00:09:53.159 --> 00:09:54.694 >> MIKE BEVIS: We can measure that. 227 00:09:54.694 --> 00:09:57.897 That's recording data 24 hours a day, 228 00:09:57.897 --> 00:09:59.999 year after year after year. 229 00:09:59.999 --> 00:10:01.935 >> TOM WAGNER: Hey! So one of the other things too is, 230 00:10:01.935 --> 00:10:05.071 how do we take this kind of measurement you've made here, 231 00:10:05.071 --> 00:10:06.639 with literally a GPS device 232 00:10:06.639 --> 00:10:09.142 out in the field banged into the rock? 233 00:10:09.142 --> 00:10:11.344 How do you combine that with satellite information 234 00:10:11.344 --> 00:10:13.179 to get a big picture? 235 00:10:13.179 --> 00:10:14.280 >> MIKE BEVIS: All the satellite... 236 00:10:14.280 --> 00:10:16.983 all the techniques have got the strengths and the weaknesses. 237 00:10:16.983 --> 00:10:18.118 Uh so there is... for example, 238 00:10:18.118 --> 00:10:20.687 GRACE is incredibly precise, 239 00:10:20.687 --> 00:10:23.156 it can measure a tiny change in mass, 240 00:10:23.156 --> 00:10:25.625 but it's not always sure what that mass is. 241 00:10:25.625 --> 00:10:27.994 It could be the mass of the rock is changing 242 00:10:27.994 --> 00:10:30.063 if you've got post-glacial rebound 243 00:10:30.063 --> 00:10:32.932 or it could be the ice or some combination. 244 00:10:32.932 --> 00:10:35.068 >> MIKE BEVIS: So in that case, 245 00:10:35.068 --> 00:10:36.970 uh, you have to make a correction 246 00:10:36.970 --> 00:10:39.239 for what the vertical movement of the ground is 247 00:10:39.239 --> 00:10:41.541 so you're not spoofed by a rock change 248 00:10:41.541 --> 00:10:43.276 rather than an ice change. 249 00:10:43.276 --> 00:10:44.878 It turns out that correction 250 00:10:44.878 --> 00:10:46.546 is about the same size as the answer. 251 00:10:46.546 --> 00:10:48.348 So if you get the correction wrong, 252 00:10:48.348 --> 00:10:51.117 you start to get errors in you answer. 253 00:10:51.117 --> 00:10:52.585 So GPS can help with that 254 00:10:52.585 --> 00:10:54.988 because this is going to sense both elastic rebound 255 00:10:54.988 --> 00:10:57.190 and the slower viscous rebound. 256 00:10:57.190 --> 00:11:00.126 And in general, you want to combine different instruments 257 00:11:00.126 --> 00:11:03.530 so that each instrument is compensating with its strengths 258 00:11:03.530 --> 00:11:05.832 for the weaknesses of the other instruments. 259 00:11:05.832 --> 00:11:06.699 >> MICHELLE: And this is something 260 00:11:06.699 --> 00:11:08.167 that I think most people don't think about, 261 00:11:08.167 --> 00:11:10.737 the fact that the Earth, you know, solid land itself 262 00:11:10.737 --> 00:11:12.305 is actually elastic, 263 00:11:12.305 --> 00:11:14.741 but as the ice melts it's rebounding. 264 00:11:14.741 --> 00:11:16.042 >> MIKE BEVIS: Yeah, like for example, 265 00:11:16.042 --> 00:11:19.145 I first realized this, uh, in a big way 266 00:11:19.145 --> 00:11:21.114 when we were looking at GPS stations 267 00:11:21.114 --> 00:11:22.882 in the Central Amazon basin. 268 00:11:22.882 --> 00:11:25.485 We noticed that these stations were going up and down 269 00:11:25.485 --> 00:11:27.954 like 16 millimeters every year. 270 00:11:27.954 --> 00:11:29.189 And then... and then we looked at 271 00:11:29.189 --> 00:11:30.590 the height of the Amazon River 272 00:11:30.590 --> 00:11:32.725 and we saw that as the river was going up 273 00:11:32.725 --> 00:11:33.960 the ground was going down, 274 00:11:33.960 --> 00:11:36.296 as the river went down the ground was going up. 275 00:11:36.296 --> 00:11:38.264 It was just the weight of the water 276 00:11:38.264 --> 00:11:40.900 deflecting the surface downwards. 277 00:11:40.900 --> 00:11:41.834 >> TOM WAGNER: You've got... how many stations 278 00:11:41.834 --> 00:11:43.303 do you have in around Greenland? 279 00:11:43.303 --> 00:11:44.571 >> MIKE BEVIS: We have 50 in Greenland. 280 00:11:44.571 --> 00:11:47.907 We have a similar number in West Antarctica. 281 00:11:47.907 --> 00:11:49.776 >> TOM WAGNER: Wow! And any fascinating results 282 00:11:49.776 --> 00:11:50.510 from any of those stations particularly? 283 00:11:50.510 --> 00:11:51.344 >> MIKE BEVIS: Yeah there's a lot, 284 00:11:51.344 --> 00:11:53.346 I mean, for example, you see the places 285 00:11:53.346 --> 00:11:54.514 where people already knew 286 00:11:54.514 --> 00:11:55.982 is the major ice loss 287 00:11:55.982 --> 00:11:58.484 like the Jakobshavn glacier or Thwaites glacier, 288 00:11:58.484 --> 00:12:01.287 there is where you also see the ground rising the fastest. 289 00:12:01.287 --> 00:12:04.123 One of the interesting things is we see that, 290 00:12:04.123 --> 00:12:06.893 almost everywhere it's accelerating. 291 00:12:06.893 --> 00:12:10.096 So for in Jakobshavn it was rising about 292 00:12:10.096 --> 00:12:12.599 12 millimeters a year in 2008. 293 00:12:12.599 --> 00:12:14.601 By the end of 2012, 294 00:12:14.601 --> 00:12:17.370 it was going up like 32, 33 millimeters a year. 295 00:12:17.370 --> 00:12:20.306 >> TOM WAGNER: The ground is coming up 33 millimeters a year. 296 00:12:20.306 --> 00:12:22.242 >> MIKE BEVIS: Yeah, more than an inch a year 297 00:12:22.242 --> 00:12:25.044 just because of the release of the weight of the ice. 298 00:12:25.044 --> 00:12:26.012 >> MICHELLE: Wow! 299 00:12:26.012 --> 00:12:26.879 >> TOM WAGNER: Hey, now, is it hard... 300 00:12:26.879 --> 00:12:29.115 it must be pretty tough to put these stations in, 301 00:12:29.115 --> 00:12:30.583 in the Polar Regions. 302 00:12:30.583 --> 00:12:31.384 >> MIKE BEVIS: It's challenging 303 00:12:31.384 --> 00:12:34.287 because they've got to run all year, right? 304 00:12:34.287 --> 00:12:37.824 And so, for a large part of the year, the winter, 305 00:12:37.824 --> 00:12:39.359 there is no sun, 306 00:12:39.359 --> 00:12:43.096 and so, you have to charge up huge banks of batteries 307 00:12:43.096 --> 00:12:44.464 so you can get through the night. 308 00:12:44.464 --> 00:12:47.100 So these are very large, heavy systems. 309 00:12:47.100 --> 00:12:50.103 I think we spent like $2 million on helicopter fees 310 00:12:50.103 --> 00:12:51.971 just to install G-NET. 311 00:12:51.971 --> 00:12:53.773 Uh all this weight goes in 312 00:12:53.773 --> 00:12:55.241 and then... and then, you... 313 00:12:55.241 --> 00:12:58.044 the sun charges those batteries all summer long 314 00:12:58.044 --> 00:12:59.679 and then you can run all through the winter 315 00:12:59.679 --> 00:13:01.748 and send the data out via satellites. 316 00:13:01.748 --> 00:13:03.716 >> TOM WAGNER: God! Amazing! 317 00:13:03.716 --> 00:13:05.785 >> MICHELLE: Now, the Earth rebounding, 318 00:13:05.785 --> 00:13:08.321 actually sort of bounding up after the weight gets taken off, 319 00:13:08.321 --> 00:13:09.622 it must go very slowly. 320 00:13:09.622 --> 00:13:11.791 This isn't something that just happens immediately. 321 00:13:11.791 --> 00:13:13.960 Is there also something about the history of the ice 322 00:13:13.960 --> 00:13:16.329 and how the ice has changed that's in your data as well? 323 00:13:16.329 --> 00:13:17.530 >> MIKE BEVIS: Yeah, there are actually two... 324 00:13:17.530 --> 00:13:19.198 two ways the Earth behaves. 325 00:13:19.198 --> 00:13:20.600 There's an elastic response, 326 00:13:20.600 --> 00:13:21.901 which is literally instantaneous. 327 00:13:21.901 --> 00:13:25.405 So as you lose the ice, there's an instantaneous adjustment. 328 00:13:25.405 --> 00:13:27.407 But then the Earth also behaves viscously. 329 00:13:27.407 --> 00:13:31.844 It will flow away from a... a stress like a weight. 330 00:13:31.844 --> 00:13:34.180 And that's... in most of the world, 331 00:13:34.180 --> 00:13:37.583 that takes 10,000 years, say, to happen. 332 00:13:37.583 --> 00:13:42.422 So the ground all around Fennoscandia is rising now, 333 00:13:42.422 --> 00:13:43.990 not because of what's happening now, 334 00:13:43.990 --> 00:13:47.126 but because what happened 12.000 years ago 335 00:13:47.126 --> 00:13:48.828 when the ice suddenly disappeared. 336 00:13:48.828 --> 00:13:49.762 >> TOM WAGNER: God, amazing! 337 00:13:49.762 --> 00:13:51.864 Hey, Mike, thank you very, very much for joining us. 338 00:13:51.864 --> 00:13:53.333 We really appreciate you coming in. 339 00:13:53.333 --> 00:13:55.301 >> MICHELLE: Now we're going to take a really close look 340 00:13:55.301 --> 00:13:57.537 at what's going on inside the ice. 341 00:13:57.537 --> 00:13:58.738 And, we're going to start 342 00:13:58.738 --> 00:14:00.406 by looking at the very surface of the ice 343 00:14:00.406 --> 00:14:02.308 because that's where a lot of the melt is happening. 344 00:14:08.981 --> 00:14:10.249 >> NARRATOR: A short helicopter flight 345 00:14:10.249 --> 00:14:12.251 from the edge of the Greenland ice sheet 346 00:14:12.251 --> 00:14:15.088 lies a 27-square mile network of streams 347 00:14:15.088 --> 00:14:18.024 draining the surface of the ice as it melts in the sun. 348 00:14:20.660 --> 00:14:22.862 This summer, an interdisciplinary team 349 00:14:22.862 --> 00:14:24.130 of NASA-funded researchers 350 00:14:24.130 --> 00:14:26.532 set up a camp near the end of that network, 351 00:14:26.532 --> 00:14:29.469 where a large melt pond emptied into an outlet stream, 352 00:14:29.469 --> 00:14:31.704 which then, a few hundred meters later, 353 00:14:31.704 --> 00:14:33.473 disappeared under a snow bridge 354 00:14:33.473 --> 00:14:36.075 and into a stunning and dangerous moulin, 355 00:14:36.075 --> 00:14:38.377 a hole in the ice leading far below. 356 00:14:43.583 --> 00:14:45.885 The team had many tools at their disposal 357 00:14:45.885 --> 00:14:47.920 including drones to map the area 358 00:14:47.920 --> 00:14:50.523 and provide a comparison for satellite measurements. 359 00:14:53.426 --> 00:14:56.195 They also employed what was essentially a boogie board 360 00:14:56.195 --> 00:14:57.964 mounted with a Doppler instrument 361 00:14:57.964 --> 00:15:00.600 measuring the depth of the river and the speed of its flow. 362 00:15:01.601 --> 00:15:02.735 Working in shifts, 363 00:15:02.735 --> 00:15:05.304 they conducted 72 straight hours of measurements 364 00:15:05.304 --> 00:15:08.441 across the stream. 365 00:15:08.441 --> 00:15:11.944 They also made a series of short helicopter flights upstream 366 00:15:11.944 --> 00:15:14.480 and placed floating sensors into three tributaries 367 00:15:14.480 --> 00:15:16.716 to measure the water as it moved. 368 00:15:41.707 --> 00:15:42.842 About an hour later, 369 00:15:42.842 --> 00:15:45.111 the team was thrilled to see all three drifters 370 00:15:45.111 --> 00:15:47.713 pass by their camp within a matter of minutes, 371 00:15:47.713 --> 00:15:50.683 presumably relaying a few last observations 372 00:15:50.683 --> 00:15:52.752 before disappearing into the moulin. 373 00:16:02.929 --> 00:16:04.363 But measuring meltwater runoff 374 00:16:04.363 --> 00:16:06.299 was only part of the effort. 375 00:16:06.299 --> 00:16:09.202 Other researchers joined the team to measure the albedo 376 00:16:09.202 --> 00:16:11.971 or the brightness of the snow and ice in the region. 377 00:16:13.406 --> 00:16:14.807 This albedo determines 378 00:16:14.807 --> 00:16:17.310 how much of the sun's energy will be absorbed, 379 00:16:17.310 --> 00:16:19.946 and therefore, how fast the surface will melt. 380 00:16:22.081 --> 00:16:23.349 From helicopters, 381 00:16:23.349 --> 00:16:25.952 researchers measured incoming solar radiation 382 00:16:25.952 --> 00:16:28.554 and compared it to the light reflected by the ice. 383 00:16:29.889 --> 00:16:32.758 They also imaged the ice using a digital camera, 384 00:16:32.758 --> 00:16:35.394 creating these beautiful high-resolution mosaics 385 00:16:35.394 --> 00:16:38.297 to better map the region. 386 00:16:38.297 --> 00:16:40.366 After a short but intense field season, 387 00:16:40.366 --> 00:16:43.002 the researchers packed up camp and left the ice. 388 00:16:43.002 --> 00:16:44.904 Hopeful that the data they'd acquired 389 00:16:44.904 --> 00:16:46.606 could help shed light on the future 390 00:16:46.606 --> 00:16:49.075 of the Greenland ice sheet. 391 00:16:49.075 --> 00:16:51.244 >> MICHELLE: Now, we're going to go to some of our colleagues, 392 00:16:51.244 --> 00:16:53.412 who are actually out at the Jet Propulsion Laboratory today 393 00:16:53.412 --> 00:16:54.814 and we're going to talk to Larry Smith 394 00:16:54.814 --> 00:16:56.816 from the University of California, Los Angeles 395 00:16:56.816 --> 00:16:59.552 and Vena Chu from the University of California, Berkeley. 396 00:16:59.552 --> 00:17:01.554 And Tom, maybe you can ask them about the research. 397 00:17:01.554 --> 00:17:02.421 >> TOM WAGNER: Hey, Larry and Vena, 398 00:17:02.421 --> 00:17:03.689 thanks for joining us today. 399 00:17:03.689 --> 00:17:04.757 I don't know if you could see it 400 00:17:04.757 --> 00:17:06.759 but we just showed some video of you guys out in the field. 401 00:17:06.759 --> 00:17:09.161 Can you tell us a little bit about your field network 402 00:17:09.161 --> 00:17:10.663 and what it is that you're measuring? 403 00:17:12.765 --> 00:17:14.300 >> LARRY SMITH: Sure, absolutely. 404 00:17:14.300 --> 00:17:18.271 Our project focuses on the hydrology of the surface, 405 00:17:18.271 --> 00:17:21.007 the melting surface of the Greenland ice sheet, 406 00:17:21.007 --> 00:17:24.877 and this is a surprisingly little-studied field 407 00:17:24.877 --> 00:17:27.313 in Glaciology for this part of the world, 408 00:17:27.313 --> 00:17:30.182 but it's an important one for society 409 00:17:30.182 --> 00:17:31.417 and for sea level rise 410 00:17:31.417 --> 00:17:34.086 because, already, 411 00:17:34.086 --> 00:17:36.622 melting of the surface of the Greenland ice sheet 412 00:17:36.622 --> 00:17:39.792 is thought to contribute about half to two-thirds 413 00:17:39.792 --> 00:17:42.094 of the total mass loss from Greenland 414 00:17:42.094 --> 00:17:45.097 as measured by GRACE, for example, 415 00:17:45.097 --> 00:17:49.135 with the remainder being from solid ice calving losses. 416 00:17:49.135 --> 00:17:50.269 But the... 417 00:17:50.269 --> 00:17:53.372 these predictions are very often based on, 418 00:17:53.372 --> 00:17:54.874 regional climate models 419 00:17:54.874 --> 00:17:57.043 and so what our measurements are attempting to do 420 00:17:57.043 --> 00:17:58.844 is to provide some of the first, 421 00:17:58.844 --> 00:18:01.047 real-world "in situ" measurements 422 00:18:01.047 --> 00:18:02.214 of meltwater production 423 00:18:02.214 --> 00:18:04.383 and runoff on the surface of the ice sheets 424 00:18:04.383 --> 00:18:08.287 to try to verify and validate these model predictions 425 00:18:08.287 --> 00:18:10.289 of future sea level rise. 426 00:18:10.289 --> 00:18:11.257 >> TOM WAGNER: Hey, now, Vena, 427 00:18:11.257 --> 00:18:12.825 you're one of the purple that goes out in the field 428 00:18:12.825 --> 00:18:16.495 and does all the hard work, right? 429 00:18:16.495 --> 00:18:17.797 >> VENA CHU: Yeah, I've been going there for 430 00:18:17.797 --> 00:18:19.198 about eight years now. Yeah, a lot of field time. 431 00:18:19.198 --> 00:18:20.733 >> TOM WAGNER: So tell us about some of the gear 432 00:18:20.733 --> 00:18:22.234 you take into the field 433 00:18:22.234 --> 00:18:26.305 and what kind of measurements you actually make? 434 00:18:26.305 --> 00:18:28.741 >> VENA CHU: Well the first goal is just to get the camp set up 435 00:18:28.741 --> 00:18:31.877 so we have multiple tents and all our camping gear. 436 00:18:31.877 --> 00:18:34.780 But we also have, uh, we are measuring discharge, 437 00:18:34.780 --> 00:18:37.917 so the actual amount of water going through these rivers. 438 00:18:37.917 --> 00:18:40.519 So we have a sort of like boogie board set up 439 00:18:40.519 --> 00:18:42.521 that we take across the river. 440 00:18:42.521 --> 00:18:44.390 It's a sort of a Doppler system 441 00:18:44.390 --> 00:18:46.158 that measures how the fast the water is flowing 442 00:18:46.158 --> 00:18:47.927 and how deep the water is flowing. 443 00:18:47.927 --> 00:18:50.196 >> TOM WAGNER: Yeah. So what I can't get over, though, 444 00:18:50.196 --> 00:18:51.731 it seems like you guys are also talking about, 445 00:18:51.731 --> 00:18:53.933 it seems like there has been a big increase recently 446 00:18:53.933 --> 00:18:55.501 in the amount of melting that's gone on 447 00:18:55.501 --> 00:18:57.303 on the surface of Greenland, 448 00:18:57.303 --> 00:18:59.038 and tell us about that, 449 00:18:59.038 --> 00:19:00.473 tell us kind of what you're seeing? 450 00:19:00.473 --> 00:19:02.508 I know that some of the rivers flow pretty fast. 451 00:19:02.508 --> 00:19:03.576 >> LARRY SMITH: Sure. 452 00:19:03.576 --> 00:19:05.745 The satellite record shows that, 453 00:19:05.745 --> 00:19:09.682 while bumpy with warmer years and cooler years, in general, 454 00:19:09.682 --> 00:19:15.955 the overall trend has been an increasing extent, intensity, 455 00:19:15.955 --> 00:19:19.592 and duration of the melt season on the surface of the ice. 456 00:19:19.592 --> 00:19:22.428 But these course resolution satellites 457 00:19:22.428 --> 00:19:24.330 are often microwave-based, 458 00:19:24.330 --> 00:19:28.901 don't have the, the granularity 459 00:19:28.901 --> 00:19:31.804 to see the fine-scale structures and physical processes 460 00:19:31.804 --> 00:19:35.574 that are routing this water off the ice sheet. 461 00:19:35.574 --> 00:19:37.276 And this is actually very important 462 00:19:37.276 --> 00:19:39.345 because one of the key questions is, 463 00:19:39.345 --> 00:19:42.715 how much of that melt on the surface of the ice, 464 00:19:42.715 --> 00:19:45.818 particularly as it expands deeper into the interior, 465 00:19:45.818 --> 00:19:49.488 how much of that melt water is actually escaping the ice sheet 466 00:19:49.488 --> 00:19:51.357 to contribute to sea level rise? 467 00:19:51.357 --> 00:19:54.927 At the moment, our assumption is that all of it does. 468 00:19:54.927 --> 00:19:56.996 But in fact, it's entirely plausible 469 00:19:56.996 --> 00:19:58.164 that perhaps some of it... 470 00:19:58.164 --> 00:20:01.667 some fraction of it, is retained by the ice sheet, 471 00:20:01.667 --> 00:20:04.904 refrozen at the surface or stored within the ice sheet. 472 00:20:04.904 --> 00:20:07.306 And that's why these field measurements 473 00:20:07.306 --> 00:20:09.608 and also higher-resolution satellite 474 00:20:09.608 --> 00:20:12.511 and airborne technologies such as Operation IceBridge, 475 00:20:12.511 --> 00:20:15.247 such as the WorldViews, uh, series of satellites, 476 00:20:15.247 --> 00:20:18.584 these provide additional finer-scale resolution 477 00:20:18.584 --> 00:20:20.419 to study these processes 478 00:20:20.419 --> 00:20:22.788 and confirm that indeed this melt on the surface 479 00:20:22.788 --> 00:20:25.124 is escaping the ice sheet to the global ocean. 480 00:20:25.124 --> 00:20:26.092 >> TOM WAGNER: Thanks! Hey, Michelle, 481 00:20:26.092 --> 00:20:28.194 I understand we might have some video? 482 00:20:28.194 --> 00:20:29.829 >> MICHELLE: That's right. We actually have some video about 483 00:20:29.829 --> 00:20:32.865 what it's like to work in these pretty extreme conditions. 484 00:20:32.865 --> 00:20:33.999 >> UNIDENTIFIED SPEAKER: This is the best time! 485 00:20:33.999 --> 00:20:36.469 How lucky are we to come up here in Greenland! 486 00:20:36.469 --> 00:20:37.536 >> UNIDENTIFIED SPEAKER: Something about this place, 487 00:20:37.536 --> 00:20:42.808 uh, gets under our skins and we keep coming back. 488 00:20:42.808 --> 00:20:43.909 >> UNIDENTIFIED SPEAKER: You can only reach 489 00:20:43.909 --> 00:20:46.479 this area here with helicopter. 490 00:20:46.479 --> 00:20:48.347 >> UNIDENTIFIED SPEAKER: We're camping in the ablation zone. 491 00:20:48.347 --> 00:20:50.382 It's very wet as you can see. 492 00:20:50.382 --> 00:20:52.118 >> UNIDENTIFIED SPEAKER: Water is running everywhere. 493 00:20:52.118 --> 00:20:54.253 It's flowing into these chutes and channels 494 00:20:54.253 --> 00:20:58.023 which are getting bigger and faster with every second. 495 00:20:58.023 --> 00:21:00.559 If someone... goodness help us 496 00:21:00.559 --> 00:21:02.995 were to ever fall into one of these, 497 00:21:02.995 --> 00:21:05.731 uh, there would be no hope. 498 00:21:05.731 --> 00:21:07.233 >> ÅSA RENNERMALM: So we are very careful 499 00:21:07.233 --> 00:21:09.101 with our safety procedures. 500 00:21:09.101 --> 00:21:13.439 The most important here is that we all come back home. 501 00:21:13.439 --> 00:21:17.443 >> GRACE ANDREWS: It is a difficult environment to work in 502 00:21:17.443 --> 00:21:19.044 Um, it's cold here. 503 00:21:19.044 --> 00:21:22.815 There are problems with equipment. 504 00:21:22.815 --> 00:21:24.183 When you have problems with equipment, 505 00:21:24.183 --> 00:21:27.520 it's hard to get replacements. 506 00:21:27.520 --> 00:21:30.623 It takes weeks to get things shipped up. 507 00:21:30.623 --> 00:21:32.725 The temperatures, and in my case, 508 00:21:32.725 --> 00:21:34.260 the sediment load of rivers 509 00:21:34.260 --> 00:21:38.597 makes it hard to actually do the sample collection. 510 00:21:38.597 --> 00:21:42.835 But it's also the most inspiring 511 00:21:42.835 --> 00:21:46.305 and thrilling environment to work in. 512 00:21:46.305 --> 00:21:48.574 Every day I go out in the fields, 513 00:21:48.574 --> 00:21:52.077 I look around at my environment, 514 00:21:52.077 --> 00:21:55.314 the ice, the river, how dynamic it is, 515 00:21:55.314 --> 00:21:58.551 and it reminds me why I'm out there 516 00:21:58.551 --> 00:22:02.888 and I absolutely love it. 517 00:22:02.888 --> 00:22:04.456 >> VENA CHU: One of the hardest things there is 518 00:22:04.456 --> 00:22:05.958 just working in those environments. 519 00:22:05.958 --> 00:22:08.427 I mean, the fact is that we're working in an area 520 00:22:08.427 --> 00:22:10.663 that not many people work uptil, you know, 521 00:22:10.663 --> 00:22:12.865 in the last five, you know, six years or so. 522 00:22:12.865 --> 00:22:14.934 People don't really work on the ice sheet 523 00:22:14.934 --> 00:22:16.802 when it's melting all around you, 524 00:22:16.802 --> 00:22:18.571 just even camping is hard, 525 00:22:18.571 --> 00:22:21.407 and, you know, we're dealing with limited helicopter hours. 526 00:22:21.407 --> 00:22:24.410 So if you need more equipment or something breaks 527 00:22:24.410 --> 00:22:26.779 and, one of the big things that we dealt with was, 528 00:22:26.779 --> 00:22:28.914 you know, how do we keep batteries warm 529 00:22:28.914 --> 00:22:31.884 and, uh, how do we set up camps so that, you know, 530 00:22:31.884 --> 00:22:33.385 rivers aren't flowing around us 531 00:22:33.385 --> 00:22:36.555 and melting out around our tent. 532 00:22:36.555 --> 00:22:38.224 >> TOM WAGNER: Hey, can you tell us a little bit 533 00:22:38.224 --> 00:22:40.192 about what happens? 534 00:22:40.192 --> 00:22:41.360 Where does the water go? 535 00:22:41.360 --> 00:22:42.461 We understand a lot of it doesn't, say, 536 00:22:42.461 --> 00:22:43.996 flow directly off the ice sheet 537 00:22:43.996 --> 00:22:48.267 but it goes into these big holes in the ice. 538 00:22:48.267 --> 00:22:50.369 >> VENA CHU: In fact, these sinkholes are called Moulins. 539 00:22:50.369 --> 00:22:54.073 In fact, what we've seen is that all the rivers on the ice, 540 00:22:54.073 --> 00:22:56.542 the majority of them actually go into these sinkholes 541 00:22:56.542 --> 00:22:59.078 rather than forming long rivers toward the end of the ice. 542 00:22:59.078 --> 00:23:02.948 So we particularly set up these camps right near these moulins 543 00:23:02.948 --> 00:23:04.216 so we can measure how fast 544 00:23:04.216 --> 00:23:06.318 and how much water is going into them. 545 00:23:06.318 --> 00:23:07.686 And, like you were saying before, 546 00:23:07.686 --> 00:23:09.822 the significance of these moulins 547 00:23:09.822 --> 00:23:10.990 and these sinkholes is that 548 00:23:10.990 --> 00:23:13.993 it takes water into the bottom of the ice sheet, 549 00:23:13.993 --> 00:23:15.894 and that's where it can really affect 550 00:23:15.894 --> 00:23:17.997 how fast the ice is flowing. 551 00:23:17.997 --> 00:23:19.665 And, the more that's melting, 552 00:23:19.665 --> 00:23:22.234 the more water can go inside. 553 00:23:22.234 --> 00:23:23.669 We've seen in some of our, 554 00:23:23.669 --> 00:23:25.971 you know, high-resolution satellite maps 555 00:23:25.971 --> 00:23:29.108 that there are thousands of these holes, 556 00:23:29.108 --> 00:23:31.510 thousands of these rivers draining into the ice sheet, 557 00:23:31.510 --> 00:23:33.445 and at higher elevations than we have 558 00:23:33.445 --> 00:23:35.014 ever really known about before. 559 00:23:35.014 --> 00:23:38.217 Just with the availability of better satellite imagery, 560 00:23:38.217 --> 00:23:40.119 higher resolution data we're able to 561 00:23:40.119 --> 00:23:43.122 actually see just how many of these rivers are, 562 00:23:43.122 --> 00:23:45.324 you know, bringing water into the bottom of the ice sheet 563 00:23:45.324 --> 00:23:48.894 where it can affect the ice dynamics and the ice flow. 564 00:23:48.894 --> 00:23:50.629 >> TOM WAGNER: Joining us now is Dr. Sophie Nowicki. 565 00:23:50.629 --> 00:23:53.098 We're going to talk a little bit about the actual work 566 00:23:53.098 --> 00:23:57.136 that we do to understand what's going on inside the ice sheets. 567 00:23:57.136 --> 00:23:58.871 And first, we're going to show you some more video 568 00:23:58.871 --> 00:24:01.707 from NASA's Operation IceBridge. 569 00:24:01.707 --> 00:24:03.742 Hey, so Sophie, tell us what we're looking at right now? 570 00:24:03.742 --> 00:24:04.977 >> SOPHIE NOWICKI: It's a very nice image. 571 00:24:04.977 --> 00:24:06.111 Basically, you're seeing 572 00:24:06.111 --> 00:24:08.480 what is white is ice flowing into the sea, 573 00:24:08.480 --> 00:24:10.749 those low ponds, they are kind of darker. 574 00:24:10.749 --> 00:24:12.851 And you can see that ice has very complex features, 575 00:24:12.851 --> 00:24:14.920 so different types of river of ice... 576 00:24:14.920 --> 00:24:15.988 I mean, river of water. 577 00:24:15.988 --> 00:24:17.323 So those are very different to 578 00:24:17.323 --> 00:24:18.657 what Larry was showing you before. 579 00:24:18.657 --> 00:24:19.825 This is really hard ice. 580 00:24:19.825 --> 00:24:20.926 >> TOM WAGNER: This is actual ice? 581 00:24:20.926 --> 00:24:22.294 This isn't water going into the ocean? 582 00:24:22.294 --> 00:24:24.763 This is something that's like an ice cube out of my fridge. 583 00:24:24.763 --> 00:24:26.332 >> SOPHIE NOWICKI: Yes, and then, you know, ice cube. 584 00:24:26.332 --> 00:24:28.734 So what you can map now with this... 585 00:24:28.734 --> 00:24:31.170 with our measurement tools' capabilities, 586 00:24:31.170 --> 00:24:33.038 it's the actual height of the ice. 587 00:24:33.038 --> 00:24:39.078 And as time goes, you see this is a height of the surface 588 00:24:39.078 --> 00:24:40.245 -- >> TOM WAGNER: Okay. So over here, 589 00:24:40.245 --> 00:24:41.914 we've got our vertical axis. 590 00:24:41.914 --> 00:24:44.350 That's meters, that's height of the ice. 591 00:24:44.350 --> 00:24:46.719 And then what, this is along the flight line itself? 592 00:24:46.719 --> 00:24:47.853 >> SOPHIE NOWICKI: Exactly. 593 00:24:47.853 --> 00:24:49.521 >> TOM WAGNER: Okay. And this is the height of the ice 594 00:24:49.521 --> 00:24:51.657 going down and that's the water out there? 595 00:24:51.657 --> 00:24:52.691 >> SOPHIE NOWICKI: Yes. 596 00:24:52.691 --> 00:24:54.093 And so you can see there's a big drop. 597 00:24:54.093 --> 00:24:55.594 That's where the ice meets the ocean. 598 00:24:55.594 --> 00:24:58.097 And this drop, the second, is going backwards, 599 00:24:58.097 --> 00:24:59.498 at the moment, in time. 600 00:24:59.498 --> 00:25:00.532 >> TOM WAGNER: Whoa! 601 00:25:00.532 --> 00:25:01.800 So that's the ice front backtracking? 602 00:25:01.800 --> 00:25:03.035 >> MICHELLE: It's going all the way back. 603 00:25:03.035 --> 00:25:04.770 >> SOPHIE NOWICKI: Yeah. Like a five-kilometers jump in time. 604 00:25:04.770 --> 00:25:06.238 So it's a very... even though, you know, 605 00:25:06.238 --> 00:25:07.906 you think about ice as an ice cube, 606 00:25:07.906 --> 00:25:09.174 it's actually very dynamic. 607 00:25:09.174 --> 00:25:10.909 It kind of moves back and forth. 608 00:25:10.909 --> 00:25:12.111 >> TOM WAGNER: So -- >> 609 00:25:12.111 --> 00:25:13.112 MICHELLE: Let's talk a little bit about 610 00:25:13.112 --> 00:25:14.980 how this data was taken because this is very dramatic, right? 611 00:25:14.980 --> 00:25:16.815 >> MICHELLE: Operation IceBridge is an aircraft - 612 00:25:16.815 --> 00:25:18.017 >> SOPHIE NOWICKI: Yes. 613 00:25:18.017 --> 00:25:19.818 >> MICHELLE: and the aircraft actually flies over Greenland 614 00:25:19.818 --> 00:25:22.921 and Antarctica and it bounces lasers off the ice. 615 00:25:22.921 --> 00:25:24.089 >> SOPHIE NOWICKI: It does. 616 00:25:24.089 --> 00:25:26.225 One of the measurements that they do is that they measure, 617 00:25:26.225 --> 00:25:27.926 they bounce lasers off the surface 618 00:25:27.926 --> 00:25:30.429 and it goes back, but they also kind of have other measurements, 619 00:25:30.429 --> 00:25:31.597 which hopefully we'll see later, 620 00:25:31.597 --> 00:25:32.998 that goes through the ice. 621 00:25:32.998 --> 00:25:35.100 And what's amazing is that Greenland is so big. 622 00:25:35.100 --> 00:25:38.537 It's about, uh, I mean, a quarter of the size of the US, 623 00:25:38.537 --> 00:25:42.608 but they flow... NASA has flown over quite a big portion 624 00:25:42.608 --> 00:25:45.144 of that over the last few years. 625 00:25:45.144 --> 00:25:47.813 >> ROBERT HALLBERG: So the research, project 626 00:25:47.813 --> 00:25:51.216 that I was involved in this past week is looking at 627 00:25:51.216 --> 00:25:54.720 the calving of tidewater glaciers. 628 00:25:54.720 --> 00:25:57.556 So there are fjords here in Greenland 629 00:25:57.556 --> 00:26:00.726 where the water comes right up to the face of the glacier. 630 00:26:00.726 --> 00:26:04.730 The water down below is warm and salty. 631 00:26:04.730 --> 00:26:07.933 There is meltwater that comes shooting out 632 00:26:07.933 --> 00:26:10.803 through large gaps of the base of the - 633 00:26:10.803 --> 00:26:13.505 of the ice sheets right into the water, 634 00:26:13.505 --> 00:26:16.041 and that creates these turbulent plumes of water 635 00:26:16.041 --> 00:26:18.744 that draw yet more warm water in. 636 00:26:18.744 --> 00:26:21.180 And it's this interaction between the ice 637 00:26:21.180 --> 00:26:23.849 and the ocean that may help to regulate, 638 00:26:23.849 --> 00:26:26.785 how quickly sea level will rise. 639 00:26:26.785 --> 00:26:29.588 Our climate models, because they are global 640 00:26:29.588 --> 00:26:31.356 and have to run for centuries, 641 00:26:31.356 --> 00:26:32.724 we can only resolve down 642 00:26:32.724 --> 00:26:34.626 to scales of order a few kilometers. 643 00:26:34.626 --> 00:26:37.296 And yet all the action of that ice shelf front 644 00:26:37.296 --> 00:26:39.998 is happening on scales of just a few hundred meters. 645 00:26:39.998 --> 00:26:44.169 It's fun and exciting and it's stunning to watch. 646 00:26:44.169 --> 00:26:46.105 But one of our challenges is figuring out 647 00:26:46.105 --> 00:26:49.641 how to incorporate all that... all that action 648 00:26:49.641 --> 00:26:51.477 that's happening in small scales 649 00:26:51.477 --> 00:26:55.113 and put it into global-scale models. 650 00:26:55.113 --> 00:26:56.648 It's absolutely essential. 651 00:26:56.648 --> 00:27:00.185 It's the processes that are going on in the fjords 652 00:27:00.185 --> 00:27:02.554 and up on the ice cap that control 653 00:27:02.554 --> 00:27:06.124 how the system is going to evolve. 654 00:27:06.124 --> 00:27:09.061 We know that sea level is rising, 655 00:27:09.061 --> 00:27:11.763 we know that the ice sheets are losing mass, 656 00:27:11.763 --> 00:27:13.699 but we need to understand why, 657 00:27:13.699 --> 00:27:16.201 because it's only that why that helps us 658 00:27:16.201 --> 00:27:19.404 to project how things will change in the future. 659 00:27:19.404 --> 00:27:20.806 >> MICHELLE: And it turns out that that "why" 660 00:27:20.806 --> 00:27:23.275 is actually kind of a complicated question to answer 661 00:27:23.275 --> 00:27:26.378 because we cannot see directly inside the ice sheets. 662 00:27:26.378 --> 00:27:27.579 >> TOM WAGNER: Yeah. And one of the things 663 00:27:27.579 --> 00:27:28.580 that's always impressed me is, 664 00:27:28.580 --> 00:27:30.449 when you look at the modeling results that came out 665 00:27:30.449 --> 00:27:32.251 of like the IPCC report, 666 00:27:32.251 --> 00:27:35.053 our best projections for future sea level rise; 667 00:27:35.053 --> 00:27:37.990 Sophie, you were involved with that, there is a huge spread. 668 00:27:37.990 --> 00:27:39.825 You know, like we talk about sea level rise 669 00:27:39.825 --> 00:27:41.760 in the next hundred years being, 670 00:27:41.760 --> 00:27:45.163 "Is it a foot, is it five feet, could it be more?" 671 00:27:45.163 --> 00:27:47.566 Tell us about how those models are made? 672 00:27:47.566 --> 00:27:49.935 Like what goes into them, as a start? 673 00:27:49.935 --> 00:27:51.803 >> SOPHIE NOWICKI: So you have to think of a model 674 00:27:51.803 --> 00:27:54.239 as a virtual laboratory that I'm building. 675 00:27:54.239 --> 00:27:55.974 I'm putting all of the things that I think that matters, 676 00:27:55.974 --> 00:27:57.809 so the snowfall, the bedrock, 677 00:27:57.809 --> 00:27:59.511 how the bedrock reacts. 678 00:27:59.511 --> 00:28:02.080 And then basically, we let it mix together 679 00:28:02.080 --> 00:28:03.949 and kind of explore and understand, 680 00:28:03.949 --> 00:28:05.817 the way that if I poke my system, 681 00:28:05.817 --> 00:28:07.185 what's going to happen. 682 00:28:07.185 --> 00:28:08.620 So if you look at my projection, 683 00:28:08.620 --> 00:28:09.922 there is a spread 684 00:28:09.922 --> 00:28:11.990 because we try lots of different scenarios. 685 00:28:11.990 --> 00:28:13.458 Maybe you want to kind of see, 686 00:28:13.458 --> 00:28:15.360 you know, is the snowfall 687 00:28:15.360 --> 00:28:17.095 going to matter more in a hundred years, 688 00:28:17.095 --> 00:28:18.597 is it going to be the ocean? 689 00:28:18.597 --> 00:28:20.632 And as then just showed in the video before, 690 00:28:20.632 --> 00:28:23.001 I mean, ice-ocean interaction is quite complex. 691 00:28:23.001 --> 00:28:24.303 >> TOM WAGNER: Right, but take us back to the basics 692 00:28:24.303 --> 00:28:25.604 just for a second, right? 693 00:28:25.604 --> 00:28:27.673 So you talked about we've got this numerical model 694 00:28:27.673 --> 00:28:30.242 that describes how the ice flows into the ocean. 695 00:28:30.242 --> 00:28:31.443 It also takes... you've got 696 00:28:31.443 --> 00:28:33.478 how much snow falls on the surface of the ice. 697 00:28:33.478 --> 00:28:36.448 But then you mentioned something like the bedrock underneath, 698 00:28:36.448 --> 00:28:39.384 how does the bedrock affect an ice sheet model 699 00:28:39.384 --> 00:28:41.086 that's useful for sea level rise? 700 00:28:41.086 --> 00:28:42.588 >> SOPHIE NOWICKI: So that's a good question 701 00:28:42.588 --> 00:28:44.256 because before Operation IceBridge 702 00:28:44.256 --> 00:28:45.891 we had no idea what the bedrock looked like. 703 00:28:45.891 --> 00:28:47.426 And that's one of the good...for me, 704 00:28:47.426 --> 00:28:48.827 one of the most beautiful return 705 00:28:48.827 --> 00:28:51.563 about Operation IceBridge is the shape of the bed. 706 00:28:51.563 --> 00:28:55.367 It matters because it tells me how big my ice is, 707 00:28:55.367 --> 00:28:57.436 volume of the ice that's available to flow. 708 00:28:57.436 --> 00:28:58.837 So it's one thing, how much ice do I have? 709 00:28:58.837 --> 00:29:00.238 >> TOM WAGNER: How much ice is there? Okay. 710 00:29:00.238 --> 00:29:01.607 >> SOPHIE NOWICKI: But also, it also matters 711 00:29:01.607 --> 00:29:03.909 because, you know, imagine you are skiing downhill. 712 00:29:03.909 --> 00:29:06.244 You go quite fast because it's going downhill. 713 00:29:06.244 --> 00:29:07.479 So the ice is the same thing. 714 00:29:07.479 --> 00:29:10.949 I'm going to go fly... I just go down quite fast. 715 00:29:10.949 --> 00:29:13.685 But if I have to fly... if I have to slide down 716 00:29:13.685 --> 00:29:14.820 if you have skii uphill, 717 00:29:14.820 --> 00:29:16.622 you have to really do lots of hard work. 718 00:29:16.622 --> 00:29:18.023 It's the same thing for the ice. 719 00:29:18.023 --> 00:29:20.125 If the bedrock changes and they have to go uphill, 720 00:29:20.125 --> 00:29:21.326 it's hard work for me. 721 00:29:21.326 --> 00:29:22.427 >> TOM WAGNER: Okay. 722 00:29:22.427 --> 00:29:23.595 >> MICHELLE: And this must affect the way 723 00:29:23.595 --> 00:29:24.730 that the ice is melting. 724 00:29:24.730 --> 00:29:26.698 I mean, if there is this terrain underneath Greenland 725 00:29:26.698 --> 00:29:28.033 that we're only just aware of, 726 00:29:28.033 --> 00:29:30.335 I mean, we discovered this giant canyon system 727 00:29:30.335 --> 00:29:32.204 from the data from Operation IceBridge. 728 00:29:32.204 --> 00:29:33.405 >> SOPHIE NOWICKI: That is correct. 729 00:29:33.405 --> 00:29:34.706 And then also those canyons that are basically 730 00:29:34.706 --> 00:29:36.108 the size of the Grand Canyons, 731 00:29:36.108 --> 00:29:39.211 this is also where some of the water that Larry showed you 732 00:29:39.211 --> 00:29:41.113 going into the surface is going to be trapped 733 00:29:41.113 --> 00:29:43.982 and locked down and those are going to affect my ice flow. 734 00:29:43.982 --> 00:29:46.218 >> TOM WAGNER: So - okay, but one of the other things too 735 00:29:46.218 --> 00:29:47.185 with the bedrock. 736 00:29:47.185 --> 00:29:49.454 So we've been talking recently about Antarctica 737 00:29:49.454 --> 00:29:51.623 and last year we had those papers come out where we said, 738 00:29:51.623 --> 00:29:54.226 "Oh my gosh, part of Antarctica is unstable now 739 00:29:54.226 --> 00:29:56.428 and the sea level is going to rise rapidly!" 740 00:29:56.428 --> 00:29:57.963 Tell us about what they found 741 00:29:57.963 --> 00:29:59.731 and how that affects models. 742 00:29:59.731 --> 00:30:02.000 >> SOPHIE NOWICKI: So there basically... 743 00:30:02.000 --> 00:30:04.469 as Operation IceBridge was flying over, 744 00:30:04.469 --> 00:30:05.437 they managed to kind of 745 00:30:05.437 --> 00:30:07.039 so there is a big bump in the bed, 746 00:30:07.039 --> 00:30:08.740 and those bumps in the bed means that 747 00:30:08.740 --> 00:30:12.844 when the ice is changing due to a warmer ocean, 748 00:30:12.844 --> 00:30:14.946 when the ice is retreating back 749 00:30:14.946 --> 00:30:17.516 into the interior of the ice sheet, 750 00:30:17.516 --> 00:30:18.717 if I have a little low bump 751 00:30:18.717 --> 00:30:20.419 then I can basically anchor myself. 752 00:30:20.419 --> 00:30:21.787 And that's basically why knowing 753 00:30:21.787 --> 00:30:23.355 the bed is so important because, 754 00:30:23.355 --> 00:30:24.656 "Do I have a place to anchor myself 755 00:30:24.656 --> 00:30:27.559 as I'm collapsing or do I don't have a bump in the bed 756 00:30:27.559 --> 00:30:29.194 and therefore I keep on going?" 757 00:30:29.194 --> 00:30:30.629 >> TOM WAGNER: Uh-huh, so literally the... 758 00:30:30.629 --> 00:30:33.165 when you retreat past the anchor point, 759 00:30:33.165 --> 00:30:36.501 the ice pops up and it can begin almost to float. 760 00:30:36.501 --> 00:30:37.669 >> SOPHIE NOWICKI: It can begin to float, 761 00:30:37.669 --> 00:30:38.637 and then it's just like, 762 00:30:38.637 --> 00:30:39.705 you know, when you are 763 00:30:39.705 --> 00:30:40.806 -- >> TOM WAGNER: And we're talking about hundreds, 764 00:30:40.806 --> 00:30:42.974 ice that's how thick, hundreds of feet? 765 00:30:42.974 --> 00:30:45.010 >> SOPHIE NOWICKI: Yes, it is hundreds of feet. 766 00:30:45.010 --> 00:30:48.513 So it's quite impressive, actually, 767 00:30:48.513 --> 00:30:50.382 how dynamic the ice can be. 768 00:30:50.382 --> 00:30:51.717 >> TOM WAGNER: Okay, so getting back to it, right? 769 00:30:51.717 --> 00:30:53.985 You know, people, I think one of the problems 770 00:30:53.985 --> 00:30:55.654 that people get into is they say, 771 00:30:55.654 --> 00:31:00.559 okay, scientists, give us a projection. 772 00:31:00.559 --> 00:31:02.127 You know somebody wants to put a power plant 773 00:31:02.127 --> 00:31:03.662 and they want to know how high sea level 774 00:31:03.662 --> 00:31:05.397 is going to rise in a hundred years. 775 00:31:05.397 --> 00:31:06.465 Right? 776 00:31:06.465 --> 00:31:07.866 We give them a spread that goes, you know, 777 00:31:07.866 --> 00:31:08.867 in a hundred years from now, 778 00:31:08.867 --> 00:31:10.235 it's anywhere from one to five feet, 779 00:31:10.235 --> 00:31:13.905 how does a result like that affect the projections? 780 00:31:13.905 --> 00:31:16.374 >> SOPHIE NOWICKI: Yeah. It's hard 781 00:31:16.374 --> 00:31:18.009 because when you have those... 782 00:31:18.009 --> 00:31:21.947 those projections of like... of the wide range, 783 00:31:21.947 --> 00:31:23.915 it's because it's due to the fact 784 00:31:23.915 --> 00:31:25.450 that we're using different models, 785 00:31:25.450 --> 00:31:27.452 we're using different data sets. 786 00:31:27.452 --> 00:31:29.387 Sometimes, you know, I maybe using in my bed 787 00:31:29.387 --> 00:31:31.423 and then somebody else is using in a different bed, 788 00:31:31.423 --> 00:31:34.392 and so those all come to play in a way that we couldn't know, 789 00:31:34.392 --> 00:31:38.263 and that's why the spread is actually at the moment, 790 00:31:38.263 --> 00:31:40.766 you know, is good because we'll... 791 00:31:40.766 --> 00:31:43.335 we have something to try to work forward to refining, 792 00:31:43.335 --> 00:31:45.270 and NASA is doing a huge amount of work 793 00:31:45.270 --> 00:31:46.571 to refining this spread, 794 00:31:46.571 --> 00:31:48.140 because of course I'm not happy to tell you, 795 00:31:48.140 --> 00:31:51.309 I don't know if it's going to be one feet or five feet. 796 00:31:51.309 --> 00:31:52.778 I would rather be able to tell you it's going to be 797 00:31:52.778 --> 00:31:54.813 two and-a-half foot for planning. 798 00:31:54.813 --> 00:31:56.014 >> SOPHIE NOWICKI: But at the moment, 799 00:31:56.014 --> 00:31:56.982 this is just the way it is, 800 00:31:56.982 --> 00:31:58.416 the future is real uncertain 801 00:31:58.416 --> 00:32:00.051 and that's what we're dealing with. 802 00:32:00.051 --> 00:32:01.553 >> TOM WAGNER: Hey, guys! 803 00:32:01.553 --> 00:32:03.588 >> JOSH WILLIS: Well, yeah, the... 804 00:32:03.588 --> 00:32:07.559 the oceans are definitely eating away at the, 805 00:32:07.559 --> 00:32:09.628 Greenland ice sheet from the edges. 806 00:32:09.628 --> 00:32:12.063 We've known pretty well, for a long time 807 00:32:12.063 --> 00:32:13.465 that the surface is melting. 808 00:32:13.465 --> 00:32:15.333 We can see that melt from space. 809 00:32:15.333 --> 00:32:19.104 And, you know, Larry and Vena 810 00:32:19.104 --> 00:32:20.472 were out on the ice 811 00:32:20.472 --> 00:32:25.243 watching the rivers of meltwater dive down into these moulins, 812 00:32:25.243 --> 00:32:27.245 but, more recently, 813 00:32:27.245 --> 00:32:29.748 research has started to suggest that, 814 00:32:29.748 --> 00:32:32.784 the ice is actually being eaten away at the edges. 815 00:32:32.784 --> 00:32:36.388 Remember, a lot of these glaciers which carry the ice 816 00:32:36.388 --> 00:32:39.391 away from the ice sheet and into the oceans 817 00:32:39.391 --> 00:32:41.760 actually sit right in the oceans. 818 00:32:41.760 --> 00:32:44.062 They literally have a toe in the water, 819 00:32:44.062 --> 00:32:46.798 and that makes them susceptible to warming 820 00:32:46.798 --> 00:32:48.700 and the intrusion of warm water 821 00:32:48.700 --> 00:32:52.070 from the edges which can melt away at the glaciers. 822 00:32:52.070 --> 00:32:53.104 >> TOM WAGNER: Tell us a little bit about 823 00:32:53.104 --> 00:32:54.906 like the continental shelf around Greenland, 824 00:32:54.906 --> 00:32:56.508 its relationship to the ocean, 825 00:32:56.508 --> 00:32:59.044 and that's relationship to the ice? 826 00:32:59.044 --> 00:33:00.479 >> JOSH WILLIS: Well, what's really interesting, 827 00:33:00.479 --> 00:33:02.814 Tom, is that the water around Greenland 828 00:33:02.814 --> 00:33:04.816 is sort of upside-down. 829 00:33:04.816 --> 00:33:06.785 You have warm water 830 00:33:06.785 --> 00:33:08.954 underneath a layer of cold water. 831 00:33:08.954 --> 00:33:10.755 Normally, it's the other way around, right? 832 00:33:10.755 --> 00:33:11.990 Warm water rises. 833 00:33:11.990 --> 00:33:14.960 But the waters around Greenland are actually, 834 00:33:14.960 --> 00:33:16.461 what we call "inverted," 835 00:33:16.461 --> 00:33:18.663 meaning that the warm water is actually at depth 836 00:33:18.663 --> 00:33:21.166 and it's at depth because it's extra salty. 837 00:33:21.166 --> 00:33:22.901 This water comes from the Atlantic, 838 00:33:22.901 --> 00:33:24.536 it's a very salty ocean. 839 00:33:24.536 --> 00:33:26.771 The cold water comes from the arctic 840 00:33:26.771 --> 00:33:29.174 and it's very fresh so it sits on top. 841 00:33:29.174 --> 00:33:32.444 What this means is that the warm water has to climb up 842 00:33:32.444 --> 00:33:35.313 the continental shelf and reach into the fjords 843 00:33:35.313 --> 00:33:37.616 in order to interact with the glaciers. 844 00:33:37.616 --> 00:33:40.118 So one of the things we're really interested in is 845 00:33:40.118 --> 00:33:42.621 just how that water might get there, 846 00:33:42.621 --> 00:33:46.224 what pathways it might take along the continental shelf. 847 00:33:47.325 --> 00:33:48.460 >> TOM WAGNER: We're showing some video now 848 00:33:48.460 --> 00:33:49.961 of what it's like to do that work. 849 00:33:49.961 --> 00:33:51.830 Can you tell us about the oceanographic measurements 850 00:33:51.830 --> 00:33:56.668 that you actually make and what goes into making them? 851 00:33:56.668 --> 00:33:58.103 >> JOSH WILLIS: Yeah, absolutely. 852 00:33:58.103 --> 00:33:59.671 So this is really exciting because, 853 00:33:59.671 --> 00:34:03.208 this ship has sailed into a fjord, 854 00:34:03.208 --> 00:34:06.845 which is a long trench carved by an ancient glacier 855 00:34:06.845 --> 00:34:09.314 and is now filled with water and they're, 856 00:34:09.314 --> 00:34:10.782 deploying instruments. 857 00:34:10.782 --> 00:34:12.651 Some of them are called 'moorings' 858 00:34:12.651 --> 00:34:15.554 which sit on the bottom and collect data for a long time, 859 00:34:15.554 --> 00:34:18.490 and some of them are CTDs which, 860 00:34:18.490 --> 00:34:20.625 are one-time measurements of the ocean. 861 00:34:20.625 --> 00:34:22.961 You can see the ship pushing away icebergs 862 00:34:22.961 --> 00:34:25.263 and folks paddling through the slush. 863 00:34:25.263 --> 00:34:28.300 It's really hard work, and it's really difficult. 864 00:34:28.300 --> 00:34:30.168 And, right now, we actually have a ship, 865 00:34:30.168 --> 00:34:32.237 the 'Cape Race' which you see right there 866 00:34:32.237 --> 00:34:33.972 at the end of the video, 867 00:34:33.972 --> 00:34:36.041 which is collecting data about the shape 868 00:34:36.041 --> 00:34:37.943 and depth of these fjords, 869 00:34:37.943 --> 00:34:39.344 because that's really important 870 00:34:39.344 --> 00:34:40.812 for understanding how that warm water 871 00:34:40.812 --> 00:34:43.982 can climb up onto the shelf and reach the glaciers. 872 00:34:43.982 --> 00:34:45.650 >> TOM WAGNER: So tell me a little bit. 873 00:34:45.650 --> 00:34:48.853 You go out and you make a few point measurements, right? 874 00:34:48.853 --> 00:34:51.122 How do you synthesize all this stuff together? 875 00:34:51.122 --> 00:34:52.424 You know to get at those big... 876 00:34:52.424 --> 00:34:54.359 like, what are the big picture-specific questions 877 00:34:54.359 --> 00:34:55.660 you're trying to answer 878 00:34:55.660 --> 00:34:58.129 and how do you put all those things together? 879 00:34:58.129 --> 00:35:00.665 >> JOSH WILLIS: Well, most people would tell you a model, 880 00:35:00.665 --> 00:35:02.100 but I'm going to say, you just need 881 00:35:02.100 --> 00:35:04.102 a whole lot of those point measurements. 882 00:35:04.102 --> 00:35:07.138 In fact, we've only just begun 883 00:35:07.138 --> 00:35:09.441 to study the oceans around Greenland. 884 00:35:09.441 --> 00:35:10.642 While there have been a lot of, 885 00:35:10.642 --> 00:35:12.577 moorings placed 886 00:35:12.577 --> 00:35:15.747 and some surveys that have happened for a long time 887 00:35:15.747 --> 00:35:19.451 in a very few places, the vast majority of the area 888 00:35:19.451 --> 00:35:21.853 around the island of Greenland is just unmeasured 889 00:35:21.853 --> 00:35:23.355 in terms of the ocean, 890 00:35:23.355 --> 00:35:25.256 not just how salty 891 00:35:25.256 --> 00:35:27.692 or how fresh or warm or cold the water might be, 892 00:35:27.692 --> 00:35:29.327 but even how deep it is. 893 00:35:29.327 --> 00:35:31.763 In fact, there are huge areas around Greenland 894 00:35:31.763 --> 00:35:34.666 where we have no depth measurements so we don't know 895 00:35:34.666 --> 00:35:37.569 if there are deep trenches, or sills 896 00:35:37.569 --> 00:35:40.071 that this warm water might have to climb over. 897 00:35:40.071 --> 00:35:43.241 So we have a whole lot of observations to make, and, 898 00:35:43.241 --> 00:35:45.944 right now we've actually begun making 899 00:35:45.944 --> 00:35:48.747 those kinds of observations with the new mission, 900 00:35:48.747 --> 00:35:51.883 'Oceans Melting Greenland' or 'OMG'. 901 00:35:51.883 --> 00:35:53.151 >> TOM WAGNER: Yeah, and I think we're going to share 902 00:35:53.151 --> 00:35:56.488 some video now of how the aircraft work for OMG. 903 00:35:56.488 --> 00:35:58.023 >> MICHELLE: So describe this mission here. 904 00:35:58.023 --> 00:36:00.025 >> JOSH WILLIS: Yeah. So what you're seeing here 905 00:36:00.025 --> 00:36:02.327 is, an aircraft 906 00:36:02.327 --> 00:36:05.163 measurement of the height of the ice. 907 00:36:05.163 --> 00:36:07.499 And, this is a measurement that will fly once a year. 908 00:36:07.499 --> 00:36:09.968 We're also measuring ocean temperatures 909 00:36:09.968 --> 00:36:12.470 using deployable instruments. 910 00:36:12.470 --> 00:36:15.373 So these are being dropped out of back of the aircraft 911 00:36:15.373 --> 00:36:17.542 They fall through the water and measure 912 00:36:17.542 --> 00:36:19.044 temperature and salinity, 913 00:36:19.044 --> 00:36:21.579 and then a small float actually radios that data 914 00:36:21.579 --> 00:36:23.048 back to the airplane. 915 00:36:23.048 --> 00:36:27.285 So those two campaigns will happen every year 916 00:36:27.285 --> 00:36:28.753 for about five years, 917 00:36:28.753 --> 00:36:31.222 but we also have, ship-based measurements 918 00:36:31.222 --> 00:36:33.024 of the sea floor depth, 919 00:36:33.024 --> 00:36:36.227 and finally, an airplane that measures gravity. 920 00:36:36.227 --> 00:36:38.029 And the gravity measurements are important 921 00:36:38.029 --> 00:36:40.765 because that also tells you about 922 00:36:40.765 --> 00:36:42.734 the depth of the sea floor. 923 00:36:42.734 --> 00:36:44.269 Whenever you fly over a trench, 924 00:36:44.269 --> 00:36:46.271 the pull of gravity is a little bit weaker, 925 00:36:46.271 --> 00:36:49.074 and that's how we can infer on a lot of places 926 00:36:49.074 --> 00:36:50.508 where we can't drive the ship, 927 00:36:50.508 --> 00:36:52.577 we can infer how deep the water is. 928 00:36:52.577 --> 00:36:56.081 So all four of these campaigns are part of the 929 00:36:56.081 --> 00:37:00.418 Oceans Melting Greenland Mission which started this year. 930 00:37:00.418 --> 00:37:02.253 We have the ship in the water right now, 931 00:37:02.253 --> 00:37:07.325 and next year we'll be starting to fly the airplanes. 932 00:37:07.325 --> 00:37:09.027 >> MICHELLE: The really dramatic interface of the land 933 00:37:09.027 --> 00:37:10.495 and the ocean and ice. 934 00:37:10.495 --> 00:37:11.963 Can you tell us, is there anything special about 935 00:37:11.963 --> 00:37:14.499 the geography of a fjord that affects how the ice 936 00:37:14.499 --> 00:37:16.167 and the ocean work together? 937 00:37:16.167 --> 00:37:18.403 >> JOSH WILLIS: Uh the glaciers dug out these trenches, 938 00:37:18.403 --> 00:37:21.039 uh, on their path off the land 939 00:37:21.039 --> 00:37:22.507 and towards the ocean 940 00:37:22.507 --> 00:37:26.745 and left behind avenues for this warm water 941 00:37:26.745 --> 00:37:30.682 to sneak up from the deep and interact with the glaciers. 942 00:37:30.682 --> 00:37:34.786 So a lot of what scientists are focusing on today 943 00:37:34.786 --> 00:37:39.791 is this interface where water meets ice meets land 944 00:37:39.791 --> 00:37:42.794 because that's where the real action 945 00:37:42.794 --> 00:37:46.064 is in terms of the ocean-ice interaction. 946 00:37:46.064 --> 00:37:49.100 As we heard about before, a lot of the meltwater 947 00:37:49.100 --> 00:37:52.937 from the surface actually digs down through the ice sheet 948 00:37:52.937 --> 00:37:56.141 and it finds its way to the ocean actually 949 00:37:56.141 --> 00:37:58.209 at the bottom of the ice. 950 00:37:58.209 --> 00:38:00.145 So it often, you know, in some cases, 951 00:38:00.145 --> 00:38:02.580 it comes out right at the bottom of the ice, 952 00:38:02.580 --> 00:38:04.482 and then because it's light 953 00:38:04.482 --> 00:38:06.351 and fresh, it surfaces. 954 00:38:06.351 --> 00:38:08.386 That can pull warm water 955 00:38:08.386 --> 00:38:10.188 in towards the bottom of the glacier 956 00:38:10.188 --> 00:38:11.823 and increase melting, and that's what 957 00:38:11.823 --> 00:38:14.359 we're really looking for with OMG. 958 00:38:15.627 --> 00:38:17.162 >> MICHELLE: So here we see these little arrows 959 00:38:17.162 --> 00:38:18.763 are indicating the flow of the ice? 960 00:38:18.763 --> 00:38:20.131 >> TOM WAGNER: Right. So here we are, 961 00:38:20.131 --> 00:38:21.499 the blue is the ocean. 962 00:38:21.499 --> 00:38:22.734 Those blue lines are showing 963 00:38:22.734 --> 00:38:24.502 the direction of flow of the ice. 964 00:38:24.502 --> 00:38:26.804 And you can see what happens is it's kind of slow on the sides, 965 00:38:26.804 --> 00:38:28.806 then it gets into this racetrack in the middle 966 00:38:28.806 --> 00:38:31.643 and it goes out to the ocean. 967 00:38:31.643 --> 00:38:34.045 And what's so fascinating about this is that 968 00:38:34.045 --> 00:38:35.947 you can see kind of right at the front. 969 00:38:35.947 --> 00:38:37.682 This stuff is like... some people call it 970 00:38:37.682 --> 00:38:39.884 like the cork in the bottle, you know. 971 00:38:39.884 --> 00:38:42.020 And that... these processes that Josh's team 972 00:38:42.020 --> 00:38:43.721 is studying under OMG, 973 00:38:43.721 --> 00:38:47.225 they are looking at how the ocean causes 974 00:38:47.225 --> 00:38:49.861 the ice to fracture more easily, 975 00:38:49.861 --> 00:38:51.930 pull that cork out of the bottle, 976 00:38:51.930 --> 00:38:54.032 and let the ice behind it speed up 977 00:38:54.032 --> 00:38:55.967 and really dump in the ocean. 978 00:38:55.967 --> 00:38:57.101 >> MICHELLE: We're really seeing just how many 979 00:38:57.101 --> 00:38:59.070 complex interactions are going on here that 980 00:38:59.070 --> 00:39:00.738 as the air warms that affects the ice, 981 00:39:00.738 --> 00:39:03.074 as the ocean warms that affects the ice as well. 982 00:39:03.074 --> 00:39:04.509 So this is one of the reasons we see 983 00:39:04.509 --> 00:39:06.644 such dramatic changes at the poles. 984 00:39:06.644 --> 00:39:07.679 >> TOM WAGNER: Yeah, and it's one of the reasons 985 00:39:07.679 --> 00:39:09.247 that NASA gets involved in this work. 986 00:39:09.247 --> 00:39:11.115 You know you need a lot of new technology to do this. 987 00:39:11.115 --> 00:39:13.251 A lot of its remote sensing which means 988 00:39:13.251 --> 00:39:15.086 we make measurements from far away, 989 00:39:15.086 --> 00:39:16.521 from aircraft or satellites. 990 00:39:16.521 --> 00:39:18.556 But then we kind of take the view of trying to model it 991 00:39:18.556 --> 00:39:20.725 and pull all those little pieces together. 992 00:39:20.725 --> 00:39:23.294 This is a Jakobshavn glacier from Greenland, 993 00:39:23.294 --> 00:39:24.996 one of the most important outlet glaciers, 994 00:39:24.996 --> 00:39:27.098 it drains quite a bit of Greenland. 995 00:39:27.098 --> 00:39:31.603 This is where the front of the glacier was in 1850. 996 00:39:31.603 --> 00:39:34.005 This is where the glacier was today. 997 00:39:34.005 --> 00:39:35.974 And this is actually, really recent stuff 998 00:39:35.974 --> 00:39:38.109 from just a few days ago, that shows you just how much 999 00:39:38.109 --> 00:39:40.612 ice can be lost over the course of a couple of days. 1000 00:39:42.247 --> 00:39:43.548 >> MICHELLE: So we're actually seeing ice 1001 00:39:43.548 --> 00:39:44.582 cracking up right there, 1002 00:39:44.582 --> 00:39:45.917 that's the change that we're looking for? 1003 00:39:45.917 --> 00:39:47.085 >> TOM WAGNER: Right. >> MICHELLE: Yeah. 1004 00:39:47.085 --> 00:39:48.152 >> TOM WAGNER: But I mean -- and you are talking, 1005 00:39:48.152 --> 00:39:49.254 again, this is like 1006 00:39:49.254 --> 00:39:51.189 kilometer-scale type events, you know. 1007 00:39:51.189 --> 00:39:52.390 >> TOM WAGNER: This ice, actually here is 1008 00:39:52.390 --> 00:39:53.625 some footage of the thing itself. 1009 00:39:53.625 --> 00:39:55.660 So there are some great pictures of these, 1010 00:39:55.660 --> 00:39:57.895 but what people have done is compared the sizes of 1011 00:39:57.895 --> 00:40:00.865 the chunks of ice breaking off to like buildings. 1012 00:40:00.865 --> 00:40:02.533 And so, some of these chunks you're looking at, 1013 00:40:02.533 --> 00:40:04.736 they are like as big as the US Capitol building. 1014 00:40:04.736 --> 00:40:05.837 >> JOSH WILLIS: I think, you know, 1015 00:40:05.837 --> 00:40:09.607 one of the striking things about that image of the ice 1016 00:40:09.607 --> 00:40:13.077 breaking off is the timeline that's associated with it. 1017 00:40:13.077 --> 00:40:15.146 If you look carefully, 1018 00:40:15.146 --> 00:40:19.250 that data goes back to the late 1800s. 1019 00:40:19.250 --> 00:40:21.252 So this glacier has been retreating, 1020 00:40:21.252 --> 00:40:25.023 steadily for the last 150 years. 1021 00:40:25.023 --> 00:40:28.626 And it's happening, you know, 1022 00:40:28.626 --> 00:40:31.696 on a glacial time-scale, very rapidly. 1023 00:40:31.696 --> 00:40:34.632 So we're really interested in trying to study just 1024 00:40:34.632 --> 00:40:37.969 how these things are proceeding 1025 00:40:37.969 --> 00:40:39.737 and what the role of the ocean might be 1026 00:40:39.737 --> 00:40:41.673 in helping to drive them. 1027 00:40:41.673 --> 00:40:44.742 Clearly, if those things are being eaten away at the edges, 1028 00:40:44.742 --> 00:40:46.477 we need to be able to quantify that 1029 00:40:46.477 --> 00:40:50.515 if we ever hope to predict sea level rise into the future. 1030 00:40:50.515 --> 00:40:51.582 >> TOM WAGNER: Hey, Josh! 1031 00:40:51.582 --> 00:40:53.851 Now you are kind of a man who's a Jack of all trades. 1032 00:40:53.851 --> 00:40:55.687 We're also going to talk now about Jason-3 1033 00:40:55.687 --> 00:40:57.188 as we kind of finalize our program 1034 00:40:57.188 --> 00:40:58.189 and we're going to start talking about 1035 00:40:58.189 --> 00:41:00.625 what are the things that are coming next for NASA. 1036 00:41:00.625 --> 00:41:02.293 Can you tell us a little about Jason-3? 1037 00:41:02.293 --> 00:41:03.561 And I understand we have a picture of it 1038 00:41:03.561 --> 00:41:05.496 to put up that you might talk to. 1039 00:41:05.496 --> 00:41:07.665 >> JOSH WILLIS: Well, the Jason missions 1040 00:41:07.665 --> 00:41:09.200 are really in my opinion, 1041 00:41:09.200 --> 00:41:12.003 one of our most important means 1042 00:41:12.003 --> 00:41:16.708 of measuring the human impact on the global climate. 1043 00:41:16.708 --> 00:41:20.578 Because these missions measure the total volume 1044 00:41:20.578 --> 00:41:23.147 of the ocean basically once every ten days, 1045 00:41:23.147 --> 00:41:24.849 we can really watch how, 1046 00:41:24.849 --> 00:41:28.653 the entire planet is responding to climate change, 1047 00:41:28.653 --> 00:41:30.688 with kind of one single number, 1048 00:41:30.688 --> 00:41:33.324 and these satellites have been providing 1049 00:41:33.324 --> 00:41:36.627 that record since the early 1990s, 1050 00:41:36.627 --> 00:41:38.963 and we're really looking forward to Jason-3 1051 00:41:38.963 --> 00:41:41.065 in order to continue that record. 1052 00:41:41.065 --> 00:41:43.701 A lot of folks ask, "Well, what's new about Jason-3?" 1053 00:41:43.701 --> 00:41:45.470 And I like to say, "Well, it's going to measure 1054 00:41:45.470 --> 00:41:48.239 the next five years instead of the last five years." 1055 00:41:48.239 --> 00:41:51.042 And really, that's a big deal in climate science. 1056 00:41:51.042 --> 00:41:55.113 A lot of what we need are long records to be able to compare 1057 00:41:55.113 --> 00:41:57.348 what's going on to the ice 1058 00:41:57.348 --> 00:42:02.520 and the oceans today with how they were decades ago. 1059 00:42:02.520 --> 00:42:04.222 >> TOM WAGNER: I think what people forget is 1060 00:42:04.222 --> 00:42:06.324 some of the big components of the Earth's system, 1061 00:42:06.324 --> 00:42:08.559 they behave on decadal timescales. 1062 00:42:08.559 --> 00:42:10.661 Like the Pacific Decadal Oscillation. 1063 00:42:11.963 --> 00:42:13.564 So tell us a little about that. 1064 00:42:13.564 --> 00:42:14.832 >> JOSH WILLIS: Yeah, absolutely. 1065 00:42:14.832 --> 00:42:16.100 One of the things that, 1066 00:42:16.100 --> 00:42:17.735 the satellite altimeters 1067 00:42:17.735 --> 00:42:19.670 do is they measure sea level, 1068 00:42:19.670 --> 00:42:21.339 not just everywhere around the globe, 1069 00:42:21.339 --> 00:42:23.541 but in each place around the globe. 1070 00:42:23.541 --> 00:42:26.711 So you can see clearly where the Pacific Ocean 1071 00:42:26.711 --> 00:42:30.314 is rising quickly, like in the West Pacific 1072 00:42:30.314 --> 00:42:32.417 near Indonesia and Australia. 1073 00:42:32.417 --> 00:42:34.919 They've been getting hammered with rates of sea level rise 1074 00:42:34.919 --> 00:42:38.322 that are three times as large as the global average. 1075 00:42:38.322 --> 00:42:41.225 So they are getting way more than their fair share 1076 00:42:41.225 --> 00:42:42.894 of sea level rise. 1077 00:42:42.894 --> 00:42:47.131 We on the West Coast, here in California, 1078 00:42:47.131 --> 00:42:49.233 have been getting less than our fair share. 1079 00:42:49.233 --> 00:42:51.569 In fact, in some places sea levels have actually 1080 00:42:51.569 --> 00:42:55.206 fallen very slightly, and that sometimes can give us 1081 00:42:55.206 --> 00:42:57.308 a sort of false sense of security. 1082 00:42:57.308 --> 00:42:59.410 You know, global sea levels are rising 1083 00:42:59.410 --> 00:43:02.647 and we're going to have to pay that debt of, 1084 00:43:02.647 --> 00:43:05.817 sea level rise that we didn't get in the last 20 years 1085 00:43:05.817 --> 00:43:09.020 probably sometime in the next 20 years. 1086 00:43:09.020 --> 00:43:10.521 >> TOM WAGNER: Josh, thanks a lot for joining us today! 1087 00:43:10.521 --> 00:43:11.522 We really appreciate it! 1088 00:43:11.522 --> 00:43:12.957 Good luck with that mission! 1089 00:43:12.957 --> 00:43:14.659 >> MICHELLE: So we've talked a lot today about 1090 00:43:14.659 --> 00:43:15.960 all kinds of different scientists 1091 00:43:15.960 --> 00:43:17.261 that are studying ice, 1092 00:43:17.261 --> 00:43:18.863 that are studying ocean level rise, 1093 00:43:18.863 --> 00:43:21.432 and one of my big questions is, "What comes next?" 1094 00:43:21.432 --> 00:43:22.867 >> TOM WAGNER: Yeah. So NASA has actually got 1095 00:43:22.867 --> 00:43:24.168 a bunch of missions coming up 1096 00:43:24.168 --> 00:43:25.503 that's going to help us with this. 1097 00:43:25.503 --> 00:43:26.871 You know, so the next thing that's going to happen 1098 00:43:26.871 --> 00:43:28.439 is the Grace Follow-On Mission 1099 00:43:28.439 --> 00:43:31.142 which we're hoping is going to provide a higher resolution 1100 00:43:31.142 --> 00:43:33.978 look at this mass loss and change of the ice sheets. 1101 00:43:33.978 --> 00:43:36.147 Then after that, we have the ICESat-2 launch. 1102 00:43:36.147 --> 00:43:38.816 An ICESat is this laser altimeter that goes and -- 1103 00:43:38.816 --> 00:43:41.018 literally, it's like a laser pointer in space, 1104 00:43:41.018 --> 00:43:42.987 tells us very precisely the height of the ice 1105 00:43:42.987 --> 00:43:44.689 over the entire planet. 1106 00:43:44.689 --> 00:43:46.524 It even also gets used to measure global forest 1107 00:43:46.524 --> 00:43:48.092 heights and abundance. 1108 00:43:48.092 --> 00:43:49.427 And so then after that we will have 1109 00:43:49.427 --> 00:43:51.195 what's called the NISAR Mission, 1110 00:43:51.195 --> 00:43:53.030 which is a mission jointly with India, 1111 00:43:53.030 --> 00:43:55.233 that's a new radar mapper, that's going to tell us 1112 00:43:55.233 --> 00:43:57.935 a lot about how the velocity of the ice flow 1113 00:43:57.935 --> 00:43:59.670 to the ocean has been changing. 1114 00:43:59.670 --> 00:44:01.639 So what we are really hoping is that we can pull 1115 00:44:01.639 --> 00:44:02.974 all this information together 1116 00:44:02.974 --> 00:44:04.842 and really narrow down those error bars 1117 00:44:04.842 --> 00:44:06.377 on the estimates of sea level rise 1118 00:44:06.377 --> 00:44:08.246 and help society plan. 1119 00:44:08.246 --> 00:44:09.814 >> MICHELLE: And it may surprise you to know 1120 00:44:09.814 --> 00:44:12.817 that so many NASA resources are being used to study the ice, 1121 00:44:12.817 --> 00:44:14.118 to study the Earth. 1122 00:44:14.118 --> 00:44:15.319 So when people ask you the question, 1123 00:44:15.319 --> 00:44:17.288 "Why is NASA studying ice?" 1124 00:44:17.288 --> 00:44:18.389 What's your answer? 1125 00:44:18.389 --> 00:44:19.724 >> TOM WAGNER: You know, it's a pretty simple answer. 1126 00:44:19.724 --> 00:44:21.058 This is global question. 1127 00:44:21.058 --> 00:44:22.860 You need to measure all the different parts of the system 1128 00:44:22.860 --> 00:44:25.363 at once and you need different technologies to do it, 1129 00:44:25.363 --> 00:44:26.564 and new technologies, 1130 00:44:26.564 --> 00:44:28.299 and that's what NASA excels at, you know. 1131 00:44:28.299 --> 00:44:30.935 And so we build the satellites and the technologies 1132 00:44:30.935 --> 00:44:33.037 and the aircraft to make these kinds of measurements 1133 00:44:33.037 --> 00:44:35.172 and we put people in the field to help pull it together. 1134 00:44:35.172 --> 00:44:37.375 But I should say too, we also work with our partners. 1135 00:44:37.375 --> 00:44:39.043 You know, the National Science Foundation, 1136 00:44:39.043 --> 00:44:42.046 the Department of Energy, NOAA, the USGS, 1137 00:44:42.046 --> 00:44:43.781 they are also all working on this problem 1138 00:44:43.781 --> 00:44:45.183 and we all work together. 1139 00:44:45.183 --> 00:44:47.451 >> MICHELLE: So NASA is studying many different aspects 1140 00:44:47.451 --> 00:44:49.287 of how the oceans are changing, 1141 00:44:49.287 --> 00:44:51.222 and this is something that's happening right now. 1142 00:44:51.222 --> 00:44:53.124 This is something that's going to affect all of our lives, 1143 00:44:53.124 --> 00:44:55.560 no matter how close we actually live to water. 1144 00:44:55.560 --> 00:44:58.596 So on behalf of NASA and all the scientists of NASA, 1145 00:44:58.596 --> 00:45:00.631 one of the things I can say is, 1146 00:45:00.631 --> 00:45:04.302 our Earth is changing, and at NASA, we're on it.