Climate Change and Polar Ice

Narration: Michael Starbin and Waleed Abdalati


00:00:01:17 00:00:52:13 [music] 00:00:55:14 00:01:26:10 Hello everyone, I'm Michael Starobin and 00:01:27:23 welcome to the Goddard Space Flight Center. 00:01:30:15 Earth is a water planet. 00:01:32:20 Water covers more than 70% of our planet's surface 00:01:36:16 and largely governs so many things from climate 00:01:39:16 change to the sustenance of life on earth. 00:01:42:24 What you may not realize is the vital importance 00:01:45:07 played by the solid part of our planet's 00:01:47:18 water inventory. 00:01:49:21 Ice at the earth's poles, largely governs 00:01:52:22 planetary health. 00:01:54:27 NASA studies ice from space with powerful 00:01:57:20 advanced satellites, and that's largely the spark 00:02:01:01 behind today's lecture. 00:02:03:09 Joining us today is Doctor Waleed Abdalati a 00:02:06:22 Glaciologist from the NASA Goddard Space Flight 00:02:08:20 Center and an expert in high altitude glaciers and 00:02:12:13 sheet ice. 00:02:13:27 Waleed's career is marked by nine expeditions to 00:02:17:23 remote Greenland and Canadian Arctic Wilderness. 00:02:22:08 In the last 10 years he's also had leadership 00:02:24:12 positions at NASA, including management of 00:02:27:10 the Cryospheric Sciences Research Program and 00:02:30:02 serving as head of the Cryospheric Sciences 00:02:32:17 Branch at the Goddard Space Flight Center. 00:02:35:27 In 1991 he earned his Masters Degree from the 00:02:39:04 University of Colorado and in 1996 from the same 00:02:42:06 school his PhD. 00:02:44:11 But prior to joining NASA he worked as an engineer 00:02:47:18 in the aerospace industry. 00:02:49:20 I hope you'll welcome Waleed Abdalati as he 00:02:52:00 joins us now at the podium and we discuss, are we 00:02:55:00 waking sleeping giants? 00:02:56:04 Waleed. 00:02:57:01 [applause] 00:02:59:04 Thanks Michael. 00:03:03:00 All right, well thank you very much for being here 00:03:06:05 and I'd like to start with just a couple of words. 00:03:09:12 I do science, I do it here at Goddard Space Flight 00:03:11:29 Center and science is great, it's fun, it's 00:03:14:04 interesting, I think you'll get that as you see 00:03:16:29 what I go through - the presentation that I go 00:03:20:12 through, but more significantly than that, 00:03:22:19 as interesting as the science is to people like 00:03:25:06 me and to some of you out in the audience, the 00:03:28:20 potential of that science really isn't realized 00:03:32:07 until the information has been communicated, 00:03:35:14 the information has been heard. 00:03:37:18 So it's really you in the audience, here, in the 00:03:40:18 audience on the internet, in the audience looking at 00:03:43:08 your IPod's, however you're receiving this 00:03:46:13 information that should be congratulated or feel 00:03:50:18 proud or recognized that you're doing something 00:03:53:12 good simply by listening to the information and 00:03:56:15 hopefully carrying some of it forward. 00:03:58:23 So I'm going to talk about the earth's 00:04:00:04 changing ice cover. 00:04:01:28 The earth's ice is one of the most rapidly changing 00:04:04:28 aspects of the climate system, of the earth's 00:04:08:10 system and I'm going to take you through some of 00:04:11:09 those changes and what they mean for earth and 00:04:14:00 why we care. 00:04:15:09 And I subtitle this, Are We Waking Sleeping Giants, 00:04:18:07 we'll revisit this later in the talk. 00:04:22:05 So I'm going to start with a picture of the moon and 00:04:25:19 the reason I do this is I'm at NASA, I've been at 00:04:29:08 NASA for 12 years and my fascination with NASA 00:04:32:23 started as a child, as a five year old watching the 00:04:35:28 lunar landing, Apollo 11, Neil Armstrong, Buzz 00:04:39:14 Aldrin not far behind him while Michael Collins 00:04:42:22 orbited waiting for his colleagues to safely 00:04:45:09 return to the orbiter so they could go home. 00:04:48:13 And I was transfixed as a child, as every kid in my 00:04:52:05 generation was, just enamored with NASA, the 00:04:55:04 moon, the space program, and in my own little five 00:04:57:21 year old mind I was an astronaut, I was an 00:05:02:08 explorer, right there in the back yard with my best 00:05:05:06 friend Matt Perry. 00:05:06:21 We used to sit in his kitchen, drink Tang and 00:05:10:10 walk that, you know walk, out to the swing set, or 00:05:14:09 our spaceship and we'd climb aboard with much 00:05:18:18 circumstance and we'd swing like kids do. 00:05:22:03 And we were swinging on our spaceship flying 00:05:24:03 through the air and we do, like all kids do, we go 00:05:26:27 out as far as the swing set would go, as high up 00:05:29:14 as it would take us, let go, jump off, go flying 00:05:32:26 through the air and land. 00:05:35:06 Right there on the moon, right there 00:05:36:20 in Matt Perry's backyard. 00:05:38:24 And it was Matt's yard, Matt's Tang, Matt's swing 00:05:41:21 set so Matt got to be Neil Armstrong. 00:05:45:13 I got to be Buzz Aldrin which was 00:05:47:06 great and occasionally there was a third kid who 00:05:50:08 would play with us who we'd let be Michael 00:05:52:24 Collins and the catch was he wasn't allowed to jump 00:05:55:09 off the swing set, he had to just sort of stand 00:05:57:26 there and swing with us. 00:05:59:26 Or swing and wait for us. 00:06:02:29 But we had a great time, great memories and therein 00:06:05:26 began my fascination with space, the space program 00:06:09:29 and as time went on, just a few years later NASA 00:06:13:28 revealed something else to me that was equally as 00:06:16:04 fascinating and in some ways more fascinating and 00:06:19:24 that was an image of the earth in it entirety, the 00:06:22:28 whole beautiful object and I again became transfixed 00:06:29:08 and had tons and tons of questions. 00:06:31:17 You know, why so much of it blue? 00:06:33:19 Why is the land green? 00:06:34:24 Why is some of the land brown? 00:06:36:07 How come this area here is more blue 00:06:37:29 than this area here? 00:06:39:19 Why are the clouds where they are, 00:06:40:26 where were they yesterday? 00:06:41:28 Where will they be tomorrow? 00:06:43:04 I was a pain in the neck, I would pepper my parents 00:06:45:19 with these questions. 00:06:47:00 "Ah, go away, go back to the moon, go play." 00:06:51:18 But really these were powerful questions in the 00:06:54:04 mind of a young child and they remained or even grew 00:06:58:07 more powerful as I got older and eventually went 00:07:02:16 to school with this in mind, went to graduate 00:07:04:27 school and have since made a career of studying the earth. 00:07:08:20 And I show this because when people think about 00:07:10:26 NASA and think about space, it's critical to 00:07:14:11 remember that one of the most important aspects of 00:07:17:03 our portfolio here at NASA is studying the earth, as 00:07:21:05 a planet, as a system, and now I'm going to talk to 00:07:25:06 you about a particularly important aspect of that 00:07:27:24 planetary system, and that's the earth's ice 00:07:30:12 cover in the Arctic and the Antarctic, the polar 00:07:33:20 ice cover. 00:07:34:27 Now to sort of set the mood or the context I'm 00:07:38:01 going to show you a few pictures just to kind of 00:07:40:01 give you a feel for this. 00:07:41:20 These areas are very pristine, very pure, 00:07:45:09 places that humans just haven't set foot. 00:07:48:05 This is a picture from the Antarctic Peninsula. 00:07:52:05 These places are raw, rugged, nature in its most 00:07:55:29 austere form. 00:07:57:14 This is from the northern tip of the Canadian archipelago. 00:08:02:20 These places are vast, they're enormous, ice, 00:08:06:10 hundreds if not thousands of miles in any direction 00:08:09:27 you look. 00:08:11:03 This was a place I called home for a few weeks in 00:08:14:07 2004 on the Peterman Glacier. 00:08:17:12 This is a kitchen tent, the work tent, 00:08:19:09 the sleep tents. 00:08:21:07 This guy snored and as time went on his tent went 00:08:24:25 more and more to the right. 00:08:26:23 This must be early in the field campaign because by 00:08:30:11 the end he wouldn't have been in the picture. 00:08:32:10 The other thing I like about this is I've never 00:08:34:15 in any job I've had, had a better commute, just a few 00:08:38:03 feet from sleep tent to office. 00:08:41:24 These places are humbling. 00:08:43:18 You can't go to a place like this and not feel 00:08:47:08 humbled by what you see. 00:08:49:24 Just the unique character, the natural beauty, 00:08:53:10 absolutely spectacular. 00:08:55:17 These places are beautiful, the way the 00:08:57:18 light interacts with the ice, the high latitudes 00:09:01:18 tend to filter out some of the blue lights leaving a 00:09:04:05 red hue, but at the same time the ice and water 00:09:07:06 tends to preferentially scatter blue lights giving 00:09:10:14 it a blue hue and the competing effects of these 00:09:12:19 are really, really quite spectacular. 00:09:16:13 And these places are changing, they're changing a lot. 00:09:20:16 This is the caving front where the icebergs break 00:09:23:10 off into the sea of the Jakobshavn Ice Stream. 00:09:26:17 You're going to hear me talk a lot about this, one 00:09:28:15 of the fastest glaciers in the world, but the ice 00:09:31:03 flows from the ice stream and from the land high up 00:09:33:29 in the upper left, out into the fjord where the 00:09:37:05 icebergs break off into the sea. 00:09:40:09 And this is a close up of that caving front, so this 00:09:42:24 is a wall of ice, about as tall as a football field is long. 00:09:47:23 So this is about 100 yards high and the helicopter I 00:09:51:04 was in is probably about as big as this black spot 00:09:56:03 here, maybe a little bigger when I took this picture. 00:09:58:22 You can imagine, 50 yards of ice above you, 50 yards 00:10:01:08 of ice below you, you can see the fracture here as 00:10:05:09 this is about to spill into the sea making 00:10:07:29 enormous icebergs and the hundred yards is really 00:10:12:20 the tip of the iceberg, quite literally. 00:10:15:06 It's about ten times as tall as this floating 00:10:21:03 portion, or the area above the water is high. 00:10:23:21 So these areas are remarkable 00:10:26:05 and they're changing. 00:10:27:19 Well does it matter that a place none of you will 00:10:30:21 probably go to, although I hope you can, and I 00:10:32:27 strongly recommend it for any of you, that a place 00:10:36:15 like this is changing? 00:10:37:20 Well it turns out that it does and it does for 00:10:40:02 several reasons. 00:10:41:21 This is the Arctic sea, the Arctic sea ice which 00:10:44:12 is a thin veneer of frozen ocean water at the 00:10:46:22 surface, could be a few inches thick, could be a 00:10:49:24 few feet thick, could be a few tens of feet thick 00:10:52:22 where the ice rafts and ridges onto itself, but 00:10:56:20 generally a few inches to a few feet thick, 00:11:00:25 depending on where you are on the edge. 00:11:03:04 Blankets or caps the arctic ocean and also the 00:11:06:23 Antarctic in the case of Antarctic Sea ice, 00:11:10:17 trapping ocean heat, trapping ocean moisture, 00:11:12:28 separating the ocean from the atmosphere and it's 00:11:15:23 the presence of this sea ice and the formation and 00:11:18:19 retreat throughout the year of the sea ice that 00:11:21:09 effects global climate. 00:11:23:14 Climate worldwide, throughout recorded human 00:11:26:13 history has come to depend on the presence of this 00:11:29:09 ice, this buffer between the ocean and the atmosphere. 00:11:33:06 It also effects ocean circulation by exchanging 00:11:36:02 salt between the ice and the ocean, effecting ocean 00:11:39:27 density, causing the movement of sea water as 00:11:44:00 the dense ocean water sinks. 00:11:45:27 The Greenland ice sheet, it's most obvious 00:11:48:21 contribution to the global earth system is in context 00:11:52:08 of sea level rise. 00:11:53:26 Greenland holds the equivalent of 23 feet of 00:11:56:14 sea level, that if were all to melt or disappear, 00:12:00:06 that's how much the oceans would rise. 00:12:02:21 Antarctica about nine times as much, so there's 00:12:05:16 well over 200 feet of sea level stored in the ice sheets. 00:12:10:11 Now that's not going to disappear anytime too 00:12:13:06 soon, but the question is what's going to happen in 00:12:15:28 the next few decades or the next century? 00:12:18:04 What fraction of Greenland and Antarctica are going 00:12:21:06 to disappear and what does that mean for sea level? 00:12:25:26 Speaking of sea level, one reason we care, I mean 00:12:28:27 it's intuitive, oceans rise, that's bad, but 00:12:31:12 populations tend to be centered or concentrated 00:12:34:25 in coastal regions. 00:12:37:06 Generally low lying coastal regions. 00:12:39:25 But even if it's not low lying, the fact that 00:12:42:01 there's so much coastal erosion as the rising seas 00:12:44:20 lap against the land, poses threats to areas 00:12:48:04 that are not necessarily right at the sea level, 00:12:51:11 and the encroachment of water over barrier 00:12:53:25 islands, over low lying coastal regions makes 00:12:56:27 areas more vulnerable to flooding, to storm surge, 00:13:01:06 as the seas rise. 00:13:03:09 Now this is the most vulnerable part of the 00:13:05:08 United States to sea level rise, the whites show 00:13:08:08 population density, the green is just land area, 00:13:11:15 the blue is water. 00:13:13:00 These are areas that are affected by a one meter 00:13:15:17 rise in sea level. 00:13:17:16 One meter, three feet is not significantly outside 00:13:21:28 the range of predictions for the coming century, in 00:13:24:19 fact it's quite possible we could see this much sea 00:13:28:17 level rise in the coming century. 00:13:31:14 It's not just the United States however, this is a 00:13:34:00 worldwide concern, or an issue of impact worldwide, 00:13:39:11 in particular areas like Bangladesh, or parts of 00:13:42:20 India, some areas where the nations may not have 00:13:45:24 the resources to cope with this rise in sea level. 00:13:50:09 Huge implications, turns out could be a cost 00:13:54:00 worldwide of about a trillion dollars, trillion 00:13:56:23 US dollars as a result of a one meter rise in sea 00:14:00:28 level, impacting 145 million people worldwide. 00:14:06:22 Tremendous societal human economic implications of 00:14:10:28 sea level rise. 00:14:12:19 Finally another reason we care about what's going on 00:14:15:10 in the polar regions is the fact that they're 00:14:17:11 among the most sensitive to climate change and 00:14:20:10 that's because ice is white, it reflects 00:14:23:11 incoming sunlight. 00:14:24:28 As it starts to melt it gets darker or it exposes 00:14:27:28 darker surface below, on land or at sea, and rather 00:14:31:25 than reflect that light, that energy gets absorbed 00:14:35:09 which causes the surface to warm, which causes more 00:14:38:00 ice to melt, which exposes more dark surface, which 00:14:42:01 causes the surface to warm, and so on. 00:14:44:12 It's a self compounding effect or positive 00:14:47:01 feedback we call it, once it starts to happen, it 00:14:50:20 wants to keep on going. 00:14:52:10 Now fortunately nature does a wonderful thing 00:14:54:21 every year, she pushes a reset button and the ice 00:14:58:06 freezes in the winter, snow falls on the land and 00:15:00:27 all is wonderful in the world of ice cover 00:15:04:03 and reflectants. 00:15:05:13 But that's not exactly the case as we're going to hear, 00:15:07:26 as we go through a little further. 00:15:10:14 Now I love this picture for a lot of reasons. 00:15:13:11 You probably picked up just like that that these 00:15:15:12 are graduate students doing graduate work. 00:15:19:09 These are friends of mine actually and I show this 00:15:23:19 and I say to people, you know this says a lot about 00:15:27:04 the challenges of polar research. 00:15:29:07 This says everything about the challenges of polar 00:15:33:08 research quite frankly. 00:15:34:15 And you may look at that and say, yeah, I get that, 00:15:36:12 it looks cold. 00:15:38:14 It looks dangerous, it looks hard to get to. 00:15:41:15 The clothes are ugly. 00:15:42:19 All kinds of things. 00:15:44:19 All of that is true, but that's not what I'm 00:15:48:04 talking about. 00:15:49:10 What this says to me as a scientist, it talks about 00:15:51:24 the challenges or presents the challenges of scale, 00:15:55:23 of perspective, of context. 00:15:59:02 How do you turn a measurement like this into 00:16:01:14 something meaningful about an entire continent? 00:16:05:04 This is temperature data provided by a colleague of 00:16:08:28 mine, Joey Comiso, showing from about 1982 to about 00:16:13:24 2004 the temperature trends on the surface 00:16:17:03 of Antarctica. 00:16:18:07 A lot of the Antarctic surface was actually 00:16:20:21 cooling in that time for reasons I can explain 00:16:23:21 later or off line, but the coastal regions, the area 00:16:27:06 around West Antarctica actually warming 00:16:30:25 quite substantially. 00:16:32:02 Those guys in the last picture were just a little 00:16:34:04 spec on an ice flow right here. 00:16:36:23 What does that information tell you about all of 00:16:39:29 Antarctica, land and sea ice? 00:16:42:16 Quite frankly, not much, until it's coupled with 00:16:46:11 satellite observations, with large scale 00:16:50:10 observations or information about the 00:16:52:13 behavior of the entire region. 00:16:56:00 Context, scale, and perspective, it's this 00:16:58:26 perspective at this scale in the context of all the 00:17:02:01 other changes on earth that really are essential 00:17:05:13 to understanding how the ice is changing. 00:17:08:21 Now this is what I call ice sheets 101, this is 00:17:11:09 your one slide on how ice sheets work. 00:17:14:06 Ice sheets grow when snow falls and not all of it 00:17:17:26 melts, and next year more snow falls and not all 00:17:20:08 melts, and you just build up more and more and more 00:17:23:10 snow until eventually it compresses under its own 00:17:25:19 weight and spreads out to the sides. 00:17:28:15 A colleague of mine Richard Alley likens this 00:17:30:23 to pouring really thick pancake batter on a 00:17:33:09 griddle, you know you build it up in the middle 00:17:35:29 and under its own weight it spreads to the edge and 00:17:38:08 maybe even spills off the griddle as is the case here. 00:17:41:23 So it grows through snowfall, through 00:17:43:25 accumulation, spreads under its own weight, and 00:17:47:10 as the ice gets to the edge, the low lying edge 00:17:49:27 it can melt on the surface and that melt water 00:17:52:07 can run off. 00:17:53:16 It can melt from underneath as it extends 00:17:55:27 into the oceans and the sea water melts it, or it 00:17:58:17 can break off forming icebergs, it can cav icebergs. 00:18:03:00 Now the remarkable thing is in a warming climate 00:18:05:28 all of these processes increase. 00:18:08:23 Melt increases, the flow rate increases and the 00:18:11:22 amount of snow that falls likely increases as warm 00:18:15:08 air can hold more water vapor than cold air. 00:18:18:14 So the question as always been, okay, well how much 00:18:21:15 increase snow fall, how much will increased snow 00:18:25:10 fall offset the increased melt and increased flow? 00:18:28:17 And it's been something that people have working 00:18:30:12 very hard to understand for many years. 00:18:32:25 I'm going to get into that. 00:18:34:24 I want to call your attention now to the 00:18:37:02 Antarctic ice sheet. 00:18:39:20 This is an image, an AVHR image of Antarctica and 00:18:44:13 this is a depiction of what it would look like 00:18:47:02 with all the ice removed, I mean it wouldn't be red 00:18:49:26 and white, but the point here is that the areas in 00:18:53:01 blue are below sea level. 00:18:55:28 So much of Antarctica rests on a bed that's 00:18:59:19 below sea level and in fact west Antarctica which 00:19:04:02 holds the equivalent of about five meters sea 00:19:06:15 level is almost entirely on what we call a soft bed till. 00:19:10:08 A soft deformable bed below sea level. 00:19:14:21 So it's kind of sitting there precariously with 00:19:17:05 the potential to spill into the sea. 00:19:21:20 Antarctica holds the equivalent of 65 meters of 00:19:24:11 sea level, the temperatures are well 00:19:26:05 below freezing, not too much melt in Antarctica. 00:19:29:15 The west Antarctic ice sheet is about five meters 00:19:32:03 sea level and the question is how unstable is this? 00:19:36:17 Well we don't know for sure, but what we do know 00:19:39:22 is this area, which has been dubbed the weak under 00:19:42:17 belly of the west Antarctic ice sheet by 00:19:44:26 Terry Hughes of the University of Maine many 00:19:47:00 years ago is an area around the Amundsen Sea, 00:19:51:00 the Pine Island and Thwaites Glaciers that is 00:19:53:29 sort of the focal point or the locus 00:19:56:24 of potential instability. 00:19:59:09 If it's going to go, it's probably going to go here 00:20:02:15 and what would a collapse look like? 00:20:04:12 Well the glaciers would likely accelerate. 00:20:08:11 The grounding line where the ice flows off of land 00:20:11:19 into the sea would likely retreat. 00:20:14:01 The caving front where the icebergs form would likely 00:20:17:08 retreat and the whole thing would start to sink 00:20:20:07 or thin, depress in surface elevation. 00:20:24:06 We can monitor all of these processes from 00:20:26:28 space, the flow, to some extent the accumulation, 00:20:30:17 the melt rates, the moving of the caving front, the 00:20:33:24 movement of the grounding line, and what are we seeing? 00:20:36:19 Well we're seeing the glaciers accelerate, we're 00:20:40:10 seeing the grounding line retreat, grounding lines. 00:20:43:16 We're seeing the caving fronts retreat and we're 00:20:45:24 seeing significant thinning or shrinking of 00:20:48:14 the ice in these areas. 00:20:50:10 We can't say conclusively that a collapse is 00:20:53:06 underway or beginning and I need to say by collapse, 00:20:56:11 in glaciological terms I don't mean, boom, the 00:20:59:06 whole thing slides off in a week and ocean's rise, 00:21:03:11 you know that's the stuff of horror movies, but I 00:21:07:10 mean over a few hundred years. 00:21:09:00 That's huge if five meter sea level rise occurs in 00:21:14:19 200 years, that's enormous, even if you just 00:21:16:23 assume a linear relationship and two 00:21:19:18 meters a year or something like that. 00:21:22:25 We can't say a collapse is underway, but what we can 00:21:25:17 say is the behavior we're seeing is consistent with 00:21:27:28 collapse and it's got our attention. 00:21:31:15 So let me know call your attention 00:21:33:21 to the Antarctic Peninsula. 00:21:35:21 I mentioned, let's see if the, much of the Antarctic 00:21:40:24 surface has been cooling, but the area around the 00:21:43:17 Peninsula has been one of the most rapidly warming 00:21:45:27 places on earth. 00:21:49:29 This area up here and this is what's called the 00:21:52:08 Larsen B, or what was called the Larson B Ice Shelf. 00:21:56:25 Been there about 10,000 years, about 700 feet thick. 00:22:02:08 This is an area about the size of the state of Rhode 00:22:03:22 Island and for reasons I never understood it seems 00:22:07:06 the standard unit of measure for icebergs is 00:22:09:11 small New England states. 00:22:11:11 This is Rhode Island. 00:22:15:01 Watch this now, 700 feet thick, 10,000 00:22:18:12 years old, this happened in 2002, this is January 31st, 00:22:23:24 few days later, a month later, a couple days 00:22:26:16 later, and about a week and a half after that. 00:22:30:01 About six weeks time this whole bunch of ice just 00:22:34:27 disappeared, just catastrophically broke up. 00:22:39:01 And this was floating ice, we didn't know it could 00:22:41:12 happen this fast, over this large a scale and 00:22:44:07 this fast, until we watched and the satellites 00:22:47:11 enabled us to watch. 00:22:48:17 Well this was floating ice, so as it broke up it 00:22:51:20 didn't really increase sea level, it's kind of like 00:22:54:22 when you have a glass of water with ice in it, once 00:22:57:00 your ice is floating, when it melts your water level 00:22:59:18 does not rise. 00:23:03:06 But the removal of this buttress, or this barrier 00:23:06:00 to flow resulted in the acceleration of all the 00:23:09:03 glaciers that fed it. 00:23:12:05 So in fact one glacier, the Crane accelerated by a 00:23:15:12 factor of eight in response to the removal of 00:23:18:02 this ice. 00:23:19:07 So all of this ice all of a sudden just started 00:23:21:11 flushing into the sea, very, very rapidly. 00:23:24:18 Now that doesn't go on forever, the ice adjusts 00:23:27:15 to new boundary conditions, but what it 00:23:29:05 said very conclusively is there is a quick link 00:23:32:18 between today's climate and the stored ice on the 00:23:35:15 ice sheet. 00:23:38:15 Again, the start of the period and the end of the 00:23:40:22 period, very rapid loss of ice. 00:23:44:03 Now I'm going to take you to Greenland, the 00:23:46:19 Jakobshavn ice stream, I've spent a lot of time 00:23:49:02 on this ice sheet, mostly here, which is quite 00:23:53:03 lovely, recommend it to anyone. 00:23:55:13 This is the Jakobshavn ice stream, now this is going 00:23:57:27 to pause for a second and you're going to see these 00:24:00:04 blue dots in the image. 00:24:01:19 These are melt ponds, they're undulations in the 00:24:04:15 surface of the ice sheet in which melt water 00:24:07:18 accumulates and forms these melt ponds, I'll 00:24:10:03 talk more about that in a couple of slides, but for 00:24:12:18 now, we're going to zoom into the main ice stream 00:24:15:17 which flows here and out to here. 00:24:19:06 This is the fjord where the icebergs flow out to 00:24:21:29 the sea. 00:24:23:03 This is the main ice stream and we use 00:24:24:26 satellites to track the velocities. 00:24:26:25 You see the mainstream, the tributary, and what we 00:24:29:15 call draw down where ice gets entrained into the 00:24:32:19 main flow, the main ice stream. 00:24:35:27 Icebergs cave here, flow out to the sea, this area 00:24:40:05 is floating, this is broken up ice, this area 00:24:43:09 is on land. 00:24:44:20 And in about 2000 after being stable for 50 years, 00:24:48:27 2001 this caving front where the icebergs break 00:24:52:14 off to the sea started to retreat about a mile a 00:24:56:14 year so that in five years it retreated five miles 00:25:02:24 which was the equivalent of the preceding 100 years. 00:25:07:16 Much more rapid change, you can see the historic 00:25:10:17 record here, the new record here, much more 00:25:13:17 rapid change. 00:25:14:23 Well what happened? 00:25:16:10 This, the Jakobshavn ice stream, one of the fastest 00:25:21:04 glaciers in the world, moving about four miles a 00:25:22:23 year, doubled its speed. 00:25:25:18 So those flow vectors, those lines you saw, 00:25:28:24 started going twice as fast and now you remember 00:25:31:19 that draw down, that area where ice gets entrained 00:25:37:08 in the main flow, well if you double the speed, you 00:25:41:15 pull in a whole lot more ice. 00:25:43:21 Now a colleague of mine likens this to, Ian 00:25:46:25 Joughin at the University of Washington, squeezing a 00:25:49:24 tube of toothpaste when there's dried toothpaste 00:25:51:22 at the end, you get kind of a little bit out. 00:25:54:08 You clear away that caked on toothpaste, squeeze it 00:25:56:23 again and you just get a good fast flow of toothpaste. 00:26:01:28 That's what's happened in here, that floating ice 00:26:06:00 has been a barrier to flow. 00:26:07:13 It's been cleared out, and out goes the ice and as 00:26:10:20 this ice gets flushed out to the sea, this whole 00:26:13:12 area starts to sink, starts to thin. 00:26:16:16 What you're looking at here is elevation data 00:26:19:18 from the ICESat Mission, the ice, cloud, and land 00:26:22:16 elevation satellite, measures the topography of 00:26:25:06 the ice. 00:26:26:12 Reds are slight growth and blues and purples are 00:26:29:22 large thinning. 00:26:31:11 So you can see the whole drawdown, the whole 00:26:33:19 draining of ice in this area in response 00:26:36:18 to that acceleration. 00:26:39:06 It's not just there though; it's all along the 00:26:40:26 southeastern coast of Greenland and part of the 00:26:43:24 Northwestern Coast of Greenland. 00:26:45:15 This is happening all over the ice sheet. 00:26:49:10 Now think about that waking sleeping giants comment. 00:26:52:26 As ice around the perimeter melts, the 00:26:55:04 glaciers are all, or nearly all accelerating. 00:27:01:01 This is an actual movie taken by a guy named Jason 00:27:05:26 Amundson at the University of Alaska in 00:27:07:24 Fairbanks of the caving at the front of Jakobshavn 00:27:11:18 Ice Stream. 00:27:12:28 This is a 20 minute time lapse, condensed for your 00:27:15:23 viewing pleasure, and this is taller than the Empire 00:27:20:21 State Building as you'll see right here, and again 00:27:23:28 the tip of the iceberg. 00:27:26:12 And about as big as a small city block, a huge 00:27:28:29 amount of ice just breaking off, falling out 00:27:32:20 to the sea and in a steady state condition this 00:27:35:22 breaks off backwards but the ice flows forward and 00:27:38:24 the caving front stays about where it is, but in 00:27:41:08 Jakobshavn it's been losing more than it's been 00:27:44:05 replenishing and this is largely contributing to 00:27:48:27 the acceleration of the glacier flow. 00:27:51:10 Well it isn't just the ice speed that's increasing; 00:27:54:11 the amount of melt is increasing as well. 00:27:56:17 When I was in graduate school, when I wasn't out 00:28:00:22 sitting on one of those ice flows or out on the 00:28:03:09 ice sheet, I figured out a way to track melt from 00:28:07:01 space, determine how much it's melting. 00:28:09:09 And this is a graph from the year to year melt 00:28:11:12 variability, this is a figure showing the areas 00:28:14:23 that recently have been experiencing surface melts 00:28:17:18 on the Greenland ice sheet. 00:28:19:08 Melt has gone up about 30% in the last 29 years and 00:28:22:23 the big question is what happens to all of that 00:28:25:02 melt water? 00:28:26:17 Well remember the melt ponds, the accumulation of 00:28:29:21 melt water. 00:28:33:05 There are hundreds of them along the western flank of 00:28:34:24 the ice sheet and parts of the east. 00:28:37:11 They can drain very rapidly. 00:28:41:00 They're kilometers wide or a few miles wide in some 00:28:43:19 cases, and meters or 10, as much as 20 feet deep in 00:28:48:06 some areas. 00:28:50:16 Just water sitting there. 00:28:53:26 This is a picture of a melt lake, just for 00:28:56:20 context and the close up of one of the crevassed areas. 00:29:02:01 The melt water fills these basins, these undulations, 00:29:04:20 eventually it builds up, there's enough pressure 00:29:06:28 that the water finds a way through these tunnels or 00:29:09:26 moulins as they're called, into the ice, to the 00:29:12:26 bottom of the ice through a quarter mile, half mile, 00:29:17:09 three quarters of a mile in some cases, of ice. 00:29:20:18 It flows along the interface between the ice 00:29:23:07 and the bedrock, lubricating that 00:29:25:04 interface, causing the ice to accelerate in the 00:29:27:29 summer time. 00:29:29:10 In some cases this ice goes twice as fast in the 00:29:31:27 summer during high melt years as it does in the winter. 00:29:36:13 So the melt is kind of, I'll let you watch that again. 00:29:38:22 The melt is kind of a double or triple whammy. 00:29:43:17 As the melt increases, the ice sheet will shrink by 00:29:48:06 melt water running off to the sea, just direct loss 00:29:50:29 of water. 00:29:52:08 It will continue to shrink by the summer acceleration 00:29:57:10 induced by this melt water spreading on the bottom. 00:30:00:06 And it will also continue to shrink as the buttress 00:30:03:07 or barriers to flow at the margin melt 00:30:05:23 in the coastal region. 00:30:06:29 So it's not simply, it gets hotter, there's more 00:30:10:12 melt, the ice shrinks. 00:30:11:27 There are multiple mechanisms, some of them 00:30:14:05 potentially very unstable at work here, all 00:30:17:12 contributing to the erosion or loss of the ice sheet. 00:30:22:08 This is what one of those things looks like where 00:30:25:16 the melt water flows down into the moulin or into 00:30:29:20 the tunnel. 00:30:32:03 This is the mouth of the moulin, and this is sort 00:30:34:07 of a network of streams as water starts to run in. 00:30:36:29 Once, you know this was likely a whole area that 00:30:40:19 was a lake and once the drainage occurs the water 00:30:43:02 forms these channels and over time some of these 00:30:46:07 channels can get quite large as this water erodes. 00:30:50:20 The acceleration, the increase melt changes in 00:30:52:27 accumulation, the nature of the flow, they all have 00:30:56:09 some topographic expression. 00:30:58:20 So NASA, to understand this, one of the 00:31:01:19 satellites we've launched is called ICESat, the 00:31:04:02 ice, cloud and land elevation satellite. 00:31:07:01 And it's a satellite, flies along, fires laser 00:31:09:11 pulses at the surface, this is Antarctica here, 00:31:12:29 measures the travel time of the laser pulses and 00:31:15:09 from that we can figure out how tall or figure out 00:31:20:02 the elevation of the ice and when we stack these up 00:31:22:24 over time. 00:31:24:15 I'll let you watch it again. 00:31:25:27 We stack these up over time we get a three 00:31:28:29 dimensional depiction of the ice cover. 00:31:32:09 When we watch the three dimensional structure of 00:31:34:17 the ice change in time, we get the elevation change. 00:31:38:19 We can figure out, I'm going to pause it in a 00:31:40:24 second, we can figure out where the ice is growing, 00:31:44:09 where it's shrinking, and the rate and nature of 00:31:47:25 that shrinkage and growth, actually a little further, 00:31:51:05 tells us what's causing the changes, flow, melt, 00:31:55:07 accumulation, and you can see here we're off the ice 00:31:58:10 sheet onto the sea ice. 00:31:59:18 We can measure the surface of the ice sheet, the 00:32:01:07 surface of the sea ice, the surface of the water, 00:32:04:10 to help us understand how thick the sea ice is 00:32:08:08 actually by differencing it from the surface 00:32:10:17 of the water. 00:32:12:04 So this topographic information helps us 00:32:14:25 figure out how and why the ice is changing, and I 00:32:18:06 come back to the image of Greenland, you see this 00:32:20:19 little bull's eye where Jakobshavn accelerated? 00:32:23:22 You see similar behavior in the east coast and in 00:32:27:00 the north. 00:32:28:07 We start to get two things, an assessment of the 00:32:30:21 contribution of the ice sheet's change to sea 00:32:32:28 level, and we start to get an understanding of the 00:32:35:22 mechanisms that are driving that change. 00:32:38:01 Again, red is slight growth, slight thickening 00:32:42:00 as snow fall accumulates. 00:32:44:00 Blues and purples are large thinning, 00:32:47:12 big changes. 00:32:48:17 Another tool we use to understand the ice is 00:32:50:28 called GRACE, the Gravity Recovery and Climate Experiment. 00:32:53:22 These are two satellites that fly along with a 00:32:55:25 certain distance between them and when they reach a 00:32:58:11 gravity anomaly like an ice sheet, if we pretend 00:33:01:10 my computer is an ice sheet, the speed of the 00:33:04:11 satellite changes as a result of that gravity 00:33:07:07 anomaly, so that when the first one reaches that, 00:33:11:09 flies over that heavy mass it will accelerate and 00:33:14:03 then when the second one reaches it will 00:33:15:15 accelerate, so the distance here is the same 00:33:18:11 as the distance here, but the separation here tells 00:33:21:19 us how big this mass is underneath, 00:33:24:16 or how that's changing. 00:33:26:04 And this is just an example of applying this 00:33:28:16 to the Alaskan glaciers, all you need to take away 00:33:31:16 from here is that the yellow is an area of 00:33:34:19 slight growth and the blue is an area of very large 00:33:38:15 loss, the shedding of this ice, the wastage of this 00:33:42:16 glacier ice to the sea in the Alaskan glaciers. 00:33:47:00 An important thing, a theme emerges here. 00:33:49:25 The losses seem to be very large, the gains seem to 00:33:53:15 be very small. 00:33:54:20 The loss is consistently outweighing the gains. 00:33:58:07 I want to turn your attention now to Arctic 00:34:00:10 sea ice, remember I said a thin veneer of frozen sea water. 00:34:04:17 The Arctic sea ice has been changing and it's 00:34:06:25 been changing a lot. 00:34:08:02 This sort of depicts how thin it really can be and 00:34:11:17 how it can sort of acts as a buffer between the water 00:34:14:29 and the atmosphere. 00:34:16:20 The ice grows in the winter, shrinks in the 00:34:18:26 summer, and grows in the winter and so on. 00:34:20:13 I want you to look at the summer minimum here and 00:34:23:12 the winter maximum here. 00:34:25:18 Again the summer minimum when it's 00:34:26:20 at its smallest point. 00:34:30:13 This summer minimum, what we call the perennial ice 00:34:32:25 cover, this is the thick hearty ice, the stuff that 00:34:35:21 survives the summer melt, says a lot about the state 00:34:39:15 of the Arctic climate and a number of people in 00:34:43:03 academia and here at Goddard Space Flight 00:34:45:27 Center, Joey Comiso again in particular have been 00:34:49:07 tracking the changes of this ice cover in time and 00:34:52:21 if you watch it in time, this is the date on the 00:34:55:00 bottom, 1979 to 2005, your eye should be able to 00:34:59:11 discern that this ice has been shrinking. 00:35:02:14 From 1979 to 2005 it's been shrinking quite a 00:35:07:12 bit, almost 10% per decade. 00:35:10:16 This is the early part of the record and the late 00:35:13:04 part, so you can see a sizable amount is lost and 00:35:16:07 in 2005 we're especially concerned about the rate 00:35:19:27 of loss of ice cover. 00:35:22:08 And then 2007 came. 00:35:24:04 So this was the previous 2005 minimum, 2007 lost 00:35:29:04 23% more ice, or had 23% less ice than 2005. 00:35:36:12 Compare that to the overall average, this is 00:35:38:28 an area about the size of the continental United 00:35:40:22 States and you can see tremendous loss of ice cover. 00:35:47:10 It's kind of an interesting and somewhat 00:35:49:29 telling story and that is, if you look right here, 00:35:54:01 this is the Northwest Passage through the 00:35:56:20 Canadian Archipelago. 00:35:59:12 People have been searching for a navigation route 00:36:01:25 through there, or hoping for one for years. 00:36:04:10 In 1905, I should say in 1903, '04, '05, Roald 00:36:10:03 Amundsen who was the first to reach the South Pole, 00:36:14:28 sailed across this, traversed the Northwest Passage. 00:36:18:02 Took him three years and it followed dozens of 00:36:20:14 failed attempts, sometimes tragically. 00:36:24:16 In 2007 a 76 year old retired hog farmer from 00:36:29:16 Minneapolis sailed this in 73 days. 00:36:34:24 Things are changing, it's a different world out there. 00:36:39:16 We don't know if 2008 is going to be worse, better, 00:36:43:03 who knows. 00:36:44:10 But what we do know is that as this ice starts to 00:36:46:04 disappear even when nature pushes that winter time 00:36:49:13 reset button, it doesn't quite replace it with the 00:36:53:10 same thick ice that takes years to build up, it 00:36:56:19 replaces it with a thinner, more vulnerable 00:36:59:13 ice cover so the tendency or the potential for the 00:37:03:05 decay or the rapid loss, just keeps increasing. 00:37:08:21 Again it's a self compounding affect. 00:37:11:07 This is very telling, this is observed changes in 00:37:15:07 Arctic Ice Cover. 00:37:16:29 These are what the models predicted, 16 different 00:37:20:12 climate models, or actually 14 I think, but 00:37:24:02 most of the models used in the IPCC assessment, if 00:37:28:23 you take the ensemble average and the 00:37:30:21 variability about them, you get the blue here. 00:37:34:01 Reality has actually been much worse. 00:37:36:15 These models are conservative and it turned 00:37:39:01 out that at the end of 2007 we're about where the 00:37:41:29 models predicted we'd be in 2050. 00:37:45:06 We're early, we're ahead of schedule and that's not 00:37:47:20 always a good thing. 00:37:49:09 So it raises questions about the rate of decline 00:37:52:09 and the implications for climate. 00:37:54:08 One of the reasons the models have problems is 00:37:58:21 there's very little thickness information on 00:38:02:02 the sea ice and I mentioned the ICESat 00:38:04:01 mission and the Europeans will be launching a 00:38:07:13 mission called CryoSat in 2009, designed to measure 00:38:11:05 the thickness, but in the case of ICESat, the laser 00:38:14:14 beams, you remember the animation, strike the 00:38:17:15 surface of the ice, surface of the water, the 00:38:19:27 surface of the ice, and from that we can determine 00:38:22:00 what's called free board height, the height of the 00:38:23:26 ice and snow above the water and from that we can 00:38:26:27 estimate the thickness. 00:38:28:17 So ICESat has been providing 00:38:30:01 thickness information. 00:38:31:28 This is the thickness of the ice in the fall of 2003. 00:38:36:25 Blue is about one or two meters thick. 00:38:39:03 Reds and yellows about three or four meters thick. 00:38:42:09 You see in 2007 the thin stuff was gone, the thick 00:38:47:07 stuff got very thin. 00:38:50:02 So there's a lot more ice in the Arctic now that 00:38:52:27 looks more like the vulnerable ice of 2003. 00:38:56:28 So what's in store? 00:38:58:19 We don't know for sure, but there's sort of a 00:39:01:05 preconditioned set up to more substantial and more 00:39:05:06 rapid loss of ice. 00:39:07:09 So let's go a little further out in the future 00:39:10:20 and envision an ice free arctic which is very 00:39:13:04 likely in our future. 00:39:15:21 Maybe it's 10 years out, maybe it's 50 years out, 00:39:18:12 we don't know, but as the ice shrinks these things happen. 00:39:22:09 More heat is absorbed by the planet. 00:39:24:18 There's the potential for new climate patterns. 00:39:27:10 There are changes in wildlife habitat and 00:39:29:20 ecosystem structures. 00:39:31:19 Trans-pole shipping becomes possible via the 00:39:34:05 northwest or northeast passage as is shown here. 00:39:38:25 Getting goods from Asia to Western Europe via the 00:39:42:08 pole is much cheaper than the southerly route and up 00:39:48:01 through the Suez Canal. 00:39:50:12 Significant economic impacts potentially. 00:39:53:22 Improved access to resources. 00:39:55:16 There are resources in the Arctic, the Arctic Ocean, 00:39:58:26 at the bottom of the Arctic Ocean. 00:40:00:27 Get rid of the ice, access improves. 00:40:03:18 Increased security issues. 00:40:05:08 We will no longer have a frozen northern border, we 00:40:08:04 will have a navigable northern border 00:40:10:28 in North America; raises new security issues. 00:40:15:18 Other recent changes, high latitude surface 00:40:18:29 temperatures have been warming more than the rest 00:40:21:15 of the earth. 00:40:23:10 A lot of Antarctica has been cooling on the 00:40:25:10 surface but that's changing and there are 00:40:27:11 reasons for that but as the globe continues to 00:40:30:17 warm, Antarctica is starting to catch up in 00:40:33:13 that way. 00:40:34:21 Permafrost frozen soil is melting, releasing methane 00:40:38:21 which is a green house gas. 00:40:41:09 Arctic sea ice is melting sooner. 00:40:44:08 Lake and river ice is breaking up sooner, snow 00:40:47:21 is melting earlier. 00:40:50:25 Ocean and atmospheric circulation is changing. 00:40:55:13 I want to point out with the Arctic Sea Ice 00:40:58:01 shrinkage, that multi year perennial ice cover is 00:41:01:04 shrinking now about 10% per decade, the ice in 00:41:05:00 Antarctica is actually growing at about 1% per decade. 00:41:10:07 So again, large losses, small gains. 00:41:14:02 The losses seem to be significantly larger on 00:41:16:22 land and sea than the gains we're finding. 00:41:21:16 If we look now at the record in the ice core, 00:41:24:04 I'm just about done here, there's a climate record 00:41:26:29 held in ice cores. 00:41:29:03 They trap past climate either in the air in the 00:41:32:11 bubbles in the ice, or just the chemical 00:41:34:06 structure of the ice itself. 00:41:36:24 If we go back 400,000 years, we've been warm before. 00:41:41:14 This is part of the natural ice age cycle, 00:41:44:07 there's about 100,000 year periodicity rapid warming, 00:41:47:26 slow cooling, rapid warming, slow cooling, and 00:41:50:11 so on. 00:41:51:17 What's notable about this is that the warming which 00:41:54:09 is red precedes the carbon dioxide levels. 00:41:58:07 As the earth warms, carbon dioxide is released from 00:42:02:27 the oceans and CO2 goes up. 00:42:07:14 We're at a place now where not only is carbon dioxide 00:42:11:02 much higher than it's been in the past, but it hasn't 00:42:14:29 been caused by a warming. 00:42:17:29 It's not the release of CO2 that's stored in the 00:42:20:21 ocean, it's been caused by the industrial revolution 00:42:25:07 and human effects. 00:42:26:18 So we're at a place in time now where the CO2 is 00:42:29:15 preceding rather than following the warming and 00:42:33:01 it's a different structure which then leads to 00:42:36:17 questions about climate stability. 00:42:40:22 We see sort of a self correction as the earth 00:42:43:26 and the sun orientation changes on many thousands 00:42:47:08 of years scales, but when we talk about climate 00:42:50:13 stability the big question that arises is are 00:42:54:06 climates stable, or are they unstable. 00:42:57:23 A stable one, a stable system of any kind is one 00:43:00:16 that if you perturb it a little bit it will return 00:43:02:21 to its original state, like a marble in a bowl. 00:43:06:02 You nudge it a little, it will swirl around, but it 00:43:07:28 will come back to the bottom of the bowl. 00:43:10:12 Turn the bowl over, put the marble on top, you now 00:43:12:15 have an unstable system, you nudge it a little, it 00:43:15:08 will move away from that state. 00:43:17:20 So the question with climate is, okay we've 00:43:21:28 been in a pretty stable regime here, we've been in 00:43:25:13 a pretty stable situation, we've nudged it a little, 00:43:27:29 it's come back. 00:43:30:07 Are we pushing it to some new state? 00:43:34:05 We don't know. 00:43:35:09 These are the big questions with CO2 forcing 00:43:39:13 green house gases in general. 00:43:41:14 So in summary, space based observations, remember 00:43:45:00 those two guys on the ice flow, provide a critical 00:43:48:00 perspective and context for understanding how the 00:43:51:16 ice is changing. 00:43:53:03 Glaciers and ice sheets are contributing to sea 00:43:55:14 level rise at an increasing rate. 00:43:58:25 I didn't go too much into it, but if we look at the 00:44:00:06 90s compared to now, there is more ice being put into 00:44:03:23 the oceans than there was back then. 00:44:06:10 Large parts of the ice sheet, large areas are 00:44:08:21 growing a little. 00:44:11:26 Parts of the margins are shrinking a lot and the 00:44:14:27 losses are significantly outweighing the gains. 00:44:17:28 Glaciers and ice sheets respond quickly to changes 00:44:20:13 in climate. 00:44:22:05 Doesn't take thousands of years like we once 00:44:24:02 thought, it takes days in some cases, hours. 00:44:30:15 Sea ice is declining substantially in the 00:44:32:19 Arctic, much more rapidly than models predict, but 00:44:36:08 it's increasing a little in the Antarctic and the 00:44:39:12 impact of these changes could be large. 00:44:42:02 And then I want to leave you with a couple of thoughts. 00:44:44:21 If you think about that carbon dioxide and 00:44:46:15 temperature curve, climatologically we're in 00:44:51:21 a new place. 00:44:52:27 This is unfamiliar territory for us and the 00:44:55:17 world's ice cover is really responding in 00:44:58:20 significant ways. 00:45:01:17 How we as a society do in the face of these changes 00:45:05:10 depends on three things. 00:45:07:04 How big the changes are, how quickly they come, and 00:45:10:23 our ability to anticipate them. 00:45:13:07 So a lot of us are watching very carefully, 00:45:16:07 working very hard to try and figure out how the ice 00:45:19:14 is changing, why, and what that means for life on earth. 00:45:23:17 We're trying to anticipate the changes, we're trying 00:45:26:01 to anticipate how big and fast they'll be, and 00:45:29:00 trying to assess the impacts of potentially 00:45:31:23 mitigating those changes. 00:45:33:26 But these three bullets really will define how we 00:45:37:22 fair in the future in the face of these changes. 00:45:41:08 And then I want to leave you with one last thought 00:45:43:28 and that is this, come back to where I started. 00:45:46:26 I think of the earth, when I talk to public 00:45:49:13 audiences, as a mosaic of stories, it's a lot of 00:45:52:19 little stories telling one hugely important story and 00:45:56:24 that's the story of the planet earth. 00:45:59:20 I've shared with you the story of the earth's ice 00:46:02:19 cover, I want you to understand that there are 00:46:05:11 many others that sync up with that, that come 00:46:08:17 together that really define where we're going 00:46:12:14 as a planet, as a society and it's crucial, it's 00:46:16:18 crucial that we get that story right and an 00:46:20:25 important step in that is paying attention to what's 00:46:23:22 going on, taking the time to learn what's going on, 00:46:27:03 which is what you're doing today and which is why I 00:46:29:19 really appreciate your attention today, 00:46:33:11 and sharing it with some friends. 00:46:34:29 So thanks for listening to the story of the ice and 00:46:38:20 think about it in the context of the story of 00:46:41:11 the earth. 00:46:42:08 Thanks. 00:46:43:16 [applause] 00:46:48:18 I think in the time we have I'm happy to 00:46:50:29 answer any questions. 00:46:54:17 Okay. 00:46:55:23 And I would like to start with the conclusion that 00:46:57:10 you made, look at the system as you looked at it 00:46:59:22 as a physical system that we are probably able to 00:47:04:25 disturb it's stability. 00:47:07:29 Don't you think that in any physical system if you 00:47:10:14 disturb it, there is a time scale for the response? 00:47:16:07 A time response. 00:47:17:10 I feel like we are disturbing the system by 00:47:21:15 ultra projenic effects, especially CO2 in a very 00:47:25:17 short period of time. 00:47:28:01 Do you think that the system is accelerating and 00:47:31:13 could take some time to respond to compensate for 00:47:33:26 the disturbance? 00:47:35:07 That's a great question. 00:47:36:29 If I can summarize, we put a big forcing on the 00:47:42:16 system, it takes awhile for the system to respond, 00:47:46:09 are there effects that are still coming based on what 00:47:49:08 we've done already? 00:47:51:24 The answer to that is absolutely and in fact I 00:47:56:14 don't remember the exact numbers but if we turned 00:47:58:29 off CO2, green house forcing right now I think 00:48:02:19 for the next 50 years, the oceans aren't done 00:48:05:18 absorbing that so I think for the next 50 years we 00:48:07:21 should expect a resultant warming and an analogy I 00:48:11:17 always use, it sounds silly, but I think it's 00:48:14:05 perfect, is you put a turkey in the oven, turn 00:48:18:11 your oven up to 500 degrees, your turkey gets 00:48:21:10 warmer and warmer and it reaches the desired 160 or 00:48:24:25 180 degrees depending on which FDA standard you 00:48:27:12 choose to adhere to. 00:48:29:07 Turn off your oven. 00:48:31:16 Your turkey will still cook, it will still get hot. 00:48:34:15 You're not adding heat, but it hasn't finished 00:48:37:15 absorbing the heat you put in and so the green house 00:48:40:25 forcing we've done to date has been like cranking up 00:48:43:21 the oven. 00:48:45:05 The earth, and this is a terrible analogy, but the 00:48:47:07 earth is the turkey and even if we stop that 00:48:52:01 influx there will be ongoing absorption 00:48:54:19 of that energy. 00:48:55:28 And it isn't clear where that will ultimately take us. 00:48:59:00 Now some people say, "Well then what's the point, the 00:49:04:06 die is cast so to speak." 00:49:07:08 But it really comes back to this right here. 00:49:13:04 We can still grapple with magnitude and rate and we 00:49:16:14 do need to be prepared for whatever is coming. 00:49:19:20 So it is essential that we figure out how to slow 00:49:24:14 things down, make them less, even if it is going 00:49:27:18 to keep going. 00:49:31:21 There have been some reports of past changes in 00:49:34:25 climate being caused by depressurizing buried 00:49:39:14 methane deposits. 00:49:42:03 Do we know currently of such deposits in existence 00:49:45:16 today, these clathrates in the Arctic? 00:49:49:20 Yeah, the Arctic actually has huge methane deposits 00:49:53:19 in the form of permafrost, both on land and in the 00:49:56:23 ocean and unfortunately a lot of the Arctic where 00:50:03:18 this is stored may be three, four degrees below 00:50:08:13 the melting point and the predicted warming and sort 00:50:12:01 of the average scenario, nothing too harsh, nothing 00:50:14:23 too benign is on the order of seven degrees in these areas. 00:50:19:21 So it's quite likely that these methane deposits, at 00:50:23:29 least a significant portion of them, will be 00:50:26:17 released and will further contribute 00:50:30:14 to green house warming. 00:50:31:21 Methane is actually a more powerful green house gas 00:50:34:27 than carbon dioxide. 00:50:38:29 Again the magnitude, it isn't clear, the rate, it 00:50:42:09 isn't clear, but it's there. 00:50:44:06 You know the system is primed and ready to have 00:50:47:22 all this happen, so these are questions we're 00:50:50:09 grappling with. 00:50:52:11 There's currently a lot of concern in the ocean 00:50:54:21 biology community about the road map for future 00:50:57:21 satellite missions and maybe the lack thereof and 00:51:01:24 budget concerns. 00:51:03:00 What's the future look like as far as satellites 00:51:06:03 in the measurements for your line of work? 00:51:11:08 The future of satellites in general hasn't looked 00:51:18:02 that good for awhile. 00:51:21:24 We had the earth observing system in a concerted 00:51:24:24 effort toward a global, you know an integrated 00:51:28:02 observing system for the earth. 00:51:30:20 We're now really starting to realize the benefits of 00:51:33:22 those observational capabilities but there's a 00:51:37:05 lag between replenishing that capability and ocean 00:51:40:04 biology is certainly one of those areas. 00:51:44:25 There was the decadal survey which was a survey 00:51:50:11 undertaken or led by the National Research Council 00:51:53:01 did, I think a great job of laying out a strategy 00:51:56:17 for how to go forward in earth observation and so 00:52:02:28 it's a ten year plan, or a ten year strategy that 00:52:06:16 lists a number of missions and a sequence for these 00:52:08:27 missions to help us prepare for the future and 00:52:12:05 understand what's happening to the planet. 00:52:14:20 It turns out that one of their top priorities was 00:52:19:01 the changing ice cover because it is changing so 00:52:21:02 rapidly and has such significant climate impacts. 00:52:25:20 So I'm actually, for ice, optimistic, you know 00:52:30:26 they've asked for the ICESat II mission, the follow 00:52:33:15 on to the ICESat mission. 00:52:37:11 Destiny mission which is a radar and lightar mission 00:52:40:25 to measure deformation of earth and vegetation 00:52:44:03 structure but also the flow characteristics of ice. 00:52:47:06 So I think there are pretty good things in 00:52:50:06 store for ice measurements, the question 00:52:52:13 really is how quickly can that be implemented and 00:52:56:19 what about all the other stuff that's in the queue? 00:52:59:16 You know there's a lot of science to be done, we're 00:53:04:06 just learning how the system works and now is 00:53:06:25 the time to be making the investments for the future. 00:53:11:16 I think with that we need to close off but I'd like 00:53:14:04 to thank you for coming and I'd like to thank you 00:53:16:14 for your attention and you know I have probably the 00:53:23:16 most googleable name on the information super 00:53:26:04 highway, so Waleed Abdalati, look for me and 00:53:29:23 I'll answer any of your questions. 00:53:32:05 Thanks. 00:53:33:04 [applause] 00:53:34:22 [music] 00:53:37:10