1 00:00:21,240 --> 00:00:24,300 Jane: This is But Why: A Podcast for Curious Kids. I'm Jane 2 00:00:24,345 --> 00:00:28,545 Lindholm. On this show, we take questions from curious kids all 3 00:00:28,545 --> 00:00:32,385 over the world, and we find cool people who can offer answers. 4 00:00:32,865 --> 00:00:37,965 Today, I'm at Solheimejokull. That's a glacier in southern 5 00:00:37,965 --> 00:00:42,405 Iceland. It's been around for 400 to 600 years. We're visiting 6 00:00:42,405 --> 00:00:46,530 it to see what a glacier looks like. But you have sent us a lot 7 00:00:46,530 --> 00:00:50,250 of glacier questions over the years, so we're going to go now 8 00:00:50,250 --> 00:00:53,430 to the University of Iceland to talk with somebody who can 9 00:00:53,430 --> 00:00:55,290 actually explain what they are. 10 00:00:55,720 --> 00:00:57,400 Guðfinna Aðalgeirsdóttir: My name is Guðfinna 11 00:00:57,460 --> 00:01:01,000 Aðalgeirsdóttir. It's a very long Icelandic name. 12 00:01:01,480 --> 00:01:04,120 Jane: As you may have figured out by now, But Why went to 13 00:01:04,120 --> 00:01:07,600 Iceland! That's an island country in the north Atlantic 14 00:01:07,600 --> 00:01:11,800 Ocean, a little closer to Europe than it is to North America. One 15 00:01:11,800 --> 00:01:14,140 of the things we wanted to learn more about while we were 16 00:01:14,140 --> 00:01:18,640 visiting was glaciers. So after walking around, looking at an 17 00:01:18,640 --> 00:01:21,760 amazing glacier called Solheimejokull, we went in 18 00:01:21,760 --> 00:01:24,520 search of someone who could explain this geological 19 00:01:24,520 --> 00:01:28,225 phenomenon to us. But to do that, we had to leave the 20 00:01:28,225 --> 00:01:32,005 glacier go into the capital city of Reykjavik, where we walked to 21 00:01:32,005 --> 00:01:35,245 the University of Iceland and into the bright and sunny 22 00:01:35,245 --> 00:01:39,385 science building. That's where we found Guðfinna 23 00:01:39,925 --> 00:01:42,805 Aðalgeirsdóttir in her office where she works as a professor 24 00:01:42,925 --> 00:01:45,625 when she's not out walking around on glaciers herself. 25 00:01:45,625 --> 00:01:49,090 Guðfinna Aðalgeirsdóttir: So I'm a glaciologist, and I became a 26 00:01:49,090 --> 00:01:53,050 glaciologist because I'm really interested in skiing, and I 27 00:01:53,050 --> 00:01:59,410 found this way of traveling on ice and snow as a job through my 28 00:01:59,410 --> 00:02:03,790 interest and because I found this group of people who were 29 00:02:03,790 --> 00:02:07,750 researching glaciers. So I didn't know that this existed 30 00:02:07,810 --> 00:02:12,655 when I started, but I learned geophysics, so I was interested 31 00:02:12,655 --> 00:02:16,615 in math and physics, and what I do now is I measure the 32 00:02:16,615 --> 00:02:18,715 glaciers, I model them. 33 00:02:19,020 --> 00:02:22,080 Jane: That might sound like she spends her days sculpting models 34 00:02:22,080 --> 00:02:26,520 of glaciers out of air clay or something. But sadly, no. Or 35 00:02:26,520 --> 00:02:30,720 maybe not sadly, because Guðfinna Aðalgeirsdóttir seems 36 00:02:30,720 --> 00:02:35,580 to really like her job. What she means by modeling is that she 37 00:02:35,580 --> 00:02:39,960 uses math and physics to create computer models for glaciers, 38 00:02:40,020 --> 00:02:43,485 which are paired with climate models. Those models can help 39 00:02:43,485 --> 00:02:46,725 researchers figure out what might happen to glaciers under 40 00:02:46,725 --> 00:02:50,085 different conditions over the next many years. And of course, 41 00:02:50,085 --> 00:02:54,825 as a professor, she also teaches students, and she does get to 42 00:02:54,825 --> 00:02:55,425 ski. 43 00:02:55,540 --> 00:02:58,000 Guðfinna Aðalgeirsdóttir: No, I ski a lot, so I take every 44 00:02:58,000 --> 00:03:01,000 opportunity I have. For example, this spring, we were on 45 00:03:01,660 --> 00:03:05,620 Mýrdalsjökull, and then we drive on the glacier, and then I had a 46 00:03:05,620 --> 00:03:10,420 rope, and I could be towed behind the car in that trip. So 47 00:03:10,600 --> 00:03:13,120 then I didn't have to sit in the car, but I was on the skis 48 00:03:13,120 --> 00:03:16,300 behind the car, towed by a rope. And then we traveled to the 49 00:03:16,300 --> 00:03:19,765 measurement location. And then when we gone and we did the 50 00:03:19,765 --> 00:03:22,465 measurement, we drilled the thickness of the snow layer to 51 00:03:22,465 --> 00:03:25,765 measure how much it was snowing during the wintertime, and then 52 00:03:25,825 --> 00:03:31,045 I was towed to the next measuring place on the skis. And 53 00:03:31,045 --> 00:03:33,745 then when everybody went home, I skied down the glacier. So that 54 00:03:33,745 --> 00:03:36,745 was a great ski trip, but a measuring trip at the same time. 55 00:03:37,400 --> 00:03:40,660 Jane: I have to just say, right now, it is not safe for you to 56 00:03:40,660 --> 00:03:44,500 be towed behind a car on skis, unless this is something you're 57 00:03:44,500 --> 00:03:47,380 specifically doing as an adult for your job in a very 58 00:03:47,380 --> 00:03:50,380 controlled way. Do not try that at home. 59 00:03:51,380 --> 00:03:53,120 Guðfinna Aðalgeirsdóttir: Well, that's true, yes. So we should 60 00:03:53,120 --> 00:03:55,580 be very careful, and you have to train a lot to be able to do 61 00:03:55,580 --> 00:03:56,000 this. Yes. 62 00:03:56,000 --> 00:03:59,540 Jane: But wait, we're getting out over our skis. That's an 63 00:03:59,540 --> 00:04:01,880 expression people use to mean "we're getting ahead of 64 00:04:01,880 --> 00:04:05,900 ourselves and might fall over." We haven't really explained yet 65 00:04:05,960 --> 00:04:09,500 what a glacier is. So let's do that now. 66 00:04:09,920 --> 00:04:12,500 Eana: My name is Eana. I'm nine years old. I live in Victoria, 67 00:04:12,500 --> 00:04:14,705 British Columbia, and my favorite season is winter, 68 00:04:14,705 --> 00:04:17,585 because it's close to my birthday, and I love snow. And 69 00:04:17,585 --> 00:04:20,225 my question is, how are glaciers formed? 70 00:04:21,080 --> 00:04:25,580 Kira: My name is Kira. I live in Barrie, Ontario. I am six years 71 00:04:25,580 --> 00:04:29,120 old. How do glaciers get there in the first place? 72 00:04:29,240 --> 00:04:31,040 Jane: What is a glacier? 73 00:04:32,380 --> 00:04:35,140 Guðfinna Aðalgeirsdóttir: That's a good question. So glacier is 74 00:04:35,500 --> 00:04:41,980 ice, and the ice is formed because the precipitation of 75 00:04:41,980 --> 00:04:47,320 last winter didn't melt in the following summer. So that means 76 00:04:47,320 --> 00:04:50,680 that there was a positive mass balance there. This region 77 00:04:50,680 --> 00:04:55,465 gained and when there is a sequence of year where there is 78 00:04:55,465 --> 00:05:00,265 snow left in the autumn, buried then under next winter snow 79 00:05:00,265 --> 00:05:06,145 layer, then that accumulated snow is compacted. And when once 80 00:05:06,145 --> 00:05:10,225 that has become densified, so that the snow that was like 81 00:05:10,225 --> 00:05:13,705 fluffy and flurry in the beginning is compacted into 82 00:05:13,765 --> 00:05:20,050 glacier ice, then it can start to flow. And the flowing happens 83 00:05:20,050 --> 00:05:24,910 because the thickness of the ice is high enough or large enough. 84 00:05:25,210 --> 00:05:29,770 So once the thickness is large enough that the ice can start 85 00:05:29,770 --> 00:05:33,190 deforming under its own weight. And you can think of this as 86 00:05:33,190 --> 00:05:37,870 honey. If you put a honey on the table, and it may be, may be 87 00:05:37,870 --> 00:05:42,535 like a pile, and the pile then kind of floods out because the 88 00:05:42,535 --> 00:05:45,835 thickness is too high for the surface tension, if you like. 89 00:05:46,300 --> 00:05:50,080 Jane: So a glacier is snow that forms on top of land and gets 90 00:05:50,080 --> 00:05:54,820 squished down year after year as more snow falls, and not all of 91 00:05:54,820 --> 00:06:00,040 it melts. Over time, that snow pack gets so heavy and compacted 92 00:06:00,040 --> 00:06:04,500 that it turns to ice, and then that ice starts to move under 93 00:06:04,500 --> 00:06:08,580 the force of its own weight. That is a glacier. And one of 94 00:06:08,580 --> 00:06:11,460 the most important things is that glaciers aren't really 95 00:06:11,460 --> 00:06:14,220 glaciers until they start to move. 96 00:06:14,520 --> 00:06:16,860 Guðfinna Aðalgeirsdóttir: You can have snow packs that are 97 00:06:16,860 --> 00:06:21,800 just sitting there, but as soon as the thickness of that ice is 98 00:06:21,800 --> 00:06:25,940 large enough that the weight of that ice column is really 99 00:06:25,940 --> 00:06:30,500 pushing it to flow and deform under its own weight. And 100 00:06:30,500 --> 00:06:33,200 specifically, if the slope underneath, so the bedrock 101 00:06:33,200 --> 00:06:36,920 underneath is maybe steep, then the glacier can start flowing 102 00:06:36,920 --> 00:06:41,800 downhill, and then it has become a glacier. So it's ice that 103 00:06:41,800 --> 00:06:43,900 flows, and then you have a glacier. 104 00:06:44,620 --> 00:06:47,380 Jane: And glaciers can only form on land, right? We're not 105 00:06:47,380 --> 00:06:49,120 talking about icebergs. 106 00:06:49,960 --> 00:06:52,960 Guðfinna Aðalgeirsdóttir: Well, some icebergs are carved off 107 00:06:52,960 --> 00:06:56,080 glaciers, so they are formed on a glacier. And there are many 108 00:06:56,200 --> 00:06:59,860 icebergs. For example, the Titanic, the iceberg that caused 109 00:06:59,860 --> 00:07:03,960 the Titanic to sink was breaking off Greenland ice sheet. That's 110 00:07:03,960 --> 00:07:06,540 another thing that I find interesting, the glacier ice 111 00:07:06,540 --> 00:07:09,480 flowing off and breaking off in the fjords, for example, in 112 00:07:09,480 --> 00:07:13,260 Greenland, that's the oldest ice, because that has been 113 00:07:13,260 --> 00:07:16,800 formed somewhere way up and has been transported down to the 114 00:07:16,800 --> 00:07:19,560 axis of the glacier and is breaking off. 115 00:07:19,980 --> 00:07:23,780 Jane: So it's almost like a conveyor belt where the new snow 116 00:07:23,840 --> 00:07:26,420 gets buried and goes down and down and down, and then 117 00:07:26,420 --> 00:07:29,840 eventually it comes out at the snout, and that's the older ice. 118 00:07:30,020 --> 00:07:33,140 And that newer snow is pushing down from the top and sort of 119 00:07:33,140 --> 00:07:36,980 pushing that older ice continually downwards or 120 00:07:36,980 --> 00:07:40,400 outwards. How old are glaciers? 121 00:07:40,960 --> 00:07:42,940 Guðfinna Aðalgeirsdóttir: That's very dependent on the location, 122 00:07:43,060 --> 00:07:46,240 like we're in the world, but also we're on the glacier, like 123 00:07:46,240 --> 00:07:49,480 we were saying, the conveyor belt. So the youngest ice is on 124 00:07:49,480 --> 00:07:53,080 the top in the accumulation area, and then the oldest is at 125 00:07:53,080 --> 00:07:58,840 the snout. And the glacier ice in Iceland is probably up to 126 00:07:58,840 --> 00:08:02,860 800, 900 years old. So that's the time that it takes for the 127 00:08:02,860 --> 00:08:06,445 ice to be transported with a conveyor belt that the ice 128 00:08:06,445 --> 00:08:11,425 itself down towards the axis. There are places that are much 129 00:08:11,425 --> 00:08:15,805 older, much, much older. The Greenland ice sheet and the 130 00:08:15,805 --> 00:08:18,805 Antarctic ice sheet. They are much bigger. There are, like 131 00:08:18,805 --> 00:08:23,065 whole continents covered with ice, and the ice in Greenland, 132 00:08:23,065 --> 00:08:29,650 it's about 130,000 years old, and they have found around 1 133 00:08:29,650 --> 00:08:31,870 million year old ice in Antarctica. 134 00:08:32,470 --> 00:08:36,370 Jane: Ice that is a million years old? Imagine putting that 135 00:08:36,370 --> 00:08:40,150 in your glass of water. Just kidding. Scientists do collect 136 00:08:40,150 --> 00:08:43,270 some of that ice, but they don't just let it melt in a glass. 137 00:08:43,810 --> 00:08:47,950 Professor Aðalgeirsdóttir says that ice is like a time capsule. 138 00:08:48,250 --> 00:08:51,835 It contains a record of the precipitation, the snow and rain 139 00:08:51,895 --> 00:08:56,095 that fell a million years ago, and the bubbles trapped inside 140 00:08:56,095 --> 00:08:59,215 the ice are a time capsule telling us about the air a 141 00:08:59,215 --> 00:09:03,175 million years ago, so we can learn a lot about the past from 142 00:09:03,175 --> 00:09:04,015 glaciers. 143 00:09:04,540 --> 00:09:08,740 Coco: Hello. My name is Coco. I'm eight years old. I'm from 144 00:09:08,740 --> 00:09:13,780 St. George, Utah, and my question is: how does algae get 145 00:09:13,780 --> 00:09:15,820 into glaciers and turn them pink? 146 00:09:16,180 --> 00:09:17,980 Guðfinna Aðalgeirsdóttir: Yes, this is a very interesting 147 00:09:17,980 --> 00:09:23,920 question, and the surface of the glacier can't be variable. And 148 00:09:24,340 --> 00:09:27,040 the question about the algae, I don't actually know, but I 149 00:09:27,040 --> 00:09:31,105 think, and that's my wild guess, now. I think that algae are 150 00:09:31,105 --> 00:09:35,305 blown onto the glacier and start growing, and then they can, 151 00:09:36,085 --> 00:09:39,205 well, you can think, well, what can grow on a surface that is 152 00:09:39,325 --> 00:09:44,785 freezing at the freezing point, even, and very cold, and there 153 00:09:44,785 --> 00:09:49,825 is no soil to grow. But apparently those algae quite 154 00:09:49,825 --> 00:09:52,990 like the cold surface, and there may be the solar radiation give 155 00:09:52,990 --> 00:09:56,290 them enough energy to grow, and that causes kind of like a 156 00:09:56,290 --> 00:09:57,250 reddish hue. 157 00:09:57,900 --> 00:10:01,140 Jane: We checked on this, and the color is coming from algae. 158 00:10:01,500 --> 00:10:05,340 The algae itself is green, but it has a secondary red pigment 159 00:10:05,340 --> 00:10:09,120 called a carotenoid. In the summer, the algae can turn on 160 00:10:09,120 --> 00:10:12,780 their red pigments as a protective barrier against UV 161 00:10:12,780 --> 00:10:16,440 radiation from the sun. It's kind of like sunscreen. But this 162 00:10:16,440 --> 00:10:19,620 red color causes the algae to absorb heat instead of 163 00:10:19,620 --> 00:10:23,205 reflecting it, and that leads to glaciers that melt faster than 164 00:10:23,205 --> 00:10:26,625 white ones. Pink isn't the only color you can see in a glacier. 165 00:10:26,625 --> 00:10:30,705 Sometimes a glacier looks blue. The more dense the ice, meaning 166 00:10:30,705 --> 00:10:33,885 it has fewer air bubbles and is packed down under its own 167 00:10:33,885 --> 00:10:38,085 weight, the more likely it is to look blue. Those large, dense 168 00:10:38,085 --> 00:10:41,325 ice crystals are absorbing some wavelengths of light and 169 00:10:41,325 --> 00:10:44,670 scattering the blue light back to your eyes so it looks blue. 170 00:10:45,330 --> 00:10:48,810 Generally speaking, the older the glacier ice, the more likely 171 00:10:48,810 --> 00:10:52,770 it is to appear blue. But glaciers can be other colors, 172 00:10:52,770 --> 00:10:56,790 too. They can be white, blue, pink, brown, black and more. 173 00:10:57,330 --> 00:11:00,210 Guðfinna Aðalgeirsdóttir: In Iceland, that color changes can 174 00:11:00,210 --> 00:11:04,170 be because dust is blown. It's very windy in Iceland and in the 175 00:11:04,170 --> 00:11:08,595 highlands is basically a desert. And our sand, because it's a 176 00:11:08,595 --> 00:11:12,555 volcanic island, our sand is very black. So the black sand is 177 00:11:12,555 --> 00:11:16,995 blown onto the glacier, and that causes like a dark, darkening of 178 00:11:16,995 --> 00:11:20,355 the surface. There can be even sand dust from Sahara on, some 179 00:11:20,355 --> 00:11:25,515 places in the Alps, and that sand is kind of yellowish and, 180 00:11:25,515 --> 00:11:30,240 and then the algae contains the surface color. And anything that 181 00:11:30,240 --> 00:11:33,120 is blown onto the glacier will have an effect. 182 00:11:33,480 --> 00:11:35,820 Jane: The darker the surface of the glacier, the faster it 183 00:11:35,820 --> 00:11:38,820 melts. Speaking of which, when we come back, we'll talk a 184 00:11:38,820 --> 00:11:41,880 little bit about how increasing global temperatures are 185 00:11:41,880 --> 00:11:45,780 affecting glaciers around the world. And did you know you can 186 00:11:45,780 --> 00:11:47,760 find glaciers in the tropics? 187 00:11:49,580 --> 00:11:53,600 This is But Why: A Podcast for Curious Kids. I'm Jane Lindholm. 188 00:11:53,720 --> 00:11:56,900 We're learning about glaciers with scientist and professor, 189 00:11:57,560 --> 00:12:01,220 Guðfinna Aðalgeirsdóttir, a professor and glaciologist at 190 00:12:01,220 --> 00:12:04,400 the University of Iceland. Remember at the beginning of 191 00:12:04,400 --> 00:12:08,000 this episode, when I said I was standing at a glacier? You can 192 00:12:08,000 --> 00:12:11,225 see glaciers from a lot of Iceland. Even though only about 193 00:12:11,225 --> 00:12:15,065 10% of the country is covered by ice, these glaciers are a very 194 00:12:15,065 --> 00:12:18,125 striking feature of the landscape, and some of the 195 00:12:18,125 --> 00:12:21,665 glaciers are pretty easy to walk right up to and touch, like the 196 00:12:21,665 --> 00:12:25,685 one we visited. I asked Professor Aðalgeirsdóttir to 197 00:12:25,685 --> 00:12:28,505 tell us about the glacier we had visited before we went to her 198 00:12:28,505 --> 00:12:32,045 office. It's called Solheimejokull. It looks like a 199 00:12:32,045 --> 00:12:36,110 big pile of dirty black ice and snow tumbling down in between 200 00:12:36,110 --> 00:12:40,070 two valleys and piling up on itself. It actually starts 201 00:12:40,070 --> 00:12:43,310 higher up in the Icelandic Highlands as part of a much 202 00:12:43,310 --> 00:12:48,410 larger glacier, an ice cap called Mýrdalsjökull. That ice 203 00:12:48,410 --> 00:12:51,290 cap is on flatter land and kind of spreads out in all 204 00:12:51,290 --> 00:12:55,370 directions. And Solheimajokull is an outlet glacier, where the 205 00:12:55,370 --> 00:12:57,755 ice is heading downwards toward the sea. 206 00:12:57,000 --> 00:13:00,300 Guðfinna Aðalgeirsdóttir: So Solheimajokull is flowing 207 00:13:00,600 --> 00:13:06,180 towards south, towards the coast in Iceland. And this outlet 208 00:13:06,180 --> 00:13:11,400 glacier is like a long tongue, and it's bending a little bit 209 00:13:11,580 --> 00:13:17,520 down into this valley, and the end of it is now in a lake, and 210 00:13:17,520 --> 00:13:21,945 the lake formed only maybe 15, 20 years ago. I'm not exactly 211 00:13:21,945 --> 00:13:25,905 the same the exact date of it. And that lake is forming because 212 00:13:25,905 --> 00:13:30,585 the glacier is getting shorter. And the glacier is a little bit 213 00:13:30,585 --> 00:13:34,485 like a conveyor belt, and it's transporting the snow 214 00:13:34,485 --> 00:13:38,505 accumulated on the big ice cap, Mýrdalsjökull, down into the 215 00:13:38,505 --> 00:13:42,645 lower region. And the glacier is also like your bank account, a 216 00:13:42,645 --> 00:13:45,390 little bit, that you put something in, in it in the 217 00:13:45,390 --> 00:13:49,110 wintertime. So the snow comes in the winter time and that certain 218 00:13:49,110 --> 00:13:51,570 amount, and we go and measure that in the springtime, how much 219 00:13:51,570 --> 00:13:55,470 was coming into the glacier. And then during the summertime, at 220 00:13:55,470 --> 00:13:59,730 the lower region, and but also high up, is ablation. So 221 00:13:59,730 --> 00:14:05,310 ablation is how much is melting, and the ablation is then also a 222 00:14:05,310 --> 00:14:09,675 certain amount. And then come the bank account that you can 223 00:14:09,675 --> 00:14:12,975 say that mass balance of the glacier, if you take more out 224 00:14:12,975 --> 00:14:15,315 than you put in, the glacier is going to get shorter. 225 00:14:15,720 --> 00:14:19,320 Jane: And solheimajokull has been shrinking recently. 226 00:14:19,840 --> 00:14:23,740 Guðfinna Aðalgeirsdóttir: Yes, since 1995, so now 30 years, 227 00:14:23,980 --> 00:14:28,780 it's getting shorter, sometimes 50, up to 100 meters a year. And 228 00:14:28,780 --> 00:14:34,060 we know this because we go and measure every year the position 229 00:14:34,060 --> 00:14:37,660 of the snout. So we call it the snout where the glacier ends, 230 00:14:38,140 --> 00:14:43,405 and the snout is now in the lake. So it's not only melting 231 00:14:43,765 --> 00:14:48,985 on the surface, at the snout, but it's also breaking off into 232 00:14:48,985 --> 00:14:52,885 the lake. So then that's called calving, because it's kind of 233 00:14:52,885 --> 00:14:56,905 like calf being broken off the of the snout of the glacier. So 234 00:14:57,205 --> 00:15:01,765 so the ablation possibilities are breaking off into the lake 235 00:15:02,065 --> 00:15:04,525 and melting at the surface, because the high temperature. 236 00:15:05,140 --> 00:15:08,320 Jane: given how cold it needs to be for a glacier to form, you 237 00:15:08,320 --> 00:15:11,560 might be surprised to learn you can actually find glaciers in a 238 00:15:11,560 --> 00:15:15,040 lot of places on earth. You can even have a glacier in the 239 00:15:15,040 --> 00:15:20,080 tropics or near the equator, but you need to have more snow that 240 00:15:20,080 --> 00:15:24,940 falls than the snow that melts year after year after year. So 241 00:15:24,940 --> 00:15:28,405 for that to happen in really warm parts of the world, you 242 00:15:28,405 --> 00:15:32,425 usually need to go up. If there are very tall mountains where 243 00:15:32,425 --> 00:15:36,085 the air is cold, even if it's tropical, down below, you might 244 00:15:36,085 --> 00:15:37,465 be able to find a glacier. 245 00:15:37,900 --> 00:15:39,580 Guðfinna Aðalgeirsdóttir: In Africa. There is the Mount 246 00:15:39,580 --> 00:15:43,120 Kilimanjaro, and we find a glacier there that is actually 247 00:15:43,120 --> 00:15:47,380 shrinking quite fast at the moment. But in the tropics, if 248 00:15:47,380 --> 00:15:49,660 you get high enough, you can find glaciers. 249 00:15:49,780 --> 00:15:57,340 Chet: My name is Chet. I'm five years old. Ontario, Canada, and 250 00:15:57,520 --> 00:16:04,765 my question is: why glaciers are formed, and they shape the land? 251 00:16:05,620 --> 00:16:08,740 Jane: Sometimes, where we live in North America, people will 252 00:16:08,740 --> 00:16:11,620 talk about the landscape and say, "Oh, that was formed in the 253 00:16:11,620 --> 00:16:15,460 last ice age when the glaciers receded." And here in Iceland, 254 00:16:15,700 --> 00:16:18,400 we often hear, "this is a landscape that has been shaped 255 00:16:18,400 --> 00:16:23,740 by volcanoes and glaciers." How do glaciers shape a landscape? 256 00:16:25,040 --> 00:16:27,680 Guðfinna Aðalgeirsdóttir: They are really like bulldozers. So 257 00:16:27,740 --> 00:16:31,100 in areas where there is sand underneath a glacier, they're 258 00:16:31,100 --> 00:16:35,240 basically just shoveling the sand like bulldozer in front of 259 00:16:35,240 --> 00:16:39,260 them, and they create what we call frontal moraines. And those 260 00:16:39,260 --> 00:16:43,820 moraines are then like marking of a bulldozer that has pushed 261 00:16:43,820 --> 00:16:48,785 the material in front of it. They also carve the valley. So 262 00:16:48,785 --> 00:16:53,465 valley is V-shaped, kind of like a V if there is only a river at 263 00:16:53,465 --> 00:16:58,205 the bottom that is carving the landscape, but if a glacier then 264 00:16:58,205 --> 00:17:02,945 starts to fill that valley, then it carves and create, kind of 265 00:17:02,945 --> 00:17:08,825 more like U-shape, and it kind of grinds the bedrock underneath 266 00:17:08,825 --> 00:17:12,350 it and transport it. Remember, it's a conveyor belt, so it 267 00:17:12,350 --> 00:17:17,210 transports the rocks that they grounded from the sides. And 268 00:17:17,210 --> 00:17:20,750 then we can see that V-shaped valley haven't seen the glacier, 269 00:17:21,050 --> 00:17:24,470 but the U-shaped valley, those are the valleys that the glacier 270 00:17:24,470 --> 00:17:25,550 has formed. 271 00:17:26,260 --> 00:17:28,900 Jane: And if we think of it as that bulldozer and it's pushing 272 00:17:28,900 --> 00:17:32,380 that material forward, then sometimes it also leaves that 273 00:17:32,380 --> 00:17:35,260 material there, and does that form new hills or mountains? 274 00:17:35,260 --> 00:17:38,920 Because, again, we're thinking of like a bulldozer for a giant, 275 00:17:39,040 --> 00:17:42,040 not a bulldozer that any of us could drive so you could see a 276 00:17:42,040 --> 00:17:46,360 hill or a mountain that was sort of left behind, like pushed over 277 00:17:46,360 --> 00:17:48,520 there, and then just discarded by the glacier? 278 00:17:48,580 --> 00:17:52,525 Guðfinna Aðalgeirsdóttir: Exactly. And this is how we know how big 279 00:17:52,525 --> 00:17:55,765 the Laurentide ice sheet was in North America. And the 280 00:17:55,765 --> 00:17:59,425 Scandinavian ice sheet, how big they were, because we see those 281 00:17:59,425 --> 00:18:04,525 land forms that exactly those bulldozed hills that are then 282 00:18:04,525 --> 00:18:08,005 the leftovers off that big bulldozer that is now gone. 283 00:18:09,140 --> 00:18:12,200 Jane: I think that's kind of amazing to think about someone 284 00:18:12,200 --> 00:18:17,660 like you can go walk outside and see into the past, because you 285 00:18:17,660 --> 00:18:21,320 know how this landscape was formed. And I wonder if in your 286 00:18:21,320 --> 00:18:24,560 head, you can almost picture what it might have looked like 287 00:18:24,920 --> 00:18:27,740 1,000 years ago, or 10,000 years ago. 288 00:18:28,260 --> 00:18:30,600 Guðfinna Aðalgeirsdóttir: Yes, and even shorter distances, 289 00:18:30,600 --> 00:18:34,140 because we see, for example, in Solheimejokull, where you were, 290 00:18:34,320 --> 00:18:37,860 we can see now how big the glacier was because the 291 00:18:37,860 --> 00:18:42,180 vegetation hasn't come yet. So in areas where the glacier has 292 00:18:42,180 --> 00:18:45,960 recently been removed or retreated from, there are not 293 00:18:45,960 --> 00:18:49,680 vegetation yet, but in areas that have been uncovered or 294 00:18:49,680 --> 00:18:53,085 released from the glacier longer time ago, we see that there is 295 00:18:53,085 --> 00:18:58,305 moss and maybe some grass visible. So the landscape is 296 00:18:58,305 --> 00:19:03,465 really telling us how big the glaciers were and how extensive 297 00:19:03,465 --> 00:19:06,645 they were, and that's what we are using to read the landscape 298 00:19:07,185 --> 00:19:13,350 and of course, the climate tells us that we understand this 299 00:19:13,350 --> 00:19:15,990 relationship, that if you get cooler climate, the glacier can 300 00:19:15,990 --> 00:19:18,750 grow, and when it gets warmer, the glacier can shrink. 301 00:19:18,420 --> 00:19:22,160 Jane: And shrinking is What many glaciers are doing right now. 302 00:19:22,227 --> 00:19:26,368 Glaciers are always changing, growing and shrinking over time. 303 00:19:26,434 --> 00:19:30,509 But right now, they're shrinking all over the world, and at a 304 00:19:30,576 --> 00:19:34,783 fast rate, because our climate is getting warmer. Some glaciers 305 00:19:34,850 --> 00:19:38,924 are even disappearing. But if glaciers have gotten bigger and 306 00:19:38,991 --> 00:19:42,531 smaller, appeared and disappeared over the whole long 307 00:19:42,598 --> 00:19:46,271 history of the earth, why do researchers like Professor 308 00:19:46,338 --> 00:19:50,279 Aðalgeirsdóttir think that what's happening to glaciers now 309 00:19:50,346 --> 00:19:53,619 is a problem and not just part of a normal cycle? 310 00:19:53,600 --> 00:19:55,940 Guðfinna Aðalgeirsdóttir: They grow and shrink as a response to 311 00:19:56,000 --> 00:19:59,120 temperature changes and precipitation changes, and they 312 00:19:59,120 --> 00:20:03,620 are very sensitive, actually. But what they also are, they 313 00:20:03,620 --> 00:20:08,300 have a long memory, so they are kind of integrating their 314 00:20:08,300 --> 00:20:15,320 climate over long periods, and their response is telling us how 315 00:20:15,320 --> 00:20:19,325 the climate has been changing. And we see records from 316 00:20:19,325 --> 00:20:22,445 different regions in the world, and and more and more 317 00:20:22,445 --> 00:20:25,205 information from the ice cores, from the big ice sheets, 318 00:20:25,505 --> 00:20:31,685 indicate and sort of confirm this idea of ice ages and and 319 00:20:31,685 --> 00:20:36,065 interglacial periods, so those warmer periods in between, and 320 00:20:36,065 --> 00:20:41,030 those are natural, and those are kind of because of the distance 321 00:20:41,030 --> 00:20:44,450 of the earth to the sun is changing, and that is causing 322 00:20:44,450 --> 00:20:50,810 the ice ages to form. Also the tilt of the earth axis and the 323 00:20:50,810 --> 00:20:56,210 wobbling speed is also changing, and that combination causes the 324 00:20:56,210 --> 00:21:01,790 ice ages and the warmer periods. And those are happening on long 325 00:21:01,790 --> 00:21:06,455 time scales, like 40,000 years and 100,000 years time scales. 326 00:21:06,815 --> 00:21:11,435 So now, if we think of those timescales, like 100,000 years, 327 00:21:12,575 --> 00:21:17,675 and compared to the time since we started burning fossil fuels, 328 00:21:17,975 --> 00:21:23,915 that's only 150 years ago, and also building up that amount of 329 00:21:23,915 --> 00:21:26,660 fossil fuel that we are burning out that takes millions of 330 00:21:26,660 --> 00:21:32,480 years, like the reservoirs that we are using now for our energy 331 00:21:32,480 --> 00:21:38,060 consumptions have been formed over millions of years. And in 332 00:21:38,060 --> 00:21:44,780 the span of 150 years, and I say 150 because often, often we talk 333 00:21:44,780 --> 00:21:49,085 about 1850 as the beginning of the Industrial Revolution, and 334 00:21:49,325 --> 00:21:53,285 when we started having, like fuel engines, and started 335 00:21:53,285 --> 00:21:58,085 burning coal for heating our houses and and fuel and gas. And 336 00:21:58,265 --> 00:22:01,805 of course, there's a lot of technical evolution, really 337 00:22:01,805 --> 00:22:06,125 rapid evolution of technology, and we managed to start flying 338 00:22:06,125 --> 00:22:10,205 between the continents and using a lot of energy. And in that 339 00:22:10,205 --> 00:22:16,370 period, we have emitted by burning the fossil fuels, the 340 00:22:16,370 --> 00:22:21,530 CO2 in the atmosphere, and that is causing the temperature at 341 00:22:21,530 --> 00:22:26,690 the surface to warm up. And now what has been natural and maybe 342 00:22:26,690 --> 00:22:31,010 variable over the different regions in on the surface of 343 00:22:31,010 --> 00:22:34,670 Earth, we are now seeing very clear signals. All the glaciers 344 00:22:34,670 --> 00:22:40,535 in the world are responding. We have already warmed the planet 345 00:22:40,595 --> 00:22:46,055 on average, 1.1 degree. And all the glaciers are telling us that 346 00:22:46,055 --> 00:22:50,315 they can feel that. So the clear signal everywhere, from 347 00:22:50,315 --> 00:22:54,575 Patagonia to Svalbard Icelandic glaciers, the Himalayan 348 00:22:54,575 --> 00:22:57,335 glaciers, and, of course, the big ice sheets in Greenland and 349 00:22:57,335 --> 00:23:01,280 Antarctica, they are starting to shrink. So let's just make that 350 00:23:01,280 --> 00:23:06,080 thought experiment and say the temperature rise stopped at 1.1 351 00:23:06,080 --> 00:23:09,860 degree, the glaciers, and it depends on how... size or the 352 00:23:09,860 --> 00:23:13,880 bit how big the glaciers are, they will take few decades to 353 00:23:13,880 --> 00:23:17,540 adjust. So the conveyor belt has to kind of figure out what the 354 00:23:17,540 --> 00:23:23,345 new size should be, and then they would be about 40% smaller, 355 00:23:23,585 --> 00:23:27,305 or the amount of the volume, amount of current glacier will 356 00:23:27,305 --> 00:23:34,325 be about 40%. If we continue to warm, the more of this ice will 357 00:23:34,325 --> 00:23:39,725 be lost. So the message from the glaciers is really stop the 358 00:23:39,725 --> 00:23:43,985 warming as fast and as soon as possible and as much as 359 00:23:44,030 --> 00:23:44,630 possible. 360 00:23:45,530 --> 00:23:48,230 Jane: There have been agreements made among many countries to 361 00:23:48,230 --> 00:23:51,530 limit greenhouse emissions, the gasses we put into the 362 00:23:51,530 --> 00:23:55,370 atmosphere that are contributing to a warming climate. Countries 363 00:23:55,370 --> 00:23:59,210 have worked to reduce emissions so we can limit that average 364 00:23:59,210 --> 00:24:03,950 climate warming to two degrees. But those agreements don't seem 365 00:24:03,950 --> 00:24:07,295 to be making a difference so far, and countries sometimes 366 00:24:07,295 --> 00:24:10,175 change their mind about what they're willing to do, depending 367 00:24:10,175 --> 00:24:13,775 on who's the president or prime minister or political leader at 368 00:24:13,775 --> 00:24:17,795 any given time. Sometimes, countries or governments even 369 00:24:17,795 --> 00:24:21,095 decide they no longer want to be part of the agreements, like the 370 00:24:21,095 --> 00:24:25,115 United States did at the beginning of 2025 with something 371 00:24:25,115 --> 00:24:29,195 called the Paris Climate Agreement. Pretty much every 372 00:24:29,300 --> 00:24:33,200 scientist agrees climate change is happening at an alarming 373 00:24:33,200 --> 00:24:37,160 rate, and it's going to affect all of us. But governments 374 00:24:37,160 --> 00:24:41,360 disagree about what to do. Professor Aðalgeirsdóttir says 375 00:24:41,360 --> 00:24:44,480 she thinks all countries are going to have to deal with it 376 00:24:44,540 --> 00:24:48,080 one way or another, whether we like it or not, and the ways we 377 00:24:48,080 --> 00:24:51,860 change our policies could wind up happening very quickly as the 378 00:24:51,860 --> 00:24:54,125 climate forces us to think differently. 379 00:24:54,780 --> 00:24:56,760 Guðfinna Aðalgeirsdóttir: Many places are using renewable 380 00:24:56,760 --> 00:25:00,180 energy, and they're called renewable energy because they 381 00:25:00,180 --> 00:25:03,840 are not using their fossil fuels, their coal and oil and 382 00:25:03,840 --> 00:25:07,860 the gas that are burning and emitting CO2 in the atmosphere, 383 00:25:08,280 --> 00:25:11,760 and replacing it with solar energy or wind energy and and I 384 00:25:11,760 --> 00:25:14,280 think we could use tidal energy as well. There are a lot of 385 00:25:14,280 --> 00:25:18,360 energy sources, geothermal, and there are energy sources that we 386 00:25:18,465 --> 00:25:22,545 know how to harness, and we know that they're not emitting CO2, 387 00:25:23,025 --> 00:25:25,965 but it's kind of like comfortable to still use and it 388 00:25:25,965 --> 00:25:29,625 all the systems are built on the fossil fuels. But I think the 389 00:25:29,625 --> 00:25:33,045 decision, once we make the decision to say, "Okay, we 390 00:25:33,045 --> 00:25:37,245 really need to swap," I think that will happen fast. We are on 391 00:25:37,245 --> 00:25:40,845 the verge of transition, and this is why we are talking about 392 00:25:40,845 --> 00:25:44,970 the transition. We really need to move into this renewable 393 00:25:44,970 --> 00:25:48,510 energy regime, because we understand that the regime that 394 00:25:48,510 --> 00:25:53,490 we have had in the last 150 years is both not good for the 395 00:25:53,490 --> 00:25:57,510 climate and it's also not sustainable, because we're going 396 00:25:57,510 --> 00:25:59,790 to run out of those fossil fuels anyway. 397 00:25:59,260 --> 00:26:03,275 Jane: And glaciers are helping us understand the urgency needed 398 00:26:03,345 --> 00:26:07,219 to move in a new direction. That's it for this episode. 399 00:26:07,290 --> 00:26:11,445 Thanks so much to Professor Guðfinna Aðalgeirsdóttir at the 400 00:26:11,516 --> 00:26:15,531 University of Iceland for talking about glaciers with us. 401 00:26:15,601 --> 00:26:19,616 As always, if you have a question about anything, have an 402 00:26:19,687 --> 00:26:23,913 adult record you asking it on a smartphone using an app like 403 00:26:23,983 --> 00:26:27,576 voice memos, then have your adult email the file to 404 00:26:27,646 --> 00:26:31,520 questions@butwhykids.org. But Why is produced by Melody 405 00:26:31,591 --> 00:26:36,028 Bodette, Sarah Baik and me, Jane Lindholm at Vermont Public and 406 00:26:36,099 --> 00:26:40,255 distributed by PRX. Our video producer is Joey Palumbo, and 407 00:26:40,325 --> 00:26:44,411 our theme music is by Luke Reynolds. If you like our show, 408 00:26:44,481 --> 00:26:48,989 please have your adults help you give us a thumbs up or a review 409 00:26:49,060 --> 00:26:53,356 on whatever podcast platform you use. It helps other kids and 410 00:26:53,427 --> 00:26:57,653 families find us. We'll be back in two weeks with an all new 411 00:26:57,724 --> 00:27:00,119 episode. Until then, stay curious!