[MUSIC] Hello, my name is Mark Serreze. I'm a professor in the Department of Geography at the University of Colorado Boulder. I'm also the Director of the National Snow and Ice Data Center and we're all about snow and ice well. I think if we really want to understand the Arctic. What's happening to the Arctic, we first need to understand a little bit about arctic geography. Well the place to start there is to think about the geographic bounds of the art whom we think about the Arctic. What do we really mean by that? Well, there's really two ways in which we can define the Arctic. And the first is that the Arctic is the region north of the Arctic Circle. Which is 66 and a half degrees north. The Arctic Circle defines that latitude at which we have one day of the Midnight Sun. That is 24 hours of daylight. And one day of polar darkness or Polar Night. That's 24 hours of night. So that's one way to look at it. And that's very much just the astronomical definition of the Arctic. But another way to think about the Arctic is that it's the region north of the 10 degree C July isotherm. That is, north of that isotherm is colder in July than 10° C south of that. It's warmer than that. Why that's another good definition of the Arctic is that. That 10 degree July isotherm broadly corresponds to the northern tree line. North of that, it's too cold for trees to grow. South of that, it's warm enough in summer so that trees can grow. This image here shows these two definitions. We see first the Arctic Circle 66 and a half degrees north. Anything north of that is what we would call the Arctic by that definition. But also we also see here that 10-degree July isotherm. Now the thing is that that other definition of the Arctic based on temperature. We would say that in some longitude the Arctic actually extends. Well south of the Arctic Circle, well, another longitudes extends well north of the Arctic Circle. So again, we have two different ways that we can think about Arctic is a geographic region. Which one should we choose really? It depends on the sort of question we might be asking. I think you could really use either. The Arctic has a number of nations that border within it or have land within it. As we might expect, these are called Arctic Nations and there's eight of them. And these are nations with sovereignty over lands that lie within the Arctic Circle. So they're using that that astronomical definition of the Arctic Circle, 66 and a half degrees north. What are those nations? Russia, Russia has a tremendously long Arctic coast line. The United States, because of its coasts along Alaska. Canada, obviously, Iceland. Denmark, because Denmark has sovereignty over the island of Greenland. And Norway, Finland, and Sweden, Nordic countries. Well, these nations form what we call the Arctic Council. This is an intergovernmental form of these Arctic Nations that are focused on Arctic issues. And they have particular concerns with meeting the needs of the indigenous peoples of the north. Well, who lives in the Arctic? Well, the Arctic as we might think, is fairly sparsely populated. So only about 4 million people that live in the Arctic and most of the people there are non-indigenous. That means they came from somewhere else. But there's many indigenous peoples to the Arctic. And they go by many names, the Nenet, the Inupiat. Remember that the Arctic has been peopled for many many thousands of years. Now the Arctic, some people think about the Arctic is just all snow and ice or treeless tundra. And that's far from the truth. Highly varied environments in the Arctic. Now the Arctic is really in its most simple sense, an ice-covered ocean that is surrounded by land. But that's the polar opposite of, if you excuse the pun, of the Antarctic. Which is a high cold ice sheet that's surrounded by ocean. And the Arctic lands themselves are also very varied, mountains, plains, tundra, and forest. It's far from a uniform environment. This picture is showing the Arctic and the Antarctic. The Arctic is on the right and as you can see, it's ice. And that's the area shown in white, basically surrounded by land. Whereas the Antarctic on the left, is this high, cold ice sheet. The Antarctic is much, much colder than the Arctic. And actually is one of our two polar regions. The Arctic is actually the warm one. Well, let's think about these Arctic lands. What do you see? Well, that image on the left, that is snow-covered tundra. That is an area north of the Brooks range actually looking South to the foothills of the Brooks range on the right. That's a picture I took of from the island of Svalbard. And that's on the North Atlantic, way up North about 70 degrees north. And that's a snow-free tundra. So that's a summer environment that you're looking out there. That was taken sometime in July as I recall. But it's many different aspects as well. The Arctic is also very mountainous. That image on the left that I took along the Dalton Highway. That's the Pipeline Road. It's the road that goes all the way from Fairbanks up to the North Slope of Alaska. The image on the right also on that Dalton Highway. And it shows that a lot of the Arctic north of the Arctic Circle is again, it's trees, Boreal forest. So we have to get away from this thinking that Arctic lands are just tundra. That's not the case at all. One of the other remarkable things about the Arctic is that it's underlain by permafrost, perennially frozen ground. Any ground that is below the freezing point for at least two consecutive years is viewed as permafrost. And all the colored areas that you see on that image, that's permafrost. Permafrost has many impacts on the environment. Only certain types of things of trees for example. Or vegetation is going to be able to thrive in a permafrost environment. It has a big impacts on things like river runoff, many different things. So permafrost is really a key aspect of the Arctic environment. Now it would be very remiss without mentioning the Greenland ice sheet. The Greenland ice sheet is one of our planets two ice sheets. The other one's the Antarctic ice sheet. The Greenland ice sheet is the smaller of the two. Now, how much ice is on the Greenland ice sheet or is contained within it, if it all melted? It would be about seven meters of sea level. Now, that's a lot. Actually it pales in comparison to the Antarctic which is about 70 meters of sea level. But 7 meters is still a lot. Well, are we going to lose the end of the Greenland ice sheet? Not really for a long long time, but it is losing mass. It is contributing to sea level rise. And so this is something that scientists are very concerned about. And are looking at very closely. That figure on the left is just a showing of the Greenland ice sheet. At the top of the Greenland ice sheet at the summit. There's over 3,000 meters of ice almost 10,000 feet of ice. The image on the right is just in what we call the Ablation Zone of the ice sheet. Looking out towards some summer melt streams and some melt ponds. But this is an area of intensive research. Turning now to the Arctic Ocean, that figure on the left is shrowing a submarine, actually. A Conning tower of a submarine. This is a submarine that has surfaced through the Arctic Ocean. The fellow on the left there is a carrying a rifle. Because this is a polar bear country. This is a the realm of the polar bear is the Arctic Ocean. The figure on the right someone took that of me some years ago. But it shows that a lot of the Arctic Ocean is actually ice free as well. Again, it's a highly varied environment. But the real thing about the Arctic that has so many scientists alarmed. And very interested is that this is a region in rapid change. It's really the most rapidly changing area on our planet. We know that the Arctic is warming faster than the rest of the planet. This even has a name. It's called Arctic amplification. We know that the Greenland ice sheet is melting down. I mentioned that before. We're not going to lose the entire ice sheet for a long, long, long, long time. That's not going to happen, but it is melting down. And it is contributing to sea level, as are Arctic ice caps and glaciers. It's pretty much a global thing as well. Thawing permafrost. I mentioned that much of the Arctic land area is underlain by permafrost. That permafrost is warming and in places, it's thawing. Now that has a big effect on things like infrastructure and ecosystems. There's another thing out there called the permafrost carbon feedback that a lot of these permafrost areas. There's a lot of frozen carbon in these areas, frozen peat lands and things like that. The concern is as we warm up the Arctic and we thaw that permafrost, the little microbes in the soil become active. And what they do is they breathe out carbon that goes back to the atmosphere as carbon dioxide or methane. But those are greenhouse gases. So if we raise the level of greenhouse gases by thawing permafrost, it makes it even warmer. And more of the permafrost thaws and it becomes even warmer, a nasty little feedback. The shrinking Arctic sea ice cover, the Arctic sea ice cover is shrinking, in all seasons. Most notably at the end of summer. Compared to where we were in the early 1980s in September. Now, we've lost about 40% of it. Now that has big impacts again on ecosystems. But it also has impact on things like the accessibility of the Arctic. As we lose the Arctic, it becomes more accessible to shipping, access to natural resources. So it really is a very big issue, the shrinking Arctic sea ice cover. And what we have to remember Is that the impacts of Arctic change, they're local to global. They can affect all of us. We need to know more about the Arctic change. Why it's changing, how it's changing. And this is where the Mosaic Expedition comes in. Here we're freezing a ship, a number of ships in the Arctic Ocean. And we're going to have scientists from all over the world measuring what's happening to Arctic. Measuring what's happening in the Arctic Ocean, in the Arctic atmosphere. From this information, we'll understand more about how and why the Arctic is changing. We can use this information to develop better climate models. So that we can better predict where the Arctic is going to be headed through the remainder of this century.
