[SOUND] [MUSIC] Welcome to the course on the changing Arctic. In this course, we will try to show you what the Arctic is and its characteristics, both physical and biological and human, and how it's changing. Of course, we all know what the Arctic is, don't we? It's white, it's cold, it's dark, it's harsh, and it's a long way off. It's not that easy. If we try to understand what the Arctic is, it depends on our perspectives. But we can't get away from one basic fact, and that is that the Arctic is defined by the Arctic Circle and daylight. So the Earth goes around the Sun on an annual basis. And, of course, it spins on its axis everyday, giving us night and day, night when it's away from the Sun and day when it's facing the Sun. But when it's spinning on that axis, that axis isn't vertical. Look at the picture. The axis is at an angle. And what that means is if we look at the Arctic night and the winter solstice, that means that within the Arctic Circle, it's dark because that area is always away from the Sun, because of the tilt of the Earth. So, at midday on midsummer's day, the Sun is below the horizon. You cannot see the Sun. The opposite is the summer solstice when the tilt of the Earth is towards the Sun. And then everything north of the Arctic Circle receives energy from the Sun and daylight. So at midnight on midsummer's day, you can see the Sun above the horizon. So that is a fundamental characteristic which determines, and of course, the amount of radiation coming in from the Sun determines the climate and the heat received of the planet. But it's not that easy. That climate regime is modified by ocean currents. And here you see the great conveyor belt, currents which cover the whole world. It's a multitude of currents working together. The reds one are the warm surface currents flowing through the tropics into the Arctic, exchanging heat in the Arctic, and then sinking as cold water and returning back past eastern Canada, and eventually to the Antarctic, and back again into the Pacific and warming up. And that conveyor is going on all the time. What this does is it makes sure that Western Europe is warmer than it would otherwise be, and eastern Canada is colder than it would otherwise be. And the effect is huge. So if we look at the polar bears, these are polar bears at Churchill, Manitoba in Canada. And they are as far away from the North Pole as Helsinki is, and other capitals of Scandinavia and cities in Britain and Russia. The environmentalists and ecologists like myself, we have another definition of the Arctic, which is based not just on the climate regime or latitude is based on the environment that we see. So it's an indirect measure, if you like, and it's the area north of the treeline. Here you see the latitudinal treeline in Siberia. And you can see the forest in the distance, the taiga. North of that is the Arctic tundra. That treeline is responding to temperature, so it's controlled very largely by temperature. So our definition of the Arctic and the tundra is that area north of the latitudinal treeline. That Arctic region in terms of bioclimatic regions is the greatest one on Earth. It covers 30 degrees of latitude from just over 50 degrees north all the way to 84 degrees north, which is the farthest most point of land. And the environments that are captured in that 30 degrees of latitude stretch from the polar deserts of High Arctic Canada and Greenland all the way through the taiga. And here you see the southern taiga in Siberia. Now that description has been very stable in time, static in time if you like, but we have to remember that the Arctic has been changing over thousands and tens of thousands of years. More than 10,000 years ago, we had the Ice Age. And we had vast areas of land, which are now the continental shelves underneath the Northern Sea. And these plains or steppes were covered by giant herbivores like the mammoth and the woolly rhinoceros, and their predators like the saber-toothed tiger. So the Arctic has always been changing. It's characterized by permafrost. And we'll learn more about permafrost later, but this is a state of the ground, frozen state of the ground, which leads to lots of patterning. And we will see how that forms landscapes and also captures carbon over thousands of years. Understanding that carbon, which is a feedback to the climate system, is an extremely important part of our science. And here is one example of research looking at the energy exchange between the changing Arctic and the atmosphere, and the feedback that that will generate, and also the take-up of the greenhouse gases out or contribution of greenhouse gases to the atmosphere. We saw that the Arctic has been changing in the past, through the last ice age, for example. Since then, what has been happening recently is that superimposed on the natural changes we have a man-made change through extra greenhouse gas emissions that have been put in the atmosphere by human activities. And here is a plot of what has happened to our temperature regime between 1960 and 2011. And these aren't observations. They've been interpolated. A computer has put different observations together, so this suggests there are more observations than there actually are. But nevertheless, it demonstrates dramatically that the Arctic is that area of planet Earth which is warming faster than anywhere else. And if we look at the small graphic, then that moves from the Antarctic with a small rate of change through the Equator, which is accelerated change, then into the Arctic or the High Arctic. And there, you see, dramatically, that it is the Arctic which is warming more than anywhere else. Now the changes we see in the physical environment, like the cryosphere, the frozen part of the planet, the ice and snow, respond to physical properties. And their changes are quite predictable and what we would expect. But when we look at the biological changes, we'll see later that they are not at all what we expect. In fact, the changes are much less than we would expect. So the plot here is a plot of vegetation development since 1982, with again the color coding with the dark colors in the maximum rate of change. But in fact, you see lots of areas that haven't changed. And if you look at the top graphics, you see a landscape and vegetation in 1970 Greenland, and below in 2009. And although ponds changed, the vegetation hasn't changed at all. And when we look in between the globe, the map, and the photos you see, the pixels, 12 kilometer pixels, and there again, you see no change. But if we just drop to the bottom pair now, you see what's happening in Swedish Lapland. There you see the pixels show dramatic change, and then you see photos of where trees and shrubs have come in in the last 30 years. So something is going on here which we don't really understand. It is a very complex process, much more complex than the physical parts of the environment. What do these changes mean for people? Well, these changes that we see, the physical environment, the biological environment, they have effects for local peoples, for example, insecure weather and ice conditions that make hunting and traditional foods difficult to gather. And it also affects the global communities through things like sea level rise. But although it's doom and gloom a little bit, there are some opportunities. And we will discuss those in a later episode. The course that you are about to listen to is mainly built on a book produced by a network of Arctic research stations called INTERACT. And that network covers all the Arctic countries and countries neighboring the Arctic territories too. We came together to produce a book of the science at those stations and it's called the INTERACT Stories of Arctic Science. Here is one two-page spread which produces one particular stories, but there are about 60 stories in this book. This course is based on that book. Why do we call it stories? Why isn't this a formal science book? Well, we have learned from the indigenous peoples of the Arctic. And they have passed on their unique tradition and ecological knowledge by telling stories. That's how they passed knowledge from generation to generation to generation. So we are learning from the indigenous people by telling you stories of science so we can pass that knowledge down to you. The stories try to inspire and recruit young generations of researchers because the stories will talk about adventure working on important topics in harsh but exciting conditions. There will also be some stories in the book about unexpected adventures, such as a polar bear at a research station. INTERACT has a process of transnational access, where it funds scientists to go into the Arctic. And it's the stories of those researchers that you will learn from throughout the course. And I wish you luck and enjoyment, and I hope you get inspired and willing to contribute to understanding changes in this beautiful part of the world. >> Which is true? A, effects of climate on snow and ice are as expected and similar to effects on ecosystems. B, effects on snow and ice are not as expected and similar to those on ecosystems. C, effects on snow and ice are as expected, but often contrast with effects on ecosystems. D, effects on snow and ice are not as expected, but effects on ecosystems are expected.
