What will I learn? After taking this course you will have an understanding of Arctic landscapes, how they were formed and how they are changing. You will also learn how scientists from countries around the North are working together to understand how these changes will affect the People of the North and the global community. You will experience a range of scientific topics, up-to-date-methods for understanding our environment, and the current consensus views on the future of the Arctic environment. Do I need prior knowledge? No prior knowledge is needed for this course; participants should only come equipped with natural curiosity and a willingness to invest time in understanding an environmental issue of global concern. The terms and concepts are targeted at an educated public, not specialists, but resources will be provided so those who are motivated can explore some issues in more depth.
Lecture 1. Introduction
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來自 National Research Tomsk State University 的課程
The Changing Arctic
104 個評分
從本節課中
What is the Arctic, where is it and why should we be interested in it?
This module will introduce the INTERACT basis of the course and brief description as well as give different definitions of the Arctic, characteristics of the Arctic, peoples of the Arctic, Ecosystem Services and global connections.
與講師見面
Terry V. CallaghanProfessor of Botany, Honorary Doctor
[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.
