The Arctic Ocean surrounds with its freezing, icy waters the northern edges of Europe, Asia and America It shows up from a satellite as a bright snowcap on our Planet Earth, covered by a thick layer of snow and sea-ice.

It had long been a dream to use the Arctic sea waters as a short-cut between the Atlantic and Pacific Oceans, at least during the short summer season.

In 1906, Roald Amundsen established himself as a sailor and explorer when he took a 70-foot boat through the entire length of the Northwest Passage The journey led from the North Atlantic through the Canadian Arctic Archipelago, then along the northern coast of North America, reaching the Pacific Ocean at the Bering Strait after a 3 years' long voyage, most of the time ice-bound fighting for survival.

For the last 100 years the Northwestern passage was rarely open for a short period in the summer time. However, in the last 3 years a growing number of sailing adventurers are traversing this waterway without meeting any serious ice, even in vessels as small as a 7.5 m long catamaran such as this: Clearly Arctic ecology is most fragile and affected by small temperature changes

We asked research scientist Dr. Greg Flato, from the Canadian Centre for Climate Modeling and Analysis, to share his views on the rapid melting of Arctic sea ice and its repercussions on the rest of the globe.

The Centre is located on Vancouver Island near the Pacific coast of Canada. Dr. Flato's main research focus is global climate modeling, sea-ice dynamics and thermodynamics, and the role of the cryosphere meaning the ice areas of the Earth, on climate.

He has published around 50 journal articles and book chapters in the area of sea-ice and global climate modeling, and was a lead author of a chapter in the United Nations Intergovernmental Panel on Climate Change’s (IPCC) Fourth Assessment Report

SUPREME MASTER TV:
Hallo, Dr. Flato, thank you for joining us, welcome.

Dr. Flato:
Thank you.

SUPREME MASTER TV:
Today we will be talking about ice, ocean ice. And that is, of course, in the context of global warming.

Many people already agree that we are entering a period of climate change. Particularly in the Arctic, where the permafrost is melting, glaciers are receding and sea ice is also disappearing, it becomes a most dramatic process.

Could you introduce to our viewers how this process actually looks at this time how much ice do we lose, let’s say within the last 50 years, where the observations were very accurate．

Dr. Flato:
OK, well maybe I could start first just by talking about how the climate is changing, and how it’s changing in the Arctic and what is the driver for the changes that we see in the ice.

One of the things that’s important to realize is that as the climate warms as we put more greenhouse gases into the atmosphere, the atmosphere near the surface warms up but that warming isn’t uniform over the globe.

It warms more at the high latitudes particularly in the Arctic, than it does at the lower latitudes, and the reason for that is that the sea ice and the snow at the high latitudes are very reflective, they reflect sunlight and act to cool the climate, whereas at the lower latitudes the surface is darker.

Now when you start to warm up the climate, that bright surface, the ice and the snow begin to melt away, and expose the dark underlying surface, either the ocean or the land.

And that dark surface absorbs more of the solar radiation, acts to warm the climate more which acts to melt more of the ice.

It’s what we call a positive feedback. And so that positive feedback acts to amplify the warming at high latitudes.

Dr. Flato:
So what we see in the temperature record is that the high latitudes, particularly in the Arctic, have warmed more than at the lower latitudes.

Then the snow is receding and the sea ice is receding What we’ve seen from direct observations since the late 1970’s when we have very accurate satellite measurements of the sea ice, is that the ice cover in the Arctic has been shrinking year by year.

Dr. Flato:
The area covered by ice, we have very good observations of, because that’s something we can see directly from satellites What we see is that the area has been slowly shrinking over the last 30 years.

The annual average rate has been about 3% per decade decline. In the Arctic, the ice extent is at its maximum in the winter time, and then melts back in the summer time, that’s the normal annual cycle.

So if you look at the summer time minimum, the area that’s covered by ice at its minimum in the summer, that has been declining at a rate of about 8% per decade over the last 30 years. And in the last 5-10 years particularly, that rate seems to have been increasing dramatically. And last summer, the summer of 2007, we saw a record minimum in sea ice extent in the summer that was much lower than any previous year.

                                                  (Image Credit- nasa.gov)
SUPREME MASTER TV:
By how much． Because the alarm just started so much in 2007.

Dr. Flato: 
Yes, we have various pictures, you can get pictures on the internet to look at this I have one figure here which just shows this, which you maybe can’t see too well here, but it’s the average summertime [ice] was something like 9 million square kilometers.

And last summer it was down to about 5, a little over 5.

So a very dramatic reduction of almost a half.

SUPREME MASTER TV:
40%, right．

Dr. Flato:
Yeah, about 40% decline.

SUPREME MASTER TV:
That’s a lot. That’s really very impressive.

HOST:
You’re watching Planet Earth: Our Loving Home on Supreme Master Television. We continue our discussion with Dr. Greg Flato on the dramatic Arctic sea ice melt and the climatic consequences thereof.

It has been evidenced that ecological changes accelerate in the Arctic. The average ocean ice-cover in September 2007 was about 40% below of what is expected in an average year, based on the last two decades, and by 23 percent below the previous record low established in September 2005.

Dr. Flato:
So when you look at pictures of the Arctic, a vast area of the western Arctic was completely ice free this past summer.

SUPREME MASTER TV:
That is northern Canada mostly, right．

Dr. Flato:
Yeah, so the Arctic Ocean north of Canada and between Eastern Siberia, that part of the Arctic Ocean was almost completely ice free this summer and it is much more rapid than what climate models have projected was going to happen.
 
So that’s got scientists thinking about why it is that the observed ice extent in the Arctic has been declining much more rapidly than we expected based on these climate models.

So there’s a lack of understanding right now.

SUPREME MASTER TV:
So these alarming statements came based on satellite pictures [from] NASA, which you just said neither models could predict, and scientists like Jay Zwally, for example, started to think that perhaps we are approaching this tipping point, where things get amplified, this positive feedback mechanism you just described, works in a catastrophic form, in a self propelling form, that models, which are still pretty linear, can not predict.

And the statement was that around 2012, there will be no ice in the Arctic

So the question is, can it come back with a few good winters, or when it gets to that point is it a permanent change which may last for hundreds or thousands of years．

What does it mean, that ice will not come back．

Dr. Flato:
Well that’s still an open question.

This past summer, as I said was a remarkably low year for sea ice. And it was a combination of things that led to that.

There is the overall warming of the climate. And naturally as the climate warms, the amount of ice is going to reduce.

But superimposed on that for the last several years the wind in the Arctic has been rather different than it was historically. The sea ice floats on top of the ocean and is moved around by the winds and the ocean current.

And what’s happened over the last few years is that a lot of the ice has been pushed over to the Eastern part of the Arctic and out into the North Atlantic.

So it’s a combination of warming and circulation that have led to this anomalous summer.

Dr. Flato:
Now the question is how much of one versus the other.

How much of it is wind versus warming. And is the wind connected with the warming．

These are all open questions at the moment.

SUPREME MASTER TV:
So basically we don’t have tools for prediction at this stage, once this melting became so vast.

Dr. Flato:
That’s correct.

SUPREME MASTER TV:
Because that’s like a new qualitative picture.

Dr. Flato:
Yes, we’re into territory that we haven’t really experienced before.

SUPREME MASTER TV:
So the question is, can it come back with a few good winters, or when it gets to that point is it a permanent change which may last for hundreds or thousands of years．

What does it mean, that ice will not come back．

Dr. Flato:
Well that’s still an open question.

This past summer, as I said was a remarkably low year for sea ice. And it was a combination of things that led to that.

There is the overall warming of the climate. And naturally as the climate warms, the amount of ice is going to reduce.

But superimposed on that for the last several years the wind in the Arctic has been rather different than it was historically. The sea ice floats on top of the ocean and is moved around by the winds and the ocean current.

And what’s happened over the last few years is that a lot of the ice has been pushed over to the Eastern part of the Arctic and out into the North Atlantic.

So it’s a combination of warming and circulation that have led to this anomalous summer.

Dr Flato:
The winter time ice cover is of course expanding back as it must, as the winter gets colder.

What we will have to wait and see is next summer, whether there was enough new growth of ice this winter to cause the summer minimum in 2008 to be less dramatic that it was this past summer.

So at the moment we don’t really have the tools to make a very good prediction of this, because as I mentioned, the models we have are already unable to predict this.

                                                     (Image Credit- nasa.gov)

SUPREME MASTER TV:
What is the role of the Arctic ice and the water exchange with the Arctic Ocean for the global climate．

Dr Flato:
Well, the Arctic is impressive, in a sense, in that it collects water from a large area of the Northern Hemisphere.

So many large rivers from North America and Eurasia drain into the Arctic. So the drainage basin that drains water into the Arctic is very large. So what we see in the Arctic is that the surface layer of the Arctic is very fresh compared to most other oceans in the world.

There’s this very fresh surface layer and then a deeper, saltier but warmer layer underneath it. And that fresh surface layer is important because it keeps the deep warmer ocean from mixing its heat up to the surface and allows the ice to form every winter at the surface.

That fresh water gets circulated around in the Arctic driven by the winds, and it comes out through the North Atlantic, between Greenland and Spitsbergen, down a current along the east coast of Greenland, and that fresh water then gets into the North Atlantic, where it affects the deep convection and the overturning circulation in the North Atlantic.

Dr Flato:
So it plays an important role in controlling how the circulation in the North Atlantic works and how the heat is transported from the tropical Atlantic to the high-latitude Atlantic.

Again it’s an area that we don’t really fully understand, but there is evidence that when there’s lots of fresh water coming out of the Arctic, it suppresses this deep mixing in the northern North Atlantic, and that then has implications for how heat and water are transported in the Atlantic.

The Atlantic, of course, is an important area in terms of carrying heat northward that provides warmth to Western Europe, so it does have an importance that is much larger than its area.

SUPREME MASTER TV:
That's also vertical exchange.

Dr Flato:
That’s right, so where it mixes with the deep ocean it acts to ventilate the deep ocean.

Dr Flato:
This deep circulation in the ocean is important for transporting the nutrients in the ocean, which then, when they come to the surface, supply the nutrients needed to support that plant life in the upper ocean.

The fact that the ice cover is there is important in terms of keeping the Arctic cool, because it reflects solar radiation in the summertime.

And it’s also important in terms of how much exchange there is between the deep water in the Arctic and the surface water.

So there is a connection with the nutrients in the deep water.

So as the sea ice forms, when sea ice forms in the ocean, the salt is rejected from the ice because the ice that forms is relatively fresh compared to the ocean, the water in which it forms.

And that salt, as it gets rejected from the ice, is heavy and sinks and promotes mixing in the ocean beneath it.

So if you don’t have ice then you miss that process.

Dr Flato:
We were taught from school age that we were born at the end of the ice age.

The climate of the Earth goes in cycles, that there was some period of time, maybe 55 million years ago, when even the Arctic Ocean temperature was above 20˚C.

So why can’t we expect that it would happen again and maybe Greenland would be green again, and the Arctic would have a moderate climate．

Dr Flato:
Well, I think that it’s clear that the global climate has changed over long time scales.

We have had periods of cold climate, when there were large ice sheets over much of North America and Eurasia, the so called Ice Ages, and then warmer periods in between.

We are currently in one of these warm periods in between ice ages.

So it’s certainly clear that the climate varies substantially, just from natural causes.

What is surprising, if you want to put it that way, is the rate at which the climate has changed over the past century.

The warming that we have seen in the 20th century is much more rapid and much more dramatic than what has been seen historically in terms of increases of temperature, and it’s unprecedented, at least according to the observations that we have over the last thousand years, certainly.

So the issue is the speed at which the climate is changing.

And all sorts of components of the climate have to then adjust to this rapid change.

And I think that’s the part that’s unique about the recent change in climate that we’ve seen, is the pace at which it’s occurring.

Dr Flato:
The estimates are that the large ice sheets, Greenland and Antarctica, haven’t contributed as much as the small mountain glaciers over the past century.

But that’s expected to change in the future, as first of all, the mountain glaciers become smaller and smaller and contribute less and less.
 
But also there is evidence that the large ice sheets are beginning to drain their ice into the ocean more rapidly than they have in the past.

HOST:
Through in-depth research on global warming, scientists have found that the unsustainable development of modern technology is bringing our planet’s ecosystem into a situation such that no one can predict the outcome.

Some studies have indicated that the current rate of global warming is triggering potential dangers, leading to an exacerbation of climate change.

Dr Flato:
There’s another potential positive feedback, which is as you warm the climate, you release more of these potent greenhouse gases like methane, which are stored in frozen form in the present.

So these hydrates, which are generally fairly deep on land, but fairly shallow under the ocean in the Arctic, there’s the potential to release those as the ocean warms near the sea floor.

Dr Flato:
On the land, in the permafrost areas, there’s lots of organic material that’s frozen in permafrost now that as the permafrost melts, can then begin to decompose.

HOST:
Some scientists are concerned that the release of methane in the earth’s permafrost and tundra will increase rapidly as the temperature rises.

According to recent studies, the methane stocks in these areas are so huge that the CO2 concentration in the atmosphere would at least double if all these greenhouse gases are emitted, which would be unbearable for our ecosphere.

Today, the future of humankind and our planet depends on how quickly we can all act to curb further global warming.

Dr Flato:
All I can really say is that what’s clear from the scientific evidence presented in the IPCC reports is that the amount of greenhouse gases in the atmosphere which come from the burning of fossil fuels and other human activities, that is the main driver of the climate warming that we’ve seen in the latter half of the 20th century.

Dr Flato:
The concentrations of greenhouse gases in the atmosphere have to be reduced in order to effect a reduction in the rate of warming.

HOST:
Recently, scientific observations have shown that the sun’s radiation is showing signs of weakening. Scientists hope that this may partially compensate for the impact of global warming.

SUPREME MASTER TV:
So is there any hope for some stabilizing cooling process, like recently we heard some statement from NASA solar astronomers, solar physicists, that maybe the sun's radiation will be reduced．

Could that stabilize global warming． Or in your view, would this be too small a correction．

Dr Flato:
The results in the IPCC report indicate that the forcing due to changes in solar radiation are relatively small, and can’t explain the warming in the past century, that the warming that we’ve seen is attributable to greenhouse gases and not to solar forcing, so from that point of view, it would be unlikely that changes in solar forcing would cause a remarkable reduction in the rate of warming.

Dr Flato:
As I said, the scientific evidence that we have now, as summarized in the IPCC, is that the warming we’ve seen over the last century is predominantly caused by greenhouse gas emissions into the atmosphere, which are caused by human activities.

So that’s what we understand from a scientific point of view.

The warming will continue as long as greenhouse gases keep being emitted; that is what scientific evidence indicates.

HOST:
At present, scientists are working diligently, observing changes in the Arctic ice layer, along with other factors related to global warming.