In this series, we have explored the Earth's frozen frontiers.
We have celebrated the astonishing variety of animals
that are found there.
And revealed the extraordinary ways by which they manage to survive.
At a time when our icecaps are melting faster than ever before,
we will meet the scientists and people who are dedicating
their lives to protecting our frozen planet.
And striving to turn things around while there is still time
to do so.
It won't be easy, but it's doable.
It's crucial...
..that we try to understand what the impact will be,
not just for the wildlife and the people that live there,
but for you and for me.
We start our journey in the high Arctic and the vast frozen
expanse of Greenland.
This huge island is blanketed by the largest store of ice
in the northern hemisphere.
But now it's shrinking.
Professor Alun Hubbard is a glaciologist, and he's spent
over 30 years studying the movement of ice along Greenland's coastline.
It is a beast of a glacier, that it's just growling constantly.
Thundering in the background.
Oh, there we go, bit of activity.
Carving icebergs is a natural process,
but what we've seen in the last 20 years is there's
been much more melt.
And much more ice carving off, producing huge icebergs.
So it's quite an intimidating place to be hanging out.
One thing in particular has caused this increase
in melting and carving...
We put this weather station here in 2010.
And the hottest temperature was two days ago.
At 22.37 degrees centigrade.
That is very, very hot for Greenland.
As the ice falls into the ocean, it raises sea levels globally.
These are now rising by an average of four millimetres a year.
A quarter of that comes from the Greenland ice sheet.
And scientists fear that this figure could increase rapidly.
To investigate, Alun has travelled 70 miles inland
to the top of the ice sheet, where the glaciers
start their lives as compacted snow more than a mile thick.
Here, the effects of a warming climate are only too clear.
There are thousands of these beautiful azure blue lakes,
littered across the surface of the ice sheet.
The surface has always melted in the summer, but not on this scale.
And Alun wants to know what effect the increase in meltwater
is having on the ice sheet as a whole.
The sheer quantity of water...
..shifting through the system is crazy.
Powerful torrents of meltwater are boring shafts
known as moulins into the ice sheet.
This is nuts, this a moulin actively being formed.
A moulin in Genesis.
As we speak, that water is finding the path of least resistance,
sculpting this shaft that's going deep into the ice.
And here it is.
Just toppling over a waterfall edge and dropping into the ice sheet.
But where is all this meltwater going and what impact
is it having on the structure of the ice sheet?
To find out, Alun decides to climb inside a dried up moulin.
Think it must be 15, 20 metres down here?
I'm going to go down a bit further.
It's a very narrow shaft here.
It's always been assumed that the meltwater drains straight
down and out of the bottom of the ice sheet.
But what Alun discovers is very different.
I can hear a big amount of water moving in this system.
And the water's starting to spread sideways, laterally.
So the drainage system is obviously complex.
It's interlinked.
These observations suggest that the meltwater is branching out
in every direction, causing this once rigid
structure to destabilise.
Whoa, it's a bit rotten.
Everything is rotten here.
The implications of this are frightening.
Alun believes that as the ice sheet begins to thaw, it's sliding
towards the ocean at a much faster rate.
And he's now confirmed that using time lapse photography.
The ice at the front can be moving in excess of 20 metres a day.
Which is fast.
That is a huge quantity of ice straight into the ocean.
Some of Greenland's glaciers are moving three times faster today
than they were 30 years ago.
As the climate's warming, the rate at which this ice sheet flows
is absolutely critical.
So whereas at the moment we're thinking this thing
is going to take thousands of years to melt and disintegrate.
If it does move faster and accelerate, it means centuries.
That is a really contentious and very important question
because this ice sheet has enough water in it to raise global sea
level by over seven metres.
And that's a total disaster for humanity.
Calculations predict that nearly half a billion people living
in coastal communities around the world will be displaced
by flooding by the end of the century.
But if the Greenland ice sheet slips into the ocean more rapidly,
this could all happen far sooner.
Greenland isn't the only large body of ice in the Arctic.
In winter, the ocean here freezes over, creating a cover of ice
larger than the entire United States.
This sea ice has always got smaller in summer, but today
it's rapidly disappearing.
Hotter temperatures are melting it at an unprecedented rate.
With worrying consequences for the wildlife
that depends on it.
For harp seals, the sea ice is an excellent place
for giving birth out of the water.
It provides the defenceless newborn pups with a safe space
for their first six weeks until they're big enough
to swim proficiently.
But with the sea ice disappearing increasingly fast...
..will they be able to adapt?
Coastguard 432...
Coastguard radio, coastguard 432.
In Canada's Gulf of St Lawrence, a group of seal biologists
are trying to find out.
It's a pretty dangerous, pretty inhospitable place.
But it's the perfect environment for these seals to spend the first
few weeks of their lives.
There's a group just down here to the right, now.
But the fragile sea ice is a challenging place
in which to work.
Here, let's go a little further out.
To support a two tonne helicopter, the ice must be at least
30 centimetres thick.
And the only way to find out if that's so, is with a drill.
It's just unsafe here.
There's a couple just down here below us now.
We've got a pretty short window here.
The team are trying to discover where the seals go
when they become independent.
This is a juvenile harp seal.
This is exactly what we've been out on the ice trying to find.
Hey, little guy.
They're absolutely beautiful.
We'll be putting a satellite transmitter on the top
of this animal's head so that every time the animal comes
to the surface, we can get a location estimate
for where he is at sea.
It won't harm them in any way, and in return,
the amount of information we get from them is invaluable.
We're really interested to see where these animals go,
as the ice starts to break up over the coming months.
The results from the study so far do not look encouraging.
Despite migrating huge distances, when the time comes to have pups
of their own, harp seals almost always return to the area where
they themselves were born.
But as the sea ice shrinks, so does its Suitability as a nursery.
The problem really comes about if the only ice available
in the traditional areas is very thin.
They'll still use that ice and then you get an increased mortality.
In short, the pups risk drowning if the ice isn't thick enough.
And the bigger question is will the ice continue
to exist at all?
In my lifetime, we've lost about two thirds of the summer
sea ice in the Arctic.
And it's likely that in the next 30 years we're going to end
up with an ice free Arctic in the summer.
I think one of the issues with climate change
is that it's really difficult to see.
But in the case of harp seals, it's really quite simple.
If we lose the sea ice in the Arctic, we lose the harp seals.
For harp seals, their future, it has to be said,
appears uncertain.
But what about the most famous face of climate change...
..the polar bear?
Can this keenly intelligent animal adapt to a rapidly changing world?
As the summer sea ice melts away, many polar bears
are forced to head for dry land.
Some swim up to 400 miles to get there.
This is Wrangel...
A remote island in Arctic Russia.
HE SPEAKS RUSSIAN
Without the sea ice, the hungry bears cannot hunt seals and feed
on their calorie rich flesh, but find other sources of food,
including human food supplies.
Each summer, Gennadiy is joined by polar bear expert
Dr Eric Regehr.
We need to cross that ridge. OK.
Eric wants to find out just how many bears are ending up here.
In 20 years of studying polar bears, I've never been anywhere
like Wrangel Island.
The density of bears is unlike anything I've ever seen before.
This past two years, we've seen about 500 bears.
My sense is that's just a fraction of how many are here.
BEARS GROWL
But with so many hungry animals in one place...
..is there enough food to go round?
Gennadiy, if you can keep an eye out for us, please,
like, up on the hill or just wherever you've got a good view.
All right. Thank you.
This is a hair trap.
So bears like anything that smells strong,
and so this has a little bit of spoiled cheese,
milk and fish in it.
So the goal here is to get a polar bear to come in
and put his hand or its head inside this box.
And when that happens, these little wire brushes will pull out a few
pieces of hair that we can use for scientific analyses.
You can learn a lot about polar bears just from
a piece of their hair.
We can figure out which individual it is, or you can get
information on what they're eating.
There we go.
Hair collected.
Eric's molecular studies of the polar bears' hair shows
that the bears on Wrangel appear to be finding enough food.
But with more and more bears coming here,
will there still be enough food to go round?
One of the main things we expect to happen with sea ice loss
is changes in the movements and the distribution of polar bears.
So polar bears are going to appear in places they never were before,
and they're going to disappear from places that they were.
Some coastal towns in Siberia have been overrun with up to
50 bears at a time.
BEARS GROWL
They're desperate to eat whatever they can.
And in the city of Norilsk,
one female was found an incredible 250 miles away from the coast.
Lost and starving,
she was eventually rescued.
But many are not so lucky.
They are intelligent animals, but there's simply no food on land
that could compare to the seals that the bears eat on the sea ice.
A future without polar bears would be very sad.
But the sea ice is not just essential for animals.
It's a lifeline for many of the four million people
who call the Arctic their home.
Aleqatsiaq Peary lives in Qaanaaq on Greenland's west coast,
the most northerly Inuit town in the world.
For centuries, life here has depended on the sea ice.
Not only are dog sleds a way to reach neighbouring communities,
which can be over 100 miles away,
but in a land where no crops can grow travelling over the sea ice
is a vital route to food, fur and livelihood.
But the dwindling of the sea ice is making this way of life
not only difficult, but increasingly dangerous.
Today, they must turn back.
For Qaanaaq's 650 residents
the loss of sea ice is the loss of an entire way of life,
and it is creating an uncertain future.
And there's a reason for this accelerating rate of change.
In the last 30 years, over 14 trillion tons of ice
have been lost from the Arctic, creating a vicious cycle
of ever-increasing temperatures.
Normally, large areas of snow and ice would act as a mirror,
reflecting up to 85% of the sun's rays back into space.
But as the ice melts, the great white mirror is being replaced
by the darkness of the ice-free ocean.
The dark ocean absorbs the sun's rays, so causing
even more ice to melt, creating a feedback loop that contributes
to further warming.
Because of this, the Arctic is now warming more than twice as fast
as the Earth as a whole.
That has far-reaching consequences not just for the Arctic Ocean,
but for the vast frozen lands that surround it -
the tundra.
In summer, the open tundra provides refuge for
great concentrations of life.
But today its thick surface soil that has been deeply frozen
for thousands of years is thawing.
And the pooling water is creating millions of new lakes.
Here in Alaska, we've seen a 40% increase in the lake area
since the '80s.
Professor Katy Walter Anthony has worked across Alaska
and Siberia studying their lakes.
She is interested not so much in the lakes themselves,
but in what is seeping out of them.
We are seeing a bright spot in the satellite image
that we suspect is gas bubbling.
To identify the gas in these bubbles,
Katy must collect some of it.
I'm surrounded by tiny bubbles that are rising.
Methane appears to be the dominant gas.
Methane is produced by the decaying remains of prehistoric
plants and animals.
As the frozen soil beneath the lake starts to thaw,
it releases stores of this potent greenhouse gas,
which is up to 30 times more effective than carbon dioxide
when it comes to trapping heat in the atmosphere and
accelerating global warming.
45 parts per million for these tiny bubbles.
It's rising higher and higher.
Now it's going above 70.
This is a huge amount of methane.
It could be a mega-seep.
We are discovering more and more of these methane mega-seeps.
It's just streaming out and entering into the atmosphere.
Methane can be seen escaping from lakes.
But it also rises from the land wherever the frozen soil, known as
the permafrost, begins to thaw.
And the Arctic tundra is thawing and collapsing
at an unprecedented rate.
It's concerning because permafrost, or frozen ground,
occupies about a quarter of the northern hemisphere land surface.
As permafrost thaws, if even a small fraction
if that trapped methane escapes,
it will accelerate climate warming
and you cannot reverse it.
It's clear that in the Arctic changes to permafrost on the land
and floating ice on the sea will have far-reaching consequences
to the planet as a whole.
And there is nowhere better to see the extent of
these global changes...
..than from space.
All of my life, I've thought about how this would feel to gaze
back on the planet with my own eyes.
Nasa scientist Jessica Meir has spent six months in orbit.
From the space station, you have the planet spinning beneath you.
And you're passing over it at 17,500 miles per hour.
We are going around the entire planet every 90 minutes,
so you can begin to see larger-scale phenomenon
in ways that you just can't experience on the ground.
And we can see the change in these systems over time.
We cannot deny that we are having an incredible effect on
the fate of our planet.
And the effect that we have as humans on our planet...
Right there, actually, I'm looking down at several fires.
I'm not sure where those are.
Let's take a quick peek.
So right now we're flying over Europe and I can see
some fires over in that direction.
And that is, of course, something that we have to contend
more and more with as our climate changes.
As the Arctic warms, wildfires are not only getting more intense
but they're breaking out in parts of the northern hemisphere
where they have never occurred before.
FIRE BLAZES
SIRENS WAIL
Some scientists believe that unusually warm air rising in
the Arctic is disturbing high-altitude wind currents
like the polar jet stream.
Once disturbed, the jet stream produces hotter and drier
conditions much further south.
All of these factors that contribute to wildfires - the temperature,
the soil moisture, the presence of trees and shrubs and other fuel -
have either strong, direct or indirect ties to climate change.
A warming Arctic may not only be responsible
for the outbreak of wildfires.
But it may also be leading to extreme weather conditions
across the whole of the northern hemisphere.
I've always cared so much about the environment and known
that we all need to do our part in protecting it.
But after seeing this view with my own eyes, after seeing
all of those ecosystems from up here, it really makes it
resonate even more loudly.
Outside the Arctic, there's another frozen realm that stretches
across the world's continents.
Our high mountains.
Home to an extraordinary array of species.
But here, too, there's a problem.
Across the world, mountain glaciers, which have existed for
tens of thousands of years, are shrinking and vanishing.
By the end of this century, some ranges may have
no ice remaining at all.
And this will affect not just animals, but people too.
Ice lost from the mountain glaciers from the great ranges of the world
has a huge a consequence for the populations downstream,
and that consequence is their water supply.
Glaciers in the Himalayas are the source of ten of the largest
rivers in Asia, which together provide reliable, fresh water
for around a billion people downstream.
If the glaciers disappear, so too will the water they supply.
We know that these glaciers are losing about a half a metre
of ice a year.
What we don't know is how much ice is left.
So if we know how many metres of ice are left, we can work out how long
they'll last, how long this water supply will keep going.
Dr Hamish Pritchard is part of a team of scientists
who have devised a new instrument to measure one of
the largest Himalayan glaciers.
What we're putting together here is a long frame structure,
and it's designed to hang underneath a helicopter.
We're going to put a radar on it and the radar will send out
the radio waves and then they'll bounce back off the bottom
of the glacier, and we'll be able to measure how thick the ice is.
Once his team know how thick the ice is, they can start to work out
how long it will last.
Yeah, it's a nervous moment.
We're just waiting for it to get lifted off up for the first time.
But hopefully it's going to be nice, steady, stable,
a nice easy lift-off.
But we're about to find out.
That line is clear.
The load is lifting.
OK, it's north of the...
..to the Khumjung area.
Hi. It's Hamish here. How was your flying?
Yeah, when the wind picks up it's a little more squirrelly,
but no problems otherwise.
Yeah, you might want to gain a little bit of height there.
Yeah, no problem.
OK, we'll fly out and then head towards Everest.
After hours of scanning, the projection for this particular
glacier is finally revealed.
Yeah, that's pretty nice and clear.
I can see exactly how thick that ice is.
That's about 150 metres.
So at the current rate of melting,
this section would last maybe 200 to 300 years.
But we know that the melt rates are increasing.
And this is one of the biggest glaciers,
so there are many, many glaciers which are much smaller than this
with much thinner ice.
And they're going to be disappearing much, much earlier than that.
Water is already scarce in parts of Asia.
And as glacial water supplies dry up, there will be
even less to go round.
So what happens if these glaciers disappear...
..is that, in dry summers, the rivers dry up.
Tensions rise, especially between nations that
share water across borders.
So one of the big risks of losing this ice is that it raises
the risk of conflict.
And that's a frightening prospect.
If I have a one-year-old son.
Children born at the same time as him will see this happen.
We need to act now to turn those trajectories around.
There's no doubt that large tracts of our frozen wilderness
are undergoing dramatic changes.
But what about the largest body of ice of all,
Antarctica?
We have already seen how even here animals living around the fringes
are starting to be affected by climate change,
including chinstrap penguins.
PENGUINS SQUAWK
But for another penguin, the Adelie, the consequences
are even more extreme.
I arrived here for the first time in 1974.
This part of the world was just incomprehensibly wild.
It was filled with life.
Antarctica absolutely captured me.
Professor Bill Fraser has dedicated his entire 45-year career
to studying the Adelie penguin.
What really fascinated me was the incredible
hardiness of these penguins.
Feisty, determined,
beautiful little animal.
But this environment is changing.
In the last 45 years, the tremendous warming that has
occurred has had an incredible impact.
The changes have been very rapid, more rapid than anyone anticipated.
Bill has witnessed first-hand how these changes have affected
one of the largest colonies of Adelies on the western side
of the Antarctic Peninsula.
Four decades ago, this area contained 20,000 adults.
Currently, we only have somewhere in the order of 400 breeding pairs.
One of the issues that Adelies are clearly experiencing right now
is just the increasing rainfall.
Adelies are a creature of the high Antarctic.
They evolve in a dry, cold polar system.
They simply cannot tolerate being continuously wet.
The chicks are soaking.
The rain is penetrating their down,
breaking down their ability to insulate themselves.
That's why you see they're shivering, because they're just
trying to maintain their body temperature and they can't.
It's sad.
This tiny chick at this point has zero chances of surviving.
They can't even react to the presence of a predator.
We are standing,
looking at climate change actually killing off these Adelie penguins,
one at a time.
Before he leaves Antarctica for the last time, Bill is visiting
an island that was once an Adelie paradise.
When we used to walk onto this island,
you could immediately hear the Adelies.
They were everywhere.
In 1974, the populations here were somewhere in the order
of over 1,000 breeding pairs.
All that remains are these little pebbles scattered throughout
the area, stones that were used in former nest sites.
The pebbles are still visible.
They're very abundant.
But the birds are gone.
This is where we recorded the first island-wide extinction
of Adelie penguins.
And now the silence that exists here is pretty overbearing.
Um...
There's no... There's no words that can really describe
what I'm feeling at the moment.
We're working with canaries in the coal mine.
Adelie penguins are without a doubt indicator species that are telling
us that the globe is changing, the globe is getting warmer.
It's happening.
And we need to do something about it.
The disappearance of Adelie penguins along the Antarctic Peninsula
is just one example of how record-warming temperatures are
affecting life here.
But warming temperatures are also affecting the very coastline itself
with serious implications for global sea levels.
Across the glaciological community, we've identified that sea level rise
from Antarctica is the most pressing question for
the next 50 to 100 years.
And we as a collaborative group
have come together to try and understand it,
and governments have come together to try and understand it
because it's important.
Professor Sridhar Anandakrishnan has been working in the polar
regions for over three decades.
He's part of a team of scientists undertaking the largest Antarctic
expedition for more than 70 years.
Their destination is a remote part of western Antarctica called
the Thwaites Ice Shelf.
Without getting out on the ice, you can't measure things
underneath the ice.
Going to take-off.
Those kinds of things can't be done from space.
They can't be done by drones or aircraft flying over it.
You actually have to go and put your instruments on the ice.
The interior of Antarctica is covered in a giant sheet of ice.
Which for millennia has been slowly flowing to the coast.
But because it's so cold here, rather than carve into the sea
the ice continues to flow out into the ocean, forming a floating
platform known as an ice shelf.
As an ice shelf grows, it begins to act as a dam, preventing
more of the ice sheet behind it from slipping into the sea.
And the Thwaites Ice Shelf holds back a body of ice
the size of Florida.
But scientists are concerned that the ice shelf itself is now
at risk of melting.
We're going down through 600 metres of ice.
And once we drill the hole,
I'm going to put the explosive charge down.
Small seismic surveys...
OK, fire in the hole.
..help establish exactly where to sink their robotic underwater probe,
which the team hope will record the temperature of the sea water
directly beneath the ice shelf.
OK, Andy, ready to descend.
Try to go a little slower.
OK.
Coming up on 75 metres. 75 metres now.
425 metres.
We've arrived at the ice-ocean interface.
Early results are not encouraging.
Have we noticed a huge change in the temperature?
Ah, yeah.
It is warm water.
Can you see it melt? Yes. Like, what's going on there?
Because of climate change,
warmer seas directly beneath the ice shelf are melting it from below.
So it's no longer a question of IF this giant dam will disappear,
but when.
When the vast ice sheet behind it spills into the ocean,
it could have catastrophic consequences for global sea levels
over the coming centuries.
The amount of water that Antarctica contains that could
go into the ocean is so huge.
This is a global problem.
The oceans are all connected together,
so as soon as a glacier puts water into the ocean
it rises all over the world.
If sea levels rise, as predicted, by the year 2050 150 million people
could be displaced from coastal areas.
And by 2070 cities, including Miami, New York, Shanghai and Mumbai
will be at risk of serious flooding.
How much water will Antarctica contribute to sea level rise?
The biggest wild card in all of that is how we as humans
affect climate.
Recently, at COP26, 120 nations came together in an effort to limit
global warming to 1.5 degrees.
Well, a 1.5 degree rise will still bring significant
changes with it.
To stand any chance of saving what remains of our frozen planet
and saving ourselves from the devastating consequences
of its loss, we must stick to this commitment and honour it
no matter how challenging it might be.
We know that climate change is happening.
We know the main driver of climate change
is human activities.
It's human emissions.
As a whole human species,
we are not recognising the impact that we're having and the fact
that we do need to do something.
But the important thing is that I believe
all of these processes are reversible.
If everybody can make the effort of doing just one thing,
reducing their carbon footprint.
Consume less. Think about what we need, what we really want.
Think more sensibly about the journeys we take,
about the food we eat,
how that's produced.
Figure out a lifestyle that is sustainable.
And we're right at the point where we can
generate all the power that we need from renewable sources
like solar and wind.
To do that, you need to really transform society as a whole.
We can speak to our representatives to try and
reconsider energy policies.
If enough of us are educated about the effects of carbon in
the atmosphere, even the most poorly educated politician
will respond to what their citizenry wants.
The awareness and the concern is greater now than it ever has been.
So that gives us some hope.
It won't be easy.
But it's doable.
If you can do something about it then do it,
instead of just thinking about it.
If you can do something about it, then do it.
We can do it.
It's within our power to do it.
We can do it.
We must do it.
Then there will be a future for the planet.
The Open University has produced a poster exploring how animals adapt
to life in the world's coldest environments.
To order your free copy, please call 0300 303 0553
or go to bbc.co.uk/frozenplanet2
and follow the links to the Open University.