Search and rescue teams are crossing Iceland's central plateau.
A few kilometres below them, a huge reservoir of molten magma
shakes the ground as it makes its way to the surface.
The question is not IF an eruption will take place,
but when...and where.
Icelanders have turned their unstable, cold, rugged island
into one of the most modern and culturally-rich nations on earth.
But they still keep one foot in the wild
and a very careful eye on the beast stirring beneath them.
Over what turns out to be an explosive year,
and through the eyes of wild foxes...
..an eider duck farmer...
..and Viking horsemen,
we'll see why everything on Iceland
remains uniquely connected to the land underfoot.
Under the eerie glow of the Northern Lights,
Iceland is in the iron grip of winter.
Lying close to the Arctic Circle,
with just a few hours of light a day,
it has endured months below zero.
At this time of year, it's hard to imagine Iceland's fiery origins,
but the island emerged as molten lava
from deep beneath the Atlantic Ocean.
It's one of the planet's newest pieces of land.
Everywhere are reminders of how little time it's had
to shed its raw, rocky character,
and how closely it's connected to the very centre of the earth.
Iceland is so new and so isolated in the North Atlantic
that, until relatively recently,
there were no land mammals here at all.
But during the last Ice Age,
when it was connected to Greenland by ice bridges and ice floes,
a very tenacious predator turned up.
The Arctic fox.
Iceland's first land mammal,
in its many colour variations, was here to stay.
But how it survived on Iceland without any of its regular prey,
like lemmings, has long fascinated scientist Ester Unnsteinsdottir.
'This is an Arctic species, it's adapted to the Arctic winter,
'which is really cold.
'And you can see it on the thick fur,
'it's the thickest fur in the universe, so very well insulating.'
It's actually better than a polar bear's
against the biting cold.
Enduring extreme weather is one thing -
its biggest challenge on Iceland is finding food.
They need to eat.
And if they don't have enough food in the wintertime,
especially before breeding, they don't manage to breed properly.
There is a remarkable lifeline.
An arm of the Gulf Stream helps to keep much of Iceland's
long, rocky coastline ice-free.
So even in winter, foxes can scavenge
the washed-up remains of fish, seabirds and sea mammals.
Only the toughest foxes hold on to a slice of good shoreline territory
and get the chance to breed.
But first, they have to find a mate.
A dark male appears to have won over a brown female.
A white male is desperate to mate with her, too.
And succeeds in grabbing her attention.
For a while, he seems to have outfoxed his rival.
But it doesn't end well for him.
The white male will have to try elsewhere.
Hopefully, this brown female, with the victor in tow,
has the strength she'll need to have a family.
For the weak or the inexperienced, winter is a punishing time.
Less than half of all foxes survive.
Sea mammals have an easier ride.
The ice-free waters offer
some of the best fishing in the North Atlantic...
..attracting not just seals, but whales and dolphins.
The fertile seas were a good reason for humans to settle here, too.
The first Vikings colonised Iceland just over a thousand years ago.
Down the generations, through fishing and farming,
they have carved out a unique way
of dealing with the many limits to life.
Most of Iceland's people, just over 300,000 of them,
are descended from the original settlers.
And many still work the land in tried and tested ways.
Even their livestock traces back to the animals
the Vikings brought with them.
Purest and most admired is the Icelandic horse.
It's smaller and much hardier than most other breeds.
Owners give them a little help towards winter's end,
but mostly, they tough out the cruellest of weather.
The best way to raise livestock here is to keep the animals semi-wild.
It gives them the character and spirit to survive
in this austere volcanic landscape.
But with little prime grazing land,
Icelanders could never rely on their livestock alone.
Long ago, the arrival of squadrons of swans, ducks and geese
would have offered relief from dwindling winter rations.
One species offered much more than a meal.
Eider ducks are among the millions of birds that are drawn to Iceland
from all around the North Atlantic.
These days, Thor Bjornsson makes an unusual living from them.
But he can't start work until the eiders have finished pairing up
and have come ashore.
He, and the birds, are waiting for spring.
Exposed all winter to brutal Atlantic storms,
Iceland has been blanketed by huge volumes of snow.
When that melts, it fills thousands of streams and rivers.
And cascades over some of Europe's
largest and most powerful waterfalls.
Iceland is so new and remote
that relatively few species have made it here.
Its hardy pioneers are always under pressure.
Even now, it's a race to make the most of longer, warmer days ahead.
After a winter of famine,
male ptarmigan are hungry to reach the buds, packed with proteins,
which are swelling at the top of willows and birches.
It's a precarious high-wire act
for a bird that spends the majority of its time on the ground.
Down on the coast, Thor is impatient
for the eiders to get on with mating.
Millions of other migrating and resident birds
are already nursing eggs, set to take advantage
of what will be a very short, but bountiful summer.
BIRDSONG
Eventually, the eiders return to the western islands of Breidafjordur,
finding the same nest scrapes
that their mothers and grandmothers used before them.
The mother duck cradles her eggs in a pillow of down
collected from her own breast feathers.
There is no other duck down like it.
It's this down that Thor wants to harvest,
but he'll need his extended family to help gather it.
Thor's farm consists of nearly 300 small islands.
And they'll have to deal with over 3,000 wild eider ducks.
It's going to be a busy few weeks.
Spring has finally reached Hornstrandir,
the craggy, lonely, north-western corner of Iceland.
After a severe winter, this female fox
is hanging around one of only two den sites.
The lack of food over the past few months will have taken its toll,
but now she has to step up a gear.
She's looking after not just herself...
..but six newborn cubs.
Her work is cut out.
She's a mum with a sky-high milk bill.
Just to keep up production, she's going to have to spend
the next weeks hunting fulltime.
Arctic foxes are feisty opportunists.
They may be small, but when livestock arrived on Iceland,
they soon worked out how to kill animals much larger than themselves.
In response, the early settlers began hunting foxes
to keep their numbers under control.
Today, foxes still take livestock
and the hunting quotas enshrined in law in the 13th century
are still in force.
On Iceland's marginal land,
the challenges facing both fox and farmer cannot be underestimated.
Making a living out here is tough.
For farmers like Halldor, horses are their pride and joy.
These days, Halldor and his son-in-law, Snorri,
mostly breed them for riding.
Horses are still better than 4x4s
on Iceland's rough tracks and mountain passes.
Just as sturdy and dependable
as when they were the backbone of Icelandic communities.
HE SPEAKS OWN LANGUAGE:
The finest horses became highly-regarded status symbols.
SNORRI IN ENGLISH: You had a lot of respect if you had the best horse.
Even if you were a poor farmer,
if you had the best horse, you had respect.
HALLDOR SPEAKS OWN LANGUAGE
SNORRI TRANSLATING: "Really important for the young guys to have a nice horse
"when they were looking for girls.
"When you came with good clothes, on a nice horse,
"you had a good chance."
Every spring, Halldor checks on his pregnant mares.
He hopes his favourite stallion will be the father.
The very best foals will be much admired at the end-of-year round-up,
but Halldor has no control over their arrival.
They give birth to their foals in secret.
Often after dark, and without help.
Halldor has to trust that his mares are robust enough to cope.
Over 3,000 eider ducks are now settled on eggs on Thor's islands.
He and his family carefully comb each rocky outcrop,
looking for nests.
Thor's unusual livelihood allows him
to spend time in the wildest parts of Iceland,
among the nature he loves so much.
'I started about 1970.
'And I was 14 years old then.
'I found it very, very nice to be with the birds, like this.
'Collecting down and all the wildlife around it.'
Thor carefully sets the eggs aside, removes the down,
and will re-cushion the eggs in soft, warm hay.
The female ducks can then return to their duties with no harm done.
His yield is limited by the number of birds that return each year.
Some years are better than others and...
..we get up to 55 kilos of eiderdown.
Normally, it's about 65 nests in one kilo of down.
Eiders have proved tricky to domesticate.
Their down can only be farmed from wild birds.
To increase overall numbers,
Thor collects and rears a few offspring
that may not otherwise survive.
'A lot of young ones, eider ducklings, die in many ways.
'Bad, er...weather, wet and windy.
'They cannot get enough food.
'So normally, they maybe raise up one duckling,
'two ducklings, something like that.
'We take one or two eggs from the nest,
'depends how many eggs are in the nest.
'When we started here, it was about something between 500 or 600 eiders
'nesting in the homeland area, but now it's more than 1,000,
'so they come back.'
While his eggs are incubating, Thor gets down to business.
Nearly three quarters of all eider duck down comes from Iceland,
and it's all gathered by hand.
Thor's family painstakingly pick the down clean
before it's bagged up for sale.
Most becomes a cosy filling for high-end duvets, quilts and jackets.
THEY SPEAK OWN LANGUAGE
Its secret may lie in the way the fibres flex and lock together,
creating thousands of minuscule air pockets.
It's such effective insulation
that it's been used to keep astronauts warm in space.
This is duck down that's flown to the moon and back.
CHIRPING
After a few days under a heat lamp, Thor's ducklings begin to hatch.
They grow quickly.
In the wild, eider ducklings can fledge after just a month.
CHIRPING
But under Thor's wing,
they stand a much better chance of making it to adulthood.
CHEEPING
For these first days, at least,
they only have eyes for their new duck dad.
They won't follow him around long-term,
but Thor will have to spend the rest of the summer
as a stay-at-home father,
teaching them skills they'll need to become wild birds.
The longest days of the year are approaching,
when the sun barely dips below the horizon.
The fullness of summer
is only really felt around the island's edges.
Hardly anything lives on the vast, ash-covered central plateau.
Its many volcanoes erupt too frequently and violently
to give life much chance.
It's like a sleeping giant that everyone's turned their back on,
but dares not forget is there.
Watching over the fox family,
Ester is spending more and more time on the Hornstrandir peninsula.
The cubs have been weaned,
but Mum's workload just gets bigger by the day.
Sibling rivalry can be lethal.
It's thought that each fight reinforces their rank in the family.
Dogged determination decides who gets most food
and who, ultimately, survives.
This mum seems to be made of particularly stern stuff
and is providing for all six of the cubs.
She's raising her family close to one of the most prolific
seabird colonies in Iceland.
There's lots of tempting food on offer.
The problem is that it's perched on sheer walls of rock.
If ever there was a high-stakes game, this mother is playing it.
One false step and she will plunge hundreds of metres
onto the rocks below.
Her cubs will effectively die with her.
SQUAWKING
She's found a kittiwake.
But with a growing family,
she will have to risk her life over and over again.
Today, she has the cliffs to herself,
but until the 1950s, foxes were in direct competition
with the people who eked out a living on this far-flung peninsula.
'It was very harsh, even for humans, you know. It was really tough.
'Bad winters and, er...not easy to survive.
'So, both for humans and foxes.
'And they were probably using the same resources,
'both space and food,
'so they were feeding on birds and eggs.
'And that's what people were also feeding on.'
On the remote island of Grimsey,
they still gather eggs from the massive summer colonies.
Its long coastline and towering cliffs of resistant volcanic rock
provide ledge space for thousands of kittiwakes and guillemots.
And burrows above for puffins.
BIRDSONG
Across Iceland, there is still the taste for seabird eggs.
A traditional and free-range alternative
to battery-farmed chicken eggs.
These days, the kit may be relatively modern,
but it still requires an old-fashioned head for heights.
Timing is crucial.
Eggs are scooped up right after laying.
The theory being that as soon as the birds realise
their egg has gone, they'll re-lay.
The collectors simply delay the hatch by a few days.
The length of cliff which each collector sweeps
is strictly controlled.
Today, these eggs are sold through supermarkets,
or traded for autumn berries from the mainland.
For many, foraging remains a part of everyday life,
tapping into the rich natural resources around them.
The most remarkable resource of all is the heat beneath their feet.
The island lies over the edge of two continental plates
that are pulling away from each other.
Iceland is being stretched apart in the middle.
It's the easiest place for boiling molten rock
to rise towards the surface.
This readily heats groundwater,
which, day to day, can be rather useful.
Long ago, Icelanders discovered how it could slow-cook
one of their most celebrated foods, lava bread.
Every household has its own secret recipe for roobrau,
but each loaf will be baked in much the same way.
Once the dough is bucketed up, it will be placed in a hot spring -
nearly every rural community has one -
and then left for 24 hours.
The immense geothermal power on offer
has transformed the lives of all Icelanders.
They live just south of the Arctic Circle.
Yet, modern, ground-heated greenhouses
allow them to ripen vegetables and fruits
that wouldn't otherwise stand a chance of growing here.
They've created a sustainable bubble
in which plants and their pollinators
defy the limits of growing on raw, northern rock.
But along with their daily bread, Icelanders are fed updates
on the many earthquakes that occur on the island.
It's as routine as the weather forecast.
And this year, it seems, more important than ever.
In late May, a swarm of 200 earthquakes
register under the Bardarbunga volcano in central Iceland.
It lies under Europe's largest glacier, Vatnajokull.
And eruptions in the past have caused catastrophic floods.
There's no evidence as yet that magma is on its way to the surface,
but pilots overflying the area
are asked to keep an eye on any changes to the ground below them.
On this extraordinary island,
ordinary life simply goes on.
There have been over a dozen eruptions
in Halldor's lifetime alone.
Right now, he has more immediate concerns.
One of his mares has just given birth.
Like many creatures that evolved on open grassland,
the foal's instinct is to get on its feet as quickly as possible.
It seems healthy.
The new foals will stay close to their mothers
for most of their first year.
But it may be the last Halldor sees of them for a long while.
Soon, all his horses will move up the valley and into the mountains.
It will give these lower pastures a break.
But the move is also important to encourage the foals to run free.
If they're to survive their first winter,
they need to become resilient.
Horses from all the farms around here
are allowed to return to their roots.
Just like the ancestral wild horse of the Eurasian Steppes,
they'll roam in large herds
and won't see their owners
for many months.
You want to keep this wildness a little bit in the horses.
And this is the best place to do that.
And it's also really important that young horses go there, foals,
to learn this as quickly as possible.
This strengthens their mind a lot to do this.
Because you never know in Iceland, if... Just...
If it gets lost on the mountains,
they know how to help themselves.
I think also for the growing of the horses and the young horses,
it's, like, it grows much better and stronger on the mountains.
The Skagafjordur region prides itself
on producing the very best Icelandic horses.
Strict rules control the breed.
A horse sold abroad is never allowed to return,
having lost the magic mix of wildness and trainability.
This is the trait Halldor's foals must develop
if they are to do him proud at the end-of-year round-up.
The short summer is pressing on.
Wild eider ducks are already leading their young broods out on the water.
The eider is a diving duck
that spends the whole winter living at sea.
It's vital they become powerful swimmers.
Thor's ducklings, too,
must begin learning how to face the trials ahead.
Younger members of the family lead the way.
They get very quickly very big and strong.
And we bring them to the sea every day, or sometimes twice a day,
to feed in the sea and swim a little bit.
Here, they'll build up their muscles and sharpen their instincts.
They're still vulnerable to the cold
and to ravenous black-backed gulls,
so the children must guide and protect them.
First days, we have to look very well after them
because they want to go away.
So we try to gather them and so they don't swim away.
This wilful streak is good.
It means they haven't been tamed.
All in all, it's a fun way for the kids to connect with nature.
And the smallest member of the family
gets to talk down to someone else.
It's home-time.
The ducklings are gently herded and counted back in.
Where they'll fluff themselves back up
in readiness for the next stage of their training.
For now, it's job done.
BIRDSONG
In Hornstrandir, the Atlantic Ocean is slowly gnawing
at what remains of a very ancient and immense lava flow.
On its unforgiving edge, the mother fox has defied the odds.
All six of her cubs are still alive.
Although life is a challenge, they currently stand
a better chance in Iceland than elsewhere in the Arctic.
'There's very few Arctic foxes left in Scandinavia.
'And they have been endangered for many, many years.
'But they're facing troubles that we are not facing here in Iceland.'
Ester believes the big problem for Arctic foxes in Scandinavia
is the northward march of the red fox, due to climate change.
As it moves into Arctic fox territory,
the red fox takes over their den sites,
competes for food and even kills adults and young.
The Arctic foxes on Iceland remain out of reach.
The island is an important stronghold for them.
Mum's job is nearly done.
In the next few weeks, the cubs will leave home.
Hunger may force them into taking livestock,
where they risk being shot.
The odds are that not all of these cubs will survive
the coming winter, or go on to breed.
But the Arctic fox has an almost heroic ability
to turn hardship into opportunity.
This mum's given them the best possible start in life.
This far north, the limits to life
for animals and humans, are very stark.
So Icelanders have never been shy of taking from nature.
Traditionally, they've harvested everything from seabirds to whales,
fish to seals, some of which they still take today.
But it's clear that if you live on an island,
especially one so remote and northerly,
you cannot take more than you need.
Ever since the Vikings first landed,
fishing the rich offshore waters
have been fundamental to the country's economy.
In the 1970s, Iceland even used gunboats
to defend a 200-mile fishing limit around their coast.
Today, with careful management,
their fisheries are some of the most sustainable in the world.
Their long-term thinking has helped other countries, too.
Icelandic rivers are important spawning grounds
for the Atlantic salmon.
But in the 1980s, salmon started to decline,
due mainly to overfishing
by commercial operations on the high seas.
By raising funds to buy out the netting operations,
effectively paying them not to fish,
millions of salmon were given a chance
to return to rivers, from Norway to North America.
The problem is far from over.
Striking a balance between harvesting and protecting
is an ongoing effort,
but Icelanders manage it in their own unique way.
It's a country where hunting and gathering
sit side by side with modern life.
A nation with a dynamic economy, built around Reykjavik,
the most northerly capital city in the world.
Cheap, clean, renewable power warms homes,
keeps the lights on and provides mains' hot water.
Even city pavements have underfloor heating.
Reykjavik's Opera House celebrates music and drama
inspired by the original Icelandic sagas.
But Icelanders are necessarily rooted in reality.
They can never forget they're living over a huge
and widening tear in the earth's crust.
And as summer draws to a close,
the giant reservoir of molten rock under them is beginning to stir.
Back on the Breidafjordur islands, wild eider offspring
are learning what to eat by watching their parents.
It's Thor's job to introduce his ducklings to the kind of food
that will keep them going out on the open water.
When they grow up, they'll be diving mainly for molluscs,
which they eat, shell and all.
Tiny crustaceans, stirred up from the shoreline,
are good starter foods.
In the end, Thor, as a surrogate duck dad,
can only give them a helping hand.
Little by little, they spread their wings,
foraging a little further from home,
becoming a little wilder every day.
But they swim then between here, close to the island
and go on their own trips feeding,
but they always come home in the evening.
So they find something in this ocean to eat,
so it make them a good start in their new life in the world.
Eventually, Thor leaves them on their own.
His nurturing work is done.
Nature will take over from here.
But Thor hopes their homing instinct
will bring them back to his islands next year.
In the high pastures, ripening blueberries
and the turning leaves mark the slide to autumn.
Even though the first snows are dusting the mountains,
it's a time eagerly awaited by farmers
in the northern area of Skagafjordur,
for it also heralds the event of their social calendar,
the annual round-up.
The horses might die up here in winter blizzards,
so farmers join forces to gather up the different herds
and drive them all down the valley.
For this year's foals,
it's a complete surprise to be near humans again
and it goes against the grain.
But this independent spirit
is exactly what Halldor and Snorri want.
It's what the Vikings saw in the ancestors of these horses
when they traded them from Mongolia
and brought them to Iceland over 1,000 years ago.
This is horse-trading nature's way.
THEY NEIGH
Somehow, each farmer must separate their own horses from the crowd.
But they're judging everyone else's at the same time.
No horse is broken in until it's at least four years old,
so most of them have a mind of their own.
But this is what they love about them.
It's been the only way to raise horses
in Iceland's harsh environment.
Their return from the mountains, though, always brings deep relief.
When all is done, Halldor and Snorri
will lead the horses back to the farm,
as generations have done before them.
The land under their feet demands respect.
And in this, of all years.
High in the central plateau,
the Bardarbunga volcano has sprung into life.
Over a thousand earthquakes in a single day
suggest a huge volume of molten rock trying to reach the surface.
But where?
Fearing massive floods
should the eruption melt the Vatnajokull glacier,
search and rescue teams evacuate a vast area.
Hour by hour, scientists track the earth tremors
that mark the movement of the magma.
The column of hot rock is snaking northwards.
Eventually, it breaks through a fissure in the plains,
just beyond the edge of the glacier.
It's big. Probably the biggest lava eruption
that we have seen for 30 years or so, I would guess.
As it turns out, nothing like it
has been seen on Iceland for over 200 years.
The fissure is about 400 metres long,
but lava pours out at nearly 300 cubic metres a second,
like a cut that won't stop bleeding.
Underneath Iceland, the Eurasian plate is pulling eastwards
and the North American plate is pulling westwards.
Until this eruption, the island has been spreading apart
at two centimetres a year.
Here, it's opening up ten times faster.
The lava is a ferocious 1,200-degrees centigrade.
It would melt even cast iron
and incinerate a human being in seconds.
This is as close as we get to seeing into the centre of the earth.
The ground shakes as the fissure splits open even further,
creating a rift that's 1.5 kilometres long.
Pumped by pressure that's been building for centuries,
superheated gas and water causes tonnes of lava
to fountain up to 100 metres into the air all along its length.
These are the same monumental forces
that created Iceland in the first place.
Over the next six months,
the lava flow covers over 85 square kilometres.
85,000 tonnes of poisonous sulphur dioxide
is released into the atmosphere every day.
In 1783, an eruption on Iceland
threw up so much ash and sulphur dioxide
that it's thought to have caused famine on a global scale
and the deaths of six-million people worldwide.
Miraculously, this fissure allows the colossal pressure
under Bardarbunga to be released slowly.
Had it gone off just a few kilometres away,
explosively, under the Vatnajokull glacier,
the picture would be very different.
It's the ultimate reminder that the lives of all Icelanders
depend on the raw forces beneath them.
A wild life,
uniquely connected to nature, it may be,
but the remarkable people and animals that live here
have learned how to work with the land,
rather than fight against it.
They've taken all of Iceland's opportunities
and challenges in their stride.
GENTLE BARK