Ice Age British Isles: A Natural History

It's not often that a ramble in the mountains turns up a great scientific discovery,

but at Inchnadamph, in the Highlands of Scotland,

something was found that was so unexpected, so astonishing,

that it helped explain how the landscape we see today was formed.

At the end of the 19th century,

a Mr Peach and a Mr Horne were exploring this area

when they came upon this cave.

Inside it,

they found something almost unbelievable.

Something that had never been found in Britain before.

But it wasn't in the mouth of the cave that they made their discovery.

Oh, no, it was way down in its darkest recesses.

Imagine exploring this eerie cave by candlelight,

especially with what was hidden deep underground.

What did they find when they got here?

They found the remains of a bear.

But not just any old bear.

This is the skull of a polar bear.

For a polar bear to have lived here,

it must have been as cold as the Arctic.

We're not talking millions of years here.

The skull they found wasn't a fossil, it was real bone.

Polar bears must have been stalking the Scottish Highlands practically yesterday.

So, could this have been a scene

not from the north of Norway or the High Canadian Arctic,

but from where Blackpool or Bristol are situated today?

A British Isles where musk ox and polar bears roamed wild?

The polar bear skull was a tantalising clue

to a past we might find hard to imagine.

It was a land locked in permanent winter.

Britain in the Ice Age.

These breathtakingly beautiful mountains are not the Himalayas.

They're not the Alps.

Neither are they a scene from Lord of the Rings.

I'm in the Ben Nevis mountain range.

As high as you can get in the British Isles, and it's like being on top of the world.

It's winter in the Highlands of Scotland.

You've never seen anything more spectacular as this. I haven't.

Over there in the distance, those bobbly bits are the Cairngorms.

This is the snowiest place in Britain.

There's snow on the mountain tops even in the middle of summer.

For all the fact that it's achingly beautiful, it's piercingly cold.

It's about minus five degrees Celsius,

but with the wind chill factor, about minus 15.

Which is why right now, up here in this beauty,

I'm the only fool here!

RADIO: Cross-border motorway remains closed around Lockerbie...

Ben Nevis may have snow all year round,

but in the rest of the country,

just one winter storm brings everything to a grinding halt.

'..across the snowbound area.

'Four times normal levels. There were 2,000 calls an hour to the AA.

'Snow making journeys tomorrow equally treacherous.'

If you're as old as me, you can recall the winter of 1963.

I was just 13.

I can remember having to dig through a six-foot snowdrift just to get out of the house.

It was a winter that dragged on and on,

with temperatures desperately low,

and ice and snow from December right through to April.

But no matter how bad winter gets,

at least we know that spring is just around the corner.

From beneath the snowy blanket, new life is poised to emerge.

Before long, Britain is green and lush once more.

The seasons change as regular as clockwork.

But even the best clocks can go wrong.

Just imagine -

what if Britain never woke from its long winter sleep?

Bluebells never burst into life

and songbirds never sang.

And imagine if that winter sleep lasted, not for a year but for much, much longer.

Well, in Britain's past, it did just that.

We experienced cold, snow and ice like never before.

Not just a few bad winters,

but hundreds of thousands of years of deep freeze

right across northern Europe.

It was one of the biggest events to influence the shape of our country.

But it was caused by something on the other side of the Atlantic.

Three and a half million years ago,

the then separate continents of North and South America became joined by a land bridge.

It caused quite a stir.

The ocean currents in the north Atlantic changed,

and warm tropical waters flowed towards our land.

Sounds like a recipe for a balmy Britain, but it wasn't.

The warm water brought moist air and rain to our western coasts,

but in the colder north it fell as snow.

At the same time, the ice sheets in the Arctic expanded,

and that's when things got worse.

They acted like a giant mirror.

The bigger they got, the more the sun's heat was reflected back into space.

A vicious circle set in

and temperatures plummeted.

Our green and varied landscape turned decidedly white and chilly.

Even the seas at our coast began to freeze.

At first, once a year, winter briefly loosened its icy grip.

Animals and plants clung on.

But gradually the winters became longer and the summers shorter.

Until eventually, they never came at all.

The plants and animals of the British Isles

were about to lose the fight.

Plants die of cold, the last ones to survive are things like this tiny willow pressed to the ground.

Mosses, lichens, the odd bit of scrubby grass,

even these will die away once the snow no longer melts in the summer.

Then, you've got an ice age.

For thousands of years, snow fell and never thawed.

The icy blanket grew thicker and thicker

and spread further and further south.

Eventually, Britain was buried in an icy tomb,

weighing billions and billions of tons.

Birmingham would have been a mile and a half beneath my feet,

which gives you some idea of the scale of this freeze up.

It would have continued northwards to Ben Nevis and beyond,

out west across Wales and most of Ireland

and eastwards over East Anglia.

It was an extraordinary freeze-up

and all that extra weight had a surprising effect,

which you can still see today.

There's nothing quite like an afternoon on the beach, is there?

Soaking up a few rays, seagulls screeching overhead,

the sound of the waves lapping gently on the shore,

the prospect of an ice cream

and a short walk to the beach for a paddle.

But on the Scottish Isle of Jura, things aren't quite what they seem.

I'm most definitely on a pebbly beach,

but there's something strange about the pebbles.

These rocks are certainly typical of those that are worn by water,

because they're all rounded and smooth.

And yet, they've got lichens growing on them.

Now lichens only grow on rocks that are stationary.

Not on those that are washed by water.

So what's going on?

While these rocks were clearly once pummelled by the waves,

they're not any more, because the sea is 40m down there.

It's hard to believe that this towering cliff

was once battered by waves.

This sea stack is now surrounded by grass, not water.

Waves carved out this arch, but it's been left high and dry.

And it's all down to ice.

Like everywhere else on Earth,

Jura today floats on molten rock about a mile beneath the surface.

Now when the great ice cap formed, the weight was so great

it pushed the Earth's surface down into the molten rock.

And as it melted, so the land rose up again

and the beach that was once here is now 150 feet up there,

and still rising.

So we had enough ice to sink an entire country.

And Jura's raised beach isn't the only oddity from our icy past.

Something strange happened further south.

There were aliens in the Yorkshire Dales.

These green and rolling hills are typical of limestone country.

But these giant rocks are certainly not limestone.

Boulders are strewn everywhere.

It looks as though they've been tipped off the back of a lorry and allowed to lie where they fell.

This field is covered in them.

They look distinctly out of place.

You can see that when you look at the rocks.

Down here the native limestone

and on top of it something completely different -

darker, lime-green lichens growing all over it,

and it's perched here like a golf ball on a tee.

You'd have to be a giant to sink a birdie with a ball this size,

and people did used to think they were left here by quarrelling giants throwing stones at each other.

At the time, it was the only explanation,

because some of these stones come from Northumberland, 100 miles away.

But giants aren't the only ones strong enough to shift these giant boulders.

For a less fanciful, but equally impressive explanation

we need to look again at Britain's icy past.

This is a glacier -

it's a river of ice.

Glaciers are majestic, impressive,

but fickle and dangerous.

If I'm going to explain the mystery of Yorkshire's stones,

I have to venture deep into the glacier's icy heart.

I've come to Norway and the Jostedalsbreen Glacier.

It's an eerily silent world of natural ice sculptures and snow,

but in truth, it's not so quiet, if you know how to listen to it.

If you take an ice pick

and make a hole in the ice...

..you can stick in one of these.

This is a geologist's microphone.

If I pack it down in there and then listen to what goes on...

CRUNCHY CREAKING

Amazing.

It's like a tall ship under full sail creaking.

SLOW, GENTLE CREAKING

CREAKING CONTINUES

GHOSTLY CREAKING

I don't know that I want to be sitting here.

It may look static, but it's most certainly on the move.

CREAKING

And these things are so big, that when they're on the move,

they're almost impossible to stop.

The movement is too slow to see,

but time-lapse cameras

show that the whole thing is slowly sliding downhill.

The sheer weight of the glacier helps to keep things moving.

The pressure on the underside is so great, that the ice melts, and acts as a lubricant.

It's the same principle that kept Torvill and Dean's skates

sliding effortlessly on the ice.

As the glaciers move, they tear up rocks from the ground,

which then freeze to their base.

They turn the whole thing into an enormous moving sheet of icy sandpaper.

When the ice melted, as it did in Yorkshire about 12,000 years ago,

the glacier's cargo of rocks was dumped miles away from home.

Because they're so out of place, these rocks are called erratics.

It's a lovely term for such inconsistent, irregular features in the landscape.

Once they were scattered all over Britain,

but over the centuries they've been tidied away by farmers, builders and gardeners.

But wherever they do still exist, they're a fascinating reminder of our glacial past.

The icy, glacial sandpaper did more than move a few boulders across the land.

Glaciers reshaped everything in their path.

They gouged out some of the British Isles' most spectacular landscapes.

Here in Killarney, in Southwest Ireland, just as in my native Yorkshire Dales

or the Lake District, or the uplands of Scotland and Wales,

the entire landscape was sculpted by ice.

This is a classic glacial valley -

broad and steep-sided -

and you can just imagine the ice bulldozing its way down here.

The surprising thing is that it only receded 15,000 years ago,

and in geological terms that's very recent.

In people terms, it's only 750 generations back!

It seems amazing that our landscape, which appears so timeless,

was formed so recently.

It's the most striking ice age land forms, the spectacular mountains and valleys,

that we've retained as wilderness on our crowded islands.

These upland sanctuaries provide a refuge for some of our most treasured wildlife.

Here animals can still live out their lives, relatively undisturbed.

The Highlands of Scotland belong to soaring golden eagles...

..and majestic red deer.

But they're also a refuge for some of our rarest animals, those that are shy of people...

..like pine martens...

..and others, such as red squirrels,

that are being pushed out by foreign intruders.

But was all of Britain covered by ice?

To find out, I'm taking a journey underground.

If you work in London and you take the tube,

to pass the time between stations, you'll probably read a novel.

But the tunnels themselves have a story to tell

and a secret to reveal.

When they dug the underground tunnels, all those years ago,

the soil they took out was all the same kind of clay and gravel, just as you'd expect...

until they got here, when suddenly it changed...

at Finchley Road.

Finchley Road tube station was the end of the line for Britain's enormous wall of ice.

When the ice melted, it left behind its load of distinctly different rocks and soils

that showed exactly where the ice stopped.

You can follow that boundary all the way across Southern England,

from Bristol, past Oxford to London's Finchley Road.

If the M4 had existed back then, you could have admired the edge of the ice sheet and its glaciers

all the way along its length.

This meant that to the south of the M4, conditions were very different.

To find out just how different,

I'll have to look for clues in a rather unexpected place.

Yes, unlikely as it may seem,

that "place" is on board a fishing boat.

Somewhere out here is more evidence of Britain's past.

This is the North Sea, 80 miles off the British coast, and I'm on a fishing trip with a difference.

I'm hoping to catch something a bit out of the ordinary.

What can a net load of starfish and crabs

tell us about conditions south of the vast ice sheet?

Well, nothing, but if you're lucky,

they're not the only things you can catch.

I'm here with Dick Moll, a specialist not in fish and crabs, but fossils.

Although, even with his help, finding what we're looking for is harder than expected.

-That's wood, isn't it? Not a...yeah.

-That's a tree.

A tree. Gardening, you see(!)

-Wood.

-Wood!

Wood!

What is that?

-Wood?

-Wood.

-Is that a bit of rib?

-No, wood.

-Oh, wood!

But with the next catch, we struck lucky.

What does this look like to you?

A tusk?

Exactly. This trawler isn't after fish or crabs,

it's fishing for mammoths.

It's a good specimen, as well.

-Excellent!

-It weighs a ton!

-Heavy?

-Very heavy. Ivory?

This is pure ivory, but fossilised.

From the bottom of our very own North Sea,

we'd just pulled up the tusk of a pre-historic mammoth.

Amazing as this was for me, out here, it's an everyday occurrence.

And it wasn't just tusks.

Don't tell me, this is the back leg of a mammoth!

-Is this the front leg?

-It's the front leg...top part.

-Have we got two pieces of one leg? Maybe?

-Maybe one animal.

These were big animals.

It'd take some dog to get its jaws around this!

So far, the remains of 50,000 mammoths

have been found at the bottom of the North Sea.

Fishermen first discovered the bones over 100 years ago.

They gave them to the local doctor for identification.

And he announced that finally, this was evidence of Noah's flood.

While opinions on Noah are divided, they were right about the flood.

During the Ice Age, so much water was locked up in glaciers and ice sheets,

that sea levels around the world were much lower than today.

The North Sea didn't exist

and the Thames was a mere tributary of the ancient German Rhine,

which ran down the middle of where the English Channel is today.

All around, was a vast plain,

a tundra, that stretched between Britain and mainland Europe.

It looked like Northern Siberia.

In the winter months, this was a cold and barren place.

Only animals adapted to sub-zero temperatures could survive.

Mammoths stood 11ft at the shoulder,

had six inches of fat under their skin

and their insulating hair was 3ft long.

Bison were here too.

At times, Southern England's deep freeze was well stocked.

Packs of Arctic wolves would have made the most of it, picking off the young and the weak.

Come the spring, there was a partial thaw,

when the land teemed with life.

In the short summer, the rich pastures attracted huge herds of grazing animals from the south.

The lower sea level meant that animals could walk to these summer pastures from mainland Europe,

across what's now the English Channel.

Imagine a great migration, like those we see today in Alaska and Siberia,

actually crossing the South Downs.

Caribou and strange antelope, called saiga,

travel with the changing seasons.

The saiga's enlarged nose enables it to breathe more easily in the icy air.

This is what life could well have looked like on the land that's now below the North Sea.

Following the herds during the late ice age, was another cold-adapted creature,

a predator that hunted not with sharp claws and teeth,

but with a sharp mind.

The first humans had arrived in Britain.

One group was well adapted to the cold - the Neanderthals.

Even though they were around for 200,000 years,

they didn't leave all that much evidence, but there's enough,

like Neanderthal bones found at Lynford in Norfolk, to give us a picture of how they lived.

The popular image of Neanderthals is that they were brutish,

uncivilised and that they spoke in grunts, but we know that's not true.

They cared for the sick and elderly, they buried their dead,

and they had a sophisticated vocabulary. What did they look like?

These make-up artists transform actors for films and TV.

They were about to give me a taste of what life might be like as a Neanderthal.

By studying fossils, we know that although a Neanderthal's skull shape

was basically the same as ours, there were differences.

Like chimpanzees and gorillas they had pronounced brow ridges.

Scientists think these were a leftover from their primate past.

Modern humans have lost them completely.

As well as a new forehead,

I was going to be fitted with a winning smile.

You'll have to push your top lip out. Push out your lower lip.

A Neanderthal's teeth would have been worn down from years of chewing tough meat, and cracking bones.

Theirs were more prominent teeth than ours,

and the surrounding jaw muscles were stronger and larger.

The most obvious difference was the nose...

large and broad,

for very good reasons.

It was packed with sinuses that warmed the freezing air, like the enormous nose of the Saiga antelope.

It made it easier to breathe and be active in the cold.

I was beginning to feel very odd.

Who's a pretty boy, then?

Not even my wife would recognise me now.

The attention to detail is amazing.

Skin colour, skin pores, wrinkles.

Everything is finely sculpted and painted by hand.

Neanderthals probably didn't shave so would have had facial hair.

But there's no evidence they were hairier than us.

And they probably didn't worry too much about hairstyle.

I can't believe anyone would know it was me.

I don't think I do.

Transformation complete.

In just four hours I've turned into a caveman.

Some scientists think Neanderthals were so closely related to us,

that if one walked down the street today, no-one would notice.

Now there's a challenge I can't refuse.

For someone who is used to being recognised in the street, it was quite nice to be lost in the crowd.

Most people didn't give me a second look.

Although occasionally I got a sideways glance...

just briefly.

Neanderthals may have lived in caves.

They may have survived the worst conditions Britain has ever seen.

They may have disappeared 30,000 years ago.

But what this little experiment shows is that, really,

Neanderthals may not have been that different from us,

after all.

But they were certainly better suited to a life in Ice Age Britain.

Their short, stocky bodies helped conserve heat, and powerful muscles

turned them into endurance athletes.

And they needed to be fit.

Neanderthals were real meat lovers.

Analysing their bones shows that it made up most of their diet.

The problem was finding it.

Southern Britain didn't have much in the way of plants,

and although the land bridge was handy for cross-channel visits,

not many animals could be found there in the winter months.

Hunting parties would travel for miles in the hope of finding real bounty

And a mammoth, by anyone's standards, is more than a mouthful.

But how could such small people tackle such huge creatures?

Well, they were bright, these Neanderthals.

They turned the natural landscape into a death trap.

They drove their prey over the edge of cliffs.

And this is one of those cliff-side traps discovered on Jersey,

in the Channel Islands, at La Cotte de St Brelade.

Mammoths met their deaths at the base of these cliffs.

Their bones - an evidence of Neanderthal butchery -

have been found right here.

They may have been cavemen, but they were cunning.

But all this talk of mammoths and Neanderthals,

glaciers and ice sheets, is telling only half the story.

For most of the last two million years the Ice Age was certainly cold,

but there's a final twist to this tale in London.

When Trafalgar Square - this great monument to Nelson -

was being built in the 1830s,

the builders dug up an extraordinary collection of exotic bones.

And these bones had a history and a story to tell.

Take this, for example.

It's 120,000 years old, and that places it slap bang in the middle of the Ice Age.

But it's not from a woolly mammoth or a polar bear.

It's from an animal you'd least expect to find in the cold.

This is the tooth of a hippopotamus.

They also found the bones of other animals that would now be more at home in Africa -

hyenas, lions, rhinoceros, and even the tooth of an elephant -

straight-tusked, mind you.

So what are these animals doing in Britain in the middle of the Ice Age?

Well, we now know that the Ice Age was not unrelentingly cold.

It was punctuated by warmer periods, some of them much warmer even than today.

And these bones prove that 120,000 years ago, right here in the centre of London,

the icy wilderness was replaced by Serengeti Plains.

It's hard to believe there could have been such dramatic swings in the climate and the wildlife.

Glaciers to swamps.

Mammoths to hippos.

But there's no doubt that's what happened here, and over much of the rest of the country too.

On safari...

in the Ice Age?

Well, the term "Ice Age" is a bit misleading actually.

"Dramatic Change Age" would be more accurate.

Wherever you live, the locality would have been gripped in ice for several thousand years,

then a warmer period would have come, then more ice and then another warmer period and so on.

In fact scientists reckon

there could have been as many as 30 separate ice ages over the last two million years.

Why have there been so many climate swings?

Because the Earth doesn't orbit the sun in a perfect and unvarying circle.

While it's orbiting it also tilts on its axis very slowly over thousands of years,

and as it tilts closer to the sun it gets warmer,

and as it tilts away from the sun, it gets cooler - cool enough to cause an Ice Age.

Around 15,000 years ago the northern hemisphere started to tilt towards the sun once again.

The great ice sheets began to melt and Britain was eventually released from its icy tomb.

As the ice disappeared so did the tundra, and the animals that lived on it.

And from beneath the ice, a very different landscape was about to emerge.

Mountains, lochs, hills and valleys...

when the ice retreated, most, if not all, of our countryside had been affected in some way,

either by the ice itself or by the torrents of water that flowed from the melting glaciers.

Everything had been altered irrevocably.

So, has the Ice Age left us completely?

Not quite.

In the remotest glens,

on the highest peaks,

it lingers even now -

in places like Rannoch Moor, where I started this journey.

If Britain is ever gripped by another ice age, this is where it will start.

And up here, as if waiting for that time to come again,

some refugees from the last big freeze can still be found.

The ptarmigan lives on the highest mountains in Scotland.

It's white winter plumage - a reminder of its Arctic roots.

This place is also home to Arctic hares.

Their shorter ears and longer hair help to keen them warm.

As the ice retreated these animals took refuge in our chilly uplands.

The last isolated pockets of Ice Age Britain.

The landscape we see today is almost entirely the result of that most recent ice age.

There's no reason to assume it'll be the last.

This is probably just a warm period before the next big freeze.

But the most dramatic effect of the last one was that when the ice melted,

the level of the world's seas rose.

Our land was cut off from mainland Europe.

The British Isles were born.