(tense music)
- [Narrator] It can be a stone cold k*ller.
And centuries ago, millions
fell victim to its wrath.
- [Kyle] If a hundred mile
per hour chunk of ice hits you
in the head, it can very easily k*ll you.
- [Narrator] How could
ice become so violent
and so powerful as to
nearly wipe out civilization
while carving out some of
America's most natural wonders?
- [Steve] It moved the
position of the Mississippi River.
- [Narrator] And has this
frozen fury of our ancient past
become the slippery slope
towards our future demise?
- As we move into the future,
if the climate state is such
that we can have severe storms
and severe weather
events coming in every year,
adapting to that kind of
extreme is very difficult.
We don't know what to prepare for.
- [Narrator] Earth, air, fire, and water,
essential for human survival,
but in their extreme...
- [Man] Coming down
right now, make your turn.
- [Narrator] To everything
and everyone in their path.
- [Man] Oh, big power black.
- Wow. - Whoa, whoa!
- [Narrator] These are stories
of Apocalypse Earth.
With every bone chilling
winter storm come predictions
of a new Ice Age.
Extended periods of freezing rain,
blinding snow storms, and
Arctic air lead many scientists
to predict a return to a frozen earth,
not seen for thousands of years.
A time when our planet was
covered in massive ice sheets
with the power to change the
shape of continents and oceans.
Evidence from the past could
provide key clues to when
and if we return to another Ice Age.
Some scientists predict
that the world is entering
a period of extreme climate disturbance.
Freezing temperatures could grip Europe
and the Northeastern
Coast of the United States,
while other regions suffer
from drought and flood.
It has happened before. (ominous music)
(bell tolling)
Generations had prospered
in the stable weather
of pre-Renaissance Europe,
but in the 1300s, without warning,
that predictable world
was turned upside down
by the so-called Little Ice Age.
- One of the things that happened was that
you had this whipsaw
going to warm, going to cold.
1309 was cold.
1315 was warm.
1317 is cold again.
And creatures and other
things respond in different ways.
You get crops rotting in
the field if it gets too wet
or germinating too early
or never germinating at all.
- [Narrator] The climate
rapidly switched back and forth
between cold and warm; wet, and dry.
But this initial erratic
climate was only a prelude
to catastrophic changes
of epic proportions.
Over the next few
centuries, (thunder crackles)
the weather continually
fluctuated at temperatures
between 0.5 and three
degrees lower than normal.
This small change was
enough to awaken an icy k*ller.
- Throughout the Alps and
throughout parts of Europe
and in fact, in North America, and Canada,
the Eastern Canadian Arctic,
we see evidence that during
The Little Ice Age, glaciers advanced.
- [Narrator] The difference
of only a few degrees
triggered a self-perpetuating
feedback cycle.
- You make a little more ice,
it reflects more of the sun.
By reflecting the sun,
the sun is not warming
us up and so it gets colder,
so you make more ice.
- [Narrator] As the glaciers expanded,
the Vikings took the first brunt
of the climate's deadly chill.
- They switched from
being a farming economy
to eating a lot from the sea
because they were having
troubles raising enough
things on their farms, apparently.
- [Narrator] But as
temperatures continue to drop,
storms and freezing winds
blasted the settlements,
even the sea held no hope of survival
for the starving Vikings.
- Around Iceland, sea ice expanded,
and the people couldn't
get out and go fishing.
And they had open
boats, not boats with decks,
so they were particularly
vulnerable to bad weather.
- [Narrator] After decades of expansion,
battle ax wielding, pillaging,
and plundering Vikings
were defeated by a
sudden drop in temperature.
(tense music)
- Well, 10 super cold years,
including one of the
coldest years on record ever
in about 1355 AD shut down Western colony
and a hundred years later,
the more Southerly
Eastern colonies shut down.
- [Narrator] The Vikings who survived
migrated south,
assimilating into populations
living in continental Europe.
Their fearless culture
receded into history.
If it hadn't been for The Little Ice Age,
the Vikings may have continued
settling in the New World
and today's America would
be a very different place.
By the end of the 14th Century,
Europe was buckling
under freezing temperatures
all winter long.
In a chain reaction ignited by
the cold and stormy weather,
one calamity followed another.
Crops failed and food
shortages spread across Europe.
The freezing cold blasted through Asia,
but that was only the beginning.
Relentless storms
k*lled at least 7 million.
The resulting floods produced
a horrific and infamous
blowback effect on Europe.
- Everybody's familiar
with the Black Death,
but the lesser known story of course
is the role that climate may have played
in unleashing it.
(ominous music)
- [Narrator] The Black Death or The Plague
was a devastating pandemic
that ravaged Europe
during the mid 14th Century.
(thunder rumbles)
The drop in temperature
changed weather conditions
causing storm patterns
to shift and intensify.
In the early 1300s,
Asia had a record breaking
series of torrential storms
and subsequent flooding.
Rats carrying the plague
thrived to these conditions.
- The animals that react
at the first are the ones
that reproduced by the zillions
and reproduce very rapidly,
where as the longer lived,
slower reproducing animals
tend to lag.
And so weedy species of every
sort seem to take advantage
of climate change and flood.
- [Narrator] Rats on ships
traveling the trade groups
spread the disease from Asia to Europe.
An already starving and
weakened population was no match
for the Black Death.
Within five years, the plague had k*lled
between 25 and 34 million people in Europe,
one-third of the population.
An estimated 40 million more
died in North Africa and Asia.
Generation after generation suffered
the relentless pounding of
extreme cold and wet weather,
pushing the starving peasant to his limit.
- Then there intense
storms and incessant rain.
Crops are rotting in the field.
There's so little sunlight
that you can't make salt
in the summer to preserve anything.
Diseases, molds, blights,
and everything else
we're beginning to afflict them.
People fell into robbery,
they lost their land, starvation.
They started eating their
livestock, dogs, and cats.
And at some point,
they even ate each other.
- [Narrator] Sophisticated
European societies
quickly crumbled, scratching
at the edges of mere survival.
Starving peasants revolted
against the aristocracy.
The political unrest and an
economic crash in England
were factors in the American Revolution.
And it was the poor of 1789 France
that fueled the French Revolution.
(tense music)
The tragic scope of The
Little Ice Age was staggering.
Millions died horrible
deaths simply because
the temperature dropped a few degrees.
- You're living on the edge
and you get just a little bit
of a cooling, it can
push you over the edge.
- Little changes in global temperatures
can have an enormous effect.
A temperature change
of five to nine degrees,
which is also within
the realm of possibility,
would just be unimaginable.
- [Narrator] The small drop in temperature
that triggered The Little Ice Age
may have been caused
by a dimming of solar output
linked to a change in sunspot activity.
(tense music)
Another factor that intensified the cooling
was something else no one
could have predicted or prevented.
During the Little Ice Age,
at least three massive volcanoes erupted:
Mt. Vesuvius in 1631, Mt. Tambora in 1815,
and Krakatoa in 1883.
All spewed particles and
gases into the upper atmosphere.
These particulates
reflected the sunlight back
into the atmosphere, cooling the earth.
- If you put a lot of volcanic debris
high into the northern hemisphere,
it's going to be everywhere
in the northern hemisphere
within just a couple of years.
No matter what part of
the earth is facing the sun
day or night, it's still
going to get less sunlight.
- [Narrator] After six centuries
of death and deprivation,
the weather finally began to warm.
- So, the Little Ice Age likely ends,
because the volcanoes quiet down,
they're not blocking the
sun, and the sun brightens
up a little bit.
So, you have warming
coming out of 1850 or 1900
into the early part of the 1900s.
- [Narrator] The Little
Ice Age may be over,
but some scientists see it as a preview
of what could occur again,
this time with even more
devastating consequences.
Coming up.
(speaking in foreign language)
- [Interpreter] How could
a snow cloud of that size
not bury whoever was
on the face when it hit?
- [Narrator] Some experts
believe that global warming
could paradoxically catapult parts
of the Northern Hemisphere
into a new Little Ice Age.
(tense music)
rn Seaboard
and Western Europe would be battered
by severe winter blizzards and ice storms.
(wind howling)
Proponents believe this
big chill would be triggered
by changes in the Atlantic Ocean.
70% of the earth's surface is ocean.
90% of all rain falls into the seas.
It is a colossal reservoir
of water carrying heat
all over the planet.
A huge ocean current system known
as the Thermohaline Circulation,
which includes the Gulf
Stream circulates warm water
north from the equator,
giving our Northeastern
Seaboard and parts of Europe
relatively temperate climates.
London, England, and Calgary, Canada
are on the same latitude,
yet London is much warmer on average.
The reason: the Thermohaline Circulation,
which brings warm
Atlantic water and air North
to the British Isles.
As the heat is absorbed
into the atmosphere,
the surface water becomes
colder, saltier, and dense.
It sinks deeply, in effect pulling
the current down behind it.
- So in the winter as
the water gets really cold,
and colder makes it contract
and contracting makes it denser
and then it sinks and
then warm water flows up
to replace it.
- [Narrator] In a self perpetuating cycle,
the thermohaline
circulation then moves south
where it warms again at the equator
and continues its cycle back up north.
This immense system is
dependent upon a delicate balance
between warm and cold
water and fresh and salt water.
Some experts believe that global warming
could disrupt this delicate system
and in a worst case
scenario create a mini Ice Age
in parts of the Northern Hemisphere.
- The oceans are warming.
Almost all the glaciers on the planet
have gotten smaller over
the last hundred years.
You're getting reductions
in sea ice in the Arctic.
Things are happening earlier in the spring
and lasting further into the fall
than they did in the past.
And so this is great
number of indicators that say,
yes, the planet is warming.
- [Narrator] According
to the Big Freeze Theory,
the rise in the ocean temperatures
could cause a shutdown
in the thermohaline
circulation that brings warmth
to the North Atlantic region.
- The total heat capacity
of the ocean is 1,100 times
that of the atmosphere.
So in my mind we really
should be trying to understand
what's going on in the ocean
to understand our future climate.
- [Narrator] Researchers from Woods Hole
Oceanographic
Institution utilize many tools
to study the changing ocean.
Remote-controlled devices
called floaters track changes
in the ocean's condition.
- They're sort of like
weather balloons for the ocean
that drift at depths for 10 days
then come to the surface reporting
the temperature and salinity as they rise
and they transmit that data to a satellite.
And we have a program to
deploy thousands of these
around the global ocean.
- [Narrator] Using the
data transmitted by tools
like floaters, scientists
create computer models
that track and then
project climate changes.
(beeping)
(crashes)
Researchers continue to find evidence
of a disturbing development:
global warming is melting
glaciers and ice sheets
causing an increase in fresh water
flowing into the thermohaline circulation,
a process they call freshening.
This fresh water could
throw off the critical balance
between temperature and salinity
that powers the thermohaline circulation.
- What it means is that those warm waters
no longer flow north and they
stopped much further south.
And so all that warmth
that would otherwise warm
the Northern Hemisphere
stays in the south, which means,
for example, there's more
energy in the atmosphere.
There are more extreme storms and so on,
but critically much colder in the north.
- [Narrator] Some experts think that if
the thermohaline circulation is disrupted,
temperatures could drop dramatically
in the North Atlantic
leading to a new Little Ice Age
in North America and Europe.
- If the thermohaline
circulation was to shut down,
the average temperature
changes resulting of that
could be anywhere between
eight to 12 degrees possibly,
but that would be on average.
And clearly the extremes that
could resolve from an average
temperature change like
that could be well beyond that.
- England France, Germany would begin
to resemble Alaska and Canada.
And those parts of the
world, particularly Alaska,
might even get colder still.
- [Narrator] In the United States,
the Northeast Coast
would be hit the hardest
with extreme temperatures
and more intense blizzards and storms.
- For example, severity
of nor'easter storms
could easily increase in
a condition where you had
increased storminess, increased wind
velocities impacting the
eastern North America.
- [Narrator] Some
experts doubt this big chill
would be nearly so dramatic,
that it would in fact be only a side effect
of the real devastation
in other parts of the world.
In the Pacific, a warmer
ocean will intensify
the El Nino rainstorm
cycle that historically batters
the Pacific Coastline.
- Even a two-degree
change if we were so lucky,
would be double the intensity
or more of the strongest
El Nino we've ever felt.
In 1998, there was a very strong El Nino,
did $100-billion damage
around the world and k*lled
tens of thousands of people.
So, even a very slight
variation from the norm
in global weather can
cause a lot of damage.
- [Narrator] In the South Atlantic,
warmer oceans will
mean intensified hurricanes
and massive storms.
- The fact that we have a
great deal of heat built up
in the ocean means
that there's plenty of fuel
for more intense hurricanes.
So it seems inevitable
that strong hurricanes
are in our future.
- If we get not just one Katrina,
but if we get five Katrinas per year
coming into different
regions of the Gulf coast
or in fact shifting to
where now these storms
are impacting along the eastern seaboard
and coming into Washington
DC and New York City,
then the consequences would be severe.
- [Narrator] And warming
oceans and warmer air
could threaten the largest
source of frozen fresh water
on the planet, massive
ice sheets at the poles.
Melting those could result in floods
never before seen on our planet.
Snow and ice can rapidly
become a deadly mix,
especially for hardcore adventure seekers.
(tense music)
The Himalayas.
This mountain range in Nepal is home
to the 14 highest peaks on earth.
It's most treacherous, the
one known is Annapurna.
- You have a mountain
that's over 26,000 feet
and a canyon right next to it going down
to only three or 4,000 feet,
so the vertical relief is just amazing.
- [Narrator] But it's a hidden danger
that gives Annapurna her
deadly reputation: avalanches.
- Over 40% of the climbers
who attempt Annapurna
do not come home.
For comparison, Mount Everest,
which is the tallest mountain
on the planet only has about
a 9% death rate.
- Looking at Annapurna you
can see why the avalanches
are so prevalent.
See those dark rock
layers leaning out of the hill,
looking like slides in a
playground for the snow
to slide off of and see that
U-shaped glacial valley there
acting like a funnel funneling
the avalanches down.
And for some reason, the
climbers like to go up that,
but that's like playing Russian roulette.
One out of five of them
are going to be k*lled.
- [Narrator] In the fall of 1997,
Annapurna is heavy with
a million tons of fresh snow
lying in wait for her next victims.
On a year long quest to
scale the world's highest peak,
veteran mountain climbers
Jesus and Jose Novas
had been in the Himalayas for months.
To document their triumph over Annapurna,
the brothers hire
cameraman Alejandro Rocha.
They brush off forewarnings
of the mountain's short temper.
(speaking in foreign langauge)
- [Interpreter] There were conditions
that could be considered favorable
to provoking an avalanche,
but you're always sure
that it won't happen.
- [Narrator] As they set
up camp at 19,000 feet,
the signs of impending disaster are clear.
(tense music)
- These guys are very well aware
that an avalanches occur.
Avalanches occur on Annapurna all the time.
If you get heavy snow and warming,
you are going to have an avalanche.
- [Narrator] Ignoring the risk,
Jesus and Jose make their ascent.
They're halfway up the
cliff face when Annapurna
springs her trap.
(suspenseful music)
A rippling frozen surge, 6,500 feet wide
careens down the mountain
at eighty miles per hour.
Alejandro watches in
terror as the snow pack
swallows his friends.
(speaks in foreign language)
Then he realizes he could be next.
(speaks in foreign language)
- [Interpreter] The cloud
was getting bigger and bigger,
it was like this big white
cloud, a huge heap of snow.
- [Narrator] Helpless and terrified,
Alejandro retreats to his only shelter,
waiting for the worst.
[Bleep]
The cameraman braces
against Annapurna's fury
as he pummels the tent with snow and ice.
(suspenseful music)
[Bleep]
Remarkably, Alejandro survives the attack.
Immediately, his thoughts
turn to the two climbers outside.
He peeks out, not knowing what he'll find.
The entire snow face, all 2,600 feet of it
has plummeted down the mountain
and the Novas brothers
are nowhere in sight.
(speaking in foreign language)
If they're still alive, it
may be only minutes
before Jesus and Jose
suffocate under tons of snow.
(speaking in foreign language)
- [Interpreter] How could
a snow cloud of that size
not bury whoever was
on the face when it hit?
- [Narrator] He scans the cliffs
desperate for any sign of life.
Finally, his camera
catches two tiny figures,
halfway up the slope.
It's Jesus and Jose
clinging to the cliff side.
- [Interpreter] I saw them
and I screamed at them
asking them if they were okay.
(speaking in foreign language)
Since I only saw two tiny
dots, quickly descending.
- [Narrator] Trudging
through waist-deep snow,
the climbers returned to camp.
(speaking in foreign language)
(man laughs)
- [Narrator] Astonished that Annapurna
has failed to bury them alive.
- [Interpreter] The avalanche
was a total surprise.
All of a sudden we
heard a crack like a boom.
It was as if something broke.
It was a dissonant bang, boom!
I said an avalanche, quick,
quick, we'll hide over here.
In no time, in just a matter of seconds,
the avalanche was on top of us.
The cliff protected us from
everything that was falling
from above, forming something of a shield.
We were under there
for about a minute or so.
It was very difficult to breath.
(speaking in foreign language)
- [Interpreter] I got as
close to the wall as possible
to avoid being hit by the chunks of ice.
We were only thinking of not falling down,
of holding on with the ice axes.
- You really have to
admire the quick thinking
of the two climbers.
To see an avalanche bearing
down on them so rapidly
and to be able to take cover
that quickly is really amazing.
- They talk about suffocating
for not being able to breathe,
but that's a heck of a
lot better than being hit
by tons of wet snow.
- [Narrator] All three
mountaineers are lucky to survive,
a rare instance of
Annapurna missing her targets.
In more recent years,
another disaster on
Annapurna would prove the rarity
of their survival.
In January of 2020, several South Korean
school teachers went missing.
Their bodies, not
discovered until that spring.
Annapurna with about one in three climbers
failing to survive the ascent
remains the deadliest
mountain in the world.
- The fatality rate for Annapurna seems
to be very, very high because
of its great prevalence of avalanches.
Inclined rock layers that are
easy for snow to slide off of
and climbers going up
glacial valleys funnels
where avalanches are directed into.
Very hard to avoid the avalanches.
Very easy to die on this mountain.
(tense music)
- [Narrator] Each day, several
hundred million metric tons
of ice on the polar ice sheet
are lost perhaps forever.
This alarms scientists
because ice sheets cover nearly
1/10th of the earth's land
and contain about 70%
the planet's fresh water.
- The potential melting
from the big ice sheets
of Greenland and Antarctica,
those are really the gorillas
in the wood shed if you
wanna talk about problems.
Far bigger than what we would get
from a few glaciers melting.
That's really a key for
civilization in this century,
what's gonna happen to the ice sheets?
- [Narrator] The same ominous phenomenon
is taking place all over the world.
The renowned snows of Mount
Kilimanjaro are disappearing.
The frozen current of
the Andes are drying up.
And the glaciers in Montana's
Glacier National Park
are vanishing.
This full blown retreat
of glaciers is the result
of an overall warming
trend across the globe.
The world's oceans are heating up.
- The climate system is changing
and it's changing at a rate
that compared to previous
decades and centuries is quite rapid.
- [Narrator] And warmer
seas mean rising sea levels.
- As water warms, it expands
so warmer water actually
takes up more volume and
increases the sea level as well.
- [Narrator] Scientists are
predicting a rise in sea level
of one to four feet by
the end of the century.
But if the significant portion
of the polar ice caps melt,
it could be much more.
- It's not totally unrealistic
to think that sea level rise
could be maybe up to 10 feet
between now and 2100.
There's a lot of ice in West Antarctica.
It's grounded below sea level
and it's inherently unstable.
So, we are concerned it
could slip away very rapidly.
And this alone could
raise sea level by 15 feet.
- [Narrator] Low lying coastal
areas could be devastated.
Entire Island nations in the South Pacific
could be swallowed by the sea.
In Bangladesh, the rice paddies
that feed millions of people
could disappear under salt water.
Untold numbers of these
people could be displaced
and become climate refugees.
And some of America's great cities:
Miami, Baltimore, New York, and Boston
may see their most expensive
waterfront properties washed away.
Even worse, warmer oceans
will cause more intense
tropical storms and hurricanes.
- A hurricane is a heat engine.
It's a monster that
devours heat and it gets it
from the upper layers of
the ocean and so the warmer
the ocean the more heat
for the hurricane to develop.
- [Narrator] Melting glaciers
could be the first sign
of this impending
environmental catastrophe.
A glacier is a slow moving
river of frozen water,
a tremendous accumulation of
snow compacted by the pressure
of its weight and turn to ice.
- It oozes very, very
slowly under the weight
of its own gravity and that's the key.
A glacier has to move, in
order to be called a glacier.
- [Narrator] Some of
these frozen rivers of ice
move as fast as two miles per hour.
During the last Ice Age,
they carved entire landscapes out of rock.
A glacial system may
be as large as a continent
or as small as a tiny
valley between mountains.
Each year when the snow
falls, new ice is added.
- A healthy glacier is one
that's getting plenty of winter
snow pack and is not melting
too much in the summer,
then it can maintain its
mass or it can even grow.
- [Narrator] These mountain
glaciers have been here
for more than 10,000 years.
Today, scientists are
monitoring their health
on a day-to-day basis.
They predict that every
one of these glaciers
will be gone by the year 2050,
but the life span of
mountain glaciers is short
compared to the rivers of ice that flow off
the polar ice sheets.
Many of these are more
than 500,000 years old.
It is these polar glaciers
that are even more crucial
to the future of the planet.
Just in terms of mass, the
polar ice caps are astounding.
- Antarctica is not at the human scale.
It's huge.
If you actually wanna count
all the individual glaciers
in Antarctica, you're talking about tens
of thousands of glaciers.
- [Narrator] Difficult to get to,
Antarctica, the seventh continent,
was not even discovered
until the 18th Century.
Since then, explorers and scientists
have been trying to gather information
about the polar ice sheets.
In particular, they wanna
know how quickly the ice caps
are melting, because this
information can tell us how fast
and how much the
world's sea levels will rise.
But the polar regions
have remained elusive.
- You have to realize that
maybe 30, 40 years ago,
we didn't even know
where all the glaciers were,
the important glaciers.
- [Narrator] For decades,
Greenland and Antarctica
proved to be too huge to accurately survey.
- What we relied on was
putting together hundreds
or thousands of individual
measurements taken
in the field by individual scientists
going and visiting a polar
ice cap and taking samples.
- [Narrator] The complete
picture of the polar regions
and all their glaciers has remained
an enormous jigsaw puzzle.
- There's no way from fieldwork
alone you could say anything
about the entire ice sheet with certainty
and with precision.
- [Narrator] Now scientists
say seeing the ice sheets
in their entirety may
be a matter of survival
for future generations.
- We really need to look at all of them,
detect the areas where
the changes are taking place
and keep an open mind
that it may not be just one
or two glaciers that are changing,
but it could be a whole coastal range
of several thousand kilometers
which is changing at the same time.
- [Narrator] These changes
in the polar ice sheets
and glaciers could spell disaster.
And what these scientists
discovered could have
a life or death impact
on millions of people
around the world.
St spectacular
photographic evidence of nature's fury,
it is by far not the only
hazard faced by those
sitting below tons of
unstable ice and snow.
(tense music)
Namestovo, Slovakia.
It's a thrilling day for
a 150 of the country's
junior hockey players.
They get to meet their idol:
13-year NHL veteran Richard Zednik.
The Slovak native survived
a brush with death in 2008,
when a player's skate cut his neck.
He never expected that a
casual Sunday training session
with his home country's up and coming stars
could also turn deadly.
But just over their heads,
mother nature is putting
the finishing touches
on a sinister plot.
- [Narrator] In Northern Europe,
there's a lot of heavy winter weather.
Snow, ice, winter storms,
seemingly everyday weather
can lead to big problems.
- Snow might not seem
that dangerous when it falls,
but to a very large, very wide flat roof,
it can be very destructive.
- [Narrator] As the young
athletes practice their moves
on the ice, ominous noises
from above get their attention.
Suddenly, the roof cracks open and buckles,
threatening to k*ll everyone underneath.
Richard and the other
adults try to hustle the children
out of harm's way before
they're crushed to death.
They flee the collapsing
arena through passageways
along the perimeter that
remained free of rubble so far,
but everyone knows the rest
of the roof might easily cave in
before they find the exit.
- The ceiling essentially unzipped.
This was a large Quonset hut.
A Quonset hut is a steel arch.
And the one problem we see with arches
is drain drifting snow,
where all the snow will
drift to one side of the arch.
And that unbalanced load
can cause an arch to buckle.
- These kinds of buildings
are always a challenge.
How do you cover a large
area with enough strength
to stand up to a stress.
And here they failed the
test, the roof collapsed.
- [Narrator] The near
fatal disaster is anything
but a triumph homecoming
for Richard Zednik.
(speaks in foreign language)
- [Interpreter] It was complete horror
when it started to collapse.
Imagine suddenly a ceiling
falling straight on your head.
I looked around and saw people in panic.
In two or three seconds,
the ceiling was on the floor.
- Given the number of
people that were in this building
and out on the ice at the time the ceiling
began to collapse,
it's remarkable that everybody survived.
And it would have been very deadly
for anybody who had been under it.
- [Narrator] For centuries,
America's early geologists
were puzzled by mysterious
marks etched into the bedrock
of much of North America,
and by lonely mountain rock
randomly scattered across the land.
(thunder crashing)
Then in 1847, a newly-appointed
Harvard university professor
came up with a radical new idea.
Geologist Louis Agassiz
compared North America's
landscape and rocks
with the geology of mountain glaciers
in his native Switzerland.
And he built on theories he had developed
in this Swiss Alps a
decade earlier to declare that
North America had once
been buried deep under ice.
Agassiz's work at Harvard
made him world-famous in his day.
But the final proof of his Ice Age theory
had to wait until the 1950s,
when new evidence came from the seabed
of the Atlantic Ocean.
That evidence is still stored to this day
in this refrigerated
laboratory at Miami University.
These thousands of
plastic tubes offer scientists
a unique window to look back
at what the weather was like
on the ancient Earth.
- These records that
you see in this room here
basically are the primary
information we have now
about the climate changes we have had
over the last two million years.
So these are really starting points
that open people's eyes about changes
which occurred during glacial periods.
- [Narrator] The mud cores were collected
by oceanographer Cesare Emiliani.
The deeper he drilled, the
further back in time he went
and the older the sample
he pulled to the surface.
- These are cores of deep sea mud.
And within the mud are small organisms,
which record the
temperature and the salinity
and the other conditions
which were prevalent
when that organism lived.
- Those tiny undersea
creatures are called formanifera.
Their chemical makeup varies,
depending on the temperature of the water
in which they grow.
So the sea bugs in different layers of mud
act as tiny thermometers,
recording how hot or cold the Earth was
at different times in its past.
(haunting music)
They reveal that just
over two million years ago,
the average annual temperature
across the lower 48 states
was around 56 degrees Fahrenheit,
about three degrees
warmer than it is today.
Then, the temperature regularly
started crashing below zero
and staying there month after month.
(dramatic music)
Huge changes happening
in what, in geological terms,
was astonishing speed.
Within 10,000 years,
the year-round average
temperature bottomed out
at just 26 degrees Fahrenheit,
about the same as the average
winter temperature in Chicago.
Even today, scientists are uncertain
what caused the
temperature to drop so quickly.
Variations in the Earth's orbit,
a change and the tilt of its axis,
and even the creation of the
Himalayan mountain range
are all prime suspects.
But one thing is certain.
With subzero temperatures all year round,
snow never melted.
A major storm can drop more
than 40 million tons of snow.
The ever-increasing weight
of snow compacted down
into thick layers of solid ice.
America's Ice Age had begun.
The ice sheets, which built
up two million years ago,
began to move, flowing as huge glaciers
across the northern U.S.
- Some of the very
large rocks can be literally
frozen on and cut off from
the rock that they came from,
and just put it right into
glacier and moved that distance.
Hundreds of miles in the glacier,
like a conveyor belt, out
to where we finally find it
on the landscape or
in an outcrop like this.
- [Narrator] The
investigator's next challenge
is finding out just how far the ice flowed,
and for that task, they
are taking to the air.
In the early morning light,
Brown spots a mysterious small hill
standing out from the flat Illinois plain.
Stripped of its camouflage layer of trees,
the shape of the hill tells Brown
the secrets of its creation.
- This gently rolling landscape
extends for about 400 miles.
We look at the land forms
and how they're shaped,
And so we can use that to unravel
the history of the Ice Age.
(lively music)
- [Narrator] The landform Brown is studying
is a mound of rubble that
geologists call a moraine.
It is an accumulation
of debris that a glacier
has plucked up from
the Earth, dragged along,
and dumped at the front edge.
This hill marks the spot where the glacier
finally stopped flowing southward.
Geologists all over the U.S have recorded
the positions of other moraine hills,
helping them map out precisely how far
North America's ice sheets spread.
Nearly 2/3 of the North American continent
was buried under ice,
but the frozen chaos did not stop there.
The challenge now facing
geologists is figuring out
how ice created some of
modern North America's
most famous features.
Coming up.
- [Man] It's like a fricking w*r zone.
- It felt like at one point
we were under as*ault.
(dramatic music)
- [Narrator] Two million
years ago, temperatures fell,
and massive ice sheets
spread out as glaciers
across much of North America.
Geologists set out to discover
what the moving ice did
to the underlying land.
Everywhere the ice had flowed,
investigators discovered
the same puzzling feature.
Lines of stones, all laid
out the same particular way.
- Really good example
of pavement of stones,
this concentration of
small rocks and cobbles
that are collected here in a line.
It's just one, one stone
or two stones thick.
- [Narrator] Scientists realized
that the stone pavements
must have been laid down
at the base of a glacier.
And even the toughest rocks
had scratches and grooves
carved into their surface.
- [Steve] Glacier carries
along other fragments of rock.
And as it's doing so
it scratches, polishes,
creates grooves in the
rock called striations.
- [Narrator] Those
scratches offered vital clues
to help uncover the history of
how the Ice Age changed America.
- So by lining my compass parallel to
the striations on this rock,
the compass tells me
that the ice is flowing
from about the northeast,
from this direction to this direction.
- [Narrator] But other scratches on rocks
found all over the
northern parts of the U.S.
run in puzzlingly different directions.
These ice-scraped rocks
in New York's Central Park
show scratches made by a glacier
that arrived from the northwest.
There's only one explanation
of the different ways
in which the ice appears to have moved.
The scratches were not all
made by a single ice sheet
as first thought, but
by many different ones.
- This phenomenon of advance and retreat,
the changing of that landscape,
happened many times.
Not just once, but many times.
- [Narrator] Everywhere the ice flowed,
it marked the underlying blocks.
- The ice changed.
The existing conditions on
the landscape was changed.
The motion of the glacial debris
changed the whole way these areas look.
- [Narrator] Grinding over the landscape
at speeds of around two feet per day,
the massive glaciers diverted
the course of ancient rivers.
Even the mighty Mississippi
was no match for the ice.
- It moved the position
of the Mississippi River.
The Mississippi River used to flow
through the middle of Illinois.
- [Narrator] A glacier
advanced across the state
and created an ice dam
across the course of the old river.
A huge lake grew at the edge of the ice,
eventually over-spilled,
and cut a new river channel
80 miles to the west.
(stately music)
The same course that
it follows to this day.
And when the ice sheets melted away,
their impact on North
America was almost as great.
They produced immense floods of water,
which all had to drain away somewhere.
- It formed a completely new landscape,
with a new river mouth, a new channel,
completely rearranging the character
of the existing landscape.
- [Narrator] Where rocks were
soft, or weakened by faults,
the glaciers had carved out
huge basins in the landscape.
When the floods came,
these depressions
rapidly filled up with water.
- Every natural lake here in
Indiana, Illinois, Wisconsin,
were all created by glaciers.
- The biggest ice-scoured basins became
what we now call the Great Lakes.
These water-filled craters in
the North American landscape
are nearly five and a half
thousand cubic miles in size.
The water they hold t could drown the whole
of New York State to a
depth of more than 600 feet.
But even that is just a tiny fraction
of the total flood
unleashed as retreating ice
poured out nearly 39,000
cubic miles of water.
The flood rushed down Niagara Escarpment,
at the rate of 42 million gallons a minute,
one and a half Olympic-sized
swimming pools every second.
And that cut a gorge seven miles long
and 180 feet deep through solid rock.
The Ice Age had created one of
the modern wonders of
the world, Niagara Falls.
(haunting music)
The investigators' next
challenge was figuring out
why the ice advanced
and retreated so often.
It wasn't until the mid 1960s
that the first real clues were discovered.
The U.S. military was building bases
in some of the Earth's
most remote locations.
- [Newsreel Narrator] This
is an ideal arctic labratory,
permanently frozen under a polar ice cap
which covers all but a few
costal areas of the island.
Geologists realized the
cores of ice being extracted
by hollow drills held a
unique historical record.
(lively music)
Those cores and many others extracted since
are housed in a laboratory
in Denver, Colorado.
- We're in the Fort Knox of paleoclimate.
What you see in these tubes is gold
in terms of what we know about climate
and what we've learned about
climate over the last 50 years.
- [Narrator] These tubes contain
three-foot-long plugs of ice,
each dug out from layer
after layer of compacted snow.
But it is what is trapped inside the ice
that most fascinates the scientists.
As each year's snow falls onto the last,
it builds up and moves packed layers
that trap air between the snowflakes.
- Ice cores are the only archive we have,
really good archive we
have, of past atmosphere.
In an ice core, you can see tiny bubbles,
and those bubbles are
air, unadulterated air
from as much as a hundred
thousand to a million years ago.
- [Narrator] The deeper
the bubble, the older the air.
- It contains not only
a temperature signal,
but it contains dust signals.
It tells about atmospheric circulation.
It contains a record of the atmosphere,
and specifically the greenhouse gases.
- [Narrator] Each ice
layer corresponds with
the precise time in Earth's history
when its snow first fell.
So by analyzing the
bubbles from any one layer,
scientists can figure out what
Earth's atmosphere was like
at any point in the past.
- Over the last million years or so,
we see fairly regular pacing
of major, major glaciations,
roughly one every 100,000 years.
- [Narrator] Some theories
suggest those colder spells
coincide with variations in
the Earth's orbit around the sun.
But that's not the only
thing the ice cores revealed.
The cores that White
has been studying suggest
that the longer the ice age
went on, the worse it became.
- Somewhere around 400,000 years ago,
we went from a period
that had lesser glaciations,
if you will, to ones
that were very, very big.
- [Narrator] But new clues suggests that
the awesome impact of
America's Ice Age didn't stop there.
Coming up.
- You've got the snowfall moving down
the side of a steep-sloped mountain
at 60 to 80 miles per hour.
No one can run that fast.
(Music)
- [Narrator] From the modern
day remnants of glaciers past
to their deposits comes the question,
how did they get there?
What forces were in play
that could carve great crevices
and deep lines seen across North America?
The answers lie right at our feet,
in some of the most recognizable
outdoor spaces on Earth.
The first clue came in New
York State, on Bear Mountain.
- No one knows for sure how thick
the ice sheet was that
came from the northwest.
But right now, we're standing
at the top of Bear Mountain,
about 1,280 feet above sea level.
What we're looking at here
are a series of chatter marks.
These are features of glacial erosion,
and they're produced by
large blocks of solid rock
embedded in the base
of a very thick glacier.
Those boulders were hinged
on this bedrock surface,
plucking pieces of
rock off as the glacial ice
moved through the area.
- Charles Merguerian's
mountaintop discovery
shows how thick the
advancing ice must have been.
- Most people think
that this glacial ice sheet
was about a mile thick or more.
- [Narrator] The marks
are clear evidence that
the New York ice sheet must have towered
about four times higher than
the Empire State Building.
(dramatic music)
Figures like this have
enabled Merguerian to estimate
the total amount of ice
that buried North America.
It's a staggering 17
million cubic miles of ice.
- Imagine this block of ice,
it's about six inches thick,
being the ice sheet that
covered North America
during the last glaciation.
You would need several billion of these,
maybe a hundred billion.
It's a number almost too big to imagine.
- [Narrator] This block
of ice weighs 27 pounds
and is just half a cubic foot in size.
But there were 17
million cubic miles of ice
covering America.
When scientists calculated
the total weight of the ice,
it was an almost
incomprehensively large figure,
68,000 trillion tons.
Unsurprisingly, such a vast weight of ice
did not just affect America.
It distorted the shape of the planet.
- I've got a beach ball
here that has a depiction
of the whole Earth,
and every continent on it.
And right here is the
outline of North America.
And during the Ice Age,
snow started to accumulate in Canada.
And as that ice thickened,
it started to flow from the
centers of snow accumulation
southward into North America,
reaching its maximum
extent right here in Illinois.
And when it did that,
this mass of ice depressed the continent.
(energetic music)
- [Narrator] Earth's
solid crust sits on top of
a layer that scientists call the mantle,
semi-molten rock which behaves a little
like hot, sticky plastic.
The weight of the vast plains of ice
pushed down inland
areas, and simultaneously
made parts of the coastline
bulge up from the sea.
But investigators also found
that in some other areas,
the ice altered the
outline of America's coasts,
the borders of the sea that define
the continent we see today.
A vital clue came in downtown Miami
in the unlikely setting of
a municipal courthouse.
- We're here in front of
this impressive building
built in the early 1900s
because of the materials
used to face its surface.
These stones are constructed
of fossilized coral reefs.
And if you know what you're looking at,
it can actually tell you quite
a bit about Florida's past
and maybe its future.
(lively music)
- [Narrator] The coral stone is made from
the hard calcium carbon and skeletons
of tiny sea creatures,
animals that only grow
in very shallow water.
But this courthouse stone was quarried
out of an ancient coral reef that now lies
a mile from the present-day
ocean and way above sea level.
- I'm standing here about
five or six feet above sea level
and walking alongside this rock face,
which is about six feet tall.
The interesting thing about this rock face,
it's actually composed
of fossilized corals.
And the fact that we're standing here today
amongst these fossil
corals tells us that in the past,
we would have been under
10 or 15 feet of water right now.
- [Narrator] The coral
stones have been dated
to around 130,000 years ago,
which means the sea level around Miami
must then have been far higher than today.
As experts tried to figure
out why the sea level
was so high then, new evidence emerged
about Florida's coral reefs,
and the mystery deepened even further.
(lively music)
Divers off the coast of
Miami found a coral reef
now submerged 450 feet under the water.
These corals grew just 25,000 years ago,
and because a reef like this
only forms in shallow water,
the scientists realized
that the sea level back then
must have been far lower than it is today.
And that means the
coastline would have been
in a completely different location.
- Right now we're about two
miles offshore Fort Lauderdale,
on the edge of the Gulf Stream.
But 20, 25,000 years ago, at the time of
sea level low stand, we would be sitting
right next to a beach here.
We'd been looking where we see today,
the ocean and the high rises in the back,
we'd be looking towards a sandy beach
in front of a gently rolling hillside.
- [Narrator] Investigators
studying the coral records
figured out that the up and
down sea levels would repeatly
have altered the entire shape of America.
- If you look at the
outline of North America,
the outline that I learned to
draw in elementary school,
if we were living years ago,
I would draw Florida differently.
- [Narrator] 25,000 years
ago, when sea levels were low,
Florida was triple the size it is today
because more land was out of the water.
Geologists realized that
the changes in sea level
around the coast were directly related to
the different levels of ice on land.
That discovery was the key to understanding
what the Ice Age had done.
(dramatic music)
Water evaporated from the oceans
and condensed in the
atmosphere to form snow.
But in the colder times,
that snow built up as
ice sheets on the land,
and with so much of the world's
total water supply locked up as ice,
the oceans simply ran short of water,
and the sea levels fell.
- When the Earth is cold,
there's more ice on the land.
And sea level is lower because of that.
When the Earth is warm,
there's less ice on the
land and sea level's higher.
And that makes sense because when that ice,
when it melts off the land,
has got to go in the ocean.
- [Narrator] But it's not just enormous
city-sized ice shelves
that can rock our world.
Sometimes it's much smaller chunks of ice
that can do the most damage,
especially when they're
raining down from above like cannonfire.
(ominous music)
Oklahoma.
Known far and wide as
the heartland of the U.S.
But this state has another
quality that sets it apart.
And this one can k*ll.
- Where did the big hailstorms hit?
The epicenter is the state of Oklahoma.
They get more than 25 of
these big hailstorms per year.
- Hailstorms tend to happen
in locations where you have
hot, moist air colliding
with relatively cool, dry air.
It's these forces that cause
the warm, moist air to rise up
and start the cycle that leads
to a thunderstorm and hail.
And Oklahoma, unfortunately,
is exactly this kind of location.
- These stones can be
moving at 100 miles per hour.
If a hundred-mile-per-hour chunk of ice
hits you in the head, it
can very easily k*ll you.
- [Man] No!
- [Narrator] A severe
thunderstorm unleashes
a hellish as*ault on the state capital.
- Oh my god. - That's insane!
- This particular hailstorm was actually
a warm front that was moving through
that caused a lot of
instability in the atmosphere.
- [Narrator] Chunks of
ice blast the entire city.
- [Man] Holy crap!
- This hailstorm reminded
me of a Civil w*r b*ttlefield
with cannonballs landing all around you.
- [Man] Baseball-size hail.
- When I see baseball
and softball-size hail,
that tells me this is an enormously
powerful thunderstorm.
- Softball-sized hail is relatively rare.
'Cause when you think about it,
here's a drop of rain
that's frozen into ice.
Ice makes it heavier.
It wants to fall, but that
means updrafts of wind
have to pick it up and hold it up.
- Then what happens is
the hailstones fall down
and melt slightly and are
coated with more water.
Then they're carried up
again by more updrafts
to be coated by an additional layer of ice.
At that point, they start to fall.
- [Bonnie] Oh my god!
- [Narrator] College student Bonnie Tibbs
is home visiting family
when their house is suddenly under siege.
- Oh my god, it's hitting the window!
This hail is loud and it's big.
And it's slamming up against our house.
It was like rocks were
being pelted at our house.
I literally moved away
from the kitchen window
and moments later, large
shards of glass were flying out.
So that's when I screamed
to get in the closet.
- [Narrator] Across town,
Mac Maddox and his fiancee
suddenly find their
homes under fire by ice.
It felt like at one point
we were under as*ault.
We hear the skylights getting busted out
and shards of glass going everywhere.
- The house is literally shaking.
It feels like there was
an army outside just
taking machine g*ns
through the entire apartment.
I started to worry about
even our lives at this point.
- [Narrator] The storm
intensifies and Mac realizes
he's under a full-force frozen as*ault.
Windows were getting busted out.
Blinds were getting ripped off
of the windows on the inside.
There were shards of siding
that was getting blown off.
It felt like we were in
the middle of a w*r zone.
- [Narrator] 20 minutes later.
- [Narrator] The Tibbs
family emerges from hiding.
- [Narrator] The onslaught
shatters windows and skylights.
- [Bonnie] Oh my god!
- [Narrator] Allowing
pounding ice to destroy
the family's belongings.
- After the skylights are completely gone,
and you've got these six
giant holes in your house,
it continued to rain.
It actually came onto
the rugs and furniture,
the walls, everything.
- It's crazy to think that your day
could start off absolutely normal.
This is the aftermath.
Windshield's shattered on my car.
And just literally matter
of minutes could turn into,
you know, your whole
livelihood getting destroyed.
- Hail like this, that
destroys car windows,
puts big dents in cars.
If a person happened to be unlucky enough
to be outside and have no shelter,
it could seriously
injure or even k*ll them.
(ominous music)
To see actually literal baseballs
and golf ba*ls flying from the sky
and totally tearing everything apart,
I don't know if I'll ever see anything
like that again in my life.
- Mother nature got us good.
We always thought we could outsmart her,
or she wasn't gonna affect us.
It's in my room!
We know that we can be affected
and that we can't outrun her.
- [Mac] It's Armageddon!
Rs melt,
the area of white
reflective surface shrinks,
replaced by Earth or ocean,
both dark surfaces that absorb more heat,
which in turn accelerates meltdown.
This is what scientists
call a feedback effect.
(energetic music)
In the last four decades,
there's been a significant loss of glaciers
in Montana's Glacier National Park.
- Since the '70s, we've
had pretty much a very rapid
and full-scale
disappearance of the glaciers.
- [Narrator] Ecologist Dan Fagre
has been monitoring their
demise for many years.
- Well, we use several ways
of monitoring the glaciers.
The first and most obvious
one is that we take pictures,
and these can be pictures
from a point in the landscape,
so you're looking at it from the side and
you can just look at the
visual changes year by year.
- [Narrator] Sequential
photos taken decades apart
show how specific
glaciers have shrunk in size.
- I can see with my own eyes
how much that glacier's disappeared.
And it's a little bit of a compelling
and alarming kind of view
because you think about glaciers
as being, you know, a steady
presence on a landscape.
And to see it disappearing
this quickly means
that we are going through
some very, very dynamic times.
- [Narrator] Here, Fagre is photographing
Salamander Glacier, which
has been losing mass rapidly.
For glaciologists, the surface
area is not the only factor
that's important in
determining a glacier's health.
- It's also how thick it is
or how much total mass.
And for that, we do a lot of
ground measurements as well.
And we can go on the glacier
with global positioning systems
and get both the area and the height.
- [Narrator] The prognosis
for Glacier National Park
is dire.
- Based on the best
measurements that we have to date,
it looks like the year 2030
is when most of the glaciers,
if not all the glaciers,
will be completely gone.
- [Narrator] A similar fate is predicted
for glaciers all over the world.
- Almost all of the world's alpine,
mountain, or valley
glaciers have been receding.
What's happening in Glacier National Park
is basically going on globally.
We're seeing that these mountains
are being transformed by climate changes.
- [Narrator] Melting glaciers
have long posed a threat
to local communities.
Like many high mountain
areas, the glaciers of Peru
were once feared for the
avalanches they unleashed.
Sometimes icy mountains
hide their true destructive nature
behind picturesque scenes of winter wonder,
spectacular beauty, secretly
poised to destroy whatever
and whomever is in its path.
(ominous music)
Odda, Norway.
Set at the base of the
Klungersetskreda Mountain,
Odda is the picturesque home
to approximately 7,000 residents.
- You've got the elevation,
you've got the topography,
you've got the mountains.
You've got lots and lots of snowfall.
- [Narrator] These majestic
peaks have stood guard over Odda
for hundreds of years,
but locals don't know that
the mountains themselves
are poised to attack.
(ominous music)
A loud rumble erupts as an
icy juggernaut races downhill.
- This avalanche begins relatively small,
but very rapidly gains force.
- [Narrator] Residents
know they're in trouble
when the Earth itself seems
to unleash a mighty roar.
(rumbling)
- It's almost like a big jumbo jet
coming down the mountainside.
- [Narrator] Police officer Johnny Helle
is stunned by what he sees out his window.
- I was thinking it will be a big disaster.
- [Narrator] As the
mountain shed seven stories
of snow, ice, and rocks,
Eivind Kopperdal videotapes
from his home across the fjord.
- This avalanche came like a big waterfall.
There was a rumbling and a very ugly noise.
- This event is triggered because of
an enormous amount of
snow leading up to the event.
And then there was a warmup.
- This avalanche was a lot of wet snow,
which means it's heavier and has more mass.
- The snow stored at a high elevation
has tremendous potential energy.
Once it breaks loose and
starts moving downslope,
that potential energy is
converted to kinetic energy,
which creates tremendous
momentum and power.
- It's pushing the air out ahead of it.
So you have gale-force winds
coming down this mountain.
- [Narrator] The onslaught
wipes out everything in its path,
including trees that
have stood for decades.
- One of the reasons why
this avalanche is so deadly
is the debris that it's
picked up along the way.
A rock or a tree or a boulder
has much more momentum
and much more force than snow.
- [Narrator] Seconds later,
the avalanche takes aim at homes,
and now lives are on the line.
- In an avalanche, your
chances of survival are very low.
You've got the snowfall
moving down the side
of a steep-sloped mountain
at 60 to 80 miles per hour.
No one can run that fast.
- The avalanche get bigger
and bigger and wider and wider,
and my God, I thought,
it's going to the houses.
- I was sure that this
would k*ll a lot of people.
- [Narrator] The snow
slide swallows a house
where a family is just
sitting down to breakfast.
- Initially it's just
knocked off its foundation.
- [Narrator] But the three people inside
don't stand a chance as
the 100-year-old structure
topples over.
- The house just disappeared in the snow.
I got a real bad, bad feeling.
- [Narrator] The 70-foot wall of ice
continues down the slope and threatens
another home near the shoreline.
But the house is spared.
- We see two houses
attacked by the avalanche.
The one on the left is
being hit by brown snow,
that's snow carrying rocks
and debris against that house.
The house being hit by the white snow
without the rocks survives.
- [Narrator] Then, after
six terrifying minutes,
an eerie silence.
- This was a very special quietness because
I felt like everything
stopped, no sound at all.
- [Narrator] Helle fears the worst,
Since the snowpack is like cement.
- I had to go out, see how
many people was k*lled,
because I was 100% certain that houses
had been smashed by this avalanche.
- Unfortunately, rescue in an avalanche
can be very, very difficult.
Even if you survive the crushing power
of the avalanche itself,
it will be very, very
difficult to find you.
(ominous music)
- That's where somebody was k*lled.
There were three people in that house.
Two of them escaped into the basement.
The third person was in a
wood-frame portion of the house
above the basement,
and they were k*lled when
the house was crushed.
- [Narrator] Since that fateful morning,
barriers have been built to
divert any future avalanches,
but the villagers know that
what's up on the mountain
is truly a higher power.
- In the path of an avalanche,
you don't have any really good options.
- You are mostly helpless.
(dramatic music)
- I feel very small compared
to what nature can do.
Can significantly impact
rising sea levels, but in Iceland,
that meltdown isn't only environmental.
It can be expl*sive.
In fact, the evidence
is mounting that Iceland
has the potential to be
the most lethal island on the planet.
A fearsome volcanic force lies beneath it,
creating powerful volcanoes
capable of generating
gigantic lava floes and
altering global climates.
(haunting music)
Yet many of Iceland's
are covered in glaciers.
Fire and ice are held
in a delicate balance.
Scientists fear if this balance were tipped
in the volcanoes' favor, Iceland
could become even deadlier.
If the remaining ice were to melt,
what effect would it have
on the activity of Iceland's volcanoes?
The first clue in the investigation
lies in these innocuous-looking
piles of rock and rubble.
They're found all over Iceland,
and yet these rocks
don't come from a volcano.
They're moraines, the geological term
for rock piles deposited
at the mouth of a glacier.
These deposits are evidence
the glaciers are shrinking.
Year by year the glacier has melted
and retreated back up the valley,
leaving a moraine like this behind.
Dr. Roberts has studied
the Vatnajokull glacier
for many years and has
noticed this dramatic trend.
- The glacier has retreated
at a remarkable rate.
Since I've been visiting the area
I've seen tremendous changes.
The ice has retreated annually
at a rate of about 200 feet per year.
This lake over here
used to be filled with ice.
I've seen the ice progressively melt.
This moraine has formed.
This whole valley has become almost bare.
Maybe in the next 20 years,
this whole glacier will disappear
and a lake will form in the Valley.
- [Narrator] Iceland's glaciers are melting
at an unprecedented rate.
With an increasing
amount of Iceland's ice caps
melting in the last 50 years,
the question that scientists
are keen to understand
is what effect this rapid melting will have
on volcanoes that lie beneath.
The only other time that glaciers
have melted this quickly
is when Iceland came
out of the last Ice Age.
But what can past events
tell us about the future?
Geologists professor Bill McGuire
is investigating how
volcanic activity changed
at the end of the last Ice Age.
And he's unearthed some surprising results.
- Around about 11 to 12,000 years ago,
you started to see quite
rapid melting of glaciers
in Iceland and elsewhere,
and that triggered a recognizable increase
in volcanic activity
because you were removing
this large mass of ice very, very quickly.
- [Narrator] The rapid melting of ice
kickstarts volcanic eruptions beneath.
- Volcanic eruptions are triggered by the
gas in the magma,
which expands to form bubbles
and the bubbles drive the eruption.
It's rather like taking the cork out of
a bottle of champagne.
Now, if you have a very heavy
weight on top of a volcano,
if there's heavy mass of water or ice,
that can help suppress eruptive activity.
- [Narrator] But when ice melts quickly,
this downward pressure
is suddenly released.
And that's when the trouble starts.
- As the ice melts,
so the pressure on the
magma underneath is reduced,
the gas in the magma can form bubbles.
They can coalesce and they
can eventually drive the magma
upwards towards the
surface and trigger either
expl*sive eruptions or effusions of lava
that can spread out over huge distances.
- [Narrator] Imagining an ice-free Iceland
isn't that far-fetched.
In fact, it's a future Iceland's leaders
are taking very seriously,
not only for its potentially
far-reaching economic impact,
but for what is likely
expl*sive geological activity.
- The question is when.
These are things that
we have to think about
and try to prepare ourselves to deal with
if they happen in our lifetime.
- [Narrator] Coming up.
- The one major difficulty
we have, the flow of glaciers
is mostly caused by what's
happening at the bottom.
And the bottom is the
part that we don't see.
Glaciers serve as vital
reservoirs for fresh water,
providing 50% of the water
nearby populations need.
- When mountain glaciers disappear,
there can be some real direct
consequences for human beings.
Case in point is some of
these valleys in the Himalayas
it is the glaciers,
particularly at the end of the dry season,
providing the drinking water for people.
So when those glaciers disappear,
those people will have to
find alternate water supplies,
or basically have to move.
- [Narrator] In the Western United States,
our dependence on glacial
ice and snow reservoirs
is just as great.
- It's about 87% of the
water that Americans
in the West have to use.
So mountains are very, very critical
in providing that water.
- [Narrator] A reduction in drinking water
is only one of the problems
caused by melting glaciers.
Equally as troubling is
what a meltdown of ice
in the polar regions will
do to sea levels worldwide.
And the melting is occurring
faster than anyone predicted.
In 2000, scientists were stunned by changes
at Antarctica's Ross Ice Shelf.
The ice shelves act as
buttresses for the glaciers,
holding them back from the sea.
Over the course of two weeks,
a 4,247-square-mile fragment,
an area the size of the island of Jamaica,
shattered and separated from the continent.
Three trillion tons of ice,
one of the world's
largest recorded icebergs,
drifted out to sea.
(ominous music)
- We're talking about
several degrees warming,
over the last century,
which is a huge number.
The ocean has been very
hot and cold, and today,
we just have no idea what's
going on with the ocean.
- [Narrator] But it's
difficult to determine
how fast the glaciers are melting.
- The one major difficulty we have,
the flow of glaciers is mostly cut short
by what's happening at the bottom.
And the bottom is the
part that we don't see.
The changes that we're
observing in the ice sheets
are more rapid, and larger
than what is predicted by models.
I think in the most extreme case,
a lot of Greenland would be removed,
and a lot of west Antarctica.
Then you could raise sea
level 10 times more than that.
30 feet.
- [Narrator] A 30-foot rise
means that many low-lying areas,
such as large portions of
Florida, would be submerged.
Today satellites are
the most important tool
that scientists have for
monitoring what's happening
to the oceans and the ice sheets.
- To see the whole ocean,
you have to do it from far away,
and you really have to do it from space.
- Satellites are able to do this for us
because they're observing 24 hours a day,
seven days a week, 365
days a year, for years at a time.
- [Narrator] Scientists
estimate about 200 billion
metric tons of ice melt away every year.
For those who study
these satellite signals,
it's an alarming picture.
Rising oceans will swallow
farmland, towns, and cities.
But unlike floods of the past,
once the waters have been
unleashed, they will not recede.
- Most places in the world,
people live within about
100 miles of the ocean.
It doesn't matter where we are.
The population lives close to the sea.
In China and Japan and Europe,
America, Africa, everywhere,
and those are the places
that are most vulnerable
to climate disruption.
They're the ones that are
gonna be hit the hardest.
- [Narrator] One catastrophe
slams into another,
like the pinball hitting its target
and ricocheting to the next.
- And so we envision a situation where
you have the West coping
with its water problems,
the hurricane zone coping with hurricanes,
the Northeast coping,
not just with windstorms,
but with hailstorms and ice storms,
which will also impose a burden.
The Midwest, we're looking
for swarms of tornadoes,
which causes an enormous
amount of insurable damage.
- [Narrator] So much uncertainty in a world
plagued with an ever-changing climate.
Change is indeed happening,
and more quickly than we might like.
If we fail to act on these
things we can change
and prepare for what we can't,
we are doomed to living
on a radically different
and hostile planet.
(ominous music)
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01x05 - Frozen Fury
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Earth, air, water and fire are essential elements in life. But what happens when these natural elements turn on humanity?
Earth, air, water and fire are essential elements in life. But what happens when these natural elements turn on humanity?