antarctica the world's greatest freezer
is melted
trillions a Gallinger training into the oceans
sea levels are rising it's happened before
and it's happening again right now it's not a
question we'll see level rise larger its
only a question of how mast that will occur
how would humans fight back before our cities
are in Indy
holding off the CD will be that major employer of the world
by 2100 massive levees to defend our coastlines
floating towns and cities
bass dams connect incontinence
it's our greatest challenge yet per
underwater called
when
of
this is New York in the 24 century sea levels have risen by 120 feet deep
manhattan is flooded what could cause such a terrifying scenario in
the answer lies here in Antarctica
where vast amounts of frozen water are locked up in ice
something TARDIS ice sheets are more than two miles thick
it smell
this size would dramatically raise sea levels
and now has already started
scientist wanna know how much frozen water the continent actually
holes
and how much global sea levels will rise if it all melt
specially-equipped aircrafts and radar beams deep into the eyes
which reflect of the bedrock and measure the depth of the ice sheet
after hundreds of flights they calculated
antarctic
contains over ninety percent to the world ice your
together with green it's enough to raise global sea levels
by an astonishing 230 of
this is what North America would look like all the planets
ice melted Europe would also shrink
London's Tower Bridge would become a solemn monument in the sea
Berlin would be flooded
as with Paris but how likely is such a scenario
is sea level rise reality or myth
I'm
Professor Peter Ward is a paleontologist in Astro biologist
he's written extensively on the history of life on Earth
today Ward wants to know what would happen to our planet if sea levels rise
put my foot
something disappear
the journey begins in the Florida Keys a chain
Highlands South Miami
he's looking for clues from the past
that may help predict the future of our planet guys
your
your just a few feet below sea level
our banks coral that had been at this location for over 4,000 years
and
during this period sea levels have been stable not just in florida
but around the world
up
but it hasn't always been like this
a few hundred yards from shore Peter visits an abandoned quarry
that reveal startling evidence from the past all your beauty
nice who did this dude City reading growth position
they're straight up very nice I came here in a very young 23 years of age
our professor brought us to this Korean said this is a perfect creation and is
looking has been coral sitting right in place
cell corals grow straight up a number for offshore from us we have the same
corals living in place and these things have to live in at least 10 feet of
water
source sitting here there's not been any volcanism nothing is lifted Florida up
how could you get this coral this high up in the air now
and less you at sea level their least another
10 feet above this it was the first indication to me that sea level which I
knew it gone down
come up and they'd never thought to be higher than it is now if history repeats
itself
our coastal cities would be inundated sea level rise is not a minute
it could happen again
just as it's happened before
the beginning at the most recent I see which was seventy thousand years ago
the ice sheet expanded the planet's land mass grew
and sea levels pearl then temperatures rose again
the ice receded sea levels climbed in eventually
settled in today's coastlines the No
but global temperatures are on the rise again
this time from humans burning huge amount to fossil fuels
0
they produce co2 in other greenhouse gases
that heat up our atmosphere
whenever global temperatures rise sea levels follow
we have emitted so much carbon dioxide
at that the amount of carbon dioxide in our atmosphere
has increased by about one-third in the last 100 years
and it is now higher than anytime since
at least a million years we expect
about 3 for even five degrees centigrade warming in this century
the warmer it gets the faster the sea level rises
that means sea level rise will get faster and faster
as we heat up the planet more good
of course predicting future sea-level rise is difficult
as the planet never before experienced the dramatic
increase in co2 the last 100 years
but Professor ROM stores climate model predicts a maximum six-foot sea level
rise this century
this higher temperatures kick in
in
once that would face
inundation this century is Miami Florida
just a few feet above sea level it has virtually no defenses against a rising
ocean
after one foot have sea level rise
these beaches would be regularly flooded at high tide
after to feed many roads would be submerged
after three feet
if a hurricane strikes the surging water would overcome sea defences
in cause flooding deep in mind
much of the region's coastal real estate would be ruined
we're looking at millions and millions and millions of dollars a real state
here
we can assume that everyone in these things
half-million to a million bucks we've got a hundred here
100 we got a billion dollars very
short here areas are here's our billion dollars houses
we get one meter three feet to see
horizon everything on these houses is yours who's gonna buy
what happens is billion dollars a real estate
by the time we get three free I mean its
call its useless is just you
scrape it off bulldozers just leave it here
just be left here
and it's not just residential properties that will be affected
take all the wars in all the places where ships
offloading on load all the goods and services in a sea level rises
even 345 feet every single one of those ports
has to be replaced the cruise ship lines
thereof billions billions of dollars in infrastructure
that even a small sea level rise tech-savvy rebuild all over
after four feet above sea level rise
electricity supplies would be affected as coastal power plants are flooded
after five feet summer florida's freshwater resources would be
contaminated with seawater
in the Everglades National Park becomes a vast Bay
after 6p
millions of floridians would have to evacuate the state so what's gonna
happen before
by 2100 will be a lease four to six feet high
this which is be about here
opinion but
there's no way that that we can keep the seat back
is it rises miami-dade county will be
severely diminished
by 2100 after six feet above sea level rise
Miami would look like this
no way to prepare for this you can't put levees
kinda sea level rise
worse any it's only a little over a hundred years old
we became a corporate 1996
at all by we may not make it for the next
here
the only way to prevent Miami from flooding would be to construct a vastly
expensive system
levees surrounding the city I'll
it would be a major engineering challenge is miami is built on porous
ground that allows
sea water to seep through
alternatively if Miami was flooded
the city would eventually have to be abandoned there are cities you can save
this is that you can save and the choices we based on
can we die cut off can we put it off for is this
too expensive not worth the price not worth the effort my
one city determined to defend itself against the sea
is New Orleans Louisiana
during Hurricane Katrina in 2005 large parts of New Orleans were flooded after
a storm surge raise
sea levels by twenty feet
the city lies several feet below sea level it
antiquated locks and levees weren't strong enough to hold back the rising
sea
as the storm pushed the Gulf surging waters into Lake born in onwards into
the city's canals
New Orleans see defense is broken fifty places
0
in we had some levee and floodwall failures in in the hurricane system
and in the combination that overtopping
the levees and the floodwalls failed calls massive flooding throughout the
city
about eighty percent in the city of New Orleans was was flooded
following Hurricane Katrina
it took weeks before the flood waters were pumped out and residents were able
to return
among work victory Wallace Taylor and her son Peter
who return home to a badly damaged house
lovers David you will let us come see about hold
it damage my heart
class 3 through like you
many no what to do
guys I think Mike Penning to
it is a heart feels is
to prevent New Orleans from flooding again the US government is investing
billions of dollars in the CDC defense
along the riverbanks the US Army Corps of Engineers is strengthening the
whirlwinds levees and locks
their work here provides future insight into the kind of construction
that may be needed to protect coastal cities around the world
against rising sea levels we learned a lot of key last
some the key lessons learned were incorporated into the designs for the
greater than once hurricane storm damage risk reduction system and that system
is a series many different aspects it has floodwalls
has pump stations has levees
there's a the series that we call them multiple lines in advance
New Orleans defense takes a unique approach against the rising water
by confronting the enemy itself
the flood surge that broke it see defense's approach the city from Lake
for a lagoon eastern New Orleans
it's here where the US Army Corps of Engineers is focusing its efforts
we've done now was removed the defense the city
I'll for about twelve miles in downtown about eight miles away
94 which is flooded we've done the mood protection downtown the hardest City
left it in there improved we've done we've moved always out
here eight miles the age Lake Borgne
for now up brand new structure which works as a primary line defense
Lawrence best United
build-up here school
ID laws that better days ago something on the worse is to build on
was the top nation worst part
building
to see behind me haha him cryin'
cross the gold
March game
we had to do is good sixty feet through the
newer material down to the old see clay and as a basis
may want undermines 103 feet piles abrasive down to 190
all tall buildings norman's
don't is based upon hines
%uh
the new seawall also has to allow ships to pass through
dry cofferdam to put in place to construct margins sector gates
the concrete is poured the dams and flood
in the gate can be completed
in New Orleans new sea defences are costing the taxpayer a hefty
fifteen billion dollars
but their design on the accounts for storm surges that build from sea levels
today
if sea levels rise by 6p
any storm surge would be higher as well in the city sea defences would have to
be heightened
at an even greater cost home
I'll not every country can afford to spend billions on C defenses
in Bangladesh
many the $250 million inhabitants live
at or just above sea level merely
three feet above sea level rise will have a devastating effect on the
country's population
turns out the the area the world would be most vulnerable
to sea level rise would be change the
rice-growing river deltas in Asian their very close to SeaWorld
even a modest three for bronze would put half the rice land in Bangladesh
underwater
Bangladesh has over 100
$220 million people and that number is rising fast
great deal that's my hand just simply gets covered by water
and again once you have salt water coming up
is not just a man discovered its the intrusion of salt
given a three-foot sea level rise wipes out pappas rice crop
their populations going up third and
their land is being shot by a third you do the math
its a catastrophe coming at us much
bangladesh is a basque money Delta that can't be defended
six feet above sea level rise spells disaster
he would displace millions probably a few at least a few
tens of millions
where they're going to go India is already built a wall
between Indian bomb attached they're anticipating gonna be a lot about
Nash starting to move looking for a place to go
abomination cell he's already won the most densely populated countries owner
and then there another eighteen or twenty
rice-growing riverdale see in Asia here body
firm in the Pearl River Delta China support that would be affected
in varying degrees by rise in sea level
by the end of the century cities and coastlines around the world
will be under siege from the rising tides everywhere
people will be building levees in sea defences to fight back
but sea level rise won't stop at 6p
they're likely to rise at an even faster rate
as the predicted melton Greenland and Antarctica accelerate
exposed cities may not have time to build new sea defences
clues about the speed future sea-level rise are found during the time of the
last
icing
as global temperatures rose the planet's my sheets melted into the sea
on sea levels increased by a staggering
390 feet until they settled at today's levels
in how fast did this happen
the answer may help predict how quickly sea levels could rise in the next
century
and how much time we have to defend our coast
Professor Rick Mortlock is one of the world's leading
experts on past sea level rise he and his team collect fossilized coral from
the seabed
in the lab the analyzing compare the exact depth and age if each sample
a clear picture emerges %uh how fast sea levels rose
thousands have years ago
we have two pieces of possible for all that was
recovered from drill cores of a Barbados so by
dating the samples and knowing the Dept which they were retrieved
we can use that information to create a point by point
reconstruction sea level for the last twenty thousand years
there's one particular sea level rise
up interest call not water pools
one day during that period of time we believe sea level rose
about 20 meters in five hundred years for about 4 to 5 meters
for 100 years mock
if the same happens again it would translate to as much as 16 feet of
additional sea level rise in the next century
factor in today's affairs
and the rise maybe even faster
if we don't get emissions under control the rate of sea-level rise
will keep accelerating and so in the next century
is not only do we get the additional five to seven feet we got the last
century that's going to happen
but we add on to so now we're looking by
2200 probably at least 15 feet
about probably twenty by 2100 the city's will know
that they are do the coastal cities in
if the oceans rose with accelerating speed
the planet's most exposed cities may not have time to build adequate sea defences
sea levels would rise by 16 feet per century
an New Orleans could blind
followed by mind
miami's the worst of a new orleans those are two cities that will have to be
abandoned image
on as southern florida is lost to the sea
other coastal regions will also struggled to hold back the tide
among miss the San Francisco Bay Area with at seven and a half million people
the San Francisco Bay Area is particularly vulnerable to sea level
rise
because of our history although the bay's peak
its very shallow two-thirds of it was less than 12 feet deep
so wats a bit was filled henry clay we're standing here
on reclaimed land and all
downtown San Francisco the financial district is on reklame blame
we've already seen seven inches of sea level rise in the bay
over the past century we know this because
the longest continuously operating tide gauge in america
is at the Golden Gate so we have a hundred and fifty-four years
data word just now beginning to realize with
accelerated sea level rise we're going to have to prepare
and have a new plan for how we deal with in the Bay Area
if sea levels rose by an additional 16 feet per century
hundreds of thousands of people would lose their homes in the Bay Area
up
to protect San Francisco Bay levees would have to be built
on a massive scale
the silver lining is the engineering will
create so many jobs holding of the sea will be the major
employer of the world by 2100 effect this is going to be
worldwide maria never damn revolution
the babies entire coastline would have to be defended with levees in
order to protect it but in the east
the sacramento-san Joaquin Delta would remain vulnerable
because it at or below sea level
the Delta as some other America's most fertile farmland
the most important part spoon is unbelievable
the proportion love human food that comes from
man that is at sea level not necessary right next to the sea
but outlive elevation that will be impacted by sea level rising single
arises a little
all those fields next to it even if they're not covered by the sea
are rendered useless for human crops by this
if the Delta in its farmland were lost to the sea
california's food supply would be in jeopardy
the Delta is also
on the main sources of fresh water on the American West Coast
this is the the heart of California's waters
26 million people drink water that comes from this estuary
it's a huge number two thirds of the population a
California gets water from this estuary
if you raise sea level even of Fort know which
in our mind is no I did is geologist said doesn't seem like much yet but as
common yeah
are you're a sealable for work that we've done
suggests that you will see soap listen to the Delta
even if the levees all stay together even if they don't me
if sea levels rise by six feet this century
local rivers will be contaminated with salt in california's main fresh water
supply will be lost
in the next century after an additional 16 feet
the entire Delta will be claimed by the sea
but there may be a way to defend both the Delta
and San Francisco Bay
san Francisco's among the the best
easiest to save the most radical solution would be put in a big damn
right across the bay under the Golden Gate Bridge
on the ocean side the sea is about a hundred and thirty feet deep
building a dam would be controversial
and would turn the bay into a freshwater lagoon but at a time of intense sea
level rise
some may consider this the best option
using cutting edge technology huge dredges could pick up sand from the sea
bed nearby
and departed is the dams foundation
the damn shallow incline would ensure maximum stability against
earthquakes breaking the power the ocean waves with news
vast pipes and pumps would be installed to keep the bay's
river water flowing out to sea
the Golden Gate damn would cost two and a half billion dollars
and could be heightened to deal with any sea level rise in the future
San Francisco and the Bay Area
would be /c
0
one region that may benefit from the US's
sea defences is the Mediterranean
its flanked by countries both rich and poor that have
thousands have years of history the Mediterranean has a unique feature
a narrowing its mouth the Straits of Gibraltar
are between 10 and 20 miles wide stretching from southern Spain
to Africa I damn could keep the rising water the Atlantic separate from the
Mediterranean
has been a plan since world war two for instance to put the damn
between the rocket gibraltar and Morocco on the African side
a damn big enough that sea level rise does not
affect the medic training
but building a dam here has one major drawback
every year the Mediterranean loses
to feet above sea level through evaporation that is compensated by the
inflow
water from the Atlantic the dam would cut this off
indicate that you be loved Tammy year ago
straight that will not be flow of water from the Atlantic so indicate that you
the flow so that would be a a preparation that we must be compensation
and that would be a permanent drop off the water after years about
rations the Mediterranean would turn into a stagnant saltwater lake
eventually the sea would dry out and if then the sea level rise
see defense engineer Peter Johansson
maps out possible solutions on how to keep the Atlantic flowing
while building the world's largest super dead
I'd look at the surroundings I looked at what
my be required said make a closure
hand them well I fault
it may be feasible
wanna be on some solutions is to use the same building techniques applied to the
Golden Gates
the dam would be twenty miles long and tower
1,250 feet above the sea bed
the same height is the Empire State Building
another solution is to keep the natural flow the Gibraltar Strait
huge amount Atlantic surface water will flow into the Mediterranean
at a much lower deck sum up the meds
saltier water will be pumped back out again that keeping this season salt
Nancy levels stable the world's greatest super day
would cost $275 billion dollars
total cost related to what may be the impact for all the city surrounds
Mediterranean it seems
acceptable it may be a solution
the Gibraltar day would be the world's largest man-made structure
using enough rock to build a thousand great pyramids
although the dam would cut off the migration marine life between the man in
the Atlantic
it would save the entire Mediterranean coastline from flooding
its certainly technologically possible the old cradle of civilization becomes
really the center civilization they would be the last coastal cities
never fact by sea level rise
by the end of the next century sea levels could rise by nearly twenty-two
feet
some cities maybe save
to the construction of super dams others that can't be defended
are lost to the sea
exposed countries too poor to build defenses are flooded
up around the world
hundreds of millions are displaced
it's likely that by the 23rd century the ice sheet will melt at an even faster
rate
in that the oceans will rise with increasing speed
the planet's growing population
in a continuing hunger for cheap energy could make it worse
the problem I see again is a number people
every new person is gonna want housing
every person's gonna need food obviously and one transportation
let's say that all this cock are gas emissions
so 6.5 billion jobs cut down by a third all or
usage and then we raise the population by 3rd all those new people
are just heading back to what we've cut away some signs
believe that our co2 levels could quadruple over the next centuries
it would mean reaching co2 levels last seen over fifty million years ago
when there was no ice on the planet and when sea levels were more than 230 feet
higher than today
in the worst-case if we are so foolish as to burn all the fossil fuels
so the carbon dioxide increases to more than a thousand parts-per-million
then there's no question we will mail all the i's
on the planet which would mean a 75 meter almost two hundred fifty-four
are rise in sea level it's not
millennia it's not going to take thousands of years
the force in a few months is so large that it will
do the whole job within time skills centuries
happily
this is the worst case scenario co2 levels triple
global temperatures dramatically increase
in the Antarctic rapidly males
the world's coastlines our road
as sea levels rise by an additional fifty feet
by the end of the 23rd century in
wondrous city that would struggle to defend itself
is London western Europe's largest metropolis
its main river the Thames is title and water levels vary by up to 22 feet
the Thames Barrier defense the city against storm surges from the sea
if the tide is unusually high the Bay Area closes its gates
in inner London is protected
if sea levels rise by 6p the barrier would have to be replaced by a huge
seawall upstream
but if they rise by fifty feet per century
there may not be enough time to build adequate sea defences
it would be disastrous situation
would mean you simply can't can happen to coastal
pie areas because you'll have a continually changing
RC levels so we really do not want to go down that path
if co2 continues to increase in a growing raid
fifty feet of sea level rise per century is a distinct possibility
the swiftly rising oceans would bypass
any new sea walls London in large part to the England
would be flooded with in a few centuries the worst case scenario is when we have
maybe
four to six feet within a day that's sick
not the kind bang where you sir to sell your house say it's gonna be okay
by you just year here trying to get outta there is going to challenge
existence a civilization
1ab London's most famous landmarks
the Tower Bridge would become a somber outpost in the sea
I mean there would be a degree of panic that we
cannot imagine
as each country tried to figure out how it somehow could
could survive
rising oceans would see underneath obsolete levees
or breach areas where there wasn't the time or money to strengthen seawalls
the rapidly rising sea levels would soon overwhelm large parts of continental
Europe
by the time although the Antarctic sea ice has melted
Denmark the Netherlands in large parts of northern Germany and France
will be lost
significant sea level rise may turn Berlin into a coastal town within
centuries
your another 100 years
in the city would be lost to the sea
the rising sea would creep up the river seine
in find its way to Paris with an elevation about 115 feet
the French capital would be vulnerable to sea level rise
after all the planets ice has melted it will slide
the affluent countries tried to protect their borders
against millions and millions with leaving
the area's most severely affected
but the stress so she with migration on this scale
are on the bench
the meltdown at the planet's ice sheets would completely transform our world
but even as our coasts are pushed back by the rising oceans
resources for humans would try to adapt
there are already plans to rescue New York
Manhattan Island is flanked by two fast flowing title rivers
the entire city is directly exposed to the north atlantic
and extremely vulnerable to sea level rise
professor Malcolm isn't oceanographer and
expert on the effects of sea level rise in New York
if Lee the worst case scenario the rapid melt down
on the ice sheet on green land the West Antarctic Ice Sheet
would happen extremely rapidly
the future of new york city is in peril so the city has two options one
either build massive defense is well to start evacuating the city and its
population
to higher ground
the flooding the New York's underground installations
would only be the first in a series of catastrophic events
after the first six feet above sea level rise part to lower Manhattan would be
submerged
if sea levels rise by 50 the water would move into Times Square
by me is the Manhattan Bridge with sea level rising 250 fate
the bridge would be have sea water lapping around the roadway
New York City as we know it would not exist
but there is a way that New York might adapt
even two extremes sea level rise
the idea is to build on walk
here in the Netherlands are several communities a floating houses
koon althaus is a visionary architect who believes these houses are the
beginning a new trend in design
in construction
to what you'll see is that people go in design floating apartment buildings
every floating structures like two hundred 200 meters woodrow to love it
and Wisconsin to visit houses
such floating cities could be built with the new lightweight material
that's like a concrete sponge the beauty about
floating cities estate you don't have to protect them from nature
they just go on a day-to-day lives with nature and we'll just go up and down
with the border
old houses designed a sea wall to protect Manhattan
with loading districts attached to it
New York gonna build a new Wall Street around it
around Manhattan so we can re designed the city around it so even having
floating leisure out in front for the L agriculture
a floating New York is still in the concept stage
but one day this may be the solution for hundreds of coastal cities facing
inundation the best silver lining the whole thing to me is that you will
require
a united world a world war against sea level
will have to bring all the squabbling
governments to act together a/c doesn't care what your national boundary is
equal opportunity water
we will have to supplant come at this in the United fashion
whether it's the construction massive sea walls
were super dams sea level rise will happen the question is not
yes but how fast and how much are
oceans will rise much will depend on our own co2 emissions
humans will need all their ingenuity
to meet the world's greatest challenge yet win7
like its
must be much
National Geographic chip