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00:00Winter 2060, off the coast of Brittany.
00:12A thick layer of ice impedes all navigation.
00:20All along the French coastline, many ports remain closed, waiting for the icebreakers' intervention.
00:30And for the third time this year, most of Europe's airports have cancelled all flights, leaving thousands of planes grounded.
00:47From Norway to Spain, from Ireland to the Urals, all of Europe is affected by this unprecedented cold wave.
00:56Reality or fiction?
01:00To be continued...
01:07These alarming predictions are part of a report recently commissioned by the American government,
01:11which seriously contemplates the breakdown of ocean currents and the European climate by the end of the 21st century.
01:20The cause of this disaster? Global warming.
01:30This foreseen catastrophe can be added to the litany of climatic accidents, which have been multiplying over recent years.
01:37Torrential and devastating floods.
01:39Deadly heat waves.
01:43Deadly heat waves.
01:46Increasingly frequent and violent hurricanes and typhoons.
01:51Enough examples to make us aware of the risk we run when we tamper with our climate.
01:55This time, the threat comes from the depths of the Atlantic Ocean, in the complexities of that most mythical of marine currents, the Gulf Stream.
02:07NEXT
02:24with weather unfit to send a person an out into, even a retired one.
02:41But Jean-Francois Véhien, barely one week retired from the post office,
02:44is determined to venture out, and in his favourite uniform.
02:50Jean-Francois is a member of the Frigodems.
02:52Amateur bathers who take to the sea in summer and winter alike,
02:56never missing an opportunity for a short swim in the Atlantic.
03:08A 20-minute dip, no matter what.
03:11This Sunday ritual would certainly be much harsher
03:14if it weren't for the relative mildness
03:16that bathes the Brittany coastline throughout the year.
03:18However, our retired postman has some notion of the current blessed by the gods
03:23that allows him to escape Sunday mass.
03:28It's possible that it's due to the Gulf Stream,
03:31which is not far from Jersey,
03:33so it should heat up the currents that pass through there, in my opinion.
03:39Mild winters, an ice-free sea,
03:44the passage of the warm Gulf Stream waters close to the Brittany coast
03:47explain in large part the famous microclimate
03:50touted in the region's tourist brochures.
03:55But one thing's for sure,
03:57there's no question of imitating the Frigodems
03:59on the other side of the Atlantic.
04:00Same time of year, same latitude.
04:16The Gulf of St. Lawrence on the Canadian coast,
04:19exactly across the Atlantic from the Bay of Dinah.
04:24In this early January,
04:25the temperature has dipped to minus 40 degrees
04:28and the thickness of the ice makes exiting Quebec harbour
04:30a tricky business.
04:32North and Enterprise, Des Grossoillers.
04:35It's still clear.
04:37It would be necessary to keep you in the south side.
04:41For one hour now,
04:43the icebreaker Des Grossoillers has been labouring
04:45to free up the channel and the route out to sea.
04:48For many months to come,
04:50all ships plying the St. Lawrence
04:51will have to take this thick ice into account.
04:54And while the absence of the Gulf Stream
04:58may not be the only reason for these severe winters,
05:01its warm waters certainly would have altered the deal.
05:05Nevertheless, on their transatlantic voyage,
05:07these waters have quite simply ignored the Canadian shores.
05:10The Highlands on the north-west coast of Scotland.
05:28Latitude 57.8 degrees north.
05:32The same latitude as Hudson Bay,
05:34kingdom of Canadian polar bears.
05:36The Highlands on the north-west coast of Scotland.
05:38It is to this barren and desolate place,
05:43the least hospitable in all of Britain,
05:45that the Gulf Stream has lovingly bestowed
05:47its most precious wedding gift.
05:55This is a very interesting shrub,
05:57or large shrub, small tree.
06:01It's Euphorbia mellifera,
06:02and it comes from Madeira,
06:06places like that,
06:07and it's got this most beautiful intoxicating smell.
06:13Smells like honey.
06:15This is Eucalyptus coxifera.
06:18You could almost imagine you was in Australia.
06:23As you can see there,
06:24we've got the Watsonias,
06:26which come from South Africa.
06:28It's amazing to think we can grow Watsonias out.
06:35Beautiful.
06:38Kevin Ball has one true passion,
06:41horticulture.
06:42And he's most fortunate, indeed,
06:44because he's in charge of one of Great Britain's
06:46most extraordinary gardens,
06:48the Inverue Gardens.
06:49A botanical folly in the middle of nowhere,
06:54the Inverue Gardens has assembled
06:56one of the richest collections
06:57of exotic plants in the world.
07:00Although we are very north,
07:02we get the influence of the Gulf Stream,
07:04which brings warm waters,
07:06you know, up this way,
07:09and sort of warms the environment,
07:11so to speak.
07:13And it's because of that Gulf Stream
07:14we're allowed to grow these Australasian plants
07:17if we've got temperatures dropping down
07:20to below minus three, minus four.
07:24It would really be suffering at that degree.
07:31But just what is this Gulf Stream?
07:34This benefactor that bathes the shores
07:36of northern Europe with its gentle warmth,
07:38protecting them from the severe winters
07:40that face their Canadian and American counterparts.
07:47There's a crowd this morning
07:50at Philadelphia's Constitution Center.
07:57Last month, an exhibition opened here
07:59commemorating the most important man
08:01in the history of the city
08:02and maybe even the country,
08:04Benjamin Franklin.
08:05In her guided tours,
08:17Paige Talbot is full of praise
08:19for this enlightened American.
08:22Franklin was not only a great inventor
08:24and not just of the lightning rod,
08:26he was also the first ambassador
08:27of the United States
08:28to the court of the King of France
08:30and one of the fathers
08:31of American independence.
08:32But the incident this admirer
08:37of the great man prefers to recount
08:39concerns an entirely different field.
08:42The story of the Gulf Stream
08:43is probably one that most people
08:45don't know that very much about.
08:46People don't even know very much
08:48about what the Gulf Stream even is.
08:51So unless you are somebody
08:53who really knows about oceanography,
08:55perhaps you have no idea
08:56that Franklin had anything to do
08:58with discovering the Gulf Stream.
09:00From time immemorial,
09:04the Gulf Stream has intrigued
09:05those navigators
09:06who crossed its path.
09:09American whalers
09:10in the early 18th century
09:12were the first to become aware
09:13of the path of this powerful current
09:15that traversed their fishing waters.
09:17Then, in 1769,
09:30when Ben Franklin
09:30was Deputy Postmaster General
09:32for the American colonies,
09:34the British authorities
09:35commissioned him
09:36to investigate
09:36why English ships
09:38crossing between Europe and America
09:40suffered delays
09:41of several weeks
09:42along the way.
09:43Franklin contacted a cousin,
09:46a former whaler
09:47in Nantucket.
09:48He consulted ship's logs
09:50and conducted experiments
09:51out at sea,
09:53all of which led him
09:54to discover the existence
09:55of a powerful current
09:57in the middle of the Atlantic.
10:02Franklin realized
10:03that depending on the route
10:05that the ship captains took,
10:07sometimes it would take
10:08much longer
10:09to cross the Atlantic Ocean
10:10than others.
10:12And so,
10:12it was working
10:13with his cousin,
10:15Timothy Folger,
10:16that he determined
10:17that there was this
10:18swiftly moving water,
10:20a stream, if you will,
10:22and he called it
10:23the Gulf Stream.
10:25And it was that stream
10:26of water
10:26that if you could get
10:27into the stream
10:28and allow it to propel you
10:30across the ocean...
10:31Armed with his discoveries,
10:45Franklin set about
10:46plotting a precise chart
10:47of this river
10:48under the sea.
10:51And it was in Paris
10:53in 1785
10:54that the very first
10:55representation
10:56of the Gulf Stream
10:57was finally published.
11:01A prized duplicate
11:03has been carefully
11:03preserved in Paris
11:04in the Department
11:05of Charts and Plans
11:06in the National Library
11:07of France.
11:12Department curator
11:13Hélène Richard
11:14continually marvels
11:15over the preciseness
11:16of Franklin's drawings.
11:17According to Franklin,
11:41the Gulf Stream
11:42stops somewhere
11:42in the middle
11:43of the Atlantic.
11:43Two centuries later,
11:49however,
11:50progress in oceanography
11:51enabled scientists
11:52to completely
11:53and accurately represent
11:54the surface
11:55of the ocean current.
11:57What we now call
11:58the Gulf Stream
11:58is a powerful surface current
12:00whose flow corresponds
12:01to 150 times
12:03the flow of all
12:04the Earth's rivers combined.
12:07Driven by the trade winds,
12:08its origins lie
12:09in the Gulf of Mexico,
12:11from which it gets its name.
12:12It carries the tropical waters
12:14from the Florida Strait
12:15to the great banks
12:16of the New World.
12:18The Gulf Stream
12:19then heads eastward
12:20where it splits
12:21into several branches,
12:22one of which carries
12:23its warm waters
12:24to the borders
12:25of the North Atlantic.
12:26It is this
12:27North Atlantic drift
12:28that one commonly
12:29associates with
12:30the Gulf Stream
12:31which is largely
12:32responsible for the
12:33mildness
12:33of European winters.
12:36But the Gulf Stream's
12:37voyage has only
12:38just begun.
12:40As soon as
12:40the tropical waters
12:41hit the Arctic Ocean,
12:42they cool abruptly
12:43and plunge towards
12:44the abyssal zone
12:45to form a loop
12:46known as
12:47thermohaline circulation.
12:51Then,
12:52like an immense
12:52conveyor belt
12:53that slows down
12:54in the ocean depths,
12:55it sets out again
12:56southward
12:56to rejoin
12:57the beginning
12:57of the Gulf Stream
12:58off the American coast.
13:01Without these
13:02beautiful mechanics,
13:03the Inveru Gardens
13:04would be a barren
13:05moor
13:05flattened by winds
13:06and the Breton
13:07frigodems
13:08would have to
13:09break through
13:09the ice
13:10for their
13:10wintertime swims.
13:11Don't miss this rendezvous.
13:39They'll be here,
13:47but just for a few
13:48hours,
13:49making the most
13:50of the rising tide
13:51in order to break free
13:52of the ocean
13:53and reach the river.
13:55This is the precise moment
13:56when the fishermen
13:57of Gironde
13:57set sail in pursuit
13:58of the Elver.
14:01The Elver
14:02is the juvenile
14:03of the eel
14:04that Sébastien
14:04has fished
14:05in the estuary's
14:06turbid waters
14:06for nearly 17 years.
14:10This tiny silverfish
14:11sells for a king's
14:12ransom of up
14:13to 800 euros
14:14a kilo.
14:17And for a few
14:18thousand Elvers,
14:19this morning
14:19marks the end
14:20of an incredible
14:20migration.
14:24After the start,
14:27almost as early
14:28as I was born,
14:31in the state
14:31of the earth,
14:32and then I spent
14:33about a year
14:34to reach the Atlantic
14:37coast.
14:38And so,
14:40in the meantime,
14:41they're feeding
14:42and changing
14:44to become
14:45the little Elvins
14:47that we see.
14:52Their adventure,
14:53however,
14:53begins on the other
14:54side of the world,
14:55off the Florida coast,
14:57in the remote
14:57Sargasso Sea.
14:59These eel larvae,
15:04only a few
15:05millimetres long,
15:06spontaneously respond
15:07to nature's
15:08mysterious call,
15:09issued from
15:10the shores
15:10of Europe.
15:17Barely hatched
15:18from their eggs,
15:18they embark
15:19upon a transatlantic
15:20cruise of more
15:21than 6,000 kilometres,
15:23despite the fact
15:24that they can
15:24hardly move,
15:26much less swim.
15:29The only solution
15:33for these newborns
15:34is to ride
15:35the ocean motorway,
15:36quite simply drifting
15:38along on the Gulf Stream's
15:39current as they make
15:40their way back
15:41to their ancestral river.
15:46And these stowaways
15:48are not the only ones
15:50who benefit
15:50from this powerful current
15:52of tropical origin.
15:59during its northbound cruise,
16:10the Gulf Stream falls
16:11in love
16:11with the Norwegian peninsula
16:12and dallas
16:14on a string of islands
16:15with the lovely name
16:16of Lofoten.
16:19Oh,
16:19for the happiness
16:20of cod
16:20and those who fish them.
16:25Carl Victor christened
16:26his boat
16:27after himself
16:27and each year
16:29at the same time
16:30he sails
16:30his namesake
16:31to the four corners
16:32of these islands.
16:37The miracle took place
16:38a few weeks earlier.
16:41Huge schools of scry,
16:43the Arctic cod,
16:44have kept their appointment
16:45on the shores
16:46of Norway.
16:46Torsken, he comes here
16:59because he has
17:00a unique
17:02choice
17:04to
17:04reaffirmate
17:06and reproduce
17:07so he has
17:09the unique
17:11temperature
17:12and the unique
17:13bond
17:15to the Gulf Stream.
17:18The trawler's first
17:22strikes
17:22are quite promising.
17:26Yet another occasion
17:28confirms
17:28how much larger
17:29Norwegian cod
17:30are than
17:30their Canadian cousins
17:31living across the Atlantic
17:33in the cold waters
17:34of Labrador.
17:36Cod fishing
17:37in the Lofoten
17:37is more than
17:38a thousand years old
17:39and is still
17:40the island's
17:41principal livelihood.
17:45Carl Victor
17:45never fails
17:46to thank
17:46the current
17:47without which
17:47human presence
17:48would have been
17:49impossible
17:49on this
17:50archipelago
17:50at the northmost
17:51edge
17:52of the Arctic circle.
17:53But this eternal
18:12process
18:12could one day
18:13be interrupted.
18:14this dreadful hypothesis
18:25was recently
18:26confirmed
18:27in a discovery
18:28made by
18:28paleoclimatologists
18:30those scientists
18:31who attempt
18:32to predict
18:32tomorrow's climate
18:33on the basis
18:34of the day
18:34before yesterday's.
18:35The basement
18:43of the chateau
18:44of Gives-sur-Yvette
18:44contains the vault
18:46of the Laboratory
18:46of Climatic
18:47Environmental Sciences.
18:50Although it looks
18:51more like a wine cellar,
18:53this is where
18:53the paleoclimatologists
18:55keep their
18:56priceless treasures.
18:57It houses
19:05kilometers
19:06of sediment
19:07core samples
19:07taken from
19:08the floor
19:09of the Atlantic Ocean.
19:11Invaluable clues
19:12that after
19:13a brief game
19:14of hide-and-seek
19:14enable
19:15Elisabeth Michel
19:16and Jean-Claude
19:17de Plessis
19:18to closely study
19:19weather variations
19:20over the past
19:21100,000 years.
19:23At first glance,
19:30the Earth's
19:30past climate
19:31seems to have
19:32followed
19:32a regular
19:32succession
19:33of cooling
19:34and warming
19:34cycles,
19:36which are
19:36visible to
19:36the naked eye
19:37in the
19:38different
19:38sediment layers.
19:42The big work
19:43that was done
19:44for the second
19:46half of the
19:4620th century
19:47was to study
19:48the succession
19:50of cold periods
19:50and cold periods,
19:51especially in
19:52the marine
19:53and there
19:53we could show
19:54that this succession
19:56was almost
19:57periodic
19:58with periodicities
19:59that we could
20:00determine
20:0020,000 years
20:0141,000 years
20:02and 100,000 years.
20:04However,
20:05in the early 90s,
20:06the discovery
20:07of a strange
20:08grey stone
20:08embedded
20:09in a sediment
20:09core extracted
20:10off the coast
20:11of France
20:11ended up toppling
20:13this beautiful
20:14theory.
20:15Look,
20:16the citrons
20:16are five.
20:18It's a bit
20:19big,
20:19so it's too big
20:20to be transported
20:20by the wind
20:21or the currents.
20:22So it's been
20:23brought up
20:23by the icebergs.
20:25So we're in
20:26the middle
20:26of the Atlantic
20:27North,
20:2750 degrees
20:28north,
20:28so you can imagine
20:29a big
20:30icebergs
20:31at these
20:31periods.
20:34This story
20:35unfolded
20:36some 20,000
20:37years ago
20:37during a
20:38major glacial
20:39era.
20:40Rapid
20:41and violent
20:41rises in
20:42temperature
20:42caused
20:42an accelerated
20:43melting
20:44of the
20:44immense ice
20:45camp
20:45that covered
20:45North America.
20:47This released
20:47thousands of
20:48icebergs
20:48into the
20:49Atlantic
20:49Ocean.
20:54Scientists
20:54might have
20:55gone on
20:56ignoring
20:56this ice
20:57breakup
20:57if these
20:58icebergs
20:58hadn't
20:59played
20:59at Tom's
20:59thumb,
21:00exporting
21:01pebbles
21:01from
21:01Canada's
21:02rocky
21:02soil
21:03and dropping
21:04them
21:04in the
21:04ocean
21:04floor
21:05off the
21:05coast
21:06of Europe.
21:11We have
21:11carrots
21:11on the
21:12Gulf of
21:15Gascogne
21:15or not
21:15very far
21:16from Gibraltar
21:16where you
21:16find the
21:17last
21:17研究
21:18that
21:18felled.
21:19The
21:19研究
21:20that
21:20felled.
21:20These
21:22massive ice
21:26breakups
21:27were a
21:27most important
21:28discovery.
21:29They
21:30demonstrate
21:30that accidents
21:31in the
21:31form of
21:31abrupt
21:32heatwaves
21:32have
21:33occurred
21:33in the
21:33immutable
21:34succession
21:34of
21:35warm
21:35periods
21:35and
21:35glacial
21:36eras
21:36which
21:37have
21:37characterized
21:37the
21:38earth's
21:38climate
21:38for the
21:39past
21:39few
21:39million
21:40years.
21:42It could be
21:43abrupt,
21:43but it's
21:43abrupt.
21:44For example,
21:45we could
21:45show that
21:46one of
21:47these
21:47emissions
21:48was
21:49produced
21:49in 70
21:50years.
21:51So you
21:52had
21:52Cro-Magnon
21:53men who
21:53were born
21:54in a
21:56particularly
21:57desagreeable
21:57and who
21:58ended
21:58their
21:58lives
21:59on a
21:59long
21:59bed
22:00with
22:01the
22:01climate
22:01of
22:02Nice.
22:05in the
22:09cold storage
22:10rooms of
22:11the
22:11laboratory
22:11glaciologists
22:12have
22:12evidence
22:13which
22:13validates
22:14this
22:14theory.
22:19Ice cores
22:20extracted from
22:21the Greenland
22:21ice cube
22:22enable
22:23Valérie
22:23Masson
22:23to know
22:24the air
22:24temperature
22:24virtually year
22:25by year
22:26for the
22:26past
22:2720,000
22:27years.
22:28An
22:31analysis
22:31of air
22:32bubbles
22:32miraculously
22:32imprisoned
22:33in these
22:33ice cubes
22:34from another
22:34time
22:35confirms
22:36that
22:36sudden
22:37heat
22:37waves
22:37occurring
22:38during
22:38major
22:38glacial
22:39eras
22:39were
22:40responsible
22:40for
22:40these
22:40iceberg
22:41breakups.
22:49But
22:50most
22:50surprising
22:51is that
22:51these
22:52temperature
22:52rises
22:53were
22:53followed
22:53systematically
22:54by
22:55episodes
22:55of
22:55rapid
22:56and
22:56violent
22:57cooling
22:57in
22:57northern
22:58Europe.
23:03We have
23:04some
23:04covered
23:05of
23:06banquises
23:06and
23:07ice
23:07are
23:07much
23:08more
23:08extended
23:08than
23:09today
23:09up to
23:10the
23:10wide
23:10of
23:10Spain
23:11at
23:11moment.
23:12At
23:12the
23:13West
23:14it
23:14corresponds
23:15to
23:15very
23:15warm
23:16periods
23:16of
23:17cold
23:17up to
23:18latitudes
23:19such as
23:19Dordogne.
23:20During
23:21the
23:21cold phases
23:21we had
23:22the
23:23soil
23:23which
23:23was
23:23geled
23:24in
23:24profondeur.
23:25So
23:25really
23:25some
23:26cold
23:27waves
23:28that
23:28touched
23:29up to
23:30the
23:30south
23:31west
23:31of
23:31France.
23:33But
23:33where
23:33did
23:34all
23:34those
23:34strange
23:34climatic
23:35ups
23:35and
23:35downs
23:36come
23:36from?
23:37Those
23:37alternating
23:38hot
23:38and
23:38cold
23:39waves
23:39that
23:39lasted
23:39only
23:40a few
23:40decades
23:40and
23:41left
23:41so
23:41many
23:42traces
23:42in
23:42the
23:43ice
23:43of
23:43Greenland.
23:43and
23:46American
23:46ocean
23:46was
23:47the
23:48first
23:48to
23:48solve
23:48the
23:49riddle.
24:06The
24:07American
24:07coast
24:08may have
24:08been
24:08snubbed
24:09by the
24:09Gulf
24:09Stream.
24:09Nevertheless
24:10Wallace
24:11Broker
24:11devoted
24:1150
24:12years
24:12of his
24:12life
24:12to
24:13this
24:13current.
24:15A
24:15professor
24:15at the
24:16prestigious
24:16Columbia
24:17University,
24:18Broker
24:18was passionately
24:19committed to
24:20better understanding
24:20how the
24:21Earth's
24:21climate
24:22is determined
24:22primarily
24:23by ocean
24:24currents
24:24and
24:25notably
24:25by
24:26those
24:26of
24:26the
24:26Gulf
24:27Stream.
24:34Well,
24:35a
24:35Gulf
24:35Stream
24:36is a
24:36big
24:37heat
24:37machine
24:37that's
24:38taking
24:39tropical
24:39heat
24:40and
24:40carrying
24:40it
24:41into
24:41cold
24:41regions
24:42of
24:42the
24:42planet.
24:43So
24:44if you
24:44didn't
24:44have
24:44the
24:44Gulf
24:45Stream
24:45it
24:45would
24:45be
24:46considerably
24:47cooler
24:48in
24:48Great
24:48Britain,
24:49France,
24:50Scandinavia.
24:53Right
24:53now we
24:53have a
24:54temperature
24:54of 42
24:55degrees
24:55in both
24:56Newark
24:56and Central
24:57Park.
24:57Should
24:57be a
24:57nice
24:57day
24:58today.
24:58Sunny,
24:59high
24:59around
25:0065
25:00degrees.
25:03Intrigued
25:03by the
25:04abrupt
25:04climate
25:05changes
25:05of the
25:05past,
25:06Wallace
25:06Broker
25:07imagined
25:07that
25:07the
25:07explanation
25:08lay
25:08in
25:08a
25:08dysfunction
25:09of
25:09this
25:09natural
25:10boiler
25:10that
25:11provides
25:11the
25:12European
25:12coast
25:12with
25:12a
25:13supplemental
25:1310
25:13degrees
25:14during
25:15the
25:15cold
25:15seasons.
25:18Well,
25:18we were
25:18faced
25:18with this
25:19mystery
25:19that
25:20the
25:21record
25:21in
25:22Greenland
25:22showed
25:23these
25:23jumps from
25:24very cold
25:24to intermediate
25:25cold.
25:26It would
25:26stay there
25:26several hundred
25:27years and then
25:28jump back
25:29and no one
25:31knew what this
25:31was.
25:32My idea was
25:34that what was
25:34happening during
25:35the glacial
25:35period is
25:36something was
25:37knocking out
25:38this conveyor
25:39system.
25:39And when it
25:41went off,
25:41the heat
25:43that it
25:44delivered to
25:45the northern
25:46Atlantic
25:47was shut
25:49down and
25:49therefore that
25:50caused a
25:51great cooling
25:52in Europe.
25:54The
25:55venerable
25:55professor then
25:56attempted to
25:56discover the
25:57origin of
25:58these sudden
25:58diversions of
25:59the Gulf
25:59stream.
26:00The answer
26:01lies where
26:02this tropical
26:02current performs
26:03its deep
26:04sea dive.
26:05When these
26:06warm, salty
26:07waters reach
26:08the Arctic
26:08Ocean, they
26:09release part of
26:10their heat into
26:11the atmosphere and
26:13into the cold
26:13waters they
26:14encounter.
26:15The result is
26:16evaporation, which
26:18increases the
26:19water's salinity
26:19and density.
26:21As they become
26:22colder and saltier,
26:24and therefore
26:24heavier, the
26:26tropical waters
26:26sink to the
26:27bottom of the
26:27sea, where they
26:28feed thermohaline
26:29circulation.
26:32These deep
26:32water formations
26:33constitute the
26:34primary engine of
26:35the ocean
26:36conveyor belt and
26:37the Gulf Stream.
26:39But if this
26:40fragile mechanism
26:41is disturbed, the
26:43entire system is
26:44likely to be
26:45interrupted.
26:47And this is
26:48precisely what
26:49happened during
26:50the last ice age.
26:52It's the fresh
26:53water, the
26:53melting of the
26:54icebergs, the
26:55flow of water in
26:57from these floods
26:59that diluted the
27:00salt.
27:02Salt is a big
27:03densifier of
27:04seawater, so if
27:05you dilute it, you
27:07prevent deep
27:09water from forming
27:10and that turns off
27:11the conveyor.
27:14In short, over the
27:15course of the last
27:16glacial era, our
27:17planet experienced
27:18many abrupt
27:19temperature rises.
27:21Only a few
27:22degrees warming
27:22were all it took
27:23to cause the
27:24gigantic iceberg
27:24breakups, the
27:26infusion of a
27:26billion cubic
27:27meters of fresh
27:28water into the
27:29North Atlantic.
27:31The result was a
27:32decline in the
27:32density of the
27:33tropical waters and
27:34the interruption of
27:35deep water
27:35formations.
27:37Therefore, divert
27:39the Gulf Stream to
27:39the south and you
27:40cause a violent
27:41cold wave in
27:42northern Europe.
27:44This is what
27:44Professor Broker
27:45called the Achilles
27:46heel of ocean
27:47circulation.
27:54I use the term
27:56Achilles heel of
27:57ocean circulation
27:58because if you
28:00disrupt a deep
28:01water formation in
28:03the northern Atlantic,
28:04you'd change
28:04everything.
28:05And if you shut
28:06down one of the
28:08ventilators, then
28:11it's going to happen
28:12somewhere else and
28:13reorganize the
28:14distribution of heat
28:16around the planet.
28:17A half-century
28:19ago, Wallace Broker
28:20presented his
28:20Columbia University
28:21students with a
28:22hypothesis that for a
28:24long time was
28:25regarded as a
28:25harbinger of ill
28:26omen by the
28:27scientific community.
28:29As an obsession
28:30long judged as
28:31madness, our
28:32current global
28:33warming could easily
28:34be a replay of the
28:35disaster movie of
28:36the past.
28:37Could successful
28:41scientists do that?
28:42Some scientists
28:43doggedly stick to
28:44their old ideas and
28:46it destroys them.
28:47And she didn't get
28:48tenure at MIT and
28:50she probably should
28:51have.
28:51During the glacial
28:52period, we know that
28:53there were times when
28:55the conveyor
28:57circulation stopped.
29:01This allowed ice to
29:02form everywhere north
29:04of Great Britain and
29:06this made northern
29:08Europe, like Siberia,
29:10it had extraordinarily
29:11cold winters, much,
29:13much, much colder
29:14than today.
29:16So the fear is that
29:17by warming the planet
29:19we may induce another
29:21stop of this conveyor
29:22and that that would
29:24return us to an ice
29:26age.
29:34Here, at the Weather
29:46Research Centre in
29:47Toulouse, the
29:48laboratories of
29:49Météo France are the
29:49first to measure the
29:50warming of our planet.
29:57Powerful calculators
29:58are occupied during the
29:59day predicting the
30:00weather for the
30:00following days and
30:01spend their nights
30:02simulating the climate
30:03of centuries to come.
30:16Serge Planton, a
30:17climate specialist for
30:18Météo France, participates
30:19in the work of the
30:20Intergovernmental Panel for
30:22Climate Change, which
30:23has been charged by the
30:24UN with evaluating
30:25scientific data on
30:26global warming.
30:27For the first time in its
30:42history, mankind is
30:44influencing the Earth's
30:45climate.
30:48Even if this issue
30:49continues to be debated,
30:51mankind's responsibility
30:52for the warming of the
30:53planet is now accepted by
30:54the vast majority of the
30:55scientific community.
30:57Automobile pollution,
30:59industrial production,
31:01deforestation, and even
31:03certain agricultural
31:04sectors like livestock
31:05breeding are among the
31:06many human activities
31:08contributing to the
31:09increase of greenhouse gases,
31:11which are principally
31:12responsible for the new
31:13global warming.
31:15Take just one example.
31:17More than six billion tons
31:18of carbon dioxide are
31:20emitted into the atmosphere
31:21each year.
31:21If the current rate
31:23continues, this figure
31:24could reach 20 billion
31:25tons by the year 2050.
31:29And certainly, development
31:30in emerging countries
31:31like China and India
31:32will not slow this pace.
31:35This information is
31:37enough to throw into
31:38disarray every computer
31:40simulation that attempts
31:41to forecast the climate
31:42of the future.
31:43The models
31:46the most complex
31:48simulent
31:49a warming
31:50for the next
31:51century.
31:51We will not talk
31:52about the prevision
31:53because there is
31:54a lot of uncertainty
31:56on the scenario
31:57of the emissions
31:57of the gas
31:58effects of the air.
31:58But the projections
32:01who are made
32:01in this scenario
32:02are a warming
32:03of the climate
32:04which,
32:06according to the
32:06forecast
32:07which was given
32:07by the PCC
32:08in 2001,
32:09it will be
32:101,5
32:11to 6 degrees
32:11compared to 1990.
32:14In any case,
32:15one thing is certain.
32:17This global warming
32:18is unprecedented
32:19in human history.
32:21And according
32:22to Serge Planteau,
32:23the predictions
32:23of rising temperatures
32:24still have some surprises
32:26in store for us.
32:27Par exemple,
32:28on pense que
32:29les canicules
32:30vont devenir
32:30de plus en plus fréquentes.
32:32Ne serait-ce
32:33qu'à l'échelle
32:33de la France,
32:34par exemple,
32:34on considère
32:35que, d'après
32:35les scénarios
32:36les plus pessimistes,
32:37on pourrait avoir
32:37une augmentation
32:38des canicules
32:39un facteur
32:39peut-être de 5 à 10
32:41à la fin
32:45du 21e siècle.
32:46From this,
32:48one can easily
32:49conclude
32:49that the present
32:50warming trend
32:51could cause
32:51the ocean
32:52conveyor belt
32:53to shut down
32:54again.
33:08Twice a week,
33:08Lars makes
33:09reconnaissance flights
33:10over the southern
33:11tip of Greenland,
33:12patrolling
33:13the ice
33:13of Nassaswak.
33:17He carries out
33:18this mission
33:18in summer
33:18and winter
33:19alike
33:19in order
33:20to advise
33:20commercial vessels
33:21on the state
33:22of the ice barrier
33:23up and down
33:24the coast.
33:26And in the nearly
33:2715 years
33:27that he has been
33:28crossing the skies
33:29of Greenland,
33:30Lars-Erik Ericsson
33:31can testify
33:32only to the fact
33:33that the ice conditions
33:35have degraded
33:35throughout
33:36this Arctic region.
33:37what we can hear
33:41and see for ourselves
33:42in a way
33:43is that
33:44the sea is open
33:45for a longer time
33:46every year
33:47before it's
33:49freezing totally
33:50and in the areas
33:51where it should be
33:51solidized.
33:53So normally
33:54we should have
33:54solidized on the west
33:55coast,
33:56from the polar circuit
33:57to the north,
33:58but nowadays
34:00the big ships
34:01can sail
34:01later on
34:03for a longer distance.
34:05So something
34:06is changing
34:07in a way.
34:08If that has to do
34:09with a global warming
34:10or if it's a cycle
34:11normally,
34:12I don't know.
34:15Scientists envision
34:16that the ice barrier
34:17will totally disappear
34:18in the summertime
34:19within the next 20 years.
34:22Added to this
34:23is the melting
34:24of the Greenland glacier
34:25which is receding
34:26at a rate
34:26of 14 kilometers a year,
34:28three times faster
34:29than at the end
34:30of the 80s.
34:32But above all
34:33there is
34:33the increase
34:34in rainfall
34:34throughout the Arctic
34:35and the flow
34:36of the rivers
34:36in North American Asia
34:37which are continuing
34:39to swell.
34:41This additional
34:42fresh water influx
34:44from many sources
34:45will very likely
34:46disrupt
34:47ocean circulation.
34:56given the extent
35:04of the threat
35:05oceanographers
35:06are taking turns
35:07at the Gulf Stream's
35:08bedside.
35:10For the past month
35:11the Oceania
35:12has been plying
35:13the grey waters
35:14of the Greenland Sea.
35:18Aboard the Polish
35:19oceanographic ship
35:20Jan Peciura
35:21and his team
35:22are determined
35:23to conduct
35:24a thorough search
35:25of these waters.
35:29For it is here
35:31beyond the Arctic
35:32circle
35:32that the current
35:33suddenly decides
35:34to plunge
35:35to the ocean floor.
35:39The Oceania
35:40is on its
35:40eighth assignment.
35:43These round trips
35:44enable the crew
35:44to meticulously plot
35:46the salinity,
35:47currents
35:47and temperatures
35:48between the ocean's
35:49surface
35:49and its depths.
35:53The objective
35:56of this painstaking
35:57data collection
35:58is the observation
35:59of the slightest
36:00change in the
36:01tropical waters
36:01that reach this spot
36:03before setting out
36:04again southwards.
36:09Recently
36:10a Norwegian team
36:11detected a drop
36:12in salinity
36:13in the bottom
36:14return current
36:15of the Gulf Stream.
36:16But the Oceania's
36:17computers reveal
36:18yet another surprise.
36:20W tym czasie
36:23obserwujemy
36:24znaczne zmiany
36:25wody atlantyckiej.
36:28Zasolenie
36:29mniej więcej
36:29utrzymuje się
36:30na takim samym
36:31poziomie.
36:32W 2004
36:34temperatura
36:36wody atlantyckiej
36:37wzrosła.
36:38No i obecnie
36:39obserwujemy
36:39z tych badań,
36:40które dotychczas
36:41zrobiliśmy,
36:43że w tym roku
36:44jest jeszcze
36:45wyższa
36:46niż w roku
36:47poprzednim
36:47o około
36:490,7
36:51stopnia
36:51Celsjusza.
36:53A rise
36:54of nearly
36:54one degree
36:55unprecedented
36:56in the history
36:57of oceanography.
37:00Co łączy się
37:01z
37:01intensywniejszym
37:05zanikiem
37:05lodu morskiego,
37:07a to z kolei
37:09oznacza
37:10dopływ
37:11wody słodkiej
37:12do
37:12systemu
37:13i również
37:15osłabić
37:16to jedno
37:17z ogniw
37:17cyrkulacji
37:19termohalinowej.
37:21The first
37:22effects
37:22of global
37:23warming
37:23on the
37:24North Atlantic
37:24are clearly
37:25detectable
37:26on the
37:26Oceania's
37:27data screens
37:27and in
37:28the ocean
37:28depths.
37:33So the
37:34inevitable
37:34question
37:35is,
37:36will global
37:37warming
37:37paradoxically
37:38sweep
37:39Europe
37:39towards
37:40a new
37:40ice age?
38:03This
38:03disaster
38:04scenario
38:04was conceived
38:05here in
38:06Woods Hole,
38:06Massachusetts,
38:07on the east
38:08coast of the
38:08United States.
38:11The Gulf
38:12Stream
38:12is a
38:13marvelous
38:13thing.
38:14It's a
38:15very strong,
38:16powerful flow
38:17which controls
38:19a lot of
38:20things,
38:21for example,
38:23our climate.
38:24And so
38:24this is one
38:25thing which
38:25makes it
38:26an attractive
38:27place to
38:29study the
38:29Gulf Stream.
38:30It's close
38:31and we can
38:33get there
38:33in a matter
38:34of one
38:34day.
38:36Terry
38:36Joyce
38:36is a
38:37researcher
38:37at the
38:37Woods Hole
38:38oceanographic
38:39institution,
38:40an independent
38:41laboratory
38:41created in
38:421930.
38:44For many
38:44years now,
38:45Terry has
38:45taken advantage
38:46of the
38:46nearby
38:46Gulf Stream
38:47to closely
38:48monitor his
38:48powerful neighbor
38:49for any
38:50sign of
38:50change.
38:52Like many
38:52at Woods
38:53Hole,
38:53he is
38:54convinced
38:54that according
38:55to this
38:55profile,
38:56any shutdown
38:56in thermohaline
38:57circulation
38:58could very
38:59well cause
39:00a new
39:00ice age.
39:02If we
39:02have an
39:03abrupt
39:04shift
39:04and the
39:06Gulf Stream
39:06shifts to
39:07the south
39:08and the
39:10heat doesn't
39:11get north
39:13as it has
39:13in the
39:14past,
39:14we'll have
39:15typically
39:16winters like
39:18winter before
39:20last,
39:21where behind
39:22me was sea
39:23ice and it
39:24was very
39:25cold.
39:26As for the
39:27probability of
39:27such cold waves
39:28returning to the
39:29North Atlantic,
39:30Terry Joyce is
39:31not much
39:32more reassuring.
39:34Most people
39:34would feel
39:35the probability
39:36is very low
39:37that it can
39:38occur in the
39:38next decade,
39:40maybe 2%.
39:41Probability
39:42would be
39:43maybe 50%
39:44in 100 years.
39:48Recently,
39:48the concerns
39:49of Terry Joyce
39:50and other
39:50scientists at
39:51Woods Hole
39:51were taken
39:52very seriously
39:53by a team
39:54of consultants
39:54at the
39:55Pentagon.
39:57In October
39:582003,
40:00Peter Schwartz
40:01and Doug
40:01Randall
40:02published a
40:02report titled
40:03An Abrupt
40:04Climate Change
40:05Scenario and
40:06Its Implication
40:07for the United
40:07States National
40:08Security.
40:10This 20-page
40:11report is
40:12something George
40:13Bush would
40:13surely prefer
40:14to keep secret
40:15because despite
40:16its reassuring
40:17title,
40:18the contents
40:19are explosive.
40:22Convinced that
40:22an abrupt
40:23climate change
40:24is imminent,
40:25its authors
40:25imagine the
40:26unthinkable,
40:28the collapse
40:29of thermohaline
40:30circulation
40:31would take
40:31place around
40:32the year
40:322010.
40:34It would
40:35impose
40:35Siberian
40:36temperatures
40:36on Europe
40:37with an
40:38increased
40:38scarcity
40:39of water
40:39resources
40:40accompanied
40:40by ever
40:41more frequent
40:41blizzards
40:42and gale
40:43force winds.
40:46Schwartz and
40:46Randall also
40:47predict
40:47unprecedented
40:48food shortages
40:49for the
40:49continent,
40:50along with
40:51the southward
40:51migration of
40:52Scandinavian
40:52and northern
40:53European
40:53populations
40:54in search
40:55of a little
40:55warmth.
40:58Elsewhere,
40:58the disrupted
40:59monsoon system
41:00would thrust
41:01China into
41:01chaos.
41:03Rising sea
41:03levels would
41:04lead to the
41:04near disappearance
41:05of Bangladesh
41:06and an
41:07unrelenting
41:07drought would
41:08descend on
41:09East Africa.
41:11In the face
41:12of multiplying
41:12conflicts around
41:13the world,
41:13the United States,
41:15also affected
41:15by the cold
41:16wave,
41:16would adopt
41:17an isolationist
41:18policy,
41:19committing its
41:19resources to
41:20feeding its
41:20own population,
41:22reinforcing its
41:22borders,
41:23and so
41:24forth.
41:25As for the
41:26eventuality of
41:27such a scenario,
41:29rather than
41:29wondering if it
41:30will occur,
41:31the authors
41:31believe it's
41:32more a question
41:33of when.
41:35If the
41:36scientific
41:36community
41:37considers
41:37alarmist
41:38many points
41:38in this
41:39report,
41:40Terry Joyce
41:41is more
41:41moderate.
41:53this exercise
42:01was not a
42:01prediction.
42:02It was a
42:03worst-case
42:04scenario.
42:05Okay, what
42:06could happen?
42:07How big might
42:08it be?
42:09Let's take the
42:10biggest numbers
42:10that people think
42:12are reasonable,
42:13apply them,
42:14and say,
42:14how will this
42:15affect?
42:17During the
42:17period of the
42:18Cold War,
42:19when I was
42:20holding my hands
42:21over my head
42:22because we
42:23were afraid
42:23of nuclear
42:24obliteration,
42:27you know,
42:27these were
42:28real fears,
42:30but they were
42:30also based on
42:31scenarios.
42:34Joyce credits
42:35the authors
42:35above all
42:36for finally
42:36showing an
42:37interest in
42:38the dramatic
42:38consequences
42:39that these
42:40abrupt climate
42:41changes hold
42:41for the entire
42:42planet.
42:44If other
42:45pentagons in
42:46other countries
42:47or other
42:48think tanks
42:48in other
42:49countries are
42:50doing that
42:50sort of
42:51exercise,
42:52it would be
42:52good.
42:53Because as I
42:53mentioned,
42:54it's not just
42:55if we have
42:56any kind of
42:57abrupt change,
42:58it's not just
42:58going to be
42:59something which
42:59will affect
43:00the third world.
43:02It's going to
43:03affect everyone.
43:04Potsdam, just
43:20outside Berlin, is
43:23the home of a
43:24young climatologist,
43:26one of the world's
43:26specialists in
43:27predicting future
43:28climate scenarios.
43:29At the Albert
43:32Einstein Institute,
43:33in the same
43:34building once
43:34occupied by the
43:35invent of
43:36relativity,
43:37Stefan Ramstorff
43:38pours over the
43:39climatic fluctuations
43:40of the future.
43:53In the institute's
43:54basement, an army
43:55of computers work
43:56day and night
43:57digesting the
43:58scientific data
43:59fed to them.
44:00Information such
44:01as the speed of
44:02currents, salinity,
44:04air temperature,
44:05and the thickness
44:05of the ice cap.
44:08Enough material
44:09to project highly
44:10sophisticated calculations
44:12and to construct
44:13all sorts of
44:14hypotheses on the
44:15eventuality of a new
44:16shutdown of ocean
44:18circulation.
44:18There is a
44:34threshold of how
44:35much fresh water
44:36you can add to
44:37the North Atlantic
44:38and if you exceed
44:39that, the
44:39circulation will
44:40shut down.
44:41I think that as
44:42the worst case,
44:43we could cross
44:44this threshold
44:45within the century
44:47and the second
44:48half of this
44:48century if we
44:50do not stop the
44:51further global
44:52warming in time.
44:54The only thing we
44:55do know is that
44:55we are moving
44:56towards that
44:56threshold because
44:57the fresh water
44:59influx into the
45:00Atlantic is
45:00increasing and the
45:02salinity is
45:03already declining.
45:04to establish this
45:08worrying forecast,
45:10Stefan Ramstorff
45:10factors into his
45:11parameters the
45:12melting of a major
45:13portion of the
45:13Greenland ice cap,
45:15namely 70% of the
45:17planet's fresh water
45:18reserves.
45:20A hypothesis judged
45:21likely if global
45:23warming continues on
45:24its crazy course.
45:26The result is a
45:28model that places us
45:29in a scenario for
45:30global climate change
45:31in the coming
45:31centuries as though
45:32we were actually
45:33there.
45:36The shutdown of
45:37ocean circulation
45:38could, therefore,
45:39take place in the
45:40second half of our
45:41century, causing a
45:42cooling of North
45:43Europe.
45:45Extensive global
45:46warming would
45:46initially compensate
45:47for this loss of a
45:48few degrees, but this
45:50would be just a
45:51simple respite, because
45:53as the year 2300
45:55approaches, the
45:56exhaustion of fossil
45:57energies like oil and
45:58gas would mean a
45:59reduction of global
45:59warming, which would
46:01then allow the North
46:01Atlantic to cool.
46:04In the long run, if
46:06carbon dioxide levels
46:08are reduced again in
46:10coming centuries, but
46:11the Atlantic circulation
46:13remains switched off,
46:15which is the situation
46:16that occurred in some
46:17model scenarios, then you
46:19can actually get a
46:20cooling of Europe by
46:21several degrees below
46:22current levels.
46:23That's still certainly
46:24not an ice age or so,
46:26but it would make
46:27agriculture in Scandinavia,
46:29for example, very
46:30difficult.
46:31The German scenario
46:32may not herald the end
46:33of the world for
46:34tomorrow, but it does
46:36predict it for the day
46:37after that.
46:40Moreover, it predicts
46:41that abrupt changes
46:42quite as dramatic could
46:43well result from this new
46:44shutdown of the
46:45conveyor belt.
46:45one thing we are pretty
46:50sure about is that this
46:51would lead to a major
46:52disruption of the
46:53ecosystems in the North
46:54Atlantic, which depend
46:56very strongly on the
46:57nutrient supply provided by
46:59these currents.
47:03The consequences would be
47:05a slight aggravation of the
47:06fishing crisis everywhere in
47:08Europe, and the
47:09modification of fish breeding
47:10grounds, like those of the
47:12Arctic cod, which could then
47:14definitely desert the coast
47:15of Norway.
47:19We know that the sea
47:21level around the North
47:22Atlantic coast would come
47:24up by about a meter in
47:25addition to the global mean
47:26sea level rise, simply
47:28because when the current
47:30changes, the surface of the
47:32Earth's ocean adjusts
47:33accordingly, and that means
47:36in this case sea level rise
47:38in the North Atlantic and
47:39dropping in the Southern
47:40ocean.
47:42Just one additional meter.
47:46That's all it takes to
47:47further threaten the densely
47:48populated coastlines of the
47:50Netherlands, the United
47:51Kingdom, and even France.
47:55In Potsdam, some 500
47:57kilometers from the sea,
47:58people seem to have realized
47:59the risk of climate change.
48:02The multitude of bicycles and
48:04trams attest to this.
48:05But that is not enough to
48:11reassure Stefan Ramsdorff.
48:13He worries about the slow
48:15pace of political decisions,
48:17in particular those which
48:18would enable Europe to reduce
48:19the greenhouse gas emissions
48:20by only 75 percent by the
48:23year 2050.
48:27I think that the politicians
48:29haven't quite grasped the
48:31urgency of this problem yet.
48:32They pay lip service to it,
48:34but the measures that have
48:35been taken are pretty
48:37half-hearted, and really
48:39time is running out.
48:41We have perhaps another 10
48:43years to really turn the
48:44tide and start this fundamental
48:47transition in our energy
48:48system towards a much higher
48:50efficiency, towards renewable
48:51energies.
48:53But if we lose another 10
48:55years and do very little,
48:57then I am very worried about
48:59the future.
48:5910 years to change the
49:02situation.
49:0510 years to engage in this
49:06decisive battle against the
49:08warming of our planet, with
49:09plenty of threats to the
49:11generations to come.
49:14My daughter is statistically
49:16going to live to the year
49:172100.
49:18This is what babies born in the
49:20last few years will do.
49:23And I am very concerned about
49:25the world that she will be
49:27living in, because if we do not
49:28tackle this problem in the next
49:3010 years or so, and really get
49:33serious about solving this, then
49:35I think by the end of the
49:37century, we will not recognize
49:38this planet.
49:39It will be a completely
49:40different place, and I don't
49:42think it will be a very good
49:43place.
49:44industrial production represents
49:49only one quarter of the emissions
49:51responsible for overheating our
49:53climate.
49:57Housing, transport, and everyday
50:00human activities make up the rest.
50:02Therefore, it is up to each of us to
50:10behave every day in such a way that we
50:12bequeath to future generations an
50:14earth as viable as the one that we
50:16inherited.
50:22Like everywhere in the world, the
50:23countdown has begun along the
50:25coasts of Europe.
50:26No one can rule out a new shutdown of
50:31ocean circulation by the end of the
50:33century.
50:36Another climatic surprise in the
50:39already lengthy list of uncertainties
50:41that weigh on the climate of tomorrow.
50:49In any case, one thing's for certain.
50:52We have a time bomb ticking away in
50:54the depths of the Atlantic Ocean, and
50:56it's vital that we disarm it now.
50:58develop four more
51:02damn stories that had been
51:05slick September.
51:07We can keep
51:10stripesetto.
51:12Alec,
51:14this is ever seen in this
51:16sort of reality, but it does not
51:18hot but deny all there
51:20getting there
51:22thanks to everybody.
51:24We have a time bomb ticking away
51:26from it,
51:26chapter seven,
51:27and again,
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