2011 okt 4_Science & Cocktails_Jørgen Peder Steffensen3
https://www.youtube.com/watch?v=nGA4Clu4-V8&t=8s
Birt 5. nóv. 2011
Iskerner og klimaændringer. En fortælling fra en 3cm i diameter, 3km lang iskerne fra Grønland. Science & Cocktails er tilbage efter sommerferien. Vi begynder med en ekspedition til en af verdens mest øde egne: Nordpolen. Jørgen Steffensen, professor ved Niels Bohr instituttet, vil berette hvordan en simpel iskerne fra Grønland kan fortælle os om fortidens klimaændringer, forurening og vulcanudbrud. Efter dette vil der kunne stilles spørgsmål i baren, hvor Lars E. Lyndgaard Schmidt og hans team serverer gammeldags cocktails, næsten så gamle som iskernen selv. Andy Benz indtager scenen med kontrabass og spontane elektroniske lyde. (alle foredrag holdes på engelsk) http://www.youtube.com/watch?v=Y0wACf... http://www.myspace.com/flowingincircles
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Fyrir 7000 árum var hitinn eitthvað hærri fram til fyrir 4000 árum, þá fór hitinn lækkandi þanngað til fyrir 2000 árum, þá hækkaði hitinn nokkuð aftur að Víkinga tímanum fyrir 1000 árum, um árið 900.
Þá lækkaði hitinn til ársins 1600, en hækkaði aðeins um árið 1700, og lækkaði svo aftur í lægsta hitann um 1850.
Á þeim tíma lærðu menn að taka ljósmyndir, og eru einhverjar kuldamyndir til frá þeim tíma.
Við sjáum einnig að þegar hitnar á norður hverli, þá kólnar á suðurhveli.
Hugsanlega eru heitir hafstraumar, sem fara stundum í norður þá verður heitara þar, og stundum í suður, og þá verður heitara þar.
Núverandi hita trúar menn, mæla breytinguna frá 1850 og til dagsins í dag¸og reyna að hræða fólkið með hita aukningunni.
Það var hægt að rækta korn á Íslandi árið 1000, og nú er hægt að rækta korn á Íslandi og ber að fagna því.
Í raun vitum við ekkert hvort fer að hitna eða kólna.
Þeir sem tala um hamfara hlýnun, nota hugmyndina til að gera fólkið hrætt, og fær þá fólkið til að samþykkja allskonar lög og reglur, sem henta víxlurunum, stjórnvöldum, sem hafa haldið fólkinu í fáfræði í fjósinu árþúsundum saman.
Með Internetinu hafa komið glufur í fjölmiðlaveldi víxlarana, og nú er hægt að dreifa sönnum fréttum og nýjum fróðleik framhjá aðal fréttamiðlunum.
Það verður að teljast af hinu góða.
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Sjálfvirka þýðingarvélin, skynjar ekki alltaf mælta málið, talað mál.
Aðeins endursagt.
Myndirnar eru óskýrar.
klikka, mynd stærri
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Árið 1850 var lægsti hiti sem verið hefur frá síðustu ísöld, (þá fundið frá ísborkjörnum, jg)
(Hamfaratrúarmenn virðast mæla frá þessu lágmarki og til dagsins í dag. jg)
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Árið 950, er áhugavert, það er þegar Víkingarnir ákváðu að
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setjast að á Íslandi og Grænlandi, og þá kom Litla ísöldin með lægri hita,
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Miðað við víkingatímann, fram til ársins 1600 lækkaði hitinn um eina og hálfa gráðu að
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meðaltali, hitnaði aftur um 18 öldina, og lækkaði síðan aftur, og var það lægsta hitastigið,
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sem mældist um 1850. Hugsanlega hafa einhverjir ykkar séð gamlar
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myndir af jöklum frá þeim tíma, en mundu að ljósmynda tæknin var fundin upp 1850, þannig
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að ef þeir tóku myndir af jöklum, þá voru jöklarnir í algjöru hámarki frá síðustu ísöld.
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Ef við viljum stöðva losun á koltvíoxíði og þvíumlíku, þá
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Við fórum að segja að koltvíoxíð gæti haft áhrif á loftslagsbreytingar, en óskaðu ekki
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að við fáum aftur veðrið fyrir 150 árum, lærðu
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Um hnattstöðuna okkar, það var ansi kalt, segjum að það sé í lagi
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Ef ég framlengi þennan feril, verða nýustu gildin hér fyrir nútímann
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Um það bil það sama og á Víkingatímanum
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Og nú er hægt að rækta kartöflur
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Í Grænlandi (aftur?) En hvernig var þessu varið á suðurhvelinu?
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Á suðurhvelinu, er allt öfugt eins og þú getur séð
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Þú sérð strax að þegar kólnar á norðurhveli
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Þá hitnar á suðurhveli,
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Setjum við svo mikla losun í andrúmsloftið
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Að breytingarnar verða hraðari? Við vitum það ekki
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koltvísýringur og metan
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Við vitum þetta ekki, skiljum þetta ekki
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Hugsanlega eru heitir hafstraumar, sem fara stundum í norður þá verður heitara þar, og stundum í suður, og þá verður heitara þar.
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Sjálfvirka þýðingarvélin, skynjar ekki alltaf mælta málið, talað mál.
Ég gef mér ekki tíma til að reyna að leiðrétta vélina.
veljum við nú svo mikið til okkar 28:05 andrúmsloftakerfi með losun okkar á 28:07 koltvísýringur og metan sem við erum 28:09 sparka þessu kerfi út af Skilton svo það 28:13 byrjar að fara að sveiflast aftur 28:17 það er vandamálið sem við þekkjum ekki núna 28:24 langar að klára með einni litlu rennibraut
Texti
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I'll take you to another very famous
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event here you have Vesuvius
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you see Napoli the bay of Napoli masoom
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is right here it will kind of come from
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Google Earth of course the famous
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eruption of 79 ad if you look at our
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counting here again 76 78 79 its bottom
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so we can say some complained you know
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that our calendars wrong and during the
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Dark Ages after the collapse of the
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Roman Empire somebody forgot to count
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the years but we feel that the Romans
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were right it was 79 AD and we arrived
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at the center it's a good check we are
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counting the right way now let's go to a
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very controversial lesson let's go to
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this place I'm not talking about the
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Greek bankruptcy anything I'm talking
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about something italia here you have the
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tiny island of Thera in the aegean sea
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also a variable panic area but a lot
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more explosive and more erratic and you
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can see the middle east this island blew
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apart sometime in the past it's called
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the famous Terra or Santorini eruption
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archaeologists have found lots of
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pottery from the Minoan culture buried
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also on Crete some of you might know
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Costas and everything here and I would
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have mine at all and things down here
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but all this was buried and the eruption
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was so big it really hurt the minimum
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culture now by looking at the pottery in
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the styles of pottery they know they had
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a vast trade with Egypt so they had a
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lot of Egyptian pottery that you find
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also here in the layers just below the
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ashes so they know was there when the
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I starting this pottery there is a cup
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this pottery is from the dynasty of
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Pharaohs also because they have all the
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Pharaohs of Egypt lined up in full
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battle already in Nazi words don't they
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have a ball way if you use this tablet
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dating method of of archeology carbon-14
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the first dates in indicated something
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around 1500 BC so 3,500 years ago that
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sort of fit in well with the Egyptian
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dynasties so everything was fine by the
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way is most likely also exactly the same
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eruption that led to the biblical tale
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of the seven plagues of Egypt because
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really many of those seven plates can be
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related to the authentic eruption the
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eternal night asked for the the frogs
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all over the place the consequences of
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tsunami up through the Nile Delta all
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the fathers who knew washed out that the
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nagas thrown up in the houses the
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mortality rate went up because of
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fluoride poisoning later on it became
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the firstborn of each family I think I
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don't think it was that selective at
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that time and when Moses led the
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Israelis across into into Palestine he
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actually did not cross the Red Sea but
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he crossed the Red Sea which is the Nile
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Delta s4 reads so he happened be much
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heavily across with it with the fewest
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people but when Pharaoh who came after
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him he was hit by the tsunami created by
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this volcano and then the Jews went
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around over here following a fire column
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by day and a smoke column by day and a
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fire column by night yeah of course
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because they could see so it all sort of
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makes a little sense that there is a
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core truth in these texts so that's why
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it's doubly interesting to
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see if we can fix this dated and Norvig
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what if you go to theorem this eruption
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and we look at the acid curve from it
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and we look at our counting we actually
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find the acid fall out that we really
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believe the theorem on probably the
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problem is it doesn't have a third name
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that name tag on it but it happened 6042
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to 6041 BC this is a hundred years and
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more it's a hundred forty is off the
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original days and it created a broth in
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the world of classical archaeology
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because now the classical archaeologists
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had to move the age of certain pharaohs
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then you don't move a king 150 years
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like that because then you're missing a
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few below and you have too many on top
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so I mean you can see you have to
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rewrite rewrite the phone book it was a
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really big thing so of course this was
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casting doubt for 20 years we were
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sitting pretty alone at the side sit
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yeah I don't be a climate researchers
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but we have this we cannot avoid luckily
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for us the latest carbon-14 days at
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theory are now at 1621 BC so now we are
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only twenty years apart and that's why I
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say okay we don't care to discuss any
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more because that's basically the same
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considering the counting era we may do
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and the dating uncertainty with one just
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accept it so this is I think where we
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also have been able to move around in
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archaeology I think this is the e
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fascinating because once you get into a
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different subject and you start to work
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with carbon-14 archaeologists and so on
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life as a physicist becomes a lot more
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fun and you know what I discovered one
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thing archeology is definitely not annex
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sighs they can easily disagree where the
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two are too late for easy Joe went to
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his five in Cambridge in two and two is
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three knocks what I can tell you that so
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another thing I would like to show you
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here is what also can be revealed by us
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course because the ice cores are made of
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stuff from the cleanest environment in
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the earth any tiny pollution that
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spreads all over the northern hemisphere
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will end up in Greenland as a signal in
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the southern hemisphere and are
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decoupled collectors force and here you
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have the fallout or actually basically
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it's a ratio between copper and aluminum
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over 8,000 years and what you see here
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is one of the earliest traces about 2500
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years ago a man-made atmospheric
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pollution through the mining of copper
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for bronze what you see here is industry
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its people the informatic melting the
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metal getting metal vapours into the
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atmosphere that goes to Greenland and
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forced down so we can easily follow that
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we can also follow the Roman economy
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going up and down because we can see the
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pollution of lead by the Roman digging
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for silver in Spain so every time Caesar
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ran out of money he makes some more
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silver coins in Spain and the byproduct
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that was led saw that wind-up agreement
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and of course today greenin is
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chock-full of the lead that we used to
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put in our petrol in cars the off stops
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outside of that is we can also measure
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today that their lead levels are going
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down because we remove the lead from the
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ice as well from the from from
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so let's go further back in time the
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Greenland ice core from North grip
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actually turned out to be a stack of
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calendar years where we've been able to
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count to count 60,000 years back in time
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it took us 20 men years to complete the
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content so it's not something you do
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overnight so this you have here is a
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climate curve vertical on a time scale
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but remember now that all these years
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are counted so we know each and every
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individual year the blue curves in
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interphase the isotope values want to
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that side call to the other side up here
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is our present climate the last 11,000
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years this is where agriculture
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developed this is the ice age the last
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ice age and we never go into the
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previous interglacial because it's done
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here but you can see we have a calendar
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and what we have is actually we have
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occurred that reveals that back in time
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the climate has flipped out a lot of
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times and when you're looking from while
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you find out hey our eleven thousand
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years are unique not only because
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they're warm but also because there's no
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sixth act to the curve we have been so
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dead lucky enough to have big climatic
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variations and that's why I think that
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the reason why human civilization
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developed agriculture cities and things
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like that simultaneously in China
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in the Middle East and South American
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things they did that because the
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conditions were right
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even during the Ice Age that was
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intellectual capacity to do but any
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agricultural tradition that I would have
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started here would have been squashed by
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the repeated climate change
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every 2,000 years ago boom each jump
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here represents a change in average
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temperature agreement of about 14
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degrees translate that into Europe
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roughly 8 to 10 degrees on average
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that's a lot so how fast did they go
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well if you expand that little thing up
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there which is the very termination of
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the ice age it becomes a curve like this
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and then it doesn't see appear so steep
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anymore this is the change between ice
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age and present day you see much more
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details you see also a climate change
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here so that's the little piece expanded
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but we can expand that even further we
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can study these this is the warming
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coming from cold getting warmer
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this is a cooling commit of cold this is
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a warming again and now the Ice Age is
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over actually these periods have
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geological names this is called this
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cold period here between the womb here
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at the warm here this quarter is called
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Younger Dryas this is called the pudding
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and it is called the elevator also in
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French
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and it's fun to hear French speaking
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these two words here that's rather funny
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and then you have all destroyers down
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here because this climatic flip-flop
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called becoming warm than becoming very
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cold again and becoming all mr6 that was
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first discovered and described in 1901
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in animal titled the clay pit a terawatt
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where they made bricks they discovered
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in the clay pit a lake sediment as the
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first slide I showed you with mother
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gray mud and dark mud
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gray mud and Dartmouth so they saw heat
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there's something going on in past
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climate there and some guys started to
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use look at the pollen and he discovered
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that during this what we call the dry as
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period which is called this one and down
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here in Denmark they found the pollen
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from the driest plant that's the last
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name for the plant and aeneas is called
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blue blue it is a high optic plant you
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only fired on the highest mountains in
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Norway today and agreement it tells you
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this is Tundra no trees high Arctic
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tundra so at this time Denmark was high
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Arctic tundra here in Denmark was paired
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to Tundra but here were about 1500 years
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1500 years wood trees moved into Denmark
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the Isaac left
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trees moved in together mark Denmark
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became beautiful lush and forested there
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the climate deteriorated the trees were
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wiped out and then what became grass
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covered and then the ice act is kicked
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back in and it became tundra for 1,000
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years before the ice fed finally ended
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you can imagine what stressed the
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ecosystem as
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under with all these very these climatic
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swings and David very fast indeed we
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studied the last one in detail this is
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the most detailed record we have of the
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ice course covering the end of the Ice
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Age
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this is eleven thousand eight hundred
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fifty years ago
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eleven thousand seven hundred years ago
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so this is a hundred fifty years this is
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one hundred fifty years this is three
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hundred years in total
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each little pin here he still thought
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here is one year over here you see occur
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on isotopic ratios going this way and
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then jumping in level and all of a
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sudden becoming that level this jump
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which had completed in one year this
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parameter tells us that all of a sudden
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from one year to the next eleven
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thousand seven hundred and thirteen
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years ago fourteen years ago the wind in
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Greenland started to blow from a
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different direction the meteorological
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system simply reorganized herself then
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as a consequence of that average
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temperature is increased by 14 degrees
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in 25 years this is completed in 25
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years
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the amount of dust blown in from China
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to Greenland decreased this curve as
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inverse axis it decreased by a factor of
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almost a hundred over 25 years and the
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annual snowfall increased by a factor of
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two in five years all these parameters
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together indicate a massive climate
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change triggered by one year to the next
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change of atmospheric circulation so we
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haven't read an evidence of climate
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flips that happens from one year to the
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next
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now if you remember all the discussions
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from the newspapers these
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about future climate with an enhanced
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greenhouse effect because we're burning
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fossil fuel you will see all the models
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that are shown as soft growing curves
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more and more co2 more and more growing
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temperatures and then they predict this
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than the other but none of these models
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can handle an atmosphere that actually
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behaves in fixed and Spurs so should you
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be scared yeah slightly because what we
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are dealing with here is a system that
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is unstable it only takes a little push
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to make it flip and the trouble is we
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don't know the triggering points and
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maybe we already are operating one of
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them so to give you an indication how
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how is it possible to warm up Greenland
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by 14 degrees in 25 years
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I mean entire Greenland and not only
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that this ice core record the 60,000
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counted years how can I talk about
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global climate based on on the corner on
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a curve like this made from Greenland I
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mean come on give me a break
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it's only a rather ice ten centimeters
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diameter and basically what it tells me
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is how climate was at that exact spot
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and nothing else
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what about 100 kilometres away this ice
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is probably the same well we have ice
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cores covering not some southern
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Greenland course some celebrating
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courses in northern reading course and
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you line them up and they tell the same
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story so we assured that the whole
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island agreement is involved in these
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climatic changes mmm what about Europe
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what about the rest
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well this curve is mimicked by
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stalagmites in China this curve is
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mimicked by
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chorus in the Bahamas so the Breeden ice
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core record is the most highly resolved
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reference to any geophysical geological
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evidence we have on climate change all
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over the northern hemisphere so it is
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the carbon copy of calm climate
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variations in the North so what about
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the South can be compared to yeah we can
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we can go on compare them here we have
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the northern one missus agreement will
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not lying it down again you see this is
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actually the present-day planet this is
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a longest record we have been playing so
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far all this we put in one body is last
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ice age and boom goes way up there this
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is the previous integration and look at
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it it's much higher than today in fact
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it's from a time 125,000 years ago when
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we know Greenland was 5 degrees warmer
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than today and global sea levels were 5
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meters higher ie less ice in Greenland
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and Antarctica this may be the climate
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we're heading for in the future so this
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is nature's last natural parallel to a
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future we might be heading for if we
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compare the blue curve is now agreement
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the red curve is a similar curve at the
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same time scale for melodica they are
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both covering one Ice Age present a
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pilot and Pandorica present a climate
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agreement but you can see the curves
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agree on one thing that group agree on
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when the ice age ends so that's a global
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phenomenon they agree on when the
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previous interglacial stops global
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phenomenon so ice ages have such a
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global both hemispheres participate but
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look now at the zigzag stuff in the
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middle
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all these abrupt changes were one year
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to the next this is something much more
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choppy than the red
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that's one one first logical explanation
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the NAM is not the hemisphere is mainly
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land and land has the ability to become
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very cold and wintertime and very hot in
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summertime well the southern hemisphere
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is mainly water so any variation will be
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much softer but let's look in detail on
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them if you can come you know combine
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the Wiggles so our colleagues did this
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this is a great nice port again with the
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wid only things 50,000 years of it or
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counted then of course in an article the
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trouble is you cannot really count the
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years because the layers are too thin so
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you have to use other dating methods so
20:39
we were stuck with one little problem
20:40
we didn't really know the age so we put
20:44
them on top with the age with you or try
20:46
to know calculate it and look like this
20:50
and then we give me a break look at the
20:54
red curve you put you slightly to the
20:56
left everything will match see that this
20:59
looks like it's offset to the right as
21:01
we push it well this top becomes that
21:04
top it can go all the way this looks off
21:07
somehow and we were tempted to do that
21:11
but luckily the bubbles help loud
21:16
because if you start to measure the
21:18
greenhouse gas methane in the box in
21:21
Greenland you get a methane greenhouse
21:24
gas comes in pressure in looking like
21:26
this I don't have all the details but
21:27
focus on these three because we have a
21:29
lot of samples from this section you can
21:31
see what we call big brother and three
21:34
sisters up here in the blue curve they
21:38
match exactly this big brother and those
21:40
three systems so when it's warm a lot of
21:44
methane is cold that's nothing but see
21:47
methane is a gas in the atmosphere so if
21:52
the methane content is highly North has
21:54
to be
21:55
because the air is mixed so let's take
21:59
the methane from the South and put on
22:02
top okay they met but they only match if
22:11
the curves are upset like that so what
22:14
we've done here is we're using their
22:16
variations in methane to synchronize the
22:19
course so we don't have to know the
22:22
exact age of the red curve because we
22:24
know where has to be put on top of the
22:26
blue one so they have to be offset like
22:30
this and now we start to understand what
22:33
the heck is going on with these very
22:36
fast climatic changes because I had we
22:39
have a problem for physicists going back
22:42
to how these happen I told you that
22:45
ingredient the temperature grew 14
22:47
degrees in 25 years in Europe they grew
22:52
technically in 25 years
22:53
stay warm all over North America the
22:56
North Atlantic temperatures grew about
22:58
10 degrees in 25 years that's a hell of
23:02
a lot of heat who is paying that bill
23:06
because the Sun didn't shine so much
23:09
more this curve tell you what's happened
23:14
we stole the heat we stole it from the
23:18
southern hemisphere it's a
23:20
redistribution of heat that's already
23:23
there every time it's cold in Greenland
23:28
the southern hemisphere warms up and as
23:32
soon as the heat kicks in an ingredient
23:34
the summit the fellow hemisphere cools
23:37
down it's like a seesaw in fact that is
23:43
what we have called that bipolar seesaw
23:46
it's the seesaw of energy going from
23:49
north to south from south to north all
23:52
controlled by the big ocean currents and
23:55
the coupling to the atmosphere
23:58
so in order to trigger these very very
24:02
massive climate events in the northern
24:05
hemisphere
24:06
you only need one little goblin with a
24:13
hand on the damn first thermostat at the
24:16
equator and you can turn the warm
24:18
equator water north or south it's in the
24:22
south north occult said it north the
24:24
South Pole that's what happened and
24:28
that's why we can explain how a tiny
24:30
little change can really make big
24:34
consequences do does this bipolar seesaw
24:40
exist today and for that purpose we go
24:44
back in detail to see in our present
24:46
very stable climate I showed you there
24:49
were hardly any variations but if we go
24:52
with a magnifying glass and look at the
24:54
last ten thousand years or eight
24:56
thousand seven thousand years in this
24:57
place this is five thousand years BC
25:01
this is 180 this is now so this is seven
25:08
thousand years this is actually spends
25:09
the entire history of human civilization
25:13
the blue curve behind me is temperatures
25:17
and they are real temperatures you can
25:20
see them here in the black numbers minus
25:24
32 minus 31 minus 30 this is Stone Age
25:30
coming into the a production Empire 5000
25:33
first pyramids then during the Bronze
25:35
Age not a hemisphere cools down
25:39
he had a minimum right here the Roman
25:41
ages I think part of the all the wars
25:45
that the Romans had to fight along the
25:46
borders and all the people moving around
25:48
was because it was so cold and northern
25:51
in the northern wastes and at least
25:53
to the east that there was a pressure to
25:56
come to southern Europe they warmed up
26:00
this is 950 interesting spot because
26:06
that's when the Vikings decided to
26:08
settle in Iceland in Greenland and then
26:11
came the Little Ice Age boom and drop
26:14
from the Viking images to sixteen
26:17
hundred of one and a half degrees on
26:21
average warming up in the 18th century
26:25
and a dip again that this is the lowest
26:28
point on record eighteen hundred and
26:30
fifty probably some of you have seen old
26:35
photographs and glaciers now remember
26:40
photography was invented 1850 so if they
26:44
took pictures of glaciers they took them
26:46
at their biggest since the last ice age
26:50
so when we want to stop emission of
26:54
carbon dioxide and things like that it's
26:56
finally started knitting carbon dioxide
26:58
to halt climate change but don't wish
27:01
yourself back to one hundred and fifty
27:04
years ago at least learn in these
27:06
latitudes because it was really cold
27:08
novel I think it's okay so it's not
27:11
actually if I extend this curve the most
27:15
recent points is that we are actually
27:17
about here now so almost matching how it
27:22
was during the Viking ages and tell you
27:24
what they started to grow potatoes in
27:26
Greenland again no this variation is
27:32
interesting how did it look in the
27:34
southern hemisphere like that that's
27:38
from an anarchic Court and you can see
27:42
even in our quiet time you can see the
27:45
seesaw when it's cooling in the north
27:47
it's warming in the south when it warms
27:49
up in the north it's cooling in the
27:51
South vice-versa so there's the
27:58
five policies of silver the trouble is
28:02
do we now pick so much to our
28:05
atmospheric system with our emissions of
28:07
carbon dioxide and methane that we are
28:09
kicking this system out of Skilton so it
28:13
starts to go cell oscillating again
28:17
that's the trouble we don't know now I
28:24
want to finish with one little slide
28:29
this littlest thing last year we hit
28:32
bedrock at me and this is you see based
28:35
on debris coming up was the ice and if
28:41
we do some analysis on this I'll show
28:44
you to you oh there's too many pictures
28:46
her
Egilsstaðir, 23.08.2019 Jónas Gunnlaugsson
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