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Oct 17

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Melting by Dallas Murphy

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Oct 17 photos by Dan Torres
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The climate is an angry beast, and we’re poking it with sticks.
Wallace Broecker, Lamont Droughty Earth Observatory

We introduced the Greenland Ice Cap in the October 7 dispatch.  To review:  Greenland is by far the largest island on Earth, just a bit smaller than Western Europe.  But only the thin coastal strip, 15 percent of the landmass, is habitable by animals and people—everyone in Greenland has a waterfront view.  All of the rest of the island is subsumed beneath a gigantic dome of ice, in area about twice the size of California, climbing 10,000 feet above sea level.  As each annual layer of snowfall accumulates it is compacted into ice by the weight of ensuing snowfalls, and the ice sheet slowly grows.  But the ice sheet can’t grow indefinitely, like a mountain, because ice is plastic stuff. 

At some point, gravity takes over, and the ice begins to spread outward away from the central dome—not uniformly, not like a spreading stain on the carpet, but in individual, irregular tongues of ice that follow the course of least resistance down through mountain valleys.  These rasping, gouging outflow glaciers dig their way to the sea, creating a new geographical feature, a flooded valley with its mouth open to the saltwater, a fjord.  Then, shoved constantly from behind by upstream ice, the glacial tongues float out over the water, where their leading edges break off as icebergs, and inevitably melt.  The entire coast of Greenland—about 6,800 kilometers from Cape Farewell in the far south to Cape Morris Jesup and back around to Cape Farewell—is composed of the same pattern: fjord-headland-fjord repeating endlessly.

Greenland’s identity is ice.

The ice in the Greenland Ice Cap is made up of freshwater.  But there is another kind of ice around Greenland and in the rest of the Arctic, that is, sea ice, or frozen saltwater.  The Arctic Ocean has always been frozen, winter and summer; its identity is also ice.  However, it is vanishing, melting at an alarming rate.  “Astounding,” “mind-boggling,” “incredible”—those were among the uncharacteristic adjectives applied by levelheaded, big-name scientists to the record meltback of 2007.  The previous, then-startling record—shattered in 2007—was set in 2005.  The records began to topple in 1998.  The pattern is clear, and serious scientists such as Mark Serreze, James Hansen, and Wieslaw Maslowski are trying to tell us that an ice-free Arctic in summer is inevitable.  The only open question is how soon.  Very soon, according to Maslowski, who at last year’s meeting of the American Geophysical Union predicted we’d see an ice-free Arctic Ocean by 2012. Mark Serreze put it baldly:  “The Arctic is screaming.”

Don’t let anyone tell you that global warming isn’t real or that it won’t affect our lives.  The entire world is warming, but the warming in the Arctic is ten times greater than anywhere else.

All right, so what?  How does it matter to those of us living south of the Arctic Circle that Arctic sea ice is vanishing?  Almost every animal living in the Arctic has adapted over tens of thousands of years to the presence of ice.  When it vanishes, they will have to adapt in tens of years to its absence or go extinct.  The endangered polar bears have received the most publicity, but they are only one of many animals whose natural habitat is sea ice; without it they cannot survive. 

But then there is another larger matter.  Arctic ice is a geophysical force.  Like tropical rainforests, polar ice shapes, moderates world climate.  If the ice goes out of the Arctic Ocean in summer, then world climate will change.  Just how and what form the changes will take are not entirely clear.  The impacts will fall first and hardest on the poorer nations of the world, but all of us everywhere will feel the change. 

And then there is the Greenland Ice Sheet, which is composed of frozen freshwater.  It’s not exactly accurate to say that the ice sheet is melting.  But those outflow glaciers are sprinting to the sea at twice the velocity of a decade ago.  In 2007 alone, the ice sheet lost enough ice to cover an area the size of the United States—twice.  Is the ice sheet itself breaking up?  Or are rising sea surface temperatures causing the disintegration of the outflow glaciers at their mouths?  Or both at once?  (On this cruise, Dr. Bob has found traces of warm Gulf Stream at the very mouth of the East Greenland fjord we measured last week.)

That convection, that sinking, we’ve been talking about on which the sustained circulation in the North Atlantic depends is itself dependent on the formation of dense water.  Temperature is a factor in the formation of dense water, but so is salinity.  No serious scientist is contending that the Gulf Stream will shut down unless the wind stops blowing and Earth stops rotating or that north-south circulation will cease.  However, serious scientists wonder just what will happen to our climate if the freshwater outflow from the Greenland Ice Sheet and the Arctic is sufficient to diminish significantly the vital convection in these very waters on which Knorr now floats.

Many questions remain, and that’s why it’s so important that Dr. Bob and his colleagues have adequate funding to continue their important work.  But one thing is clear.  All parts of nature’s great systems are inextricably connected.  If you chop down the tropical rainforests, the global climate system will change.  If the Arctic sea ice vanishes and the ice cap continues to dump massive quantities of freshwater into the North Atlantic, the global climate system will change.


Angalanitta affaa by Nick M?ller

Ulloq tallimanngorneq 17.oktober Island-ip kitaata avannani misissuinerput ingerlapparput, Island takusinnaavarput ungaseqimmalli qaqqarsuit apummik qallersimasut kisiisa takusinnaavagut. Sila nillaarissisimavoq soorlu aatsaat ukiarpalaartutut pissuseqalersimasoq, sukkut tamaana nittaalaaqqat nakkaasarput.

Ilisimasassarsiortut CTD-mik kivisitsisarlutik ullaannganiit ulapipput, nillaarimmalli pisarnerminiit oqarsarsimanerullutik umiarsuup qaavani sulipput.

Ullaakkut nerisarfitsinni ullaakkorsioraangatta pikkugisarpara amerika-miut ullaakkorsiortariaasiat, ullaakkummi iluarisarput naapertorlugu nerisassatsinnik tigusisarpugut, immulertakkanik nererusuttut toqqartarpaat immulertakkat, mannimmik siatamik piumagaanni igasunut noqqaginnassaagut. Ullumuna siuliani angalaqaterput ulaakkorsioqatigalugu, nerisai pikkuginermut puigukkiuteqqagikka, uangami taamak ullaakkorsioraluaruma ullup qeqqanut nerisinnaanissara ilimaginngilara. Pandekaagit, manniit siatat, pølseeqqat siatat arlariit qaavatigut tungusunnilluartumik sirup-mik tungusunnissaaserlugit, pandekaagiutaalli naliginnaasumik silissuseqanngillat, pisarnermiimmi silinnerupput.

Sungiusimanagit tupigusunnalaarsinnaagaluartoq, allutulli ajornarmat misilittariaqarakkit nammineq misilippakka, naatsersuutigisanniit mamanaarneruakka, isumalioraluarlungalu ullup qeqqanut nerisinnaanaviarnanga, taamaanngilarli aamma mamarluinnartunik ullup qeqqasiortippaatigut igaffimmiutta. Ila igaffimmiugut pikkorinnermut, qujanartumik nerisarisartakkagut qatsunneq ajorpagut, angalanitsinniilu mamaatsoortumik imaluunniit naammagittaaliortumi naammattoorsinngilanga.

 

Ullup qeqqasioreerluta ilisimatuut allat pequssutigisartagaat naapertorlugu, nerereerama eqqissillunga innangaalaarpunga qaarsilaarlunga, innanganera nuannerseruttortoq ikuallattoqartillugu kalerrisaarut apippallaqaaq. Taamatut pisoqartillugu atisartagarsuit annanniutit inigisatsinniitut tigoriarlugit ”main lab” – mut ilinniartinneqarnerput naapertorlugu naapippugut.

Naapiffissatsinni tamakkersimaniarlerluta eqqaalerpara usimaannami ullumikkut, ikiallattoqarataarnissaanut sungiusartussaalluta, qujanartumik piviusumik ikuallattoqanngimmat.

 

Ullup ingerlanerani nalunaarsuummik suliallit (CTD) kalerriutigivaat umiarsuup eqqaralaannguani arfermik takullutik, inortuilersutut pissuseqapajaarluta imiarsuup silataanut aniavugut, sunaaffali kingusinaapajaareersimalluta ajoraluartumik takunngitsoorlugu. Taama arfeq sorlinnguusimagaluarnerpoq, ajunngilaq aatsaavissuaq takusussaannginnama eqqarsaatiginngilara annerusumik.

 

Ullup ingerlanerni anoraa pissatsikkiartuinnavippoq, orfaasernarpullu pikkunarsiartorluni. Aallarattali ataasiaannarluta silarlussiorpugut, aalavissorluta. Tamatumap kingorna annerusumik silarlussioqqinngilagut, aallalerama ernumassutigisimagaluarpara silarlussiukulaarnissarput, ukiummi taamaasinerani millit angisuut takussaagajuttarmata avataani.

Qujanartumilli malissiornerput pikkunartumik sakkortussuseqannginnami, umiarsuarmi sulineq naliginnaasumik ingerlanneqarsinnaalluni.

 

Usi ullumikkut aallarnitsinniit angalanissatta sivisussusissaata affaa tikipparput, ullummi 15-nit angalakatalereersimavugut, inunnut nutaanut, oqaatsinut allanartunut, nerisassioriaatsimut allaanerusumut, suleriaaseq ilisimatusarnermik aallaavilik pinngortitarsiarlu tupinnartoq kusanaqisorlu alutorsaatiginermut, tassa angalanerput ullut arlaqinngitsut qaangiuppata naammassissavarput.

 

Neriuppunga ilisimatuunut naammaginartumik ilisimasassarsiorluta angalanerput pissarsiffiusimassasoq, taamatummi paasissaarsiorluni angalanerit aningaasanik annertuunik naleqartarput. Ilisimatusarnermummi aningaasaleeriaatit aningaasaleeriaatinit allaniit, naliginnaasumik annertunerusarput. Tamatigullu paasisassarsiornerit atuussaasumik paasisatigut inernilerneqarsinnaaneq ajoraluartoq, paasisat misilittakkat tullissaanut paasisassarsiorluni angalanissamut atorneqarsinnaasarput. Taamaasillunilu paasisassat naammaginartut pissarsiarisimanngikkaanni allatigut pissarsisoqartarpoq, pingaarnerpaavorli paasisanik nutaajusunik inuiaqatigiinnut tunniunneqarsinnaasunik pissarsisimalluni ilisimalersimasamik nutaajusumik angerlamut apuussinissaq.

Paasinarsiumaarpormi piffissaq nalleriarpat ilisimatuut ittuat aperisorumaarakku, piffissarli nallerpat tamanna allaaseriumaarpara qanoq angalanerput nalilerneqarsinnaanersoq, qanoq angusiffiusimanersorlu.



Last updated: October 20, 2008
 


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