{"id":2447,"date":"2020-01-01T22:40:48","date_gmt":"2020-01-01T22:40:48","guid":{"rendered":"http:\/\/www.agust.net\/wordpress\/?p=2447"},"modified":"2022-09-18T22:04:40","modified_gmt":"2022-09-18T22:04:40","slug":"hin-agnarsmaa-03-breyting-i-medalhita-jardar-a-150-arum","status":"publish","type":"post","link":"http:\/\/www.agust.net\/wordpress\/2020\/01\/01\/hin-agnarsmaa-03-breyting-i-medalhita-jardar-a-150-arum\/","title":{"rendered":"Hin agnarsm\u00e1a 0,3% breyting \u00ed me\u00f0alhita jar\u00f0ar \u00e1 150 \u00e1rum\u2026"},"content":{"rendered":"

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Grein \u00ed bla\u00f0inu S\u00e1mur f\u00f3stri, desember 2019.<\/strong><\/p>\n

Bla\u00f0i\u00f0 m\u00e1 n\u00e1lgast sem pdf h\u00e9r<\/strong><\/a>.<\/p>\n

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S\u00e1mur f\u00f3stri, desember 2019.<\/span><\/strong><\/p><\/div>\n

\u201eEn annar hlutur er forvitni, \u00fev\u00ed a\u00f0 \u00fea\u00f0 er mannsins n\u00e1tt\u00fara
\na\u00f0 forvitna og sj\u00e1 \u00fe\u00e1 hluti, er honum eru sag\u00f0ir, og vita, hvort svo er,
\nsem honum var sagt, e\u00f0a eigi\u201c<\/strong><\/em><\/span><\/h3>\n

(Tilvitnun \u00ed Konungs skuggsj\u00e1, handrit fr\u00e1 um 1275).<\/em><\/p>\n

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S\u00ed\u00f0astli\u00f0in 160 \u00e1r, e\u00f0a fr\u00e1 um 1860, hefur me\u00f0alhiti jar\u00f0ar h\u00e6kka\u00f0 um \u00fev\u00ed sem n\u00e6st 1,0\u00b0C. Ef vi\u00f0 dr\u00f6gum fr\u00e1 skammvinnar hitasveiflur sem m.a. stafa af El-Ni\u00f1o fyrirb\u00e6rinu \u00ed Kyrrahafinu, \u00fe\u00e1 er h\u00e6kkunin sem um r\u00e6\u00f0ir ef til vill n\u00e6r 0,8\u00b0C. Hva\u00f0 sem \u00fev\u00ed l\u00ed\u00f0ur, \u00fe\u00e1 er veri\u00f0 a\u00f0 mi\u00f0a vi\u00f0 h\u00e6kkun fr\u00e1 s\u00ed\u00f0ustu \u00e1ratugum Litlu \u00edsaldarinnar svok\u00f6llu\u00f0u \u00feegar loftslag var mun kaldara en \u00ed dag. Svo kalt a\u00f0 fj\u00f6lmargir \u00cdslendingar fl\u00fa\u00f0u land og settust a\u00f0 vestanhafs.<\/strong><\/span><\/p>\n

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Hin \u00f3gnvekjandi hamfarahl\u00fdnun…<\/strong><\/h3>\n

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Mynd 1:\u00a0\u00a0<\/strong> L\u00f3\u00f0r\u00e9tti \u00e1sinn \u00e1 l\u00eduritinu er \u00feaninn gr\u00ed\u00f0arlega miki\u00f0 \u00fat. Um \u00fea\u00f0 bil einn mill\u00edmetri \u00e1 hitam\u00e6linum er st\u00e6kka\u00f0ur n\u00e6stum 100 falt \u00ed 100 mm e\u00f0a 10 cm. \u00a0Allur l\u00f3\u00f0r\u00e9tti skalinn k\u00e6mist \u00e1 milli tveggja 1\u00b0 strika \u00e1 venjulegum \u00fatihitam\u00e6li. Gr\u00e6nu l\u00f3\u00f0r\u00e9ttu strikin t\u00e1kna \u00f3vissubil m\u00e6linga. Hitaferillinn er fr\u00e1 NASA-GISS. Hitam\u00e6lirinn var settur inn \u00e1 myndina \u00e1ri\u00f0 2015, en sk\u00f6mmu s\u00ed\u00f0ar kom \u00f6flugt El-Ni\u00f1o sem orsaka\u00f0i hitatopp sem ekki s\u00e9st \u00e1 myndinni. \u00dea\u00f0 breytir \u00fe\u00f3 ekki tilganginum me\u00f0 myndinni a\u00f0 s\u00fdna hve f\u00e1r\u00e1nlegt er a\u00f0 birta svona \u00fat\u00feanda hitaferla.<\/span><\/p><\/div>\n

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\u00deessi mikla \u00fat\u00feensla \u00e1 l\u00f3\u00f0r\u00e9tta skalanum gerir \u00fea\u00f0 a\u00f0 verkum, a\u00f0 almennt \u00e1ttar f\u00f3lk sig ekki \u00e1 hver hitabreytingin er \u00ed raun. Hitabreytingin vir\u00f0ist gr\u00ed\u00f0arleg og \u00f3gnv\u00e6nleg. Sannk\u00f6llu\u00f0 \u201chamfarahl\u00fdnun\u201d. \u00deetta er ekki \u00f3svipa\u00f0 \u00fev\u00ed \u00feegar horft er \u00e1 h\u00f6fu\u00f0i\u00f0 \u00e1 l\u00edtilli h\u00fasflugu me\u00f0 sm\u00e1sj\u00e1 sem er me\u00f0 100-faldri st\u00e6kkun. Litla meinlausa flugan hefur breyst \u00ed ska\u00f0r\u00e6\u00f0is \u00f3freskju!<\/p>\n

Hitabreytingin \u00e1 160 \u00e1rum sem hitaferillinn s\u00fdnir er \u00ed raun l\u00edtil breyting. H\u00fan er svo l\u00edtil a\u00f0 vi\u00f0 yr\u00f0um hennar ekki v\u00f6r \u00ed daglegu amstri. \u00c1 venjulegum degi er algengt a\u00f0 lofthitinn breytist 10 sinnum meira, og yfir \u00e1ri\u00f0 miklu miklu meira. \u00deetta er minna en munur \u00e1 hita \u00ed herbergjum heima hj\u00e1 okkur.<\/p>\n

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Hitasveiflur undanfarin \u00e1r\u00fe\u00fasund…<\/strong><\/h3>\n

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Mynd 2:\u00a0\u00a0<\/span><\/strong> Ni\u00f0urst\u00f6\u00f0ur m\u00e6linga \u00e1 \u00edskj\u00f6rnum fengnum \u00far r\u00famlega 3000 metra dj\u00fapri holu sem boru\u00f0 var \u00ed Gr\u00e6nlandsj\u00f6kul. Skammvinn hl\u00fdskei\u00f0 \u00e1 s\u00f6gulegum t\u00edma eru s\u00fdnd me\u00f0 gr\u00e6nu.\u00a0 Taki\u00f0 eftir a\u00f0 l\u00f3\u00f0r\u00e9tti skalinn vinstra meginn s\u00fdnir lofthitann \u00e1 Gr\u00e6nlandsj\u00f6kli, en l\u00f3\u00f0r\u00e9tti skalinn h\u00e6gra meginn s\u00fdnir \u00e1\u00e6tlu\u00f0 fr\u00e1vik \u00ed hnattr\u00e6num me\u00f0al lofthita, sem er talinn helmingur af hitabreytingunni \u00e1 j\u00f6klinum. Ferillinn er fr\u00e1 www.climate4you.com sem Dr. Ole Humlum pr\u00f3fessor s\u00e9r um.<\/span><\/p><\/div>\n

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\u00c1l\u00edka hl\u00fdtt var fyrir 1000 \u00e1rum og \u00ed dag.\u00a0 Bl\u00e1i ferillinn \u00e1 Mynd 2<\/strong> n\u00e6r til \u00e1rsins 1854, en hefur veri\u00f0 framlengdur lauslega til dagsins \u00ed dag me\u00f0 rau\u00f0um lit. Ferillinn er samkv\u00e6mt m\u00e6lingum \u00ed borholu \u00e1 Gr\u00e6nlandsj\u00f6kli. Sj\u00e1\u00a0\u00a0 www.climate4you.com ,\u00a0 kafla \u201cGlobal Temperature\u201d.\u00a0 \u00deetta er sem sagt \u00e1 Gr\u00e6nlandi, en ekki\u00a0 me\u00f0alhiti jar\u00f0ar, en gefur samt v\u00e6ntanlega \u00ed st\u00f3rum dr\u00e1ttum hugmynd um \u00fer\u00f3unina.<\/p>\n

Hafa ver\u00f0ur \u00ed huga \u00feegar borin eru saman \u00e1\u00e6tla\u00f0ur lofthiti fyrr \u00e1 t\u00edmum samv\u00e6mt ranns\u00f3knum \u00e1 \u00edskj\u00f6rnum, og hef\u00f0bundnum daglegum hitam\u00e6lingum, a\u00f0 upplausn \u00edskjarna-hitam\u00e6linganna er n\u00e6rri \u00fev\u00ed a\u00f0 vera 10 \u00e1ra me\u00f0altal. Skammvinnar sveiflur sem kunna a\u00f0 hafa veri\u00f0 til hl\u00fdnuna e\u00f0a k\u00f3lnunar fyrr \u00e1 t\u00edmum sj\u00e1st \u00fev\u00ed ekki e\u00f0a illa.<\/p>\n

Vi\u00f0 vitum samkv\u00e6mt \u00feessum ranns\u00f3knum og fj\u00f6lm\u00f6rgum \u00f6\u00f0rum, a\u00f0 \u00fea\u00f0 var \u00e1m\u00f3ta hl\u00fdtt \u00ed dag og fyrir 1000 \u00e1rum (Medieval Warm Period), allnokku\u00f0 hl\u00fdrra fyrir 2000 \u00e1rum (Roman Warm Period) og t\u00f6luvert hl\u00fdrra\u00a0 fyrir um 3000 \u00e1rum (Minoan Warm Period).\u00a0 Samt erum vi\u00f0 a\u00f0 hr\u00e6\u00f0ast hl\u00fdindin sem vi\u00f0 nj\u00f3tum \u00ed dag og\u00a0 \u00e1saka okkur um a\u00f0 hafa valdi\u00f0 \u00feeim. Reyndar er \u00feessum hl\u00fdindum a\u00f0eins misskipt. H\u00e9r \u00e1 landi h\u00f6fum vi\u00f0 veri\u00f0 l\u00e1ns\u00f6m og noti\u00f0 meiri hl\u00fdnunar en 0,8\u00b0, en \u00fea\u00f0 er \u00f6nnur saga.<\/p>\n

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Hin ofurlitla hl\u00fdnun…<\/strong><\/h3>\n

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Mynd 3:\u00a0\u00a0<\/strong> S\u00e9 teikna\u00f0ur hitaferill sem s\u00fdnir hl\u00fdnun jar\u00f0ar fr\u00e1 alkuli \u00ed Kelv\u00edn-gr\u00e1\u00f0um, \u00fe\u00e1 s\u00e9st ekki nein breyting. Svo l\u00edtil er h\u00fan. M\u00e6lig\u00f6gnin sem notu\u00f0 voru vi\u00f0 a\u00f0 teikna ferilinn eru fr\u00e1 NASA-GISS.<\/span><\/p><\/div>\n

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Ma\u00f0ur hl\u00fdtur a\u00f0 d\u00e1st a\u00f0 \u00fev\u00ed hve st\u00f6\u00f0ugur lofthiti jar\u00f0ar er.<\/p>\n

\u00cd v\u00edsindum er vaninn a\u00f0 m\u00e6la hitann \u00ed Kelvin gr\u00e1\u00f0um, en \u00fear byrjar skalinn vi\u00f0 alkul. S\u00f3lin hitar j\u00f6r\u00f0ina okkar fr\u00e1 alkuli \u00ed l\u00edfv\u00e6nlegan hita, e\u00f0a fr\u00e1 -273\u00b0C\u00a0\u00a0 \u00ed\u00a0\u00a0 +15\u00b0C a\u00f0 jafna\u00f0i.\u00a0 \u00dea\u00f0 er jafngilt hitun fr\u00e1\u00a0 0\u00b0K\u00a0\u00a0 til\u00a0\u00a0 288\u00b0K \u00e1 Kelvin skalanum.<\/p>\n

\u00c1 Kelvin skalanum \u00e1 Mynd 3<\/strong> er me\u00f0alhitinn 288\u00b0K (um 15\u00b0C). Hitabreytingin g\u00e6ti \u00fev\u00ed veri\u00f0 fr\u00e1 288,0\u00b0K\u00a0\u00a0 \u00ed\u00a0\u00a0 288,8\u00b0K, e\u00f0a fr\u00e1 288\u00b0K til 289\u00b0K ef vi\u00f0 teljum h\u00e6kun lofthita fr\u00e1 Litlu is\u00f6ldinni vera 1\u00b0. \u00a0\u00deetta er ekki nema um 0,3% breyting sem ver\u00f0ur a\u00f0 teljast l\u00edti\u00f0.\u00a0\u00a0\u00a0 Merkilega l\u00edti\u00f0.<\/p>\n

Einhver kann a\u00f0 malda \u00ed m\u00f3inn og segja h\u00e6kkunina vera mun meiri, e\u00f0a fr\u00e1 me\u00f0alhita lofthj\u00faps jar\u00f0ar 15,0\u00b0C\u00a0\u00a0 \u00ed\u00a0\u00a0 15,8\u00b0C sem er vi\u00f0 fyrstu s\u00fdn um 5% h\u00e6kkun. \u00dea\u00f0 er \u00fe\u00f3 markleysa a\u00f0 mi\u00f0a vi\u00f0 Celc\u00edus gr\u00e1\u00f0ur. Celc\u00edus skalinn er skilgreindur mi\u00f0a\u00f0 v\u00f0 frostmark og su\u00f0umark vatns, sem kemur m\u00e1linu ekkert vi\u00f0. Vi\u00f0 g\u00e6tum alveg eins mi\u00f0a\u00f0 vi\u00f0 Farenheit og sagt h\u00e6kkunina vera fr\u00e1 59,0\u00b0F\u00a0\u00a0 \u00ed\u00a0\u00a0 60,5\u00b0F og fengi\u00f0 \u00fat 2,5% h\u00e6kkun.\u00a0 Nei, r\u00e9tta a\u00f0fer\u00f0in er a\u00f0 mi\u00f0a vi\u00f0 Kelvin gr\u00e1\u00f0ur og \u00fe\u00e1 f\u00e6st 0,3% h\u00e6kkun \u00e1 s\u00ed\u00f0astli\u00f0num 150 \u00e1rum.<\/p>\n

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Hin s\u00edkviku kerfi…<\/strong><\/h3>\n

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Mynd 4:\u00a0\u00a0 <\/strong>Hin s\u00edbreytilegu,\u00a0 s\u00edkviku,\u00a0 \u00f3lgukenndu og ka\u00f3t\u00edsku kerfi hafs og lofts.<\/span><\/p><\/div>\n

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Loftslagskerfin samanstanda af \u00f3lgukenndu (turbulent) hafinu sem er \u00ed snertingu vi\u00f0 \u00f3lgukenndan lofthj\u00fapinn. \u00deessi kerfi eru \u00e1 reikistj\u00f6rnu sem sn\u00fdst \u00ed s\u00edfellu og er b\u00f6\u00f0u\u00f0 \u00ed s\u00f3larlj\u00f3si sem sk\u00edn \u00f3jafnt \u00e1 yfirbor\u00f0 jar\u00f0ar, mest n\u00e6rri mi\u00f0baug en minnst n\u00e6ri p\u00f3lunum. M\u00f6ndulhlli reikistj\u00f6rnunnar veldur \u00fev\u00ed a\u00f0 vetur og sumur skiptast \u00e1. S\u00edfelldur flutningur \u00e1 varma og raka \u00e1 s\u00e9r sta\u00f0 milli \u00feessara s\u00edkviku ka\u00f3t\u00edsku kerfa. Drifkrafturinn in inngeislun s\u00f3lar.<\/p>\n

\u00cd hafinu eru straumar og sveiflur sem n\u00e1 yfir t\u00edmabil sem m\u00e6last fr\u00e1 d\u00f6gum til \u00e1r\u00fe\u00fasunda. Hafi\u00f0 hefur \u00e1hrif \u00e1 lofthj\u00fapinn og \u00f6fugt. Yfirbor\u00f0 jar\u00f0ar er mj\u00f6g \u00f3reglulegt og m\u00f3tar \u00fea\u00f0 vindakerfin. Sama m\u00e1 segja um hafsbotninn sem m\u00f3tar hafstrauma, svo og landmassann sem afmarkar h\u00f6fin. Rakinn \u00ed lofthj\u00fapnum hefur gr\u00ed\u00f0arlega mikil \u00e1hrif, og er a\u00f0al \u00e1hrifavaldurinn s\u00e9 liti\u00f0 til hl\u00fdnunar af v\u00f6ldum svokalla\u00f0ra gr\u00f3\u00f0urh\u00fasa\u00e1hrifa. Jafnvel inngeislun s\u00f3lar er sveiflukennd.<\/p>\n

Stundum leggjast \u00e1hrif \u00feessara tilviljunarkenndu kerfa saman; heildar\u00e1hrif \u00feeirra geta or\u00f0i\u00f0 tilt\u00f6lulega mikil um t\u00edma, en \u00e1 \u00f6\u00f0rum t\u00edmum vinna \u00feau \u00e1 m\u00f3ti hverju \u00f6\u00f0ru og ver\u00f0a \u00fe\u00e1 \u00e1hrifin l\u00edtil. A\u00f0eins \u00fearf \u00f6rlitla breytingu \u00ed me\u00f0al sk\u00fdjafari, f\u00e1ein pr\u00f3sentstig, \u00fearf til a\u00f0 valda verulegum, jafnvel langvarandi, breytingum \u00ed hitafari jar\u00f0ar.<\/p>\n

\u00deetta ka\u00f3t\u00edska kerfi \u00e1 yfirbor\u00f0i jar\u00f0ar gerir \u00fea\u00f0 a\u00f0 verkum a\u00f0 hitafari\u00f0 getur or\u00f0i\u00f0 \u00f3lgukennt, \u00e1n \u00feess a\u00f0 ytra \u00e1reiti, svo sem breytileg s\u00f3lgeislun e\u00f0a breytilegur styrkur koltv\u00eds\u00fdrings \u00feurfi a\u00f0 koma til.<\/p>\n

Svona heg\u00f0un sj\u00e1var, lofts og sk\u00fdja hefur alltaf veri\u00f0 fr\u00e1 \u00f6r\u00f3fi alda.\u00a0 \u00deessi ka\u00f3t\u00edska heg\u00f0un er n\u00e6gileg til a\u00f0 \u00fatsk\u00fdra hitasveiflurnar undanfarna \u00e1ratugi, aldir og \u00fe\u00fasaldir, sem sj\u00e1st \u00e1 Mynd 2<\/strong>. Ekki \u00fearf a\u00f0sto\u00f0 fr\u00e1 breytilegum styrk koltv\u00eds\u00fdrings e\u00f0a breytilegri s\u00f3lvirkni, en \u00feau \u00e1hrif geta lagt sitt l\u00f3\u00f0 \u00e1 vogarsk\u00e1larnar.<\/p>\n

Vi\u00f0 getum sem d\u00e6mi um nokku\u00f0 langt\u00edma sveiflur \u00ed hafinu nefnt El-Ni\u00f1o \/ La-Ni\u00f1a fyrirb\u00e6ri\u00f0 \u00ed Kyrrahafinu (El Ni\u00f1o\u2013Southern Oscillation\u00a0ENSO), \u00a030 \u00e1ra sveifluna \u00ed Kyrrahhafinu (Pacific Decadal Oscillation PDO)\u00a0og 70 \u00e1ra sveiflur \u00ed Atlantshafinu (Atlantic Multidecadal Oscillation\u00a0AMO). \u00deekktar sveiflur \u00ed hafinu eru mun fleiri.<\/p>\n

\u00deessar innri sveiflur eru n\u00e6gjanlegar til a\u00f0 valda einar s\u00e9r \u00e1ratugal\u00f6ngum sveiflum \u00ed hitafari, en til vi\u00f0b\u00f3tar er svo ytra \u00e1reiti fr\u00e1 breytilegri heildarinngeislun s\u00f3lar, mj\u00f6g breytilegum styrk \u00ed \u00fatfj\u00f3lubl\u00e1a \u00fe\u00e6tti s\u00f3lgeislunar og breytilegum styrk s\u00f3lvindsins. \u00d6flug eldgos valda stundum skammvinnri k\u00f3lnun. Aukning koltv\u00eds\u00fdrings \u00ed andr\u00famsloftiu veldur svo st\u00edganda sem nemur r\u00famlega 1\u00b0C hl\u00fdnun fyrir hverja tv\u00f6f\u00f6ldun styrks CO2<\/sub>, t.d. \u00far 0,028% \u00ed 0.056%, og svo s\u00f6mu hl\u00fdnun um r\u00famlega 1\u00b0\u00a0 fr\u00e1 0,056% til 0,112%, \u00fev\u00ed hl\u00fdnun af v\u00f6ldum koltv\u00eds\u00fdrings fylgir logarithmiskum reglum.\u00a0 Um \u00feessar mundir er styrkur CO2 <\/sub>um 0,04%..<\/p>\n

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Mynd 5:\u00a0\u00a0\u00a0\u00a0\u00a0 <\/strong>Hnattr\u00e6nar breytingar \u00ed me\u00f0alhita lofthj\u00faps jar\u00f0ar s\u00ed\u00f0astli\u00f0in 2000 \u00e1r. Losun manna \u00e1 koltv\u00eds\u00fdringi h\u00f3fst ekki a\u00f0 r\u00e1\u00f0i fyrr en um 1850, og g\u00e6ti \u00fev\u00ed ekki hafa haft \u00e1hrif \u00e1 hitafari\u00f0 fyrir \u00feann t\u00edma. Heimildar er geti\u00f0 \u00e1 myndinni.<\/span><\/p><\/div>\n

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Hver er raunveruleikinn…?<\/strong><\/h3>\n

\u00cd fr\u00e9ttum undanfari\u00f0 hefur i\u00f0ulega veri\u00f0 fari\u00f0 rangt me\u00f0 raunverulega \u00fer\u00f3un ve\u00f0urtengdra fyrirb\u00e6ra.<\/p>\n

H\u00e9r ver\u00f0ur drepi\u00f0 \u00e1 nokkur \u00feeirra, fyrst og fremst me\u00f0 sk\u00fdringum vi\u00f0 myndir og tilv\u00edsun \u00ed v\u00edsindagreinar:<\/p>\n


\nHaf\u00edsinn…<\/strong><\/h3>\n
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Mynd 6:<\/strong>\u00a0 \u00datbrei\u00f0sla haf\u00edss nor\u00f0an \u00cdslands s\u00ed\u00f0astli\u00f0in 3000 \u00e1r.\u00a0\u00a0 Vi\u00f0 erum st\u00f6dd \u00e1 ferlinum lengst til vinstri. Haf\u00edsinn hefur lengst af undanfarin 3000 \u00e1r veri\u00f0 mun minni en undanfari\u00f0. Litla \u00eds\u00f6ldin svokalla\u00f0a sker sig \u00fe\u00f3 \u00far. Heimild: Grein Paola Moffa-S\u00e1nchez & Ian R. Hall \u00ed Nature Communications 2017.<\/span><\/p><\/div>\n

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Snj\u00f3\u00feekjan…<\/strong><\/h3>\n
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Mynd 7:<\/strong> \u00a0\u00a0 Snj\u00f3\u00feekja \u00e1 nor\u00f0urhveli fr\u00e1 1972 til 2019. Granna l\u00ednan er vikume\u00f0altal og \u00feykka l\u00ednan \u00e1rsme\u00f0altal. Rau\u00f0a l\u00ednan er leitnin yfir allt t\u00edmabili\u00f0, en engin breyting hefur or\u00f0i\u00f0 \u00e1 \u00fatbrei\u00f0slunni.\u00a0 M\u00e6lig\u00f6gn eru fr\u00e1\u00a0 Rutgers University Global Snow Laboratory. Ferillinn er fr\u00e1 www.climate4you.com.<\/span><\/p><\/div>\n

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S\u00f3lin…<\/strong><\/h3>\n
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Mynd 8:\u00a0<\/strong> \u00a0 Heildar\u00fatgeislun s\u00f3lar (TSI – Total Solar Irradiance) fr\u00e1 1610 til 2014 samkv\u00e6mt ranns\u00f3knum Dr. Judith Lean o.fl. L\u00f3\u00f0r\u00e9tti skalinn er \u00ed w\u00f6ttum \u00e1 fermetra utan lofthj\u00faps jar\u00f0ar. Ferillinn byrjar um \u00fea\u00f0 leyti sem Galileo Galilei benir fyrst sj\u00f3nauka s\u00ednum a\u00f0 s\u00f3linni.\u00a0 \u00dea\u00f0 er ef til vill tilviljun a\u00f0 kaldasta t\u00edmabil Litlu \u00edsaldarinnar var fr\u00e1 um 1650 til 1710 \u00feegar Maunder l\u00e1gmarki\u00f0 \u00ed s\u00f3lvirkni st\u00f3\u00f0 yfir. Ferillinn er fr\u00e1 vefs\u00ed\u00f0unni www.climate4you.com sem Dr. Ole Humlum pr\u00f3fessor s\u00e9r um.<\/span><\/p><\/div>\n

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Fellibyljir…<\/strong><\/h3>\n
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Mynd 9:<\/strong>\u00a0\u00a0 T\u00ed\u00f0ni \u00f6flugustu fellibylja \u00e1 j\u00f6r\u00f0inni fer l\u00e6kkandi. Ferillinn er fr\u00e1 Dr. Ryan Maue ve\u00f0urfr\u00e6\u00f0ingi.<\/span><\/p><\/div>\n

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Framt\u00ed\u00f0in og sp\u00e1l\u00edk\u00f6n…<\/strong><\/h3>\n
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Mynd 10:\u00a0<\/strong> Rau\u00f0i ferillinn er me\u00f0altal 102 sp\u00e1likana. Bl\u00e1i ferillinn er lofthiti m\u00e6ldur fr\u00e1 gervihn\u00f6ttum og s\u00e1 gr\u00e6ni lofthiti m\u00e6ldur fr\u00e1 loftbelgjum. Rau\u00f0i ferillinn er me\u00f0altal 102 sp\u00e1l\u00edkana sem s\u00fdna mismunandi svi\u00f0smydir. Sp\u00e1l\u00edk\u00f6nin s\u00fdna a\u00f0 me\u00f0altali\u00a0 3 sinnum meiri hl\u00fdnun en raunveruleikinn. Allar sp\u00e1r um \u00fer\u00f3un htastigs og d\u00fdrar m\u00f3tv\u00e6gisa\u00f0ger\u00f0ir byggja \u00e1 \u00feessum \u00f3fullkomnu l\u00edk\u00f6num. \u00a0A\u00f0eins 1 loftslagsl\u00edkan (r\u00fassneskt, ne\u00f0sta punktal\u00ednan) af 102 kemst n\u00e1l\u00e6gt raunveruleikanum. Myndin er fr\u00e1 Dr. John Christy pr\u00f3fessor \u00ed loftslagsfr\u00e6\u00f0um.<\/span><\/p><\/div>\n

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Sk\u00f3gar- og kjarreldar…<\/strong><\/h3>\n
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Mynd 11:<\/strong> \u00a0 Sk\u00f3gar- og kjarreldum \u00ed Nor\u00f0ur-Amer\u00edku fer verulega f\u00e6kkandi. Ferillinn n\u00e6r yfir t\u00edmabili\u00f0\u00a0 1600 til 2000.\u00a0 Gr\u00e6na sv\u00e6\u00f0i\u00f0 s\u00fdnir hven\u00e6r fari\u00f0 er a\u00f0 huga a\u00f0 fyrirbyggjandi a\u00f0ger\u00f0um me\u00f0 beit h\u00fasd\u00fdra og ger\u00f0 gr\u00f3\u00f0url\u00edtilla r\u00e1sa til a\u00f0 minnka botngr\u00f3\u00f0ur og \u00fear me\u00f0 eldsmat og hafa hemil \u00e1 eldunum. \u00a0Heimild: Multiscale perspectives of fire, climate and humans in western North America and the Jemez Mountains, USA. Swetnam, o.fl. 2016, Philosophical Transactions of the Royal Society.<\/span><\/p><\/div>\n

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Hafi\u00f0 og sj\u00e1varsta\u00f0a…<\/strong><\/h3>\n
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Mynd 12:\u00a0<\/strong> Breytingar \u00e1 sj\u00e1varst\u00f6\u00f0u fr\u00e1 1900 til loka \u00e1rs 2017 samkv\u00e6mt m\u00e6lingu fr\u00e1 9 vel v\u00f6ldum landf\u00f6stum m\u00e6lum. H\u00e6kkunin nemur 2,08 mill\u00edmetrum \u00e1 \u00e1ri, sem samsvarar um 20 cm \u00e1 \u00f6ld. Bl\u00e1u deplarnir eru m\u00e6ligildi einstakra m\u00e1na\u00f0a, en fj\u00f3lubl\u00e1i ferillinn er me\u00f0atal 121 m\u00e1na\u00f0a. \u00c1rlegar breytingar eru s\u00fdndar \u00e1 ferlinum sem er \u00ed mi\u00f0ju, en ne\u00f0sti ferillinn s\u00fdnir 10 \u00e1ra me\u00f0altal \u00feessara breytinga. Sj\u00e1varsta\u00f0a hefur h\u00e6kka\u00f0 me\u00f0 n\u00e1nast sama hra\u00f0a allt t\u00edmabili\u00f0 og engin breyting or\u00f0i\u00f0 \u00fear \u00e1 undanfari\u00f0.\u00a0 Ferillinn er fr\u00e1 www.climate4you.com og teikna\u00f0ur samkv\u00e6mt g\u00f6gnum fr\u00e1 \u00a0PSMSL Data Explorer.<\/span><\/p><\/div>\n

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Framt\u00ed\u00f0in og Nor\u00f0ur Atlantshafssveiflan…<\/strong><\/h3>\n
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Mynd 13:<\/strong> Hin \u00f6fluga 60 til 80 \u00e1ra sveifla \u00ed Atlantshafinu, Atlantic Multi-decadal Oscillation (AMO), hefur veruleg \u00e1hrif \u00e1 hitafari\u00f0.\u00a0 \u00c1 mi\u00f0ri si\u00f0ustu \u00f6ld var loftslag hl\u00fdtt, svo kom kuldat\u00edmabil sem vi\u00f0 nefnum stundum \u201ehaf\u00eds\u00e1rin\u201c, og svo f\u00f3r a\u00f0 hl\u00fdna aftur up \u00far 1990. N\u00fa er AMO indexinn farinn a\u00f0 falla eins og hann ger\u00f0i r\u00e9tt \u00e1\u00f0ur en \u201ehaf\u00eds\u00e1rin\u201c skullu \u00e1. \u00a0Heimild: NCAR UCAR, Climate Data Guide.<\/span><\/p><\/div>\n

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Samantekt…<\/strong><\/h3>\n
    \n
  • Loftslagsbreytingar hafa \u00e1vallt veri\u00f0 \u00ed fort\u00ed\u00f0inni og munu \u00e1vallt ver\u00f0a \u00ed framt\u00ed\u00f0inni.<\/li>\n
  • Koltv\u00eds\u00fdringur er svokalla\u00f0 gr\u00f3\u00f0urh\u00fasagas og eru \u00e1hrif \u00feess \u00e1 lofthj\u00fapinn logarithmisk. Hver tv\u00f6f\u00f6ldun hefur \u00fev\u00ed s\u00f6mu \u00e1hrif til hitah\u00e6kkunar. Hve mkil \u00feessi \u00e1hrif eru er ekki vita\u00f0 me\u00f0 neinni vissu. Ranns\u00f3nir hafa gefi\u00f0 til kynna 1K til 3K fyrir hverja tv\u00f6f\u00f6ldun \u00e1 styrk \u00feess. 1,2K er samkv\u00e6mt m\u00e6lingum og 3K skv. l\u00edk\u00f6num. (Sj\u00e1 myndband).<\/li>\n
  • Allar \u00feessar breytingar leggjast saman og er illm\u00f6gulegt a\u00f0 skilja \u00fe\u00e6r a\u00f0.<\/li>\n
  • Heildar\u00e1hrif \u00feessara breytinga hafa \u00e1 s\u00ed\u00f0ustu 150 \u00e1rum valdi\u00f0 um 0,8K til 1,0K hl\u00fdnun sem er um \u00fea\u00f0 bil 0,3% af \u00feeirri heildarhl\u00fdnun sem s\u00f3lin veldur (288K).<\/li>\n<\/ul>\n

    \u00a0<\/strong><\/p>\n

    \u201cSvo gengur \u00fea\u00f0 til \u00ed heiminum a\u00f0 sumir hj\u00e1lpa erroribus \u00e1 gang<\/strong><\/em>
    \nog a\u00f0rir leitast vi\u00f0 a\u00f0 \u00fatry\u00f0ja aftur \u00feeim hinum s\u00f6mu erroribus.
    \nHafa svo hvorir tveggju nokku\u00f0 a\u00f0 i\u00f0ja.\u201d<\/em><\/strong><\/span><\/h3>\n

    \u00a0\u00c1rni Magn\u00fasson handritasafnari.<\/p>\n

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    \u00cdtarefni:<\/h1>\n

    Einstaklega g\u00f3\u00f0ur og au\u00f0skilinn fyrirlestur Dr. John Christy loftslagsfr\u00e6\u00f0ings<\/strong>.<\/p>\n