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Heimshl\u00fdnun og Hallgr\u00edmskirkja<\/strong>. Sk\u00fdringar Met-Office:<\/span> “Global annual average temperature anomalies (\u00b0C, relative to the long-term average for 1981-2010, 2017 to November). Six datasets are shown as indicated in the legend. The grey shaded area is the 95% uncertainty range for HadCRUT4. The horizontal grey line with yellow shading indicates the approximate point at which temperatures exceed 1\u00b0C above \u201cpre-industrial\u201d levels.<\/span> The horizontal grey line is the difference from the 1850-1900 average. The yellow shading is derived from Hawkins et al. (2017).\u00a0 (bottom) differences of each data set\u00a0 from HadCRUT4 on an expanded scale”<\/em><\/p><\/div>\n Myndin er fr\u00e1 vefs\u00ed\u00f0u Met-Office, Bresku ve\u00f0urstofunni, n\u00e1nar tilteki\u00f0 \u00far grein sem nefnist\u00a0 “An overview of global surface temperatures in 2017”<\/a>.\u00a0 \u00c1 myndina hefur s\u00e1 er \u00feessi or\u00f0 ritar b\u00e6tt inn sk\u00fdringum me\u00f0 fj\u00f3lubl\u00e1um lit, \u00e1samt skuggamynd af Hallgr\u00edmskirkju.\u00a0 Sj\u00e1 sk\u00fdringar vi\u00f0 myndina \u00e1 vefs\u00ed\u00f0u Met-Office.<\/p>\n Gr\u00e1a heildregna l\u00ednan me\u00f0 gula<\/strong> <\/span>brei\u00f0a bakgrunninum, sem er \u00e1 myndinni fr\u00e1 Met-Office,\u00a0 \u00e1 a\u00f0 t\u00e1kna hve mikil heimshl\u00fdnunin \u00fearf a\u00f0 vera til a\u00f0 vera meiri en 1\u00b0C mi\u00f0a\u00f0 vi\u00f0 t\u00edmabili\u00f0 1850 til 1900, sem Met-Office kallar “pre-industrial”, \u00fe.e. t\u00edmann fyrir i\u00f0nbyltingu 19. aldar.\u00a0 \u00deetta t\u00edmabil, og jafnvel til 1920, n\u00e6r yfir s\u00ed\u00f0ustu \u00e1ratugi “Litlu \u00edsaldarinnar” svok\u00f6llu\u00f0u.<\/p>\n Strika\u00f0a fj\u00f3lubl\u00e1a<\/span> l\u00ednan er dregin 1\u00b0C<\/strong> ne\u00f0ar, en \u00feessi l\u00edna og lendir \u00fev\u00ed samkv\u00e6mt skilgreiningu Met-Office \u00e1 “pre-industial” timabilinu.<\/p>\n N\u00fa er \u00fea\u00f0 svo, a\u00f0 n\u00e6rri yfirbor\u00f0i jar\u00f0ar breytist hitastigi\u00f0 um \u00fev\u00ed sem n\u00e6st 0,7\u00b0C fyrir hverja 100 metra \u00ed h\u00e6\u00f0. Hallgr\u00edmskirkja er 75 metrar. Ef vi\u00f0 t\u00e6kjum lyftuna fr\u00e1 jar\u00f0h\u00e6\u00f0 upp \u00ed topp kirkjuturnsins myndum vi\u00f0, a\u00f0 \u00f6\u00f0ru \u00f3breyttu, ver\u00f0a v\u00f6r vi\u00f0 hital\u00e6kkun sem n\u00e6mi um 0,5 gr\u00e1\u00f0um.\u00a0 Hallgr\u00edmskirkja hefur veri\u00f0 teiknu\u00f0 inn \u00e1 myndina \u00feannig a\u00f0 h\u00e6\u00f0 hennar passar vi\u00f0 l\u00f3\u00f0r\u00e9tta \u00e1sinn, \u00fe.e. 75 metrar jafngilda h\u00e1lfri gr\u00e1\u00f0u.\u00a0 <\/em>\u00a0(Adiabatic lapse rate).<\/span><\/p>\n H\u00e6kkun lofthita fr\u00e1 s\u00ed\u00f0ustu \u00e1ratugum Litlu \u00edsaldar (me\u00f0altal \u00e1ranna 1850-1900) sem er um 0,8\u00b0C ef vi\u00f0 sleppum El-Nino toppnum, jafngildir \u00fev\u00ed breytingu \u00ed h\u00e6\u00f0 sem nemur heldur minna en tveim Hallgr\u00edmskirkjum.<\/span><\/p>\n N\u00fa er ekki v\u00edst a\u00f0 okkur \u00feyki skynsamlegt a\u00f0 mi\u00f0a h\u00e6kkun lofthita vi\u00f0 “pre-industrial” t\u00edmann 1850-1900, heldur frekar vi\u00f0 t\u00edmabili\u00f0 1960-1980 \u00feegar lofthitinn hvorki h\u00e6kka\u00f0i n\u00e9 l\u00e6kka\u00f0i, og ekki er v\u00edst a\u00f0 okkur \u00feyki r\u00e9tt a\u00f0 taka me\u00f0 \u00ed reikninginn hinn skammvinna hitatopp allra s\u00ed\u00f0ustu \u00e1ra sem stafa\u00f0i af El-Nino ve\u00f0urfyrirb\u00e6rinu \u00ed Kyrrahafinu. Ef vi\u00f0 breytum vi\u00f0mi\u00f0inu \u00e1 \u00feennan h\u00e1tt, \u00fe\u00e1 er ekki fjarri lagi a\u00f0 ein Halgr\u00edmskirkja n\u00e6gi.<\/p>\n Hallgr\u00edmskirkja er oft notu\u00f0 til a\u00f0 gefa hugmynd um h\u00e6\u00f0 mannvirkis eins og t.d. vndorkuvers, en sjaldnast lofthita eins og gert er h\u00e9r. \u00dea\u00f0 m\u00e1tti \u00fe\u00f3 reyna, en varast ber a\u00f0 taka ni\u00f0urst\u00f6\u00f0urnar allt of b\u00f3kstaflega. En \u00feetta er kannski ekki fjarri lagi…?\u00a0 \u00a0\ud83d\ude42<\/p>\n <\/p>\n <\/p>\n \u00cd lokin m\u00e1 velta fyrir s\u00e9r hvers vegna vi\u00f0 h\u00f6fum \u00e1hyggjur af hl\u00fdnun fr\u00e1 t\u00edmabilinu 1850-1900, “pre-industrial time” e\u00f0a s\u00ed\u00f0ustu \u00e1ratugum Litlu \u00edsaldarinnar svok\u00f6llu\u00f0u. \u00dea\u00f0 sakar ekki a\u00f0 sko\u00f0a tv\u00e6r hugarflugs s\u00ed\u00f0ur me\u00f0 \u00feessum vangaveltum:<\/p>\n Hva\u00f0 er e\u00f0lilegt ve\u00f0urfar\u2026?<\/a><\/strong><\/p>\n
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\nEr eitthva\u00f0 \u00f3e\u00f0lilegt vi\u00f0 \u00fea\u00f0 a\u00f0 eitthva\u00f0 hafi hl\u00fdna\u00f0 eftir a\u00f0 \u00feessu kalda t\u00edmabili lauk?
\nEr ekki r\u00f6kr\u00e9tt a\u00f0 \u00e1lykta a\u00f0 st\u00f3r hluti \u00feessarar hl\u00fdnunar hlj\u00f3ti a\u00f0 vera e\u00f0lilegur og af v\u00f6ldum n\u00e1tt\u00faunnar, e\u00f0a er r\u00e9tt a\u00f0 \u00e1lykta sem svo a\u00f0 \u00e1 t\u00edmabilinu 1850-1900 hafi hitastigi\u00f0 veri\u00f0 r\u00e9tt og hl\u00fdnunin s\u00ed\u00f0an \u00fe\u00e1 r\u00f6ng?
\nEr \u00fea\u00f0 ekki p\u00ednul\u00edti\u00f0 kj\u00e1nalegt a\u00f0 tala um “hamfarahl\u00fdnun”.<\/p>\n