{"id":572,"date":"2023-05-12T00:00:36","date_gmt":"2023-05-11T22:00:36","guid":{"rendered":"https:\/\/www.zahadyazajimavosti.cz\/?p=572"},"modified":"2023-05-11T23:04:47","modified_gmt":"2023-05-11T21:04:47","slug":"na-zemi-byl-kdysi-zar-60-stupnu","status":"publish","type":"post","link":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/2023\/05\/12\/na-zemi-byl-kdysi-zar-60-stupnu\/","title":{"rendered":"Na Zemi byl kdysi \u017e\u00e1r 60 stup\u0148\u016f"},"content":{"rendered":"<p><strong>Glob\u00e1ln\u00ed oteplov\u00e1n\u00ed v minulosti siln\u011b oh\u0159\u00edvalo na\u0161i planetu. Nov\u00e1 pr\u00e1ce klimatolog\u016f vrhla sv\u011btlo na povahu nejv\u011bt\u0161\u00edho masov\u00e9ho vym\u00edr\u00e1n\u00ed v historii Zem\u011b.<\/strong><!--more--><\/p>\n<p>\u010cl\u00e1nek britsk\u00fdch, n\u011bmeck\u00fdch a \u010d\u00ednsk\u00fdch klimatick\u00fdch v\u011bdc\u016f, zve\u0159ejn\u011bn\u00fd v \u010dasopise Science, poskytuje opravdu apokalyptick\u00fd obraz &#8211; ne\u017eiv\u00e9 oce\u00e1ny, sou\u0161e pokryt\u00e1 stepi a savanami (stromy uschly p\u0159eh\u0159\u00e1t\u00edm) sv\u011btad\u00edly bez sebemen\u0161\u00edch viditeln\u00fdch zv\u00ed\u0159at a p\u0159edev\u0161\u00edm v\u0161ude se chv\u011bj\u00edc\u00ed se z\u00e1voj hork\u00e9ho vzduchu.<\/p>\n<p>Podle v\u00fdpo\u010dt\u016f by mohla teplota oce\u00e1n\u016f v tropech p\u0159ekro\u010dit 40 stup\u0148\u016f Celsia, a na sou\u0161i by p\u0159ekro\u010dila 50 stup\u0148\u016f. P\u0159itom nejde o maxim\u00e1ln\u00ed teplotu b\u011bhem dne, ale o ro\u010dn\u00ed pr\u016fm\u011brn\u00e9 hodnoty: ve dne by bylo vedro je\u0161t\u011b v\u011bt\u0161\u00ed, ale v noci by doch\u00e1zelo k ochlazen\u00ed. Teplota vody by jen z\u0159\u00eddka poklesla pod 30 stup\u0148\u016f.<\/p>\n<p>P\u0159i teplot\u011b 40 stup\u0148\u016f horko zab\u00edj\u00ed mo\u0159sk\u00fd plankton, pot\u00e9 um\u00edr\u00e1 v\u011bt\u0161ina ryb a plaz\u016f.<\/p>\n<p>Smrt\u00ed planktonu a suchozemsk\u00fdch rostlin se sni\u017euje fotosynt\u00e9za, kter\u00e1 vyr\u00e1b\u00ed nejen kysl\u00edk, ale tak\u00e9 absorbuje oxid uhli\u010dit\u00fd. Sn\u00ed\u017een\u00ed fotosynt\u00e9zy vedlo k dal\u0161\u00edmu zv\u00fd\u0161en\u00ed koncentrace CO2 a zes\u00edlen\u00ed sklen\u00edkov\u00e9ho efektu a t\u00edm tedy i k dal\u0161\u00edmu oteplen\u00ed \u2013 a bludn\u00fd kruh se uzav\u00edr\u00e1.<\/p>\n<p><em>Permsk\u00e9 vym\u00edr\u00e1n\u00ed<\/em> (1) bylo nejv\u011bt\u0161\u00ed v historii Zem\u011b. Do\u0161lo k n\u011bmu p\u0159ed 252,2 mili\u00f3ny lety a vym\u0159elo p\u0159i n\u011bm asi 83% pozemsk\u00fdch \u017eivo\u010di\u0161n\u00fdch druh\u016f. Zachovaly se po n\u011bm jen kamenn\u00e9 fos\u00edlie: trilobiti, p\u0159esto\u017ee to byli kdysi nejhojn\u011bj\u0161\u00edm druhem mo\u0159sk\u00fdch \u017eivo\u010dich\u016f.<\/p>\n<p>Ke zji\u0161t\u011bn\u00ed, jak\u00e1 byla teplota na planet\u011b p\u0159ed \u010dtvrt miliardou let, pomohla odborn\u00edk\u016fm izotopov\u00e1 anal\u00fdza.<\/p>\n<p>V\u011bdci z\u00edskali v\u00edce ne\u017e 15.000 vzork\u016f <em>conodont\u016f<\/em> (2), kte\u0159\u00ed \u017eili v t\u00e9 dob\u011b. Tito primitivn\u00ed \u017eivo\u010dichov\u00e9 byli jedn\u011bmi z m\u00e1la, je\u017e p\u0159e\u017eili vysok\u00e9 teploty. V jejich zubech se zachovaly stopy izotop\u016f kysl\u00edku.<\/p>\n<p>Pom\u011br mezi izotopy, jak uk\u00e1zala \u0159ada p\u0159edchoz\u00edch studi\u00ed, z\u00e1vis\u00ed na teplot\u011b, p\u0159i kter\u00e9 se formovala biologick\u00e1 tk\u00e1\u0148, tak\u017ee i po stovk\u00e1ch milion\u016f let klimatologov\u00e9 dostali vcelku p\u0159esn\u00e9 \u00fadaje.<\/p>\n<p><em>&#8222;Nikdo si nemyslel,\u201c<\/em> \u0159ekl <em>Paul Vignell, profesor z University v Leeds<\/em> a jeden z autor\u016f studie \u2013 <em>\u201e \u017ee teplota stoupla tak vysoko. Douf\u00e1m, \u017ee sou\u010dasn\u00e9 glob\u00e1ln\u00ed oteplov\u00e1n\u00ed nepostoup\u00ed do podobn\u00fdch hodnot, proto\u017ee by jinak o\u017eiven\u00ed ekosyst\u00e9mu trvalo mili\u00f3ny let.&#8220;<\/em><\/p>\n<p>V\u011bdci otev\u0159en\u011b hovo\u0159\u00ed o tom, \u017ee jejich pr\u00e1ce v\u00fdznamn\u011b roz\u0161i\u0159uje poznatky o perm-triasov\u00e9m vyhynut\u00ed \u017eivo\u010dich\u016f. O glob\u00e1ln\u00edm oteplov\u00e1n\u00ed v tomto obdob\u00ed se v\u011bd\u011blo, ale nikdo netu\u0161il, \u017ee m\u011blo pr\u00e1v\u011b takov\u00e9 dopady.<\/p>\n<p>O p\u0159\u00ed\u010din\u00e1ch vym\u00edr\u00e1n\u00ed existuje mnoho hypot\u00e9z, mezi nimi sr\u00e1\u017eka s kometou nebo asteroidem, nebo prudk\u00e9 zv\u00fd\u0161en\u00ed sope\u010dn\u00e9 \u010dinnosti a emise metanu z oce\u00e1nsk\u00e9ho dna.<\/p>\n<p><strong><em>Odkazy<\/em><\/strong><\/p>\n<p><em>(1) <a href=\"http:\/\/cs.wikipedia.org\/wiki\/Permsk%C3%A9_vym%C3%ADr%C3%A1n%C3%AD\" target=\"_blank\" rel=\"noopener\">http:\/\/cs.wikipedia.org\/wiki\/Permsk%C3%A9_vym%C3%ADr%C3%A1n%C3%AD<\/a> <\/em><br \/>\n<em>(2) <a href=\"http:\/\/en.wikipedia.org\/wiki\/Conodont\" target=\"_blank\" rel=\"noopener\">http:\/\/en.wikipedia.org\/wiki\/Conodont<\/a><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Glob\u00e1ln\u00ed oteplov\u00e1n\u00ed v minulosti siln\u011b oh\u0159\u00edvalo na\u0161i planetu. Nov\u00e1 pr\u00e1ce klimatolog\u016f vrhla sv\u011btlo na povahu nejv\u011bt\u0161\u00edho masov\u00e9ho vym\u00edr\u00e1n\u00ed v historii<\/p>\n","protected":false},"author":1,"featured_media":573,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9,17],"tags":[71,70],"class_list":["post-572","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-historie","category-veda","tag-klima","tag-zeme"],"_links":{"self":[{"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/posts\/572","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/comments?post=572"}],"version-history":[{"count":1,"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/posts\/572\/revisions"}],"predecessor-version":[{"id":574,"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/posts\/572\/revisions\/574"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/media\/573"}],"wp:attachment":[{"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/media?parent=572"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/categories?post=572"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/tags?post=572"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}