Yeni ara\u015ft\u0131rma, Yerk\u00fcre y\u00f6r\u00fcngesindeki de\u011fi\u015fikliklerin Sahra\u2019n\u0131n \u00e7\u00f6lle\u015fmesini tetikledi\u011fi fikrine meydan okuyor. Bu yeni ara\u015ft\u0131rma, Sahra\u2019n\u0131n 10.000 y\u0131l \u00f6nceki verimli, ye\u015fil tabiat\u0131ndan bug\u00fcnk\u00fc \u00e7orak haline d\u00f6n\u00fc\u015f\u00fcm\u00fcn\u00fc konu almakta; ayn\u0131 zamanda, insan etkisinin \u00e7\u00f6lle\u015fme \u00fczerinde belirgin bir rol oynad\u0131\u011f\u0131 fikrini \u00f6nermektedir.<\/p>\n
Sahra\u2019n\u0131n \u00e7\u00f6lle\u015fme s\u00fcrecinin iklim ve \u00e7evresel fakt\u00f6rleriyle birlikte anla\u015f\u0131labilmesi, biliminsanlar\u0131 a\u00e7\u0131s\u0131ndan uzun zamand\u0131r hedef bir konu olmu\u015ftur.\u00a0Yerbilimlerinde S\u0131n\u0131rlar<\/em>\u00a0dergisinde, Seul Ulusal \u00dcniversitesi\u2019den (Seoul National University) arkeolog Dr. David Wright taraf\u0131ndan hen\u00fcz yay\u0131mlanan bir makale, bug\u00fcne kadar, D\u00fcnya y\u00f6r\u00fcngesindeki de\u011fi\u015fimleri veya bitki \u00f6rt\u00fcs\u00fcnde meydana gelen farkl\u0131l\u0131klar\u0131 ana itici g\u00fc\u00e7 olarak g\u00f6steren pek \u00e7ok ara\u015ft\u0131rman\u0131n sonu\u00e7lar\u0131n\u0131 ele\u015ftiriyor. Wright, Do\u011fu Asya\u2019da, Neolitik topluluklar\u0131n kal\u0131c\u0131 \u015fekilde \u00e7evreyi de\u011fi\u015ftirerek, Musonlar\u0131n i\u00e7 b\u00f6lgelere n\u00fcfuz etmesini nas\u0131l engellediklerini ortaya koyan, kabul g\u00f6rm\u00fc\u015f teorileri hat\u0131rlat\u0131yor.<\/p>\n Ayr\u0131ca, insan kaynakl\u0131 \u00e7evresel ve iklimsel de\u011fi\u015fikliklerin Avrupa, Kuzey Amerika ve Yeni Zelanda\u2019da belgelendi\u011fine ili\u015fkin verilere \u00e7al\u0131\u015fmas\u0131nda yer verip; ard\u0131ndan da benzer bir senaryonun Sahra i\u00e7in ge\u00e7erli olabilece\u011fine dair inanc\u0131n\u0131 payla\u015f\u0131yor.<\/p>\n Wright, hipotezini test etmek amac\u0131yla Sahra b\u00f6lgesi genelinde pastoral ya\u015fam\u0131n ilk izlerini belgeleyen arkeolojik kan\u0131tlar\u0131 g\u00f6zden ge\u00e7irmi\u015f ve bu kay\u0131tlar\u0131 da \u00e7\u00f6l floras\u0131n\u0131 and\u0131ran ko\u015fullarda yeti\u015febilen maki bitkisinin yay\u0131l\u0131m\u0131yla kar\u015f\u0131la\u015ft\u0131rm\u0131\u015ft\u0131r. Yakla\u015f\u0131k 8.000 y\u0131l \u00f6nce Nil Nehri\u2019ni \u00e7evreleyen b\u00f6lgelerde k\u0131rsal topluluklar g\u00f6r\u00fcn\u00fcr olmu\u015f ve bunlar bat\u0131ya do\u011fru yay\u0131lmaya ba\u015flam\u0131\u015ft\u0131r. Bu g\u00f6\u00e7le birlikte, her seferinde bodur \u00e7al\u0131l\u0131klardan meydana gelen bitki \u00f6rt\u00fcs\u00fcnde art\u0131\u015f ya\u015fanm\u0131\u015ft\u0131r ki, Wright\u2019\u0131n \u00f6ng\u00f6r\u00fcs\u00fc b\u00f6ylece do\u011frulanmaktad\u0131r.<\/p>\n B\u00fcy\u00fcyen tar\u0131msal ba\u011f\u0131ml\u0131l\u0131k b\u00f6lgelerin ekolojisi \u00fczerinde ciddi bir etki b\u0131rakm\u0131\u015ft\u0131r. Hayvanc\u0131l\u0131\u011f\u0131n da yayg\u0131nla\u015fmas\u0131yla ye\u015fil alanlar\u0131n gitgide yok oldu\u011fu g\u00f6zlemlenmi\u015ftir. Bu durum bir taraftan arazinin akl\u0131k\/beyazl\u0131k (albedo) derecesinin artmas\u0131na yol a\u00e7m\u0131\u015ft\u0131r (albedo: g\u00fcne\u015ften gelen \u0131\u015f\u0131nlar\u0131n do\u011fal bir y\u00fczeyden yans\u0131t\u0131lan\/yans\u0131yan y\u00fczdesi). B\u00f6ylelikle de atmosfer ko\u015fullar\u0131n\u0131n, Muson ya\u011fmurlar\u0131n\u0131 azaltacak kadar etkilendi\u011fi kaydedilmi\u015ftir. Musonlar\u0131n zay\u0131flamas\u0131 daha fazla bitki \u00f6rt\u00fcs\u00fc kayb\u0131na ve \u00e7\u00f6lle\u015fmeye neden olmu\u015f; nihayetinde bug\u00fcnk\u00fc Sahra\u2019n\u0131n tamam\u0131n\u0131 etkileyerek, bahsi ge\u00e7en d\u00f6n\u00fc\u015f\u00fcm\u00fcn ger\u00e7ekle\u015fmesini sa\u011flam\u0131\u015ft\u0131r.<\/p>\n Her ne kadar hipotezdeki bo\u015fluklar\u0131n doldurulmas\u0131 i\u00e7in daha fazla \u00e7al\u0131\u015fmak gerekse de Wright kayda de\u011fer bilgilerin y\u00fczey alt\u0131nda sakl\u0131 kald\u0131\u011f\u0131na inan\u0131yor: \u201cO d\u00f6nemlerde Sahra\u2019n\u0131n her taraf\u0131nda g\u00f6ller bulunmaktayd\u0131. Bu g\u00f6ller floran\u0131n de\u011fi\u015fimine dair veriler bar\u0131nd\u0131r\u0131yor. Dolay\u0131s\u0131yla, ilk etapta yerin alt\u0131na delgiler yordam\u0131yla inerek eski g\u00f6l yataklar\u0131na ula\u015fmak ve oradan gelen bulgular\u0131 ise arkeolojik a\u00e7\u0131dan inceleyerek, insanlar\u0131n mevcut ortamlar\u0131nda ne yapt\u0131klar\u0131n\u0131 \u00f6\u011frenmeyi ama\u00e7l\u0131yoruz. Bu ba\u011flamda, bitki \u00f6rt\u00fcs\u00fcn\u00fcn iklim sistemlerine etkisini modellemek fazlas\u0131yla zordur. Fakat arkeologlar ve \u00e7evrebilimciler olarak u\u011fra\u015f alan\u0131m\u0131z, bu datalar\u0131 edinerek \u00e7ok y\u00f6nl\u00fc modellerin olu\u015fmas\u0131na katk\u0131 sa\u011flamakt\u0131r.\u201d<\/p>\n Binlerce y\u0131l \u00f6nce meydana gelmesine ra\u011fmen, insan varl\u0131\u011f\u0131n\u0131n \u00e7evresel ve iklimsel bozulmalardan sorumlu olabilece\u011fi yads\u0131namaz bir ger\u00e7ektir. Wright D\u00fcnya n\u00fcfusunun takriben y\u00fczde 15\u2019inin \u00e7\u00f6l sahalar\u0131nda ya\u015fad\u0131\u011f\u0131na dikkat \u00e7ekerek, kendi ke\u015ffinin \u00f6nemini \u015f\u00f6yle vurguluyor: \u201cEkolojik d\u00fczeni de\u011fi\u015ftirmemizin sonu\u00e7lar\u0131, insan\u0131n kurak ortamlarda s\u00fcresiz olarak hayatta kal\u0131p kalamayaca\u011f\u0131 yetisiyle do\u011frudan ili\u015fkilidir.\u201d<\/p>\n \u0130leri Okuma<\/strong>:David K. Wright, \u201cHumans as Agents in the Termination of the African Humid Period\u201d,\u00a0Frontiers in Earth Science<\/em>\u00a0(2017); 5 DOI:\u00a0http:\/\/dx.doi.org\/10.3389\/feart.2017.00004.<\/p>\n","protected":false},"excerpt":{"rendered":" Yeni ara\u015ft\u0131rma, Yerk\u00fcre y\u00f6r\u00fcngesindeki de\u011fi\u015fikliklerin Sahra\u2019n\u0131n \u00e7\u00f6lle\u015fmesini tetikledi\u011fi fikrine meydan okuyor. Bu yeni ara\u015ft\u0131rma, Sahra\u2019n\u0131n 10.000 y\u0131l \u00f6nceki verimli, ye\u015fil tabiat\u0131ndan bug\u00fcnk\u00fc \u00e7orak haline d\u00f6n\u00fc\u015f\u00fcm\u00fcn\u00fc konu almakta; ayn\u0131 zamanda, insan etkisinin \u00e7\u00f6lle\u015fme \u00fczerinde belirgin bir rol oynad\u0131\u011f\u0131 fikrini \u00f6nermektedir. Sahra\u2019n\u0131n \u00e7\u00f6lle\u015fme s\u00fcrecinin iklim ve \u00e7evresel fakt\u00f6rleriyle birlikte anla\u015f\u0131labilmesi, biliminsanlar\u0131 a\u00e7\u0131s\u0131ndan uzun zamand\u0131r hedef bir konu […]<\/p>\n","protected":false},"author":433,"featured_media":12666,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[195,19,217,23],"tags":[856,199,308,309],"class_list":["post-12662","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-158-sayi","category-bilim-gundemi","category-cevre-bilimleri","category-iklim","tag-coller","tag-ekoloji","tag-iklim","tag-iklim-degisikligi"],"acf":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/posts\/12662","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/users\/433"}],"replies":[{"embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/comments?post=12662"}],"version-history":[{"count":0,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/posts\/12662\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/media\/12666"}],"wp:attachment":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/media?parent=12662"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/categories?post=12662"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/tags?post=12662"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}