Uluslararas\u0131 bir ara\u015ft\u0131rma ekibinin yeni \u00e7al\u0131\u015fmas\u0131na g\u00f6re, y\u00fckselen diazot monoksit (Nitr\u00f6z oksit) sal\u0131n\u0131m\u0131 iklim ko\u015fullar\u0131n\u0131 iyile\u015ftirme hedefinden uzakla\u015fmam\u0131za sebep oluyor.<\/p>\n
Diazot monoksit, atmosferde y\u00fcz y\u0131ldan daha uzun s\u00fcre kalabilen karbondioksitten 300 kat daha g\u00fc\u00e7l\u00fc olan bir sera gaz\u0131d\u0131r. D\u00fcnya \u00e7ap\u0131nda g\u0131da \u00fcretiminde azotlu g\u00fcbre kullan\u0131m\u0131ndaki art\u0131\u015f, atmosferdeki diazot monoksit konsantrasyonunun artmas\u0131na neden oluyor.<\/p>\n
Nature<\/em> dergisinde yay\u0131nlanan yeni \u00e7al\u0131\u015fmaya 14 farkl\u0131 \u00fclkedeki 48 ara\u015ft\u0131rma kurumundan biliminsanlar\u0131 kat\u0131ld\u0131. K\u00fcresel Karbon Projesi ve Uluslararas\u0131 Nitrojen Giri\u015fimi \u00e7at\u0131s\u0131nda toplanan biliminsanlar\u0131n\u0131n amac\u0131, diazot monoksitin k\u00fcresel kaynaklar\u0131 hakk\u0131ndaki en kapsaml\u0131 de\u011ferlendirmeyi yapmakt\u0131. Ara\u015ft\u0131rma bulgular\u0131, diazot monoksit sal\u0131n\u0131m\u0131n\u0131n, IPCC (H\u00fck\u00fcmetleraras\u0131 \u0130klim De\u011fi\u015fili\u011fi Paneli) taraf\u0131ndan geli\u015ftirilen t\u00fcm senaryolardaki sal\u0131n\u0131m oran\u0131ndan daha y\u00fcksek oldu\u011funu g\u00f6steriyor. IPCC, end\u00fcstri \u00f6ncesi d\u00f6nemden bug\u00fcne 3 \u00b0C\u2019nin olduk\u00e7a \u00fczerine \u00e7\u0131kan k\u00fcresel ortalama s\u0131cakl\u0131k art\u0131\u015f\u0131n\u0131n a\u015fa\u011f\u0131 \u00e7ekilmesini hedefliyor. Paris Antla\u015fmas\u0131 olarak bilinen antla\u015fman\u0131n \u00f6ng\u00f6rd\u00fc\u011f\u00fc uygulamalarla bu art\u0131\u015f\u0131n 2 \u00b0C\u2019den a\u015fa\u011f\u0131 \u00e7ekilmesi, 1.5 \u00b0C\u2019den y\u00fcksek olmayacak seviyelere indirilmesi ama\u00e7lan\u0131yor.<\/p>\n En y\u00fcksek art\u0131\u015f son 50 y\u0131lda Diazot monoksit, karbondioksit gibi uzun \u00f6m\u00fcrl\u00fc bir sera gaz\u0131d\u0131r. Bu molek\u00fcl, D\u00fcnya\u2019y\u0131 zararl\u0131 ultraviyole radyasyonundan koruyan stratosferik ozon tabakas\u0131n\u0131 \u00f6nemli \u00f6l\u00e7\u00fcde etkiler. Auburn \u00dcniversitesi\u2019ne ba\u011fl\u0131 Uluslararas\u0131 \u0130klim ve K\u00fcresel De\u011fi\u015fim Ara\u015ft\u0131rmalar\u0131 Merkezi’nin y\u00f6neticisi Prof. Hanqin Tian, \u201cAtmosferdeki nitr\u00f6z oksit art\u0131\u015f\u0131n\u0131n itici g\u00fcc\u00fc tar\u0131m uygulamalar\u0131d\u0131r. Hayvanc\u0131l\u0131k i\u00e7in g\u0131da ve yem talebinin art\u0131\u015f\u0131, k\u00fcresel nitr\u00f6z oksit sal\u0131n\u0131m\u0131n\u0131 daha da art\u0131racak. \u0130nsanlar\u0131n beslenme \u015fekli ile iklim de\u011fi\u015fikliklerinin \u00f6n\u00fcne ge\u00e7me \u015feklimiz aras\u0131nda bir \u00e7eli\u015fki var\u201d a\u00e7\u0131klamalar\u0131nda bulundu.<\/p>\n S\u00f6z konusu ara\u015ft\u0131rma diazot monoksit sal\u0131n\u0131m\u0131na neden olan do\u011fal kaynaklara ve insanlarla ilgili kaynaklara dair bir envanter de sunmaktad\u0131r. \u00c7al\u0131\u015fmaya g\u00f6re tar\u0131m faaliyetleri kaynakl\u0131 diazot monoksit sal\u0131n\u0131m\u0131 son 40 y\u0131lda y\u00fczde 30 oran\u0131nda artarak y\u0131lda 7.3 teragrama ula\u015ft\u0131. (1 teragram; 1 trilyon grama, 1 milyar kilograma denk gelmektedir.)<\/p>\n Ara\u015ft\u0131rmaya g\u00f6re, k\u00fcresel diazot monoksit sal\u0131n\u0131m\u0131na en b\u00fcy\u00fck katk\u0131 Do\u011fu Asya, G\u00fcney Asya, Afrika ve G\u00fcney Amerika\u2019dan geliyor. Sentetik g\u00fcbre \u00fcretimi ve kullan\u0131m\u0131ndan kaynakl\u0131 sal\u0131n\u0131mlar \u00c7in, Hindistan ve ABD\u2019de en y\u00fcksek seviyedeyken, hayvanlardan elde edilen do\u011fal g\u00fcbrenin kullan\u0131lmas\u0131ndan kaynakl\u0131 sal\u0131n\u0131mlar Afrika ve G\u00fcney Amerika\u2019da en y\u00fcksek seviyededir. Sera gazlar\u0131ndan diazot monoksit sal\u0131n\u0131m\u0131ndaki en y\u00fcksek b\u00fcy\u00fcme oranlar\u0131, \u00f6zellikle tar\u0131m ve hayvanc\u0131l\u0131\u011f\u0131n artt\u0131\u011f\u0131 Brezilya, \u00c7in ve Hindistan\u2019dan elde edilmi\u015ftir. Azotlu g\u00fcbre kullan\u0131m\u0131na ili\u015fkin politikalar\u0131n ve end\u00fcstriyel \u00fcretim sonucu olu\u015fan diazot monoksitin \u00fcretim tesislerinin bacalar\u0131ndan sal\u0131nmas\u0131n\u0131 \u00f6nleyen tedbirler nedeniyle Avrupa\u2019da diazot monoksit sal\u0131n\u0131m\u0131n\u0131n azald\u0131\u011f\u0131 belirtiliyor. Ancak tedbirler yine de yetersiz durumda.<\/p>\n Biliminsanlar\u0131, iklim krizinin en k\u00f6t\u00fc etkilerinden korunmak i\u00e7in diazot monoksit sal\u0131n\u0131m\u0131n\u0131n azalt\u0131lmas\u0131n\u0131n \u00f6nemine dikkat \u00e7ekerek durumun kritik bir hale geldi\u011fini ve yeni tedbirlerin acil olarak g\u00fcndeme al\u0131nmas\u0131 gerekti\u011fini belirtiyor.<\/p>\n Kaynak:<\/strong> SCIENCE DAILY<\/a><\/p>\n
\n<\/strong>Ara\u015ft\u0131rma ise iklim de\u011fi\u015fikli\u011fi konusunda endi\u015fe verici bir e\u011filime i\u015faret ediyor: Diazot monoksit sal\u0131n\u0131m seviyesi, end\u00fcstri \u00f6ncesi d\u00f6neme g\u00f6re y\u00fczde 20 daha y\u00fcksek bir seviyede. 1750\u2019de 270 ppb olan diazot monoksit miktar\u0131, 2018 itibariyle 331 ppb\u2019ye y\u00fckselmi\u015ftir. Son 50 y\u0131lda ise, insan faaliyetleri nedeniyle bu orandaki en y\u00fcksek art\u0131\u015f kaydedildi.<\/p>\n
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