{"id":24809,"date":"2014-11-01T12:00:17","date_gmt":"2014-11-01T10:00:17","guid":{"rendered":"https:\/\/bilimvegelecek.com.tr\/?p=24809"},"modified":"2018-05-08T12:14:03","modified_gmt":"2018-05-08T09:14:03","slug":"orneklerle-dunyada-ve-turkiyede-iklim-degisikligi-ve-degiskenligi","status":"publish","type":"post","link":"https:\/\/bilimvegelecek.com.tr\/index.php\/2014\/11\/01\/orneklerle-dunyada-ve-turkiyede-iklim-degisikligi-ve-degiskenligi","title":{"rendered":"\u00d6rneklerle D\u00fcnya\u2019da ve T\u00fcrkiye\u2019de \u0130klim De\u011fi\u015fikli\u011fi ve De\u011fi\u015fkenli\u011fi"},"content":{"rendered":"

H\u0131zla geli\u015ftirilen iklim modelleri, g\u00f6zlenen k\u0131tasal \u00f6l\u00e7ekli y\u00fczey s\u0131cakl\u0131\u011f\u0131 desenlerini ve onlarca y\u0131ll\u0131k zaman \u00f6l\u00e7eklerindeki e\u011filimleri, 20. y\u00fczy\u0131l\u0131n ortalar\u0131ndan beri g\u00f6zlenmi\u015f olan daha h\u0131zl\u0131 \u0131s\u0131nma e\u011filimini ve b\u00fcy\u00fck volkanik p\u00fcsk\u00fcrmelerden hemen sonra ortaya \u00e7\u0131kan so\u011fumay\u0131 yeniden \u00fcretmektedir. \u0130nsan etkisi, atmosfer ve okyanus \u0131s\u0131nmas\u0131nda, k\u00fcresel su d\u00f6ng\u00fcs\u00fcndeki de\u011fi\u015fikliklerde, kar ve buzdaki azalmalarda, k\u00fcresel ortalama deniz d\u00fczeyi y\u00fckselmesinde ve baz\u0131 a\u015f\u0131r\u0131 iklim olaylar\u0131ndaki de\u011fi\u015fikliklerde saptanm\u0131\u015ft\u0131r.<\/em><\/p>\n

Bu k\u0131sa makalenin amac\u0131, k\u00fcresel iklim de\u011fi\u015fikli\u011fi ile T\u00fcrkiye\u2019de g\u00f6zlenen ve gelecekte olmas\u0131 \u00f6ng\u00f6r\u00fclen iklimsel de\u011fi\u015fimlerin bilimsel bir de\u011ferlendirmesini yapmakt\u0131r.<\/p>\n

\u00d6ncelikle, konuyla ilgili iki \u00f6nemli kavram\u0131n tan\u0131mlanmas\u0131nda yarar g\u00f6rmekteyiz. Bunlardan birincisi, iklim de\u011fi\u015fikli\u011fi<\/strong>, iklimin ortalama durumunda ya da onun de\u011fi\u015fkenli\u011finde onlarca ya da daha uzun y\u0131llar boyunca s\u00fcren istatistiksel olarak anlaml\u0131 de\u011fi\u015fimler<\/em> olarak tan\u0131mlanabilir (T\u00fcrke\u015f, 2008). \u0130klim de\u011fi\u015fikli\u011fi, do\u011fal i\u00e7 s\u00fcre\u00e7ler ve d\u0131\u015f zorlama etmenleri ile atmosferin bile\u015fimindeki ya da arazi kullan\u0131m\u0131ndaki s\u00fcrekli insan kaynakl\u0131 de\u011fi\u015fiklikler nedeniyle olu\u015fabilir. \u0130klimsel de\u011fi\u015fkenlik<\/strong> ise, t\u00fcm zaman ve alan \u00f6l\u00e7eklerinde iklimin ortalama durumundaki ve standart sapmalar ile u\u00e7 olaylar\u0131n olu\u015fumu gibi \u00f6teki istatistiklerindeki de\u011fi\u015fimlerdir<\/em> (T\u00fcrke\u015f, 2010). \u0130klimsel de\u011fi\u015febilirlik, iklim sistemi i\u00e7erisindeki do\u011fal i\u00e7 s\u00fcre\u00e7lere ya da do\u011fal kaynakl\u0131 d\u0131\u015f zorlama etmenlerindeki de\u011fi\u015fimlere ba\u011fl\u0131 olarak olu\u015fabilir.<\/p>\n

K\u00fcresel iklim, atmosfer (havak\u00fcre), hidrosfer (suk\u00fcre), buz k\u00fcre, litosfer (ta\u015fk\u00fcre) ve biyosfer (ya\u015famk\u00fcre) olarak adland\u0131r\u0131lan ba\u015fl\u0131ca be\u015f bile\u015feni bulunan ve bu bile\u015fenler aras\u0131ndaki kar\u015f\u0131l\u0131kl\u0131 etkile\u015fimleri de i\u00e7eren \u00e7ok karma\u015f\u0131k bir sistemdir ve k\u0131saca \u0130klim Sistemi<\/strong> olarak da adland\u0131r\u0131l\u0131r. D\u0131\u015f zorlamalar ve etmenler, fiziksel iklim sisteminin alt sistemleri ile etkile\u015fim i\u00e7inde bulunan ve onlardan etkilenen de\u011fi\u015fiklikleri, \u00f6rne\u011fin volkanik p\u00fcsk\u00fcrmeler, G\u00fcne\u015f etkinliklerindeki de\u011fi\u015fimler ve Yerk\u00fcre \u2013 G\u00fcne\u015f aras\u0131ndaki astronomik ili\u015fkilerdeki de\u011fi\u015fiklikler gibi do\u011fal olaylar ile atmosferin bile\u015fimindeki insan kaynakl\u0131 de\u011fi\u015fiklikleri i\u00e7erir (T\u00fcrke\u015f, 2012). \u0130nsan etkinlikleri sonucunda atmosfere sal\u0131nan sera gazlar\u0131 ve aerosoller, etki s\u00fcreleri de\u011fi\u015fmekle birlikte, iklim de\u011fi\u015fikliklerine neden olabilecek ba\u015fl\u0131ca d\u0131\u015fsal zorlama ve etmenlerdir. \u0130klim de\u011fi\u015fikli\u011finin potansiyel \u2018d\u0131\u015f\u2019 nedenleri, temel olarak Yerk\u00fcre\u2019nin kat\u0131 kabu\u011fundaki levha hareketlerini, G\u00fcne\u015f etkinliklerindeki ve Yerk\u00fcre ile G\u00fcne\u015f aras\u0131ndaki astronomik ili\u015fkilerdeki de\u011fi\u015fiklikleri i\u00e7erir. Astronomik ili\u015fkiler, Milankovitch d\u00f6ng\u00fcleri olarak da adland\u0131r\u0131lan bir dizi d\u00f6nemsel de\u011fi\u015fiklikleri i\u00e7ermekte ve uzun d\u00f6nemli iklim de\u011fi\u015fikliklerinin a\u00e7\u0131klanmas\u0131 a\u00e7\u0131s\u0131ndan \u00f6nemli kan\u0131tlar sunabilmektedir (T\u00fcrke\u015f, 2013).<\/p>\n

T\u00fcrkiye ve B\u00f6lgesindeki \u0130klim De\u011fi\u015fiklikleri<\/strong><\/p>\n

Sera gazlar\u0131n\u0131n atmosferdeki birikimlerinin \u00e7e\u015fitli insan etkinlikleri nedeniyle sanayi devriminden beri h\u0131zla artmas\u0131 sonucunda kuvvetlenen sera etkisinin en \u00f6nemli sonucu, Yerk\u00fcre\u2019nin enerji dengesi \u00fczerinde ek bir pozitif \u0131\u015f\u0131n\u0131msal zorlama olu\u015fturarak, d\u00fcnya ikliminin daha s\u0131cak (bkz. \u015eekil 3, 7a), baz\u0131 b\u00f6lgelerde daha kurak (bkz. \u015eekil 7b) ve daha de\u011fi\u015fken olmas\u0131n\u0131 sa\u011flamas\u0131d\u0131r. \u0130ster k\u00fcresel isterse b\u00f6lgesel \u00f6l\u00e7ekte olsun, iklim de\u011fi\u015fikli\u011fi ekstrem (a\u015f\u0131r\u0131) hava ve iklim olaylar\u0131n\u0131n s\u0131kl\u0131\u011f\u0131nda, \u015fiddetinde, alansal da\u011f\u0131l\u0131\u015f\u0131nda, uzunlu\u011funda ve zamanlamas\u0131nda de\u011fi\u015fiklikler olu\u015fmas\u0131na neden olmaktad\u0131r. \u00d6rne\u011fin, ya\u011f\u0131\u015f, k\u00fcresel \u00f6l\u00e7ekte 1900\u20132012 d\u00f6neminde alansal ve zamansal olarak y\u00fcksek bir de\u011fi\u015fkenlik g\u00f6stermi\u015f ve ya\u011f\u0131\u015f tutarlar\u0131nda b\u00f6lgesel \u00f6l\u00e7ekte kurakla\u015fma ve art\u0131\u015f e\u011filimleri g\u00f6zlenmi\u015ftir (bkz. \u015eekil 5). Kuzey ve G\u00fcney Amerika\u2019n\u0131n do\u011fu b\u00f6l\u00fcmleri, Kuzey Avrupa ve Asya\u2019n\u0131n orta b\u00f6lgeleri ile kuzeyinde kaydedilen ya\u011f\u0131\u015f tutarlar\u0131nda \u00f6nemli art\u0131\u015f e\u011filimleri <\/em><\/strong>g\u00f6zlenirken (bkz. \u015eekil 5), \u00f6nemli kurakla\u015fma<\/em><\/strong> ya da azal\u0131\u015f e\u011filimleri<\/em><\/strong> ise Sahel, T\u00fcrkiye\u2019yi (\u015eekil 1) de i\u00e7eren Akdeniz havzas\u0131, G\u00fcney Asya\u2019n\u0131n bir b\u00f6l\u00fcm\u00fc ile Afrika\u2019n\u0131n g\u00fcneyinde etkili olmu\u015ftur (IPCC, 2013; T\u00fcrke\u015f, 2012, 2013). Ayr\u0131ca, d\u00fcnyan\u0131n bir\u00e7ok b\u00f6lgesi ve T\u00fcrkiye\u2019deki \u015fiddetli ya\u011f\u0131\u015f olaylar\u0131nda<\/em> <\/strong>(a\u015f\u0131r\u0131 y\u00fcksek ve a\u015f\u0131r\u0131 d\u00fc\u015f\u00fck ya\u011f\u0131\u015flar, vb.) ve ortalama hava s\u0131cakl\u0131klar\u0131nda <\/em><\/strong>(IPCC, 2013; T\u00fcrke\u015f, 2013) da \u00f6nemli art\u0131\u015flar<\/em> <\/strong>g\u00f6zlenmi\u015ftir (\u015eekil 2, 3).<\/p>\n

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\u015eekil 1: T\u00fcrkiye k\u0131\u015f toplam ya\u011f\u0131\u015f tutarlar\u0131ndaki uzun s\u00fcreli e\u011filimlerin alansal da\u011f\u0131l\u0131\u015f desenleri (T\u00fcrke\u015f, 2014). Ters \u00fc\u00e7gen simgeler, toplam ya\u011f\u0131\u015f dizilerindeki azalmay\u0131, art\u0131 simgeleri toplam ya\u011f\u0131\u015f dizilerindeki artma e\u011filimlerini g\u00f6sterir. \u0130\u00e7i noktal\u0131 ve dolu daha iri \u00fc\u00e7gen simgeler, s\u0131ras\u0131yla dizilerdeki % 5 ve % 1 anlaml\u0131l\u0131k d\u00fczeyindeki azalma e\u011filimlerini g\u00f6sterir.<\/figcaption><\/figure>\n
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\u015eekil 2: T\u00fcrkiye y\u0131ll\u0131k ortalama hava s\u0131cakl\u0131\u011f\u0131 dizilerindeki uzun s\u00fcreli e\u011filimlerin alansal da\u011f\u0131l\u0131\u015f desenleri (T\u00fcrke\u015f, 2014). Ters \u00fc\u00e7gen simgeler, hava s\u0131cakl\u0131\u011f\u0131 dizilerindeki azal\u0131\u015f e\u011filimlerini, art\u0131 simgeler dizilerdeki art\u0131\u015f e\u011filimlerini g\u00f6sterir. G\u00f6rece kal\u0131n ve daha kal\u0131n art\u0131 simgeler, s\u0131ras\u0131yla dizilerdeki % 5 ve % 1 anlaml\u0131l\u0131k d\u00fczeyindeki art\u0131\u015f e\u011filimlerini g\u00f6sterir.<\/figcaption><\/figure>\n

Ayr\u0131ca, uzun s\u00fcreli klimatolojik ve meteorolojik g\u00f6zlemlerden elde edilen yeni bulgular, 1950\u2019lerden beri baz\u0131 ekstremlerde \u00f6zellikle g\u00fcnl\u00fck ekstrem hava s\u0131cakl\u0131klar\u0131nda<\/em><\/strong> (\u00f6r. en y\u00fcksek ve en d\u00fc\u015f\u00fck s\u0131cakl\u0131klar, tropikal ve yaz g\u00fcnleri, vb.), donlu g\u00fcn say\u0131lar\u0131nda<\/em><\/strong> ve s\u0131cak hava dalgalar\u0131n\u0131n s\u0131kl\u0131\u011f\u0131 ve uzunlu\u011funda<\/em><\/strong> da \u00f6nemli de\u011fi\u015fiklikler ortaya \u00e7\u0131kt\u0131\u011f\u0131n\u0131<\/em><\/strong> g\u00f6stermektedir. IPCC\u2019ye (2013) g\u00f6re de, \u201cBir\u00e7ok a\u015f\u0131r\u0131 hava ve iklim olaylar\u0131nda 1950\u2019den beri de\u011fi\u015fiklikler oldu\u011fu<\/em><\/strong> g\u00f6zlenmi\u015ftir. K\u00fcresel \u00f6l\u00e7ekte, y\u00fcksek olas\u0131l\u0131kla so\u011fuk g\u00fcn ve gecelerin say\u0131lar\u0131 azalm\u0131\u015f, s\u0131cak g\u00fcn ve gecelerin say\u0131s\u0131 artm\u0131\u015ft\u0131r<\/em><\/strong>. Avrupa, Asya ve Avustralya\u2019n\u0131n geni\u015f b\u00f6lgelerinde s\u0131cak hava dalgalar\u0131n\u0131n s\u0131kl\u0131\u011f\u0131 olas\u0131l\u0131kla artm\u0131\u015ft\u0131r<\/em><\/strong>.\u201d Bu t\u00fcr de\u011fi\u015fiklikler, genel olarak Do\u011fu Akdeniz ve T\u00fcrkiye\u2019de, \u00f6zellikle 1990\u2019l\u0131 y\u0131llarla birlikte donlu ve kar ya\u011f\u0131\u015fl\u0131 g\u00fcnlerin belirgin bir \u015fekilde azalmas\u0131<\/em><\/strong>; \u00f6nemli bir b\u00f6l\u00fcm\u00fc istatistiksel olarak anlaml\u0131 olmak \u00fczere, s\u0131cak g\u00fcnlerin ve gecelerin say\u0131lar\u0131<\/em><\/strong>ile gece en d\u00fc\u015f\u00fck ve g\u00fcnd\u00fcz en y\u00fcksek hava s\u0131cakl\u0131klar\u0131n\u0131n artmas\u0131<\/em><\/strong>; g\u00fcnd\u00fcz en y\u00fcksek-gece en d\u00fc\u015f\u00fck s\u0131cakl\u0131k farklar\u0131n\u0131n<\/em><\/strong> azalmas\u0131<\/em><\/strong> \u015feklinde kendisini hissettirmi\u015ftir. Ba\u015fka bir deyi\u015fle, T\u00fcrkiye\u2019de yakla\u015f\u0131k son 25 y\u0131ll\u0131k d\u00f6nemde, hem s\u0131cakl\u0131k rejimi belirgin olarak daha \u0131l\u0131man ve s\u0131cak ko\u015fullara do\u011fru de\u011fi\u015fmi\u015f, hem de s\u0131cak hava dalgalar\u0131n\u0131n s\u0131kl\u0131\u011f\u0131nda ve \u015fiddetinde \u00f6nemli de\u011fi\u015fimler ger\u00e7ekle\u015fmi\u015ftir (T\u00fcrke\u015f, 2008, 2012, 2013).<\/p>\n

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\u015eekil 3: Y\u0131ll\u0131k ortalama y\u00fczey s\u0131cakl\u0131klar\u0131nda 1901-2012 d\u00f6nemi i\u00e7in hesaplanan do\u011frusal e\u011filim oranlar\u0131na g\u00f6re g\u00f6zlenen de\u011fi\u015fikliklerinin alansal da\u011f\u0131l\u0131\u015f\u0131 (IPCC, 2013).<\/figcaption><\/figure>\n

Bunlara ek olarak, sonraki b\u00f6l\u00fcmde g\u00f6r\u00fclece\u011fi gibi, sera gazlar\u0131n\u0131n atmosferik birikimlerindeki art\u0131\u015flar\u0131n, y\u00fczey s\u0131cakl\u0131klar\u0131n\u0131n ve alt troposfer hava s\u0131cakl\u0131klar\u0131n\u0131n yan\u0131 s\u0131ra, hava bas\u0131nc\u0131, r\u00fczgar, buharla\u015fma, bulut, ya\u011f\u0131\u015f ve nem gibi de\u011fi\u015fkenlerde b\u00f6lgesel ve k\u00fcresel de\u011fi\u015fikliklere yol a\u00e7mas\u0131 beklenmektedir. T\u00fcrkiye\u2019de ve onu \u00e7evreleyen b\u00f6lgeler i\u00e7in gelecek iklim ve iklim de\u011fi\u015fkenli\u011fine ili\u015fkin k\u00fcresel ve b\u00f6lgesel iklim model benze\u015ftirmelerinin kestirimleri, T\u00fcrkiye\u2019de genel olarak ya\u011fmur ve kar ya\u011f\u0131\u015flar\u0131n\u0131n azalmas\u0131, hava s\u0131cakl\u0131klar\u0131n\u0131n, buharla\u015fman\u0131n, s\u0131cak hava dalgalar\u0131n\u0131n ve kurakl\u0131k olaylar\u0131n\u0131n s\u0131kl\u0131\u011f\u0131 ve uzunlu\u011funun artmas\u0131 vb. \u00f6nemli iklimsel de\u011fi\u015fimlerin olaca\u011f\u0131n\u0131 ve Akdeniz havzas\u0131ndaki bir\u00e7ok \u00fclke ile birlikte gelecekte T\u00fcrkiye\u2019nin de iklim de\u011fi\u015fikli\u011finden olumsuz etkilenece\u011fini g\u00f6sterir<\/em><\/strong> (\u00f6r. IPCC, 2013; T\u00fcrke\u015f, 2012, 2013, vb.). T\u00fcm bu nedenlerle, iklim de\u011fi\u015fikli\u011finin etkilerini \u00f6nlemek ya da en az\u0131ndan azaltabilmek ve ona uyum a\u00e7\u0131s\u0131ndan, T\u00fcrkiye\u2019nin gelecekteki ikliminin \u00f6ng\u00f6r\u00fclmesi ya\u015famsal bir \u00f6nem ta\u015f\u0131r.<\/p>\n

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\u015eekil 4: (a) Kuzey Yar\u0131m K\u00fcre ilkbahar kar \u00f6rt\u00fcs\u00fcn\u00fcn kaplad\u0131\u011f\u0131 alandaki, (b) k\u00fcresel ortalama \u00fcst okyanus \u0131s\u0131 i\u00e7eri\u011findeki, (c) Arktik deniz buzunun yay\u0131l\u0131\u015f alan\u0131ndaki ve (d) k\u00fcresel ortalama deniz d\u00fczeyinde g\u00f6zlenen uzun s\u00fcreli e\u011filimler ve y\u0131llararas\u0131 de\u011fi\u015fimler (IPCC, 2013).<\/figcaption><\/figure>\n

K\u00fcresel \u0130klimde G\u00f6zlenen De\u011fi\u015fiklikler<\/strong><\/p>\n

H\u00fck\u00fcmetleraras\u0131 \u0130klim De\u011fi\u015fikli\u011fi Paneli\u2019nin (IPCC) yeni yay\u0131mlanan \u0130klim De\u011fi\u015fikli\u011finin Fiziksel Bilim Temeli Raporuna (IPCC, 2013) g\u00f6re, k\u00fcresel iklimdeki \u0131s\u0131nma kesindir<\/em> ve 1950\u2019li y\u0131llardan beri iklimde g\u00f6zlenen de\u011fi\u015fikliklerin \u00e7o\u011fu son bin y\u0131ll\u0131k d\u00f6neme kadar daha \u00f6nce hi\u00e7 g\u00f6r\u00fclmemi\u015f d\u00fczeydedir. Ge\u00e7en 30 y\u0131l\u0131n her 10 y\u0131l\u0131, yery\u00fcz\u00fcnde 1850\u2019den beri kaydedilen k\u00fcresel y\u00fczey s\u0131cakl\u0131klar\u0131n\u0131n t\u00fcm on y\u0131ll\u0131k d\u00f6nemlerinden daha s\u0131cak olmu\u015ftur. K\u00fcresel ortalama y\u00fczey s\u0131cakl\u0131\u011f\u0131 verileri, 1901 \u2013 2012 d\u00f6neminde, 0.89 [0.69 \u2013 1.08 \u00b0C g\u00fcven aral\u0131\u011f\u0131nda] \u00b0C\u2019lik do\u011frusal bir art\u0131\u015f g\u00f6stermi\u015ftir. Bu d\u00f6nem boyunca hemen t\u00fcm Yerk\u00fcre y\u00fczeyi (\u015eekil 3) ve atmosferin ya\u015fam\u0131n ve hava olaylar\u0131n\u0131n olu\u015ftu\u011fu en alt katman\u0131 olan Troposfer, k\u00fcresel olarak 20\u2019nci y\u00fczy\u0131l\u0131n ortalar\u0131ndan beri \u0131s\u0131nm\u0131\u015ft\u0131r. Ayr\u0131ca, dolayl\u0131 eski iklim verileri, Kuzey Yar\u0131m K\u00fcre\u2019de 1983 \u2013 2012 d\u00f6neminin olas\u0131l\u0131kla son 1400 y\u0131l\u0131n en s\u0131cak 30 y\u0131ll\u0131k d\u00f6nemi oldu\u011funu g\u00f6sterir. Bu d\u00f6nemde, atmosfer ve okyanuslar \u0131s\u0131nm\u0131\u015f, kar ve buz tutarlar\u0131 azalm\u0131\u015f, ortalama deniz d\u00fczeyi y\u00fckselmi\u015f ve sera gazlar\u0131n\u0131n atmosferdeki birikimleri artm\u0131\u015ft\u0131r (\u015eekil 4).<\/p>\n

Beklendi\u011fi gibi, k\u00fcresel okyanuslardaki \u0131s\u0131nma iklim sisteminde biriken enerjideki art\u0131\u015f\u0131 denetlemektedir. Bu kapsamda, 1971 \u2013 2010 d\u00f6neminde okyanuslarda biriken enerjinin % 90\u2019dan fazlas\u0131 okyanuslardaki \u0131s\u0131nmayla ba\u011flant\u0131l\u0131d\u0131r (\u015eekil 4b). \u00dcst okyanus (0 \u2013 700 m) 1971 \u2013 2010 d\u00f6neminde kesin olarak<\/em> \u0131s\u0131nm\u0131\u015fken, 1870\u2019ler ve 1971 aras\u0131nda olas\u0131l\u0131kla<\/em> \u0131s\u0131nm\u0131\u015ft\u0131r. Bu d\u00f6nemde \u00fcst okyanus \u0131s\u0131 i\u00e7eri\u011finde belirlenen do\u011frusal art\u0131\u015f e\u011filimi, olas\u0131l\u0131kla<\/em> 17 [15 \u2013 19] x 1022<\/sup> J de\u011ferindedir (\u015eekil 4b). Ayr\u0131ca, buharla\u015fman\u0131n ya\u011f\u0131\u015ftan fazla ger\u00e7ekle\u015fti\u011fi y\u00fcksek tuzluluk b\u00f6lgeleri daha tuzlu olurken, ya\u011f\u0131\u015f\u0131n buharla\u015fmadan fazla oldu\u011fu d\u00fc\u015f\u00fck tuzluluk b\u00f6lgeleri 1950\u2019lerden beri daha az tuzlu olmu\u015ftur. Okyanus tuzlulu\u011funda g\u00f6zlenen bu b\u00f6lgesel e\u011filimler, okyanuslar \u00fczerindeki buharla\u015fma ve ya\u011f\u0131\u015f\u0131n de\u011fi\u015fti\u011fine ili\u015fkin dolayl\u0131 kan\u0131tlar sunmaktad\u0131r.Gr\u00f6nland ve Antarktika buz kalkanlar\u0131 ge\u00e7en 20 y\u0131ll\u0131k d\u00f6nemde k\u00fctle kaybetmekte, da\u011f vadi ve takke buzullar\u0131 buzullar neredeyse k\u00fcresel \u00f6l\u00e7ekte k\u00fc\u00e7\u00fclmekte, Arktik deniz buzu ve Kuzey Yar\u0131mk\u00fcre ilkbahar kar \u00f6rt\u00fcs\u00fc alansal olarak azalmas\u0131n\u0131 s\u00fcrd\u00fcrmektedir (\u015eekil 4a, 4c). 19\u2019ncu y\u00fczy\u0131l ortas\u0131ndan beri g\u00f6zlenmi\u015f olan deniz d\u00fczeyi y\u00fckselmesinin h\u0131z\u0131, \u00f6nceki iki bin y\u0131ll\u0131k d\u00f6nemdeki ortalama y\u00fckselme oran\u0131ndan daha b\u00fcy\u00fckt\u00fcr. K\u00fcresel ortalama deniz d\u00fczeyi 1901 \u2013 2010 d\u00f6neminde 19 cm (0.19 [0.17 \u2013 0.21] m) y\u00fckselmi\u015ftir (\u015eekil 4d).<\/p>\n

1970\u2019lerin ba\u015f\u0131ndan beri, \u0131s\u0131nmadan kaynaklanan buzullar\u0131n k\u00fctle kayb\u0131 ve okyanuslar\u0131n termal genle\u015fmesi, g\u00f6zlenen k\u00fcresel ortalama deniz d\u00fczeyi y\u00fckselmesinin yakla\u015f\u0131k % 75\u2019inden sorumludur. Ge\u00e7mi\u015fteki deniz d\u00fczeyi de\u011fi\u015fikliklerinin ise, farkl\u0131 etmenler (\u00f6r. Yerk\u00fcre ve G\u00fcne\u015f aras\u0131ndaki ili\u015fkilerdeki de\u011fi\u015fimler) yoluyla olu\u015ftu\u011fu d\u00fc\u015f\u00fcn\u00fclmektedir.<\/p>\n

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\u015eekil 5: Do\u011frusal e\u011filim hesaplamalar\u0131na g\u00f6re, (a) 1901 \u2013 2010 ve (b) 1951 \u2013 2010 d\u00f6nemlerinde g\u00f6zlenen ya\u011f\u0131\u015f de\u011fi\u015fikliklerinin alansal da\u011f\u0131l\u0131\u015f desenleri (IPCC, 2013).Kuzey Yar\u0131mk\u00fcre karalar\u0131nda ya\u011f\u0131\u015flar, 1901\u2019den beri artm\u0131\u015ft\u0131r.<\/figcaption><\/figure>\n

Akdeniz Havzas\u0131\u2019n\u0131 ve T\u00fcrkiye\u2019nin Akdeniz ikliminin egemen oldu\u011fu bat\u0131 ve g\u00fcney b\u00f6lgelerini i\u00e7eren subtropikal ve baz\u0131 tropikal b\u00f6lgelerde ise, ayn\u0131 d\u00f6nemde ya\u011f\u0131\u015f tutarlar\u0131nda belirgin azal\u0131\u015flar g\u00f6zlenmi\u015ftir (\u015eekil 5). Bir\u00e7ok a\u015f\u0131r\u0131 hava ve iklim olaylar\u0131nda 1950\u2019den beri de\u011fi\u015fiklikler oldu\u011fu g\u00f6zlenmi\u015ftir. Y\u00fcksek olas\u0131l\u0131kla<\/em>, k\u00fcresel \u00f6l\u00e7ekte so\u011fuk g\u00fcn ve gecelerin say\u0131lar\u0131 azalm\u0131\u015f, s\u0131cak g\u00fcn ve gecelerin say\u0131s\u0131 artm\u0131\u015ft\u0131r. Avrupa, Asya ve Avustralya\u2019n\u0131n geni\u015f b\u00f6lgelerinde s\u0131cak hava dalgalar\u0131n\u0131n s\u0131kl\u0131\u011f\u0131 olas\u0131l\u0131kla <\/em>artm\u0131\u015ft\u0131r. Kuvvetli ya\u011f\u0131\u015f olaylar\u0131n\u0131n say\u0131s\u0131n\u0131n art\u0131\u015f g\u00f6sterdi\u011fi kara b\u00f6lgeleri, kuvvetli ya\u011f\u0131\u015flar\u0131n azald\u0131\u011f\u0131 karalardan olas\u0131l\u0131kla <\/em>daha fazlad\u0131r. Kuvvetli ya\u011f\u0131\u015f olaylar\u0131n\u0131n s\u0131kl\u0131\u011f\u0131 ya da \u015fiddeti olas\u0131l\u0131kla<\/em> Kuzey Amerika ve Avrupa\u2019da artm\u0131\u015ft\u0131r.<\/p>\n

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\u015eekil 6: K\u00fcresel karbon d\u00f6ng\u00fcs\u00fcn\u00fcn g\u00f6zlenen \u00e7oklu g\u00f6stergeleri: (a) Mauna Loa ve G\u00fcney Kutbu\u2019nda 1958 y\u0131l\u0131ndan beri g\u00f6zlenen atmosferik CO2 birikimlerindeki ve (b) okyanus y\u00fczeyindeki \u00e7\u00f6z\u00fcnm\u00fc\u015f CO2\u2019nin k\u0131smi bas\u0131nc\u0131 ile okyanus suyunun asitli\u011finin bir \u00f6l\u00e7\u00fcs\u00fc olan pH d\u00fczeylerinde yakla\u015f\u0131k olarak 1990\u2019lar\u0131n ba\u015f\u0131ndan beri g\u00f6zlenen y\u0131llararas\u0131 de\u011fi\u015fimler (IPCC, 2013).<\/figcaption><\/figure>\n

Karbondioksit (CO2<\/sub>), metan (CH4<\/sub>) ve diazotmonoksit (N2<\/sub>O) gazlar\u0131n\u0131n atmosferik birikimleri (konsantrasyonlar\u0131), en az son 800,000 y\u0131ll\u0131k d\u00f6nemde hi\u00e7 olmad\u0131\u011f\u0131 kadar y\u00fcksek bir d\u00fczeye ula\u015fm\u0131\u015ft\u0131r. CO2 (\u015eekil 6a), CH4 ve N2O gazlar\u0131n\u0131n atmosferdeki birikimleri, insan etkinlikleri (temel olarak fosil yak\u0131t yanmas\u0131 ve ikincil olarak net arazi kullan\u0131m\u0131 de\u011fi\u015fikli\u011finden kaynaklanan sal\u0131mlar) nedeniyle 1750 y\u0131l\u0131ndan beri artm\u0131\u015ft\u0131r.\u00a0 Bu gazlar\u0131n 2011 birikimleri, sanayi \u00f6ncesi d\u00fczeylerine g\u00f6re s\u0131ras\u0131yla\u00a0 % 40, % 150 ve % 20 oran\u0131nda artarak, ayn\u0131 s\u0131rayla 391 ppm (k\u0131saca milyonda bir), 1803 ppb (milyarda bir) ve 324 ppb (milyarda bir) d\u00fczeylerine y\u00fckselmi\u015ftir. Okyanuslar atmosfere sal\u0131nan insan kaynakl\u0131 karbonun yakla\u015f\u0131k % 30\u2019unu emerek asitlenmi\u015ftir (\u015eekil 6b).<\/p>\n

Gelecekteki K\u00fcresel ve B\u00f6lgesel \u0130klim De\u011fi\u015fiklikleri<\/strong><\/p>\n

H\u0131zla geli\u015ftirilen \u0130klim modelleri, g\u00f6zlenen k\u0131tasal \u00f6l\u00e7ekli y\u00fczey s\u0131cakl\u0131\u011f\u0131 desenlerini ve onlarca y\u0131ll\u0131k zaman \u00f6l\u00e7eklerindeki e\u011filimleri, 20\u2019nci y\u00fczy\u0131l\u0131n ortalar\u0131ndan beri g\u00f6zlenmi\u015f olan daha h\u0131zl\u0131 \u0131s\u0131nma e\u011filimini ve b\u00fcy\u00fck volkanik p\u00fcsk\u00fcrmelerden hemen sonra ortaya \u00e7\u0131kan so\u011fumay\u0131 yeniden \u00fcretmektedir.<\/p>\n

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\u015eekil 7: Yeni IPCC senaryolar\u0131na (RCP2.6 ve RCP8.5) dayanarak; (a) Y\u0131ll\u0131k ortalama y\u00fczey s\u0131cakl\u0131\u011f\u0131 (\u00b0C olarak) ve (b) y\u0131ll\u0131k ya\u011f\u0131\u015f toplamlar\u0131nda (% olarak) 1986-2005 ortalamas\u0131na g\u00f6re 2081-2100 d\u00f6neminde ger\u00e7ekle\u015fmesi beklenen model kestirimi de\u011fi\u015fiklikler (IPCC, 2013).<\/figcaption><\/figure>\n

\u0130nsan etkisi, atmosfer ve okyanus \u0131s\u0131nmas\u0131nda, k\u00fcresel su d\u00f6ng\u00fcs\u00fcndeki de\u011fi\u015fikliklerde, kar ve buzdaki azalmalarda, k\u00fcresel ortalama deniz d\u00fczeyi y\u00fckselmesinde ve baz\u0131 a\u015f\u0131r\u0131 iklim olaylar\u0131ndaki de\u011fi\u015fikliklerde saptanm\u0131\u015ft\u0131r. \u0130nsan etkisi \u00e7ok y\u00fcksek olas\u0131l\u0131kla<\/em> 20\u2019nci y\u00fczy\u0131l\u0131n ortas\u0131ndan beri g\u00f6zlenen \u0131s\u0131nman\u0131n en \u00f6nemli nedeni olmu\u015ftur (IPCC, 2013.IPCC\u2019ye (2013) g\u00f6re, sera gazlar\u0131n\u0131n s\u00fcrmekte olan sal\u0131mlar\u0131, daha fazla \u0131s\u0131nmaya (\u015eekil 7a) ve ba\u015fta buharla\u015fma ve ya\u011f\u0131\u015f (\u015eekil 7b) gelmek \u00fczere iklim sisteminin t\u00fcm bile\u015fenlerinde de\u011fi\u015fikliklere neden olacakt\u0131r. \u0130klim de\u011fi\u015fikli\u011finin s\u0131n\u0131rland\u0131r\u0131lmas\u0131, sera gaz\u0131 sal\u0131mlar\u0131n\u0131n \u00f6nemli ve s\u00fcrekli azalt\u0131lmas\u0131n\u0131 gerektirecektir. IPCC 2013\u2019teki yeni senaryolara (Temsili Konsantrasyon Yolu \u2013 RCP) dayal\u0131 \u00f6ng\u00f6r\u00fclen iklim de\u011fi\u015fikli\u011fi, senaryo farkl\u0131l\u0131klar\u0131 hesaba kat\u0131ld\u0131ktan sonra, hem desenler hem de b\u00fcy\u00fckl\u00fck a\u00e7\u0131s\u0131ndan bir \u00f6nceki IPCC Raporu\u2019ndakine (2007) benzemektedir (\u015eekil 7).K\u00fcresel y\u00fczey s\u0131cakl\u0131\u011f\u0131 de\u011fi\u015fikli\u011fi, 21\u2019nci y\u00fczy\u0131l\u0131n sonuna kadar, biri (RCP2.6) d\u0131\u015f\u0131nda t\u00fcm yeni IPCC senaryolar\u0131na (RCP\u2019ler) dayanarak olas\u0131l\u0131kla<\/em> 1850 \u2013 1900 d\u00f6nemine g\u00f6re 1.5 \u00b0C\u2019yi ve iki yeni senaryoya (RCP6.0 ve RCP8.5) g\u00f6re olas\u0131l\u0131kla<\/em> 2 \u00b0C\u2019yi a\u015facakt\u0131r. K\u00fcresel \u0131s\u0131nma, 2100 y\u0131l\u0131 sonras\u0131nda da s\u00fcrecektir. Is\u0131nma ve ya\u011f\u0131\u015f de\u011fi\u015fimleri, y\u0131llararas\u0131 de\u011fi\u015fkenlikten on y\u0131ll\u0131k de\u011fi\u015fkenliklere kadar \u00e7e\u015fitli de\u011fi\u015fkenlikler sergilemeyi s\u00fcrd\u00fcrecek ve b\u00f6lgesel olarak t\u00fcrde\u015f olmayacakt\u0131r (\u015eekil 7a, 7b).<\/p>\n

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\u015eekil 8: 1986-2005 d\u00f6nemine g\u00f6re 21\u2019nci y\u00fczy\u0131l boyunca k\u00fcresel ortalama deniz d\u00fczeyi y\u00fckselmesi kestirimleri (IPCC, 2013).<\/figcaption><\/figure>\n

T\u00fcm RCP senaryolar\u0131 i\u00e7in 2081-2100 d\u00f6nemi ortalamas\u0131na g\u00f6re de\u011ferlendirilen olas\u0131 de\u011fi\u015fim aral\u0131klar\u0131, yatay bir \u00e7izgi olarak g\u00f6sterilen ortanca de\u011fer ile birlikte dikine s\u00fctunlar \u015feklinde verilmi\u015ftir.Okyanuslar, 21\u2019nci y\u00fczy\u0131l boyunca da \u0131s\u0131nmalar\u0131n\u0131 s\u00fcrd\u00fcrecektir (\u015eekil 7a). Y\u00fczeyde biriken \u0131s\u0131 enerjisi, derin okyanusa do\u011fru ge\u00e7ecek ve okyanus dola\u015f\u0131m\u0131n\u0131 etkileyecektir. Arktik deniz buzu \u00f6rt\u00fcs\u00fc olas\u0131l\u0131kla <\/em>azalmaya ve incelmeye devam edecek ve Kuzey Yar\u0131mk\u00fcre ilkbahar kar \u00f6rt\u00fcs\u00fc, k\u00fcresel ortalama y\u00fczey s\u0131cakl\u0131\u011f\u0131 y\u00fckseldik\u00e7e, 21\u2019nci y\u00fczy\u0131l boyunca azalacakt\u0131r. K\u00fcresel ortalama deniz d\u00fczeyi 21\u2019nci y\u00fczy\u0131l boyunca y\u00fckselmesini s\u00fcrd\u00fcrecektir (\u015eekil 8). T\u00fcm IPCC senaryolar\u0131, deniz d\u00fczeyi y\u00fckselmesinin oran\u0131n\u0131n, artan okyanus \u0131s\u0131nmas\u0131 ve buzullar\/buz kalkanlar\u0131ndan artan k\u00fctle kayb\u0131 nedeniyle, y\u00fcksek olas\u0131l\u0131kla<\/em>, 1971-2010 d\u00f6neminde g\u00f6zlenen y\u00fckselmeyi ge\u00e7ece\u011fini g\u00f6stermektedir. Dahas\u0131, iklim de\u011fi\u015fikli\u011fi, atmosferdeki CO2<\/sub>\u2019nin art\u0131\u015f\u0131n\u0131 daha da b\u00fcy\u00fcterek, karbon d\u00f6ng\u00fcs\u00fc s\u00fcre\u00e7lerini etkileyecektir. Karbonun okyanuslar taraf\u0131ndan daha fazla biriktirilmesiyse, okyanus asitli\u011finin artmas\u0131na yol a\u00e7acakt\u0131r.Son olarak, k\u00fcresel iklim de\u011fi\u015fikli\u011finin pek \u00e7ok \u00f6zelli\u011finin ve etkisinin, CO2<\/sub> ve di\u011fer sera gaz\u0131 sal\u0131mlar\u0131 durdurulsa bile y\u00fczy\u0131llarca s\u00fcrece\u011fini hat\u0131rlatmakta yarar g\u00f6r\u00fcyorum. Ayr\u0131ca bu olgu, insan kaynakl\u0131 sera gazlar\u0131n\u0131n ge\u00e7mi\u015f, g\u00fcn\u00fcm\u00fcz ve gelecek sal\u0131mlar\u0131n\u0131n neden oldu\u011fu y\u00fczy\u0131llarca s\u00fcrecek \u00f6nemli bir iklim de\u011fi\u015fikli\u011fi y\u00fck\u00fcml\u00fcl\u00fc\u011f\u00fcn\u00fcn (\u00f6r. BM Kyoto Protokol\u00fc ve sonras\u0131) de varl\u0131\u011f\u0131n\u0131 s\u00fcrd\u00fcrece\u011fini g\u00f6stermektedir.<\/p>\n

Kaynaklar\u00a0<\/b><\/p>\n

1) IPCC, 2013: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.<\/p>\n

2) T\u00fcrke\u015f, M. 2008. \u0130klim De\u011fi\u015fikli\u011fi ve K\u00fcresel Is\u0131nma Olgusu: Bilimsel De\u011ferlendirme. \u0130\u00e7inde: K\u00fcresel Is\u0131nma ve Kyoto Protokol\u00fc: \u0130klim De\u011fi\u015fikli\u011finin Bilimsel, Ekonomik ve Politik Analizi<\/em> (yay. haz<\/em>. E. Karakaya), s.21-57. Ba\u011flam Yay\u0131nlar\u0131 No. 308<\/strong>, Ba\u011flam Yay\u0131nc\u0131l\u0131k: \u0130stanbul.<\/p>\n

3) T\u00fcrke\u015f, M. 2010. Klimatoloji ve Meteoroloji. Birinci Bask\u0131, Kriter Yay\u0131nevi – Yay\u0131n No. 63, Fiziki Co\u011frafya Serisi No. 1<\/strong>, ISBN: 978-605-4613-26-7, 650 + XXII sayfa: \u0130stanbul.<\/p>\n

4) T\u00fcrke\u015f, M. 2012. K\u00fcresel \u0130klim De\u011fi\u015fikli\u011fi ve \u00c7\u00f6lle\u015fme. \u0130\u00e7inde: G\u00fcn\u00fcm\u00fcz D\u00fcnya Sorunlar\u0131 \u2013 Disiplinleraras\u0131 Bir Yakla\u015f\u0131m (ed<\/em>. N. \u00d6zgen), s.1-42. E\u011fiten Kitap: Ankara.<\/p>\n

5) T\u00fcrke\u015f, M. 2013. T\u00fcrkiye\u2019de g\u00f6zlenen ve \u00f6ng\u00f6r\u00fclen iklim de\u011fi\u015fikli\u011fi, kurakl\u0131k ve \u00e7\u00f6lle\u015fme. Ankara \u00dcniversitesi \u00c7evre Bilimleri Dergisi 4<\/strong><\/em>(2): 1-32.<\/p>\n","protected":false},"excerpt":{"rendered":"

H\u0131zla geli\u015ftirilen iklim modelleri, g\u00f6zlenen k\u0131tasal \u00f6l\u00e7ekli y\u00fczey s\u0131cakl\u0131\u011f\u0131 desenlerini ve onlarca y\u0131ll\u0131k zaman \u00f6l\u00e7eklerindeki e\u011filimleri, 20. y\u00fczy\u0131l\u0131n ortalar\u0131ndan beri g\u00f6zlenmi\u015f olan daha h\u0131zl\u0131 \u0131s\u0131nma e\u011filimini ve b\u00fcy\u00fck volkanik p\u00fcsk\u00fcrmelerden hemen sonra ortaya \u00e7\u0131kan so\u011fumay\u0131 yeniden \u00fcretmektedir. \u0130nsan etkisi, atmosfer ve okyanus \u0131s\u0131nmas\u0131nda, k\u00fcresel su d\u00f6ng\u00fcs\u00fcndeki de\u011fi\u015fikliklerde, kar ve buzdaki azalmalarda, k\u00fcresel ortalama deniz d\u00fczeyi […]<\/p>\n","protected":false},"author":606,"featured_media":24818,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[166,217],"tags":[249,308,309,3136],"class_list":["post-24809","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-129-sayi","category-cevre-bilimleri","tag-atmosfer","tag-iklim","tag-iklim-degisikligi","tag-iklim-sistemi"],"acf":[],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t