Rufe kankara a cikin Tekun Arctic ya fadi zuwa mataki na biyu mafi karanci tun lokacin da aka fara sa ido kan tauraron dan adam a shekarar 1979, in ji masana kimiyya na gwamnatin Amurka a ranar Litinin.
Har zuwa wannan watan, sau daya ne kawai a cikin shekaru 42 da suka gabata daskararren kwanyar duniya ya rufe kasa da murabba'in kilomita miliyan 4 (milyan 1.5).
Arctic na iya fuskantar lokacin rani na farko mara kankara a farkon 2035, masu bincike sun ruwaito a watan da ya gabata a cikin Mujallar Nature Climate Change.
Amma duk abin da ke narkewar dusar ƙanƙara da ƙanƙara ba ya haɓaka matakin teku kai tsaye, kamar yadda narkewar kankara ba ta zubar da gilashin ruwa ba, wanda ke haifar da babbar tambaya: Wanene ya damu?
Tabbas, wannan mummunan labari ne ga berayen polar, wanda, bisa ga wani bincike na baya-bayan nan, sun riga sun kasance a kan hanyarsu ta ƙarewa.
Ee, wannan tabbas yana nufin babban sauyi na yanayin yanayin ruwa na yankin, daga phytoplankton zuwa whale.
Kamar yadda ya fito, akwai dalilai da yawa don damuwa game da illolin rage ƙanƙarar tekun Arctic.
Wataƙila mafi mahimmancin ra'ayi, masana kimiyya sun ce, raguwar zanen kankara ba kawai alama ce ta ɗumamar yanayi ba, amma wani ƙarfi ne a bayansa.
“Kawar da kankarar teku ta fallasa duhun teku, wanda ke haifar da ingantaccen tsarin amsawa,” in ji masanin ilimin kimiyyar halittu Marco Tedesco na Cibiyar Duniya ta Jami’ar Columbia ga AFP.
Amma lokacin da aka maye gurbin saman madubi da ruwan shuɗi mai duhu, kusan kashi ɗaya na makamashin thermal na duniya ya sha.
Ba muna magana ne game da yanki na tambari a nan ba: bambanci tsakanin matsakaicin matsakaicin takardar kankara daga 1979 zuwa 1990 kuma mafi ƙanƙanci da aka rubuta a yau ya wuce murabba'in kilomita miliyan 3 - sau biyu na Faransa, Jamus da Spain.
Tekuna sun riga sun sha kashi 90 cikin 100 na yawan zafin da iskar gas na ɗan adam ke samarwa, amma wannan ya zo da tsada, gami da sauye-sauyen sinadarai, ɗumbin zafin teku da magudanar murjani da ke mutuwa.
Tsarin yanayi mai rikitarwa na duniya ya haɗa da igiyoyin teku masu haɗin gwiwa waɗanda iskoki, tides, da kuma abin da ake kira thermohaline wurare dabam dabam, da kanta ke haifar da canje-canje a yanayin zafi ("dumi") da kuma tattara gishiri ("brine").
Ko da ƙananan canje-canje a cikin bel ɗin jigilar teku (wanda ke tafiya tsakanin sanduna da ke tsakanin dukkan tekuna uku) na iya yin mummunar tasiri ga yanayin.
Misali, kusan shekaru 13,000 da suka gabata, yayin da duniya ta canza daga lokacin kankara zuwa lokacin tsaka-tsakin tsaka-tsakin da ke ba da damar jinsunan mu su yi girma, ba zato ba tsammani yanayin yanayin duniya ya ragu da 'yan digiri Celsius.
Shaidar ilimin kasa ta nuna cewa jinkirin zagayawa na thermohaline wanda ya haifar da kwararar ruwan sanyi da sauri daga Arctic wani bangare ne na laifi.
"Sabon ruwa daga narkewar teku da ƙanƙara a Greenland yana rushewa da raunana rafin Gulf," wani ɓangare na bel ɗin jigilar kaya da ke gudana a cikin Tekun Atlantika, in ji wani mai bincike Xavier Fettweiss na Jami'ar Liege a Belgium.
"Shi ya sa Yammacin Turai ke da yanayi mai sauƙi fiye da Arewacin Amirka a wuri ɗaya."
Katafaren dusar kankara da ke kan kasa a Greenland ya yi asarar sama da tan biliyan 500 na ruwa mai tsafta a bara, wanda dukkaninsu suka shiga cikin teku.
Adadin rikodin ya kasance wani ɓangare saboda hauhawar yanayin zafi, wanda ke tashi a ninki biyu a cikin Arctic fiye da sauran duniya.
"Bincike da yawa sun nuna cewa karuwar hawan Arctic lokacin rani wani bangare ne saboda karancin kankarar teku," Fettwiss ya shaida wa AFP.
A cewar wani bincike da aka buga a mujallar Nature a watan Yuli, yanayin da ake ciki na sauyin yanayi da kuma farkon lokacin rani ba tare da kankara ba, kamar yadda kwamitin sulhu na Majalisar Dinkin Duniya kan sauyin yanayi ya ayyana, bai wuce murabba'in kilomita miliyan daya ba.A ƙarshen karni, beyar za su mutu da yunwa.
" Dumamar yanayi da ɗan adam ke haifarwa yana nufin berayen polar suna da ƙarancin ƙanƙara a lokacin rani," in ji jagoran binciken Stephen Armstrup, babban masanin kimiyya a Polar Bears International, ya shaida wa AFP.