Ukumbozwa kweqhwa e-Arctic Ocean kwehle kwafinyelela kwesibili ezingeni eliphansi kusukela kwaqala ukubonwa ngesathelayithi ngo-1979, kusho ososayensi bakahulumeni waseMelika ngoMsombuluko.
Kuze kube yile nyanga, kanye kuphela eminyakeni engama-42 edlule lapho ugebhezi lwekhanda lomhlaba oluqandisiwe lumboze ngaphansi kwamakhilomitha-skwele ayizigidi ezi-4 (1.5 million square miles).
I-Arctic ingase ibe nehlobo layo lokuqala elingenaqhwa ekuqaleni kuka-2035, abacwaningi babika ngenyanga edlule ephephabhukwini elithi Nature Climate Change.
Kodwa lonke lelo qhwa elincibilikayo neqhwa alikhuphuli ngokuqondile amazinga olwandle, njengoba nje ukuncibilika kweqhwa kungachithi ingilazi yamanzi, okubangela umbuzo onzima: Ubani onendaba?
Kuyavunywa, lezi yizindaba ezimbi zamabhere asezintabeni, lokho, ngokocwaningo lwakamuva, asesendleleni yokushabalala.
Yebo, lokhu ngokuqinisekile kusho uguquko olujulile lwezindawo zasolwandle zalesi sifunda, ukusuka kuma-phytoplankton kuya emikhomo.
Njengoba kuvela, kunezizathu ezimbalwa zokukhathazeka ngemiphumela emibi yokushwabana kweqhwa lasolwandle i-Arctic.
Mhlawumbe umbono obaluleke kakhulu, ososayensi bathi, ukuthi amaqhwa anciphayo akulona nje uphawu lokufudumala kwembulunga yonke, kodwa amandla aqhubayo.
"Ukususwa kweqhwa olwandle kuveza ulwandle olumnyama, okudala indlela enamandla yokuphendula," isazi sokuma komhlaba uMarco Tedesco we-Earth Institute yaseColumbia University etshela i-AFP.
Kodwa lapho indawo yesibuko ithathelwa indawo ngamanzi aluhlaza okwesibhakabhaka, cishe amaphesenti afanayo wamandla ashisayo oMhlaba amuncwa.
Asikhulumi ngendawo yezitembu lapha: umehluko phakathi kwesilinganiso esincane se-ice sheet kusukela ngo-1979 kuya ku-1990 kanye nephuzu eliphansi kunazo zonke elirekhodiwe namuhla lingaphezu kwamakhilomitha-skwele ayizigidi ezi-3 - okuphindwe kabili kwelaseFrance, iJalimane neSpain kuhlangene.
Ulwandle kakade selumunca amaphesenti angu-90 okushisa okwedlulele okukhiqizwa amagesi abamba ukushisa anthropogenic, kodwa lokhu kuza ngezindleko, kuhlanganise noshintsho lwamakhemikhali, amagagasi amakhulu okushisa olwandle kanye nezixhobo zamakhorali ezifayo.
Isimo sezulu esiyinkimbinkimbi somhlaba sihlanganisa imisinga yolwandle exhumene eqhutshwa umoya, amagagasi, nalokho okubizwa ngokuthi ukujikeleza kwe-thermohaline, ngokwako okubangelwa ukushintsha kwezinga lokushisa (“ukufudumala”) nokugcwala kukasawoti (“brine”).
Ngisho noshintsho oluncane ebhandeni lokuthutha olwandle (elihamba phakathi kwezigxobo futhi ligudluze zonke izilwandle ezintathu) kungaba nemiphumela elimazayo esimweni sezulu.
Isibonelo, eminyakeni ecishe ibe ngu-13,000 edlule, njengoba uMhlaba wawushintsha usuka enkathini yeqhwa uye enkathini yeqhwa evumela izinhlobo zethu ukuba zichume, amazinga okushisa embulunga yonke ehla ngokuzumayo ngamadigri ambalwa Celsius.
Ubufakazi besayensi yokwakheka komhlaba busikisela ukuthi ukwehla kokujikeleza kwe-thermohaline okubangelwa ukutheleka okukhulu nokusheshayo kwamanzi ahlanzekile abandayo avela e-Arctic kuyimbangela.
"Amanzi ahlanzekile aphuma olwandle oluncibilikayo kanye neqhwa eliphansi eGreenland aphazamisa futhi enze buthaka iGulf Stream," ingxenye yebhande lokuthutha eligeleza olwandle i-Atlantic Ocean, kusho umcwaningi u-Xavier Fettweiss wase-University of Liege eBelgium.
“Kungakho iNtshonalanga Yurophu inesimo sezulu esipholile kuneseNyakatho Melika endaweni efanayo.”
Iqhwa elikhulu emhlabeni eGreenland lalahlekelwa amathani angaphezu kwezigidi eziyizinkulungwane ezingama-500 amanzi ahlanzekile ngonyaka odlule, wonke avuza olwandle.
Inani elirekhodiwe ngokwengxenye libangelwa amazinga okushisa akhuphukayo, akhuphuka ngesilinganiso esiphindwe kabili e-Arctic kunayo yonke iplanethi.
"Ucwaningo oluningi lukhombisile ukuthi ukwanda kwezinga eliphezulu lasehlobo lase-Arctic ngokwengxenye kungenxa yobuncane beqhwa lasolwandle," uFettwiss etshela abe-AFP.
Ngokocwaningo olwanyatheliswa kumagazini i-Nature ngo-July, umkhondo wamanje wokuguquka kwesimo sezulu kanye nokuqala kwehlobo elingenaqhwa, njengoba kuchazwe yi-UN Intergovernmental Panel on Climate Change Climate Panel, ingaphansi kwamakhilomitha-skwele ayisigidi.ekupheleni kwaleli khulu leminyaka, amabhere ayobulawa indlala ngempela.
"Ukufudumala kwembulunga yonke okubangelwa abantu kusho ukuthi amabhere ase-polar abe neqhwa elincane olwandle ehlobo," umbhali ohamba phambili wocwaningo uStephen Armstrup, usosayensi omkhulu e-Polar Bears International, etshela abe-AFP.