Ucwaningo olunzulu oluholwa abacwaningi baseNyuvesi yase-Arizona kungenzeka ukuthi luxazulule izimfihlakalo ezimbili osekunesikhathi eside zadida ochwepheshe besimo sezulu se-paleo: Avelaphi amaqhwa ayekhona esikhathini sokugcina seqhwa eminyakeni eyizi-100,000 XNUMX edlule, futhi ayengakhula kanjani? ngokushesha okungaka?
Ukuqonda ukuthi yini eyenza imijikelezo yeqhwa yomhlaba - ukuqhubekela phambili kanye nokuhlehla kweqhwa eNyakatho Nenkabazwe - akuyona into elula, futhi abacwaningi banikele ngomzamo omkhulu ekuchazeni ukwanda kanye nokuncipha kweqhwa elikhulu ezinkulungwaneni zeminyaka. Lolu cwaningo, olushicilelwe kumagazini i-Nature Geoscience, luphakamisa incazelo yokwanda ngokushesha kwamaqhwa amboze ingxenye enkulu yeNyakatho Nenkabazwe ngesikhathi seqhwa sakamuva, futhi okutholakele kungasebenza nakwezinye izinkathi zeqhwa kuwo wonke umlando womhlaba.
Eminyakeni engaba ngu-100,000 10,000 edlule, lapho izilwane ezinkulukazi zizulazula eMhlabeni, isimo sezulu saseNyakatho Nenkabazwe saba yiqhwa elijulile elavumela ukuba akhe amaqhwa amakhulu. Esikhathini esiyiminyaka engaba ngu-XNUMX XNUMX, izinguzunga zeqhwa zendawo zanda futhi zakha amaqhwa amakhulu ahlanganisa ingxenye enkulu yeCanada, iSiberia kanye nenyakatho yeYurophu yanamuhla.
Nakuba kuye kwamukelwa kabanzi ukuthi “ukuzamazama” ngezikhathi ezithile emzileni womhlaba ozungeza ilanga kwabangela ukuphola ehlobo laseNyakatho Nenkabazwe okwabangela ukuqala kokucwebezela kweqhwa okusakazeke kabanzi, ososayensi baye bakuthola kunzima ukuchaza amashidi eqhwa ahlanganisa ingxenye enkulu yeScandinavia nasenyakatho yeYurophu. lapho amazinga okushisa epholile kakhulu.
Ngokungafani ne-Canadian Arctic Archipelago ebandayo lapho iqhwa lakha khona kalula, iScandinavia bekufanele ihlale ingenaqhwa ngenxa yeNorth Atlantic Current, eletha amanzi afudumele ogwini olusenyakatho-ntshonalanga yeYurophu. Nakuba lezi zifunda ezimbili zitholakala eduze kwe-latitude efanayo, izinga lokushisa lasehlobo laseScandinavia lingaphezu kwamaqhwa, kuyilapho amazinga okushisa ezingxenyeni ezinkulu ze-Canadian Arctic ehlala ngaphansi kwezingaqhwa ehlobo, ngokusho kwabacwaningi. Ngenxa yalokhu kungafani, izibonelo zesimo sezulu ziye zazabalaza ukulandisa ngezinguzunga zeqhwa ezinkulu ezithuthuke enyakatho yeYurophu futhi zaphawula ukuqala kwenkathi yokugcina yeqhwa, kusho umlobi oholayo walolu cwaningo, uMarcus Lofverstrom.
“Inkinga asazi ukuthi lawo maqhwa (eScandinavia) avelaphi nokuthi yini edale ukuthi ande ngesikhathi esifushane kangaka,” kusho uLofverstrom, umsizi kaprofesa wesayensi yokwakheka komhlaba nenhloko ye-UArizona Earth System Dynamics. Ilebhu.
Ukuze kutholwe izimpendulo, u-Lofverstrom usize ekuthuthukiseni imodeli ye-Earth-system eyinkimbinkimbi kakhulu, eyaziwa ngokuthi i-Community Earth System Model, eyavumela ithimba lakhe ukuthi lidale kabusha izimo ezazikhona ekuqaleni kwenkathi yakamuva yeqhwa. Ngokuphawulekayo, wandisa isizinda semodeli yeshidi leqhwa ukusuka eGreenland ukuze sihlanganise ingxenye enkulu yeNyakatho Nenkabazwe ngemininingwane ephezulu yendawo.
Besebenzisa lokhu kulungiselelwa kwemodeli ebuyekeziwe, abacwaningi bahlonze amasango olwandle e-Canadian Arctic Archipelago njenge-linchpin ebalulekile elawula isimo sezulu saseNyakatho ye-Atlantic futhi ekugcineni banquma ukuthi amashidi eqhwa angakhula noma cha eScandinavia.
Ukulingiswa kwembula ukuthi inqobo nje uma amasango olwandle e-Canadian Arctic Archipelago esalokhu evulekile, ukucushwa kwe-orbital yomhlaba kupholise iNyakatho Nenkabazwe ngokwanele ukuvumela amashidi eqhwa ukuba akheke eNyakatho yeCanada naseSiberia, kodwa hhayi eScandinavia.
Esivivinyweni sesibili, abacwaningi balingisa isimo esasingahloliwe ngaphambili lapho amashidi eqhwa asolwandle avimba izindlela zamanzi e-Canadian Arctic Archipelago. Kulolo vivinyo, amanzi asemasha ngokuqhathaniswa ne-Arctic neNyakatho yePacific - ngokuvamile adluliswa e-Canadian Arctic Archipelago - aphambukiswe empumalanga yeGreenland, lapho uquqaba lwamanzi ajulile luvame ukuvela khona. Lokhu kuphambukisa kuholele ekuvuseleleni nasekuntekeni kokujikeleza okujulile kweNyakatho ye-Atlantic, ukwanda kweqhwa lolwandle, nezimo ezipholile eScandinavia.
“Sisebenzisa kokubili ukulingiswa kwesimo sezulu kanye nokuhlaziywa kwenhlabathi yasolwandle, sibonisa ukuthi ukwakheka kweqhwa enyakatho yeCanada kungavimba amasango olwandle futhi kuphambukise ukuthutha kwamanzi kusuka e-Arctic kuya eNyakatho ye-Atlantic,” kusho uLofverstrom, “futhi lokho kuholela ekusakazweni kolwandle okubuthakathaka. nezimo ezibandayo ngasogwini lwaseScandinavia, okwanele ukuqala ukukhulisa iqhwa kuleyo ndawo.”
“Lokhu okutholakele kusekelwa amarekhodi enzika zasolwandle avela eNyakatho ye-Atlantic, abonisa ubufakazi bezinguzunga zeqhwa enyakatho yeCanada eminyakeni eyizinkulungwane ezimbalwa ngaphambi kohlangothi lwaseYurophu,” kusho uDiane Thompson, umsizi kaprofesa eMnyangweni Wezesayensi Yezwe wase-UArizona. “Amarekhodi enzika aphinde abonise ubufakazi obuqand’ ikhanda bokugeleza kolwandle ekujuleni kolwandle ngaphambi kokuba kwakheke izinguzunga zeqhwa eScandinavia, okufana nemiphumela yethu yokumodela.”
Ngokubambisana, ucwaningo luphakamisa ukuthi ukwakheka kweqhwa lasolwandle enyakatho yeCanada kungase kube isandulela esidingekayo sokuqhwaza kweqhwa eScandinavia, ababhali bayabhala.
Ukusunduza amamodeli wesimo sezulu ngaphezu kokusetshenziswa kwawo okungokwesiko kokubikezela izimo zezulu zesikhathi esizayo kunikeza ithuba lokuhlonza ukusebenzisana okwakungaziwa ngaphambili ohlelweni Lomhlaba, njengokuhlangana okuyinkimbinkimbi futhi ngezinye izikhathi okuphikisayo phakathi kwamashidi eqhwa nesimo sezulu, kusho u-Lofverstrom.
“Kungenzeka ukuthi izindlela esizihlonze lapha zisebenza kuzo zonke izikhathi zeqhwa, hhayi nje yakamuva,” esho. “Kungase kusize nasekuchazeni izikhathi ezibandayo ezihlala isikhathi esifushane njenge-Younger Dryas cold reversal (eminyakeni engu-12,900 11,700 kuya kwengu-XNUMX XNUMX edlule) eyayiphawula ukufudumala okuvamile ekupheleni kwenkathi yokugcina yeqhwa.”
Ucwaningo lushicilelwe ekuqaleni ngo I-geoscience yemvelo. NgoJuni 09, 2022.
