Abanye abantu namanje abazi ukuthi lesi simo sezulu esishisayo siqala ngqa ukwenzeka eMhlabeni. Nokho, ukufudumala kwembulunga yonke kanye nokushintsha kwesimo sezulu kuye kwenzeka emhlabeni wethu kuwo wonke umlando. Okubalulekile ukusho ukuthi akukho ukufudumala komhlaba okuke kwenzeka phambilini Sekuyisikhathi esincane njengalesi esikhona manje. Ngamanye amagama, ngumuntu, onemisebenzi yakhe engcolisayo, osheshisa inqubo yokufudumala kwembulunga yonke ngenxa yokukhishwa kwegesi ebamba ukushisa.
Cishe eminyakeni eyizigidi ezingama-56 eyedlule, uMhlaba wabhekana nokufudumala komhlaba okungazelelwe, okwaziwa ngokuthi yi i-Paleocene-Eocene Thermal Maximum (MTPE, noma i-PETM ngesifinyezo sayo esiNgisini). Ngabe ufuna ukwazi ukuthi yini ebangele ukufudumala kwembulunga yonke okugcizelele kangaka?
Ukufudumala kwembulunga yonke eminyakeni eyizigidi ezingama-56 edlule
Ngaleso sikhathi, abantu babengakaveli, ngakho-ke sasingeke sibe yimbangela yalokhu kufudumala komhlaba. Kulabo abacabanga ukuthi lokhu kungokwemvelo nokuthi uMhlaba uhlupheka ngezikhathi ezithile ukufudumala kwembulunga yonke okuholela ekuguqukeni kwesimo sezulu, nokuthi lokhu kuyinto ejwayelekile, akunjalo.
Kuyiqiniso ukuthi kwezinye izigidi zeminyaka, uMhlaba ubhekane nokwenyuka okungalindelekile kwamazinga okushisa nezinguquko kwesimo sezulu, kepha ukwenze lokho ngezikhathi zezinkulungwane nezinkulungwane zeminyaka. Ekushintsheni kwethu kwesimo sezulu njengamanje, ngakho sekuyiminyaka engaba ngu-250 kuphela kusukela ekuqaleni kwenguquko yezimboni kanye namagesi abamba ukushisa aqala ukukhishwa. Ukuze uqonde kangcono izimbangela zalezi zenzakalo, kuyasiza ukuhlaziya umsuka wokufudumala kwembulunga yonke.
Cishe eminyakeni eyizigidi ezingama-56 edlule, inani elikhulu le-carbon dioxide (CO2) elaphuma emkhathini lawakhuphula kakhulu amazinga okushisa omhlaba. I-Paleocene-Eocene Thermal Maximum ngokungangabazeki umcimbi ohlobene ukufudumala kwembulunga yonke eshesha kakhulu futhi ngokweqile ukuthi iplanethi yethu ibe nayo ngokwemvelo eminyakeni eyizigidi ezingama-66 edlule. Ukufudumala komhlaba kwahlala cishe iminyaka eyi-150.000, futhi amazinga okushisa emhlabeni akhula okungenani ngama-5 degrees Celsius, ukwanda okuqhathaniswa nezinye zezibikezelo ezenziwe ngesimo sezulu sanamuhla ngale kokuphela kwaleli khulu leminyaka.
Isizathu sokufudumala kwembulunga yonke
Lokhu kufudumala kwembulunga yonke bekuvele kungazelelwe futhi bekungadalwanga ngabantu. Ngakho-ke yini engadala ukukhuphuka kwamazinga okushisa emhlabeni wonke? Kuphakanyisiwe emphakathini wesayensi ukuthi kubangelwe ngu ukujova ikhabhoni olwandle nasemkhathini, inhlamvu yokugcina, umthombo wale carbon kanye nenani eliphelele elikhishiwe bekungaziwa kuze kube manje.
Kodwa-ke, ingaqhamukaphi imali enjalo ye-CO2 yokuthi izinga lokushisa lomhlaba wonke lenyuka ngo-5 ° C ngokwesilinganiso? Uphenyo olwenziwe ithimba lamazwe omhlaba likaMarcus Gutjahr, phambilini e iYunivesithi yaseSouthampton e-UK futhi manje e-GEOMAR (I-Helmholtz Center for Ocean Research) eKiel, eJalimane, isikisela ukuthi kungenzeka ukuthi kwakubangelwa ukukhishwa kwamagesi okuqhuma kwentaba-mlilo. Ukuze uthole ukuhlaziya okuningiliziwe kokufudumala kwembulunga yonke okuhlobene nezintaba-mlilo, ungavakashela izinhlayiya zemvelo zasemkhathini.
Kuze kube namuhla, izintaba-mlilo azinasibopho sokwanda kokuxinana kwamagesi abamba ukushisa, ngakho-ke kujwayelekile ukucabanga ukuthi esikhathini esedlule bekungekho. Kodwa-ke, kufanele kubhekwe ukuthi umsebenzi wentaba-mlilo izigidi eziningi zeminyaka eyedlule wawenzeka kaningi futhi ushushu kakhulu kunanamuhla.
Ucwaningo nezilinganiso
Inhlanganisela yokulinganisa okusha kwe-geochemical kanye nokumodela kwesimo sezulu somhlaba wonke kwasetshenziswa ukuze kutholwe imbangela yokukhishwa kwe-CO2, kunqunywe ukuthi lokhu kufudumala kwembulunga yonke okwedlulele kubangelwe ukuphindwa kabili okusheshayo kwe-geologically kwe-CO2 yomkhathi. Uma sisho igama ngokushesha sibhekisa enkathini engaphansi kweminyaka engama-25.000 (Kungakho singeke saqhathanisa lokhu kufudumala kwembulunga nalokhu okukhona njengamanje, okukude kakhulu nakho), nezintaba-mlilo okuyizo kanye eziyimbangela yalesi sikhisi.
Ngaphezu kwalokho, lokhu kungafakazelwa nawukuthi lesi sikhathi sicishe saqondana nokwakhiwa kwezindawo ezinkulu ze-basalt ocean ocean, ngenxa yodaka oluningi olusabalele phansi. Lokhu kwenzeka lapho iGreenland iqala ukuhlukana nenyakatho-ntshonalanga yeYurophu, idala iNorth Atlantic Ocean. Ukuze ufunde kabanzi mayelana nemithelela yokufudumala kwembulunga yonke olwandle, ungabheka isihloko esithi uLwandle lweCaspian.
