Abanye abantu namanje abazi ukuthi lokhu kufudumala kwembulunga yonke esikubonayo namuhla kungokokuqala kwenzeka eMhlabeni. Kodwa-ke, kunezinguquko eziningi zokufudumala kwembulunga yonke kanye nezimo zezulu ezenzekile emhlabeni wethu kuwo wonke umlando. Okusemqoka ukubalula ukuthi akukho ukufudumala kwembulunga yonke okwake 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 selokhu kwaqala inguquko yezimboni futhi kwaqala ukukhishwa amagesi abamba ukushisa.
Cishe eminyakeni eyizigidi ezingama-56 edlule inani elikhulu le-carbon dioxide (CO2) likhipha emkhathini amazinga okushisa aphakeme kakhulu emhlabeni wonke. I-Paleocene-Eocene Thermal Maximum ngokungangabazeki umcimbi ohlobene ne- 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, imbangela yokugcina, umthombo wale khabhoni, kanye nenani eliphelele elikhishiwe, kuze kube manje akwaziwa.
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 (IHelmholtz Centre for Ocean Research) eKiel, eJalimane inika umbono wokuthi kungenzeka ukuthi kungenxa yokukhishwa kwamagesi aqhuma ezintabamlilo.
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 yezilinganiso ezintsha ze-geochemical kanye nemodeli yesimo sezulu yomhlaba isetshenziselwe ukuthola isizathu sokukhishwa kwe-CO2, kunqunywa ukuthi lokhu kufudumala komhlaba ngokweqile kubangelwe ukuphindaphindeka okusheshayo kwe-CO2 yomkhathi. Lapho 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, kungabuye kufakazelwe sibonga iqiniso lokuthi ngalesi sikhathi kucishe kwaqondana nokwakhiwa kwezandiso ezinkulu zombhede wasolwandle, ngenxa yenqwaba yodaka olusabalale ngezansi. Lokhu kwenzeka lapho iGreenland iqala ukuhlukana nenyakatho-ntshonalanga yeYurophu, yakha iNorth Atlantic Ocean.