Ososayensi kanye nabezombusazwe bathi sibhekene nenkinga yomhlaba ngenxa yokushintsha kwesimo sezulu.
Kodwa buyini ubufakazi bokufudumala komhlaba futhi sazi kanjani ukuthi kubangelwa abantu?
Sazi kanjani ukuthi umhlaba uyafudumala?
Iplanethi yethu ibilokhu ifudumala ngokushesha kusukela ekuqaleni kweNguquko Yezimboni.
Izinga lokushisa elijwayelekile ebusweni boMhlaba likhuphuke cishe ngo-1.1C kusukela ngo-1850. Ngaphezu kwalokho, iminyaka engamashumi amane edlule ngayinye ibishisa kunanoma iyiphi eyandulelayo, kusukela maphakathi nekhulu le-19.
Lezi ziphetho zivela ekuhlaziyweni kwezigidi zezilinganiso eziqoqwe ezingxenyeni ezahlukene zomhlaba. Ukufundwa kwezinga lokushisa kuqoqwa yiziteshi zezulu emhlabeni, emikhunjini kanye nangama-satellite.
Amaqembu amaningi azimele ososayensi afinyelele umphumela ofanayo - ukwanda kwamazinga okushisa okuhambisana nokuqala kwenkathi yezimboni.
Ososayensi bangaphinde bavuselele ukuguquguquka kwezinga lokushisa ngisho nangokwesikhathi esidlule.
Izindandatho zezihlahla, izingqimba zeqhwa, izihlabathi zasechibini kanye namakhorali konke kuqopha uphawu lwesimo sezulu esidlule.
Lokhu kunikeza umongo odingekayo kakhulu esigabeni samanje sokufudumala. Eqinisweni, ososayensi balinganisela ukuthi uMhlaba awukaze ushise kangaka iminyaka engaba ngu-125,000.
Sazi kanjani ukuthi abantu banesibopho sokufudumala komhlaba?
Amagesi okushisa - abamba ukushisa kwelanga - ayisixhumanisi esibalulekile phakathi kokwenyuka kwezinga lokushisa nemisebenzi yabantu. Okubaluleke kakhulu yi-carbon dioxide (CO2), ngenxa yobuningi bayo emkhathini.
Singabona futhi ukuthi i-CO2 yayo ibamba amandla eLanga. Amasathelayithi abonisa ukushisa okuncane okuvela eMhlabeni okuphuma emkhathini ngqo kumaza lapho i-CO2 imunca khona amandla akhishwa imisebe.
Ukushisa amafutha kanye nokugawula izihlahla kuholela ekukhishweni kwale gesi ebamba ukushisa. Yomibili le misebenzi yaqhuma ngemva kwekhulu le-19, ngakho-ke akumangazi ukuthi i-CO2 yomoya yanda phakathi nenkathi efanayo.
Kunendlela esingabonisa ngayo ngokucacile ukuthi le CO2 eyengeziwe ivelaphi. Ikhabhoni ekhiqizwa ukushisa amafutha anezimpawu zamakhemikhali ezihlukile.
Izindandatho zezihlahla kanye neqhwa lasezindaweni ezibandayo zombili ziqopha izinguquko kumakhemikhali asemkhathini. Uma zihlolwa zibonisa ukuthi ikhabhoni - ikakhulukazi evela emithonjeni yakudala - ikhuphuke kakhulu kusukela ngo-1850.
Ukuhlaziywa kukhombisa ukuthi iminyaka engu-800,000, i-CO2 yomoya ayizange ikhuphuke ngaphezu kwezingxenye ezingu-300 ngesigidi (ppm). Kodwa kusukela ngeNguquko Yezimboni, ukuhlushwa kwe-CO2 kukhuphuke kwaze kwaba sezingeni layo lamanje elicishe libe ngu-420 ppm.
Ukulingisa kwekhompyutha, okwaziwa ngokuthi amamodeli esimo sezulu, kuye kwasetshenziswa ukukhombisa ukuthi ngabe kwenzekani emazingeni okushisa ngaphandle kwenani elikhulu lamagesi okushisa akhishwa abantu.
Zembula ukuthi ngabe kube nokufudumala komhlaba okuncane - futhi mhlawumbe ukupholisa okuthile - phakathi nekhulu lama-20 nelama-21, ukube nje izici zemvelo bezithonya isimo sezulu.
Kuphela lapho izici zomuntu zingeniswa khona lapho amamodeli angachaza khona ukwenyuka kwezinga lokushisa.
Yimuphi umthelela abantu abanawo emhlabeni?
Izinga lokushisa uMhlaba oseke walibona kakade libikezelwa ukuthi lizobangela izinguquko ezinkulu emhlabeni osizungezile.
Ukubonwa kwangempela kwalezi zinguquko kufana namaphethini ososayensi abalindele ukuwabona ngokufudumala okubangelwa abantu. Kuhlanganisa:
***Ama-ice sheet aseGreenland nase-Antarctica ancibilika ngokushesha
***Inani lezinhlekelele ezihlobene nesimo sezulu likhuphuke ngamanani amahlanu eminyakeni engama-50 edlule
***Amazinga olwandle emhlabeni wonke akhuphuke ngo-20cm (8in) ekhulwini leminyaka elidlule futhi asakhuphuka
***Kusukela ngawo-1800, izilwandle sezibe ne-asidi eningi ngo-40%, okuthinta impilo yasolwandle
Kodwa bekungafudumali yini esikhathini esidlule?
Kube nezikhathi eziningana ezishisayo ngesikhathi esidlule soMhlaba.
Ngokwesibonelo, eminyakeni ecishe ibe yizigidi ezingu-92 edlule, amazinga okushisa ayephezulu kakhulu kangangokuthi kwakungekho ziqongo zeqhwa ezisemaphethelweni ezwe futhi izidalwa ezinjengezingwenya zazihlala kude enyakatho njenge-Canadian Arctic.
Nokho, lokho akufanele kududuze muntu, ngoba abantu babengekho. Ngezinye izikhathi esikhathini esidlule, izinga lolwandle laliphakeme ngamamitha angu-25 (80ft) kunamanje. Ukuphakama ngamamitha angu-5-8 (16-26ft) kubhekwa njengokwanele ukucwilisa iningi lamadolobha asogwini emhlabeni.
Kunobufakazi obuningi bokuphela kokuphila okukhulu phakathi nalezi zikhathi. Futhi amamodeli esimo sezulu asikisela ukuthi, ngezinye izikhathi, izindawo ezishisayo kungenzeka zibe "izindawo ezifile", zishisa kakhulu ukuthi izinhlobo eziningi zezilwane zingasinda.
Lokhu kuguquguquka phakathi kokushisa nokubanda kubangelwe yizinto ezahlukahlukene, okuhlanganisa indlela uMhlaba ozamazama ngayo njengoba ujikeleza iLanga isikhathi eside, ukuqhuma kwezintaba-mlilo kanye nemijikelezo yesimo sezulu yesikhashana njenge-El Niño.
Sekuyiminyaka eminingi amaqembu abizwa ngokuthi “abangabaza” isimo sezulu ebeka ukungabaza ngesisekelo sesayensi sokufudumala komhlaba.
Kodwa-ke, cishe bonke ososayensi abashicilela njalo emaphephandabeni abukezwa ontanga manje bayavumelana ngezimbangela zamanje zokushintsha kwesimo sezulu.
Umbiko obalulekile we-UN owakhishwa ngo-2021 uthe "akunakuphikwa ukuthi ithonya lomuntu liye lafudumeza umkhathi, ulwandle kanye nomhlaba".
Ukuze uthole ulwazi olwengeziwe, sicela ubheke:https://www.bbc.com/news/science-environment-58954530
Isikhathi sokuthunyelwe: Okthoba-21-2022
