Ithonya Lolwandle Esimweni Sezulu Somhlaba Wonke
Ulwandle lumboza ngaphezu kuka-70% wobuso boMhlaba futhi luyingxenye ebalulekile ekulawuleni uhlelo lwesimo sezulu somhlaba. Uma sikhuluma ngesimo sezulu—amaphethini esimo sezulu esikhathi eside athinta izinga lokushisa, imvula, imimoya, kanye nezinkathi—indima yolwandle ayinakuhlukaniswa. Ulwandle lusebenza njengendawo enkulu yokugcina ukushisa, umthuthi wamandla ngokusebenzisa imisinga, isinki se-carbon dioxide, kanye nomshayeli womjikelezo wamanzi. Ngaphandle kwalezi zindlela, isimo sezulu soMhlaba besiyoba sibi kakhulu futhi singazinzi kangako. Lesi sihloko sihlola indlela ulwandle oluthonya ngayo isimo sezulu somhlaba , izindlela zalo ezibalulekile, kanye nezinguquko ezenzeka njengamanje ngenxa yokufudumala komhlaba.
1. Ulwandle luyindawo yokugcina ukushisa enkulu kunazo zonke eMhlabeni
Esinye sezizathu eziyinhloko ezenza ulwandle lube nomthelela omkhulu kangaka esimweni sezulu amandla alo okushisa aphezulu. Amanzi angamunca futhi agcine amandla okushisa amaningi ngaphandle kokubona ukunyuka kwezinga lokushisa okufanayo nomhlaba. Ngenxa yalokho, ulwandle lusebenza njengebhethri "lokushisa" leplanethi, limunca amandla elanga uma eningi kakhulu futhi liwakhiphe uma entuleka.
Lesi simo sichaza ukuthi kungani izindawo ezisogwini zivame ukuba nehlobo elipholile kanye nobusika obubandayo obuncane kunezindawo zangaphakathi. Emhlabeni jikelele, izilwandle zimunca ukushisa okuningi okubangelwa ukwanda kwamagesi okushisa. Izifundo eziningi zibonisa ukuthi ngaphezu kwama-90% okushisa okwengeziwe okuqongelelwe ohlelweni lwesimo sezulu kugcinwa olwandle. Lokhu kunciphisa okwesikhashana izinga lokwenyuka kwezinga lokushisa lomoya, kodwa futhi kubangela ukuthi izilwandle ziqhubeke nokufudumala, okubangela eminye imiphumela efana nokwenyuka kwezinga lolwandle kanye namagagasi okushisa olwandle.
2. Amaza olwandle: “amabhande okuthutha” athwala amandla
Izilwandle azigcini nje ngokugcina ukushisa kodwa futhi zikudlulisa kusuka kwesinye isifunda kuya kwesinye ngokusebenzisa imisinga yolwandle. Imisinga engaphezulu iqhutshwa kakhulu umoya kanye nokujikeleza koMhlaba, kuyilapho ukujikeleza kolwandle okujulile kuthonywa umehluko ekushiseni kanye nosawoti. Lokhu kuhlanganiswa kwakha uhlelo lokujikeleza komhlaba oluvame ukubizwa ngokuthi "ibhande lokuhambisa lomhlaba."
Imisinga efana neGulf Stream e-Atlantic isiza ukuthutha amanzi afudumele esuka ezindaweni ezishisayo aye ezindaweni eziphakeme, okunikeza iNtshonalanga Yurophu isimo sezulu esifudumele kunezinye izindawo eziku-latitude efanayo. Uma amaphethini amanje eshintsha, ukusatshalaliswa kokushisa komhlaba wonke nakho kuzoshintsha. Izinguquko emisinga yolwandle zingathinta nemizila yeziphepho, amaphethini emvula , kanye nokuvama kwezehlakalo ezimbi kakhulu.
Inkinga eyodwa exoxwa ngayo njalo ubuthakathaka bokujikeleza kwe-Atlantic meridional (AMOC). Uma lokhu kujikeleza kwehla ngenxa yokuncibilika kweqhwa kanye nokugcwala okukhulu kwamanzi ahlanzekile, izifunda ezithile zingase zibe nezinguquko ezinkulu zesimo sezulu zesifunda, okuhlanganisa nezinguquko emaphethini asebusika kanye nemvula.
3. Ukushintshana kokushisa nomhwamuko wamanzi: injini yesimo sezulu
Ubuso bolwandle buyindawo esebenzayo kakhulu yokushintshana kwamandla phakathi kolwandle nomkhathi. Ulwandle lukhipha ukushisa emoyeni ngokudluliswa kwamandla, ukujikeleza kwamanzi, futhi ikakhulukazi ukuhwamuka. Njengoba amanzi ehwamuka, athwala "ukushisa okucashile," okube sekukhishwa lapho umhwamuko wamanzi uhlangana ube amafu nemvula. Le nqubo iyisisusa esiyinhloko seziphepho zasezindaweni ezishisayo nezinye izinhlelo zezulu ezinkulu.
Uma ubuso bolwandle bufudumele, kulapho amathuba okuhwamuka kwamanzi eba maningi khona, okuvumela umkhathi ukuthi ubambe umhwamuko wamanzi omningi. Umhwamuko wamanzi ngokwawo uyigesi enamandla yokushisa. Ngakho-ke, ukufudumala kolwandle kungakhulisa i-feedback loop ekhulisa amandla emvula enkulu kwezinye izindawo ngenkathi kwandisa isomiso kwezinye ngenxa yezinguquko emaphethini okujikeleza komoya.
4. Izilwandle kanye nomjikelezo wekhabhoni: ukucwila kwe-CO₂ emhlabeni jikelele
Ulwandle ludlala indima enkulu ekulawuleni ukuhlushwa kwe-carbon dioxide (CO₂) emoyeni. I-CO₂ iyancibilika emanzini olwandle futhi igcinwa ngezindlela ezimbili eziyinhloko: “iphampu ebonakalayo” kanye “nephampu yezinto eziphilayo.” Iphampu ebonakalayo yenzeka lapho amanzi abandayo angaphezulu emunca i-CO₂ eyengeziwe bese ecwila olwandle olujulile, ephethe ikhabhoni nayo. Iphampu yezinto eziphilayo yenzeka lapho i-phytoplankton i-photosynthesize, iguqula ikhabhoni engaphili ibe yizinto eziphilayo; enye yayo bese icwila phansi kolwandle “njengeqhwa lasolwandle.”
Kulinganiselwa ukuthi izilwandle zimunca phakathi kwengxenye eyodwa kwezine nengxenye yesithathu yokukhishwa kwe-CO₂ emisebenzini yabantu minyaka yonke. Lokhu kusiza ekunciphiseni izinga lokufudumala komhlaba. Kodwa-ke, kunemiphumela emibi kakhulu: Ukumuncwa kwe-CO₂ kubangela ukwakheka kwe-acid olwandle. Lapho i-CO₂ isabela emanzini, yakha i-carbonic acid, eyehlisa i-pH. Lokhu kwenza kube nzima ngezinto eziphilayo ezifana ne-coral, i-shellfish, kanye ne-plankton ethile ukwakha i-calcium carbonate, okusongela uchungechunge lokudla lwasolwandle kanye nezindawo zemvelo zasogwini.
5. Umthelela wokushisa kolwandle phezu kwezimo zezulu : El Niño and La Niña
Ukwehluka kwamazinga okushisa olwandle oLwandlekazi iPacific olushisayo kuholela ku-El Niño–Southern Oscillation (ENSO), okuyimbangela enkulu yokwehluka kwesimo sezulu sonyaka . I-El Niño yenzeka lapho amanzi asePacific aphakathi nasempumalanga eshisa ngaphezu kokujwayelekile, kanti i-La Niña yenzeka lapho la manzi epholile ngaphansi kokujwayelekile.
Imiphumela yayo isakazeka emhlabeni wonke: I-El Niño ivame ukuhlotshaniswa nokwanda kwemvula ezindaweni ezithile zaseNingizimu Melika, ubusika obufudumele kwezinye izindawo, kanye nesomiso kanye nokwanda kwengozi yomlilo e-Australia nase-Indonesia. I-La Niña ingaba nomphumela ophambene, okuhlanganisa ukwanda kwemvula eNingizimu-mpumalanga ye-Asia nase-Australia, kanye nezimo ezomile kwezinye izindawo. Ngenxa yokuthi i-ENSO ithinta amaphethini omoya kanye nokuhamba kwamafu, isebenzisana nokufudumala komhlaba futhi ingakhulisa izehlakalo zesimo sezulu esibi kakhulu.
6. Iqhwa lolwandle, i-albedo, kanye nokuzinza kwesimo sezulu
Ezindaweni ezisenyakatho, ulwandle luxhumana neqhwa lolwandle ngezindlela ezithinta kakhulu isimo sezulu. Iqhwa lolwandle libonakalisa iningi lemisebe yelanga (i-albedo ephezulu). Lapho iqhwa lincibilika, ubuso bolwandle obumnyama bumunca ukushisa okwengeziwe, busheshise ukufudumala futhi buncibilikise iqhwa eliningi. Lokhu kubizwa ngokuthi impendulo yeqhwa-albedo, futhi yisona sizathu esenza i-Arctic ifudumale ngokushesha kunesilinganiso somhlaba wonke.
Ngaphezu kwe-albedo, ukuncibilika kweqhwa kwengeza amanzi ahlanzekile olwandle, okungashintsha ubuningi bamanzi futhi kuphazamise ukujikeleza kolwandle. Imiphumela ingadlulela kude nezindawo ezizungezile, njengoba ukujikeleza kolwandle kuyisimiso somhlaba wonke esixhunyiwe.
7. Ukwenyuka kwezinga lolwandle kanye nemiphumela yesimo sezulu yesikhathi eside
Ukufudumala kolwandle kubangela ukwanda kokushisa: amanzi ayanda njengoba eshisa. Kuhlanganiswe nokuncibilika kwezinguzunga zeqhwa kanye namaqhwa asemhlabeni, amazinga olwandle ayaqhubeka nokwenyuka. Nakuba kuvame ukuxoxwa ngakho ngomongo wezinhlekelele zasogwini, ukwenyuka kwezinga lolwandle kuhlotshaniswa nokushintsha kwesimo sezulu ngoba kuthinta imvelo yasogwini njengemihlume kanye namaxhaphozi. Lezi zemvelo zibalulekile njengokucwila kwekhabhoni (ikhabhoni eluhlaza okwesibhakabhaka) kanye nezithiyo zemvelo zesiphepho. Uma imvelo yasogwini yonakele, ikhono lemvelo lokumunca ukukhishwa kwegesi nokunciphisa imiphumela yesimo sezulu esibi liyancishiswa.
Ngaphezu kwalokho, izinguquko ezingeni lolwandle kanye nokushisa zingashintsha ukusatshalaliswa kwezinhlobo zasolwandle, zithinte ukudoba, futhi zithinte ukuvikeleka kokudla. Lezi zinguquko azigcini nje ngokuba zemvelo, kodwa futhi zithinta nezenhlalo kanye nezomnotho.
Isiphetho
Ulwandle luyisilawuli esibalulekile sesimo sezulu somhlaba: ukugcina nokusabalalisa ukushisa, ukushayela umjikelezo wamanzi, ukumunca i-CO₂, kanye nokuthonya izimo zesimo sezulu ezifana ne-ENSO. Kodwa-ke, lo msebenzi wokuvimbela ungaphansi kwengcindezi enkulu evela ekufudumaleni komhlaba. Izilwandle ezifudumele nezine-asidi eningi kanye nezinguquko ekujikelezeni kwegazi kungandisa ingozi yesimo sezulu esibi kakhulu, kuphakamise amazinga olwandle, futhi kuphazamise izimiso zemvelo ezisekela ukuphila kwabantu.
Ukuqonda ithonya lolwandle esimweni sezulu somhlaba wonke kusisiza sibone ukuthi ukushintsha kwesimo sezulu akuyona nje indaba yomoya nomkhathi, kodwa futhi nolwandle. Imizamo yokunciphisa ukukhishwa kwegesi, ukuvikela imvelo yasogwini, kanye nokuqapha izimo zolwandle kuyizinyathelo ezibalulekile zokugcina ukuzinza kwesimo sezulu isikhathi eside eMhlabeni.
