Ngaba Umhlaba Usengozini?

UBUSHUSHU BOMHLABA OBUGQITHISELEYO buchazwa njengeyona nto yakha yabeka ubomi babantu engozini. Iphephancwadi iScience lithi, abaphengululi bakhathazwa kukuba “akukho nto enokwenziwa ngezi ngxaki sizibangeleyo.” Abanye bathi akuyonyaniso oku. Kakade ke, abaninzi bayavuma ukuba umhlaba uya usiba shushu, kodwa abazi ukuba kubangelwa yintoni oko, bengazi nokuba kuya kuphumela entwenini. Bathi kusenokwenzeka ukuba izinto ezenziwa ngabantu zinegalelo koku, kodwa azingonobangela oyintloko. Yintoni ebangela oku kubethabethana kwezimvo?

Kaloku, ukutshintshatshintsha kwemozulu kuntsonkothile yaye akukho mntu unokukuqonda ngokupheleleyo. Enye into, abantu abayithandayo indalo bayitolika ngendlela yabo ingxelo yenzululwazi, njengaxa bechaza unobangela wokunyuka kwamaqondo obushushu.

Ngaba Ngokwenene Amaqondo Obushushu Ayenyuka?

Ngokutsho kweIntergovernmental Panel on Climate Change (IPCC) exhaswa yiUN, amaqondo obushushu ayenyuka “ngokuqinisekileyo” yaye “asinakulikhanyela” elokuba abantu babekek’ ityala. Abanye abangavumelaniyo noku, bathi izixeko ziye zisiba shushu kodwa oku kubangelwa kukwanda kwabantu ezixekweni. Ngapha koko, ubushushu belanga obutsalwa yikonkrithi nentsimbi buyehla ebusuku. Abo bakuthandabuzayo oku, bathi amaqondo obushushu asezidolophini akakubonisi oko kuqhubekayo emaphandleni.

Kanti yena, uClifford ohlala kwilali engakunxweme lwaseAlaska, uthi uye walubona olu tshintsho. Kwidolophana ahlala kuyo abantu banqumla kunxweme olunomkhenkce xa beyozingela icaribou nemoose. Ukunyuka kwamaqondo obushushu kwenza kube nzima ukuphila ngendlela ekwakuphilwa ngayo mandulo. UClifford uthi: “Kukho utshintsho emanzini, nasemkhenkceni kuquka lowo uba kuLwandle lwaseChukchi.” Uthi, olu lwandle lwaludla ngokuthi rhwelele ngumkhenkce ekupheleni kukaOktobha, kodwa ngoku umkhenkce ubakho ngasekupheleni kukaDisemba.

Ngowama-2007, ubushushu bomhlaba baphawuleka kuba umkhenkce okwiNorthwest Passage wanyibilika kangangokuba abantu batsho bakwazi ukunqumla apho okokuqala ngqa embalini. Isazinzulu esinamava seNational Snow and Ice Data Center yaseUnited States sathi: “Le nto yenzeke kulo nyaka ibonisa ukuba umkhenkce unyibilika ixesha elide elwandle kunokuba kwakunjalo ngaphambili.”

Ubushushu Bomhlaba—Bubalulekile Kwizinto Eziphilayo

Kuthiwa into ebangela oku kutshintsha, kukuba ubushushu bomhlaba (greenhouse effect) obubalulekileyo kwizinto eziphilayo buye banyuka ngokugqithisileyo. Xa amandla elanga efika emhlabeni, malunga nama-70 ekhulwini awo afudumeza umoya, umhlaba nolwandle. Ukuba oku bekungenzeki, iqondo lobushushu beliya kuba ngaphantsi kwe-18 ngokukaCelsius. Ekugqibeleni, obo bushushu buphindela esibhakabhakeni nto leyo eluncedo ukuze umhlaba ungabi shushu ngokugqithiseleyo. Kodwa ngenxa yokungcoliswa komoya, buncinane ubushushu belanga obuphindela esibhakabhakeni. Oku kunokubangela ukunyuka kwamaqondo obushushu.

Ezinye zeegesi ezinegalelo ekunyukeni kwamaqondo obushushu yicarbon dioxide, initrous oxide, nemethane, kwakunye nomphunga. Ezi gesi ziye zanda kakhulu emoyeni kwiminyaka engama-250 edluleyo, ukususela ekuqaliseni kwenguqulelo kwezorhwebo nokusetyenziswa kakhulu kwezimbiwa ezikhupha igesi, njengamalahle neoli. Kubonakala ukuba nokwanda kwemfuyo kube negalelo koku, kuba xa izilwanyana zisetyisa kuphuma imethane nenitrous oxide. Abanye abaphengululi bathi enye into ebangela ukunyuka kwamaqondo obushushu yenzeka ngaphambi kokuba abantu baqalise ukwenza izinto ezonakalisa imozulu.

Ngaba Kukutshintsha Kwemozulu Nje Okuqhelekileyo?

Abo bavakalelwa kukuba oku kutshintsha kwemozulu akubangelwanga ngabantu, bathi ibisoloko iguquguquka kwixa elidluleyo. Bacaphula oko kwakusenzeka ebudeni bamaxesha ekwakukho umkhenkce omninzi, ngexesha umhlaba wawubanda kunokuba unjalo ngoku; bemi ngelithi umhlaba uzifudumeza ngokwawo batsho bechaza ukuba kwimimandla ebandayo njengaseGreenland kwakukade kukhula izityalo ezidla ngokufumaneka kwimimandla efudumeleyo. Kakade ke, izazinzulu ziyavuma ukuba okukhona zizama ukuqonda ukuba yayinjani imozulu ngaphambili, kokukhona ziya zidideka.

Yintoni eyabangela ukuba amaqondo obushushu atshintshatshintshe ngaphambi kokuba izinto ezenziwa ngabantu zibe negalelo koku? Kusenokwenzeka ukuba enye yezinto ezibe negalelo koku ziisunspots, neesolar flares kuba zona zinokuthanani nokuguquguquka kwamandla elanga. Ngaphezu koko, ukujikeleza komhlaba okuthabatha amawakawaka eminyaka, kubangela ukuba umgama ophakathi kwelanga nomhlaba utshintshatshintshe. Enye into ephinda ibe negalelo luthuli lomhlaba olusuka kwiindawo ezazinentaba-mlilo notshintsho olwenzeka kumaza olwandle.

Ukuhlolwa Kwemozulu Ngekhompyutha

Ukuba amaqondo obushushu emhlabeni ayanyuka—enoba abangelwa yintoni na—kunokusichaphazela njani thina oku nezinto ezisingqongileyo? Kunzima ukwazi ngokuthe ngqo oko kuya kwenzeka. Noko ke, namhlanje izazinzulu ziyakwazi ukusebenzisa iikhompyutha ukuze zibone kwangaphambili ukuguquka kwemozulu. Kwezi khompyutha kukho imiyalelo efumaneka kwimithetho yemvelo, inkcazelo yemozulu nezinye izinto ezibangela ukutshintshatshintsha kwemozulu.

Kwezi khompyutha, izazinzulu zenza izinto ebezingenakukwazi ukuzenza kwimozulu yokoqobo. Ngokomzekelo, ziyakwazi “ukutshintsha” amandla elanga ukuze zibone oko kunokwenzeka kwiindawo ezinomkhenkce, emoyeni, elwandle, nendlela okunokuchaphazeleka ngayo ukunyuka komphunga, umoya, amafu nemvula. “Zinokwenza” nentaba-mlilo zize zibone ukuba uthuli olusuka kuloo ndawo ibinentaba-mlilo luyichaphazela njani na imozulu. Zinokuhlola negalelo elibangelwa kukwanda kwabemi, ukugawulwa kwamahlathi, indlela osetyenziswa ngayo umhlaba, iigesi ezibangelwa kukunyuka kwamaqondo obushushu, njalo njalo. Izazinzulu zinethemba lokuba le nkcazelo iza kuya ichana ngakumbi.

Ichane kangakanani inkcazelo ekwezi khompyutha? Eneneni oku kuxhomekeke ekuchaneni nakubungakanani benkcazelo efakwe apho. Ngenxa yoko, maxa wambi le mozulu iba ntle okanye ibe mbi kakhulu. Iphephancwadi iScience lithi: “Sekunjalo, imozulu [yokoqobo] inokutshintsha ngendlela engalindelekanga.” Sele lukho utshintsho olukhwankqisayo oluye lwenzeka kwimozulu, njengendlela oye wanyibilika ngayo umkhenkce kulwandle iArctic, nto leyo eye yothusa izazi ezininzi zemozulu. Noko ke, enoba abo banegunya lokumisela imithetho bebeyazi imiphumo yezinto ezenziwa ngabantu okanye abangazenziyo, oko bebenokukwenza bekunokuba luncedo.

I-IPCC yahlolisisa iimeko ezintandathu ezahlukahlukeneyo ezisekhompyutheni—phakathi kwazo, kuxa kukho iigesi ezininzi emoyeni nezibangela ubushushu bomhlaba, naxa kukho iigesi ezincinane emoyeni—yaye nganye kwezi meko ibangela utshintsho ngeendlela ezahlukahlukeneyo. Ngenxa yoku, abahlalutyi bacebisa ukuba kumiselwe imithetho eyahlukahlukeneyo. Le mithetho iquka ukumiselwa kwemiqathango ngokuphathelele izimbiwa ezikhupha iigesi, ukuhlawuliswa kwabo bangayithobeliyo le mithetho, ukuveliswa kwamandla enyukliya angakumbi nezixhobo zobugcisa ezingangcolisi moya.

Ngaba Le Nkcazelo Ikwezi Khompyutha Inokuthenjwa?

Abagxeki bathi izazi zemozulu “azinankcazelo yaneleyo ngokuphathelele imozulu” yaye “ezinye iinkqubo ziyazityeshela ngokupheleleyo.” Aba bagxeki bakhalazela nokuguquguquka koqikelelo olufumaneka ekhompyutheni. Esinye isazinzulu esasikho kwiingxubusho zeIPCC sathi: “Kunzima kakhulu ukuqonda oko kwenzekayo kwimozulu, kangangokuba abanye kuthi ababi nabo nobuganga bokuzama ukwazi oko kuqhubekayo nesizathu sokuba kwenzeke.”a

Kakade ke, abanye basenokuthi ukuhlala usonge izandla kuba nje ungaqinisekanga ngonobangela wale ngxaki, kukubeka ikamva labantu esichengeni. Bathi: “Xa abantwana bethu besibuza, siya kuthi kwakutheni ukuze singenzi nto ngale ngxaki?” Enoba olu qikelelo lukwezi khompyutha luchanile okanye akunjalo, into esiqiniseke ngayo kukuba umhlaba usengozini engathethekiyo. Izinto ezibangela ukuba sikwazi ukuphila zonakaliswa kukungcoliswa komoya, ukugawulwa kwamahlathi, ukufudukela kwabantu abaninzi ezixekweni, nokuphela kweentlobo ezithile zezilwanyana.

Ngenxa yoku, ngaba sinokulindela ukuba abantu bonke batshintshe indlela abaphila ngayo ukuze kulondolozwe eli khaya lethu lihle—nathi bantu? Ngaphezu koko, ukuba izinto ezenziwa ngabantu zibangela ukunyuka kwamaqondo obushushu ngokugqithiseleyo, oko kuthetha ukuba sifanele sibhinq’ omfutshane kanye ngoku senze utshintsho. Noko ke, oko kunokuthetha ukuba kumele kuqalwe ngezona zinto zibangela iingxaki emhlabeni—ukunyoluka, ukuzingca, ukungabi nalwazi, oorhulumente abangakwaziyo ukulawula kakuhle, nokungakhathali kwabantu. Ngaba loo nto inokwenzeka okanye liphupha nje? Ukuba liphupha nje, ngaba oko kuthetha ukuba akukho themba ngathi? Lo mbuzo uza kuphendulwa kwinqaku elilandelayo.

[Umbhalo osemazantsi]

[Ibhokisi/Umfanekiso okwiphepha 5]

UNOKULAZI NJANI IQONDO LOBUSHUSHU BOMHLABA?

Ukuze ukwazi ukubona indlela ekunzima ngayo oku, masenze umzekelo ngendlela yokufumanisa iqondo lobushushu begumbi elikhulu. Ngokomzekelo, ubuza kuyibeka phi ithermometer? Umoya okufuphi nesilingi ushushu kunomoya okufuphi nomgangatho. Iqondo lobushushu liya kuxhomekeka enoba ithermometer ibekwe kufuphi nefestile, ingqamene nelanga okanye isemthunzini kusini na. Nombala unegalelo koku, kuba iindawo ezimbala umnyama ziyabutsala ubushushu.

Ngoko ke, bekungayi kulunga ukuba ithermometer yakho uyibeke kwindawo enye. Bekuya kufuneka uyibeke kwiindawo ezahlukahlukeneyo uze ubale umlinganiselo. Usenokufumana amaqondo obushushu awahlukahlukeneyo suku ngalunye. Ngoko, ukuze ukwazi ukufumana umlinganiselo ochanileyo, ithermometer kuya kufuneka uyibeke kwiindawo ezahlukahlukeneyo kangangexesha elide. Ucinga ukuba kunzima kangakanani ke ukufumana umlinganiselo wobushushu bomhlaba wonke, umoya neelwandle? Ukanti, ukuze lwaziwe ngokuthe ngqo utshintsho lwemozulu, kubalulekile ukufumana loo manani.

[Inkcazelo]

NASA photo

[Ibhokisi ekwiphepha 6]

NGABA UKUSETYENZISWA KWAMANDLA ENYUKLIYA KUSISICOMBULULO?

Emhlabeni wonke, amandla afuneka ngendlela engazange ibonwe ngaphambili. Ekubeni ukutshiswa kweoli namalahle kubangela iigesi ezininzi, abanye oorhulumente bacinga ngokusebenzisa amandla enyukliya ngelithi wona akawungcolisi kakhulu umhlaba. Kodwa nako oku kubangela iingxaki.

I-International Herald Tribune ithi, eFransi, apho kusetyenziswa kakhulu amandla enyukliya, kufuneka amanzi aziikyubhiki-mitha ezili-19 lamawaka ezigidi nyaka ngamnye ukuze kupholiswe izixhobo zokuvelisa la mandla. Ebudeni bowama-2003 amaqondo obushushu anyuka kakhulu kwelo laseFransi, yaye amanzi emilambo yalapho atshisa ngendlela eyaba yingozi kwizityalo nakwizilwanyana. Ngenxa yoko amaziko amandla enyukliya kwafuneka avalwe. Ukuba amaqondo obushushu anokuqhubeka enyuka, le meko ingambi ngakumbi.

UDavid Lochbaum ongunonjineli wenyukliya kwiUnion of Concerned Scientists wathi: “Ukuba sifuna ukusebenzisa amandla enyukliya, kuza kufuneka silungise le ngxaki yokutshintsha kwemozulu.”

[Ibhokisi/Imaphu ekwiphepha 7]

IINTLEKELE EZIBANGELWE KUKUTSHINTSHA KWEMOZULU NGOWAMA-2007

Unyaka wama-2007 uye waba neentlekele ezininzi zemvelo yaye iUnited Nations Office for the Coordination of Humanitarian Affairs yakhupha izicelo ezili-14 zoncedo olukhawulezileyo—ezi zicelo zingaphezulu ngesi-4 kunezo zakhutshwa ngowama-2005. Apha ngezantsi kuchazwe ezinye zeentlekele ezehla ngowama-2007. Ukwehla kwezi ntlekele kule mimandla akuthethi ukuba ziya kuhlala zisibakho.

◼ EBritani: Abantu abangaphezu kwama-350 000 baye bachaphazeleka zizikhukula ezagqibela ukubakho kwiminyaka engaphezu kwengama-60 eyadlulayo. ENgilani naseWales kwana iimvula ezininzi ngoMeyi ukusa kuJulayi 2007 yaye iimvula ezinjalo zagqibela ukubakho ekuqaleni kowe-1766.

◼ ENtshona Afrika: Abantu abachatshazelwa zizikhukula bangama-800 000 kumazwe ali-14.

◼ ELesotho: Izityalo zalapho zonakaliswa bubushushu obugqithiseleyo nembalela. Abantu balapho abamalunga nama-553 000 kusenokufuneka bafumane ukutya okuvela kwezinye iindawo.

◼ ESudan: Emva kokuna kwezandyondyo zemvula, abantu abali-150 000 basala bengenamakhaya. Abangama-500 000 bafumana uncedo.

◼ EMadagascar: Ngenxa yenkanyamba neemvula ezinkulu, abantu abangama-33 000 baphulukana namakhaya abo yaye izityalo zabangama-260 000 zafa.

◼ EMntla Korea: Abantu abamalunga nama-960 000 bachaphazeleka zizikhukula nokukhukuliseka komhlaba.

◼ EBangladesh: Abantu abasisi-8,5 sezigidi bachaphazeleka zizikhukula yaye kwafa abangaphezu kwama-3 000 nezilwanyana ezili-1,25 lezigidi. Izindlu ezimalunga ne-1,5 lezigidi zadilika.

◼ EIndiya: Bangama-30 ezigidi abantu abachaphazelekayo zizikhukula.

◼ EPakistan: Iimvula ezikhatshwa ziinkanyamba zashiya abantu abangama-377 000 bengenamakhaya yaye kwafa abangamakhulu.

◼ EBolivia: Izikhukula zachaphazela abantu abangaphezu kwama-350 000 yaye abangama-25 000 basala bengenamakhaya.

◼ EMexico: Izikhukula zashiya abantu abamalunga nama-500 000 bengenamakhaya yaye bangaphezu kwesigidi abachaphazelekayo.

◼ EDominican Republic: Iimvula ezinkulu ezana ixesha elide zabangela izikhukula nokukhukuliseka komhlaba, yaye abangama-65 000 basala bengenamakhaya.

◼ EUnited States: Kwabakho umlilo kumzantsi weKhalifoniya yaye oko kwashiya abantu abangama-500 000 bengenamakhaya.

[Inkcazelo]

Based on NASA/Visible Earth imagery