Ingabe Iplanethi EwuMhlaba Iyasongelwa?

UKUFUDUMALA KWEMBULUNGA YONKE kuye kwachazwa njengosongo olukhulu olubhekene nesintu. Umagazini i-Science uthi okukhathaza abacwaningi “ukuthi sesiqale izinguquko eziningi ezihamba kancane kodwa ezingenakunqandeka.” Abagxeki bayakungabaza lokhu. Yiqiniso, abaningi bayavuma ukuthi umhlaba uyafudumala, kodwa abaqiniseki ngezimbangela nemiphumela. Bathi kungenzeka izinto ezenziwa abantu zinomthelela, kodwa aziyona imbangela eyinhloko. Kungani kunokungavumelani?

Phakathi kokunye, izinqubo zemvelo ezilawula isimo sezulu emhlabeni wonke ziyinkimbinkimbi futhi aziqondwa ngokuphelele. Ngaphezu kwalokho, amaqembu avikela imvelo athambekele ekukuchazeni ngokombono wawo lokho okushiwo isayensi, njengalokho okusetshenziselwa ukubonisa ukuthi kungani amazinga okushisa enyuka.

Ingabe Izinga Lokushisa Liyenyuka Ngempela?

Ngokombiko wamuva nje we-Intergovernmental Panel on Climate Change (IPCC) oxhaswe yi-UN, ukufudumala kwembulunga yonke “akunakungatshazwa,” noma kuyiqiniso; futhi “kungenzeka” ukuthi abantu yibona abanecala ngokuyinhloko. Abanye abangavumelani nalesi siphetho, ikakhulukazi ukuthi abantu banomthelela kulokhu, bayavuma ukuthi kungenzeka amadolobha ayafudumala ngenxa yokuthi ayakhula. Ngaphezu kwalokho, ukhonkolo nensimbi kubamba ukushisa kwelanga kalula futhi kuyephuza ukuphola ebusuku. Kodwa abagxeki bathi amazinga okushisa asemadolobheni awakuvezi lokho okwenzeka ezindaweni zasemaphandleni futhi angenza izibalo zembulunga yonke zinganembi.

Ngakolunye uhlangothi, uClifford, induna yomuzi ehlala esiqhingini esingasogwini lwase-Alaska, uthi ulubone ngawakhe ushintsho. Abantu bendawo yakubo banqamula eqhweni olwandle baye ezwekazini beyozingela izinyamazane ama-caribou nama-moose. Kodwa amazinga okushisa enyukayo enza kube nzima ukuphila ngale ndlela evamile. UClifford uthi: “Imisinga yolwandle isishintshile, isimo seqhwa sesishintshile, futhi indawo uLwandle lwaseChukchi olwaluba yiqhwa kuyo . . . isishintshile.” Uchaza ukuthi ulwandle lwaluvame ukuba yiqhwa ngasekupheleni kuka-October, kodwa manje akusabi njalo kuze kube ngasekupheleni kuka-December.

Ngo-2007, ukufudumala kwabonakala naseNorthwest Passage, eyavuleka ngokuphelele ngokokuqala ngqa emlandweni ogciniwe. Usosayensi oyinhloko weNational Snow and Ice Data Center e-United States wathi: “Lokho esikubone nonyaka kubonisa ukuthi inkathi yokuncibilika kweqhwa iyeluleka.”

Amagesi Abamba Ukushisa Emkhathini—Abalulekile Ekuphileni

Isizathu esivezwayo salolu shintsho ukwanda kwamagesi abamba ukushisa emkhathini, inqubo engokwemvelo ebalulekile ekuphileni kwasemhlabeni. Lapho ukushisa kwelanga kufika emhlabeni, umhlaba ubamba cishe amaphesenti angu-70 ako, kufudumeze umoya, izwe nolwandle. Ukube le nqubo ibingekho, izinga lokushisa emhlabeni beliyoba ngama-degree Celsius angu-18 ngaphansi kwezinga-qhwa. Ngokuhamba kwesikhathi, ukushisa okubanjwa umhlaba kubuyela emkhathini sekuyimisebe ye-infrared, kanjalo kuvimbele umhlaba ekushiseni ngokweqile. Kodwa uma izinto ezingcolisayo zishintsha umkhathi, kuncane ukushisa okubuyela emuva. Lokhu kungenza izinga lokushisa emhlabeni lenyuke.

Amagesi abamba ukushisa ahlanganisa isikhutha, i-nitrous oxide ne-methane, kanye nomhwamuko. La magesi aye anda kakhulu kule minyaka engu-250 edlule, kusukela kwaqala inguquko kwezezimboni futhi kwasetshenziswa kakhulu izinto zokubasa ezimbiwa phansi, njengamalahle nowoyela. Esinye isici esandisa amagesi abamba ukushisa kubonakala kuwukwanda kwemfuyo, ekhiqiza i-methane ne-nitrous oxide lapho igaya ukudla. Abanye abacwaningi baveza ezinye izimbangela zokufudumala kwembulunga abathi zazikhona ngaphambi kokuba abantu babe nethonya esimweni sezulu.

Ingabe Okunye Ukushintsha Nje Kwesimo Sezulu?

Abagxeka umbono wokuthi ukufudumala kubangelwa abantu baveza ukuthi izinga lokushisa lomhlaba liye lashintshashintsha kakhulu esikhathini esidlule. Bakhomba lokho okuthiwa inkathi yeqhwa, lapho kucatshangwa khona ukuthi umhlaba wawupholile kunendlela ongayo namuhla; futhi lapho besekela ukufudumala okungokwemvelo, baveza ubufakazi bokuthi izindawo ezibandayo, njengeGreenland, zake zaba nohlaza olutholakala ezindaweni ezishisayo. Yiqiniso, ososayensi bayavuma ukuthi uma behlehlela emuva emlandweni, kuya ngokuya kwanda ukungaqiniseki kwabo ngokuphathelene nokushintsha kwesimo sezulu.

Yini okungenzeka yabangela ukuba amazinga okushisa ashintshashintshe kangaka ngaphambi kokuba umuntu abe nomthelela? Ezinye izinto okungenzeka zaziyimbangela zihlanganisa ama-sunspot nama-solar flare, ahlobene nokushintshashintsha kwamandla elanga. Ngaphezu kwalokho, umhlaba uhamba wenze isiyingi esihlanganisa izinkulungwane eziningi zamakhilomitha futhi esithonya ibanga lomhlaba ukusuka elangeni. Kukhona nethonya lothuli lwezintaba-mlilo kanye nokushintsha kwemisinga yolwandle.

Isimo Sezulu Sokuzenzela

Uma kuwukuthi izinga lokushisa emhlabeni liyenyuka—kungakhathaliseki ukuthi iyini imbangela—lokhu kuyosithinta kanjani thina nendawo ezungezile? Kunzima ukubikezela ngokunembile. Kodwa namuhla ososayensi banama-computer anamandla, abawasebenzisela ukwenza isimo sezulu sokuzenzela. La ma-computer afakwe nezinhlelo ezinemithetho yemvelo, imininingwane yesimo sezulu kanye nezimo zemvelo ezinethonya esimweni sezulu.

Lezi zimo zezulu zokuzenzela zisiza ososayensi ukuba bahlole isimo sezulu ngendlela abebengenakukwazi ukukwenza ngayo. Ngokwesibonelo, “bangashintsha” amandla elanga ukuze babone ukuthi lokhu kunaliphi ithonya eqhweni elisezindaweni ezibandayo, ezingeni lokushisa lomoya nolwandle, ezingeni lomhwamuko, emfuthweni womoya, ekwakhekeni kwamafu, emoyeni nasemvuleni. “Bangabangela” ukuqhuma kwezintaba-mlilo bese behlola ukuthi uthuli lwazo lunaliphi ithonya esimweni sezulu. Bangahlola nethonya lokwanda kwabantu, ukugawulwa kwamahlathi, ukusetshenziswa kwendawo, ukushintsha kwamagesi abamba ukushisa, nokunye. Ososayensi banethemba lokuthi lezi zimo zezulu zokuzenzela ziyoya ngokuya zinemba kakhudlwana.

Zinembe kangakanani lezi zimo zezulu zokuzenzela zamanje? Okuningi kuxhomeke ekunembeni kwemininingwane nobukhulu bokwaziswa okufakwa kule mishini. Ngakho, izibikezelo zezulu ziyashintshashintsha kusuka kwesithokomele kuya kwesiyinhlekelele. Umagazini i-Science uthi noma kunjalo, “isimo sezulu [esingokwemvelo] singashintsha kungazelelwe.” Futhi kuye kwaba njalo kwezinye izimo, njengezinga elingavamile lokuncibilika ngokushesha kweqhwa lase-Arctic, okuye kwamangaza izazi eziningi zesimo sezulu. Noma kunjalo, ngisho noma abashaya umthetho bebenolwazi olungaphelele lwemiphumela yokwenza noma yokungenzi okuthile manje, bebengazenza izinqumo namuhla ezingase zinciphise izinkinga kusasa.

Icabanga ngalokho, i-IPCC yahlola imibiko eyisithupha yesimo sezulu sokuzenzela—kusukela kwebonisa ukukhishwa okungalawuleki kwamagesi abamba ukushisa kuya kwevamile nakuleyo ebekelwe imithetho eqinile—ngamunye owawunemiphumela ehlukile yesimo sezulu nesemvelo. Ngemva kokubheka lezi zibikezelo, abahlaziyi bakhuthaza ukuba kuthathwe izinyathelo ezihlukahlukene. Zihlanganisa ukubeka imithetho yamazinga okungcola okukhishwa yizinto zokubasa ezimbiwa phansi, ukuhlawulisa abeqa umthetho, ukukhiqiza ugesi owengeziwe ngamandla enuzi nokusungula ubuchwepheshe obungayilimazi imvelo.

Ingabe Lezi Zimo Zezulu Zokuzenzela Zingethenjwa?

Abagxeki bathi izindlela zamanje zokubikezela “zenza isimo sezulu esingaqondwa kahle sibonakale silula ngokweqile” futhi “azizinaki ezinye izimo.” Baveza nokushintshashintsha kwezimo zezulu ezenziwa nge-computer. Omunye usosayensi owahlanganyela ezingxoxweni ze-IPCC wathi: “Kunabanye bethu abawubonayo umsebenzi omkhulu wokulinganisa nokuqonda isimo sezulu esiyinkimbinkimbi kangangokuthi siyalingabaza ikhono lethu lokwazi ukuthi isimo sezulu sishintsha kanjani nokuthi kungani sishintsha.”a

Kuyiqiniso, abanye bangase bathi ukungenzi lutho ngenxa yokungabaza kuwukufaka ikusasa engozini. Bathi: “Siyobachazela kanjani abantwana bethu ngalokhu?” Kungakhathaliseki ukuthi lezi zimo zezulu zokuzenzela zinembile noma cha, singaqiniseka ngokuthi umhlaba usengozini enkulu. Imvelo esekela ukuphila emhlabeni yonakaliswa ukungcola, ukugawulwa kwamahlathi, ukwakhiwa kwamadolobha nokuqothulwa kwezinto eziphilayo, uma sibala izinto ezimbalwa nje okungekho muntu ongaziphikisa ngokufanele.

Ngenxa yalokho esikwaziyo, singalindela yini ukuthi isintu sisonke sishintshe ukuze silondoloze ikhaya lethu elihle—kanye nathi ngokwethu? Ngaphezu kwalokho, uma izinto ezenziwa abantu zibangela ukufudumala kwembulunga yonke, kungenzeka sineminyaka embalwa nje, hhayi amakhulu eminyaka, okwenza ushintsho oludingekayo. Kunoma ikuphi, ukwenza lolo shintsho bekuyosho ukubhekana nomnyombo wezinkinga zomhlaba—ukuhaha kwabantu, ubugovu, ukuntula ulwazi, ukuhluleka kohulumeni nokunganaki. Ingabe kungenzeka lokho noma kuwukuzikhohlisa nje? Uma kuwukuzikhohlisa, ingabe asinalo ithemba? Lowo mbuzo uzophendulwa esihlokweni esilandelayo.

[Umbhalo waphansi]

[Ibhokisi/Isithombe ekhasini 5]

ULILINGANISA KANJANI IZINGA LOKUSHISA KOMHLABA?

Ukuze uqonde izinselele, ubungalilinganisa kanjani izinga lokushisa legumbi elilodwa elikhulu? Ngokwesibonelo, ubungayibeka kuphi i-thermometer? Ukushisa kuyakhuphuka, ngakho umoya ongasophahleni lwendlu cishe ubuyofudumala kunomoya ophansi. Izibalo ziyophazamiseka uma i-thermometer iseduze kwefasitela, iselangeni, noma isethunzini. Umbala nawo ungase ubangele ukuba izibalo zihlukahluke, ngoba izindawo ezimnyama zikubamba kakhulu ukushisa.

Ngakho-ke, kungase kunganeli ukuthatha isibalo esisodwa. Kungase kudingeke ukuba uthathe izibalo ezindaweni ezihlukahlukene bese ubala isilinganiso. Futhi izibalo zingashintshashintsha kuye ngezinsuku nezinkathi zonyaka. Ngakho ukuze uthole isilinganiso esinembile, kungadingeka ukuba uthathe izibalo eziningi phakathi nenkathi ende. Khona-ke, cabanga ukuthi kunzima kangakanani ukulinganisa izinga lokushisa lomhlaba wonke, umkhathi kanye nezilwandle! Kodwa, lezi zibalo zibalulekile ukuze kulinganiswe kahle ukushintsha kwesimo sezulu.

[Umthombo]

NASA photo

[Ibhokisi ekhasini 6]

INGABE AMANDLA ENUZI AYIKHAMBI?

Ukusetshenziswa kukagesi emhlabeni wonke sekuqopha umlando ngokuphindaphindiwe. Njengoba ukushiswa kukawoyela namalahle kukhipha amagesi abamba ukushisa, abanye ohulumeni sebecabangela ukusebenzisa amandla enuzi njengendlela ehlanzekile yokukhiqiza ugesi. Kodwa nalokhu kunezinselele.

I-International Herald Tribune ibika ukuthi eFrance, engelinye lamazwe asebenzisa amandla enuzi kakhulu emhlabeni, kudingeka ama-cubic meter angaba izigidi eziyizinkulungwane ezingu-19 unyaka ngamunye ukuze kupholiswe izikhungo eziphehla amandla enuzi. Lapho kuhlasele ishisandlu ngo-2003, amanzi ashisayo avame ukukhishwa ezikhungweni zamandla enuzi eFrance abangela ukwenyuka kwezinga lokushisa emifuleni ngendlela eyingozi emvelweni. Ngakho, kwadingeka ukuba ezinye izikhungo zivalwe. Kulindeleke ukuba lesi simo sibe sibi nakakhulu uma izinga lokushisa lembulunga yonke lenyuka.

Unjiniyela wenuzi uDavid Lochbaum we-Union of Concerned Scientists wathi: “Kuzodingeka sixazulule inkinga yokushintsha kwesimo sezulu ukuze sisebenzise amandla enuzi.”

[Ibhokisi/Amabalazwe ekhasini 7]

IZINHLEKELE ZESIMO SEZULU NGO-2007

Ngonyaka ka-2007 kwaba nesibalo esiyingqopha-mlando sezinhlekelele zesimo sezulu esabangela ukuba i-United Nations Office for the Coordination of Humanitarian Affairs ihlabe umkhosi izikhathi ezingu-14 icela usizo—okuyizikhathi ezingaphezu kwezine kunesibalo sangaphambili sango-2005. Ngezansi kunohlu lwezinye nje zezinhlekelele ezenzeka ngo-2007. Kodwa-ke, khumbula ukuthi empeleni isenzakalo ngasinye asivezi isimo esaqhubeka isikhathi eside.

◼ EBrithani: Abantu abangaphezu kuka-350 000 bahlaselwa izikhukhula ezimbi kunazo zonke eminyakeni engaphezu kwengu-60. Ngo-May kuya ku-July, eNgilandi naseWales kwaba nemvula eningi kakhulu kusukela esikhathini okwaqala ngaso ukugcinwa kwamarekhodi ngo-1766.

◼ ENtshonalanga Afrika: Izikhukhula zahlasela abantu abangu-800 000 emazweni angu-14.

◼ ELesotho: Amazinga aphakeme okushisa nesomiso kwacekela phansi izilimo. Abantu abangaba ngu-553 000 bangase badinge usizo lokudla.

◼ ESudan: Izimvula ezinamandla zashiya abantu abangu-150 000 bengenamakhaya. Okungenani abangu-500 000 bathola usizo.

◼ EMadagascar: Lesi siqhingi sahlaselwa iziphepho nezimvula ezinamandla, ezenza ukuba abantu abangu-33 000 bashiye amakhaya futhi zacekela phansi amasimu abangu-260 000.

◼ ENyakatho Korea: Abantu ababalelwa ku-960 000 bahlaselwa izikhukhula, ukuguguleka kwenhlabathi nodaka oluningi.

◼ EBangladesh: Abantu abayizigidi ezingu-8,5 bahlaselwa izikhukhula ezabulala abangaphezu kuka-3 000, kanye nezilwane ezifuywayo eziyizigidi ezingu-1,25. Kwalimala noma kwabhidlika imizi engaba yisigidi nengxenye.

◼ ENdiya: Abantu abayizigidi ezingu-30 bahlaselwa izikhukhula.

◼ EPakistan: Izimvula ezihambisana neziphepho zashiya abantu abangu-377 000 bengenamakhaya, futhi zabulala amakhulukhulu.

◼ EBolivia: Abangaphezu kuka-350 000 bahlaselwa izikhukhula, kwathi abangu-25 000 basala bengenamakhaya.

◼ EMexico: Izikhukhula zashiya okungenani abangu-500 000 bengenamakhaya futhi kwathinteka abangaphezu kwesigidi.

◼ EDominican Republic: Imvula ewumvimbi yabangela izikhukhula nokuguguleka kwenhlabathi, okwashiya abangu-65 000 bengenamakhaya.

◼ E-United States: Imililo yequbula eningizimu yeCalifornia yaphoqelela izakhamuzi ezingu-500 000 ukuba zibaleke emakhaya azo.

[Umthombo]

Based on NASA/Visible Earth imagery