Njengoko bekutshiwo kwezinye iimeko, inqanaba lolwandle alizukunyuka ngokuthe chu okanye ngokuzinzileyo njengoko ixesha lihamba. Ukuba ukugxilwa kwee-greenhouse gases kuyaqhubeka ngoluhlobo, ukunyuka kwenqanaba lolwandle kunye namaqondo obushushu eplanethi kuya kukhawuleza kwaye kukhawuleze.
Isifundo sihlalutye ukukhula kwenqanaba lolwandle ekuhambeni kwexesha kwaye sigqibe kwelokuba lenyuke ngo-2014 ngama-50% ngokukhawuleza kunango-1993. Yintoni eyabangela ukuba ulwandle lukhuphuke ngokukhawuleza?
Ukunyibilika komkhenkce osemkhenkceni
Umgangatho weelwandlekazi ukhula ngokukhawuleza kwaye ngokukhawuleza. Ukongeza, kukho iindawo ezithi, ngenxa yobukho bemozulu egqithileyo ezinje ngezaqhwithi kunye neenkqwithela zetropiki, zityhale amanzi olwandle ngaphakathi kwaye zishiya iindawo ezininzi ezingaselunxwemeni zingenakuhlalwa.
Uphononongo lufumene isizathu sokuba kutheni ulwandle lukhula ngokukhawuleza kwaye ngokukhawuleza. Imalunga nokunyibilika komkhenkce waseGreenland. Ukwanda kwamaqondo obushushu aphakathi kwehlabathi ngenxa yokukhutshwa kwegesi ebamba ukushisa ebangelwa yimisebenzi yabantu Kubangela iipesenti ezingama-25 zokunyuka kwesantya sokunyuka kwenqanaba lolwandle. Kwiminyaka engama-20 eyadlulayo, ukunyibilika kweGreenland kwabangela kuphela ukunyuka kwenqanaba lolwandle le-5%.
Oku kunokusibonisa kwisantya ezenzeka ngaso iziganeko zendalo. Sithetha ngento yokuba kwiminyaka engama-21 kuphela, isantya sokunyibilika kweGreenland siya sikhawuleza kwaye sikhawuleza. Kuqikelelwa ukuba ngonyaka wama-2050, Akusayi kuphinda kubekho umkhenkce ehlotyeni kuMntla wePole. Oku kunokuthetha ukunyamalala kwezigidi zeedolophu eziselunxwemeni kwihlabathi liphela.
Kwi-2014, inqanaba lolwandle lenyuka malunga ne-3,3 mm / ngonyaka xa kuthelekiswa ne-2,2 mm / ngonyaka ngo-1993, batsho abaphandi kwijenali yoTshintsho lwemozulu. Ezi zigqibo zomsebenzi zibaluleke kakhulu kuba zenza uqikelelo olulumkileyo kakhulu lokunyuka komgangatho wolwandle kwixa elizayo. Kuqikelelwa ukuba ngasekupheleni kwenkulungwane, kulindeleke ukwanda kweesentimitha ezingama-60 ukuya kuma-90.
Ukuphakama kwenqanaba lolwandle ubungqina
Ubungqina bokuba ukunyibilika kweGreenland neAntarctica kukhawulezisa ukunyuka kwenqanaba lolwandle kuyanyanzelisa kwaye kuyabonakala. Ukongeza, iGreenland iyodwa inamanzi afriziweyo aneleyo okunyusa amanqanaba olwandle malunga neemitha ezisixhenxe, ke ngoko ingozi yokunyibilika ngokupheleleyo kwezi kepusi inkulu kakhulu. Uninzi lwezazinzulu ezifunda ukunyibilika kunye nokunyuka kwamanqanaba olwandle ziqikelela ukuba ngasekupheleni kwenkulungwane iya kube sele ikhule ngaphezulu kwemitha.
Ekuqaleni kwee-1990, Isiqingatha sonyuso sichazwe ngokwanda ngenxa yokufudumala, xa kuthelekiswa ne-30% kwiminyaka engama-20 kamva, ngokutsho kwabaphandi. IGreenland inegalelo kolu nyuko namhlanje nge-25% xa ithelekiswa ne-5% kumashumi amabini eminyaka eyadlulayo. Olu phononongo luncede okokuqala ukufumana iindlela ezimbini ezahlukeneyo ukuze bakwazi ukulinganisa inqanaba lolwandle.
Iindlela zokulinganisa ukunyuka kwenqanaba lolwandle
Indlela yokuqala yokulinganisa inqanaba lolwandle kukujonga igalelo kolu kunyuka kwezinto ezintathu: ukunyuka kolwandle ngenxa yokufudumala kwehlabathi, utshintsho kumthamo wamanzi agcinwe emhlabeni kwaye unyibilike kwizikhenkcezisi zomkhenkce nakwikhephu lomkhenkce eGreenland naseAntarctica.
Ngakolunye uhlangothi, indlela yesibini isebenzisa i-satellite altimetry. Oku kulinganisa umgama phakathi kwesathelayithi kunye nomphezulu wolwandle. Ngale ndlela, ukuba umgama uyehla, kukuba inqanaba lolwandle likhuphukile. Kude kube ngoku, idatha ebonelelwe yi-satellite altimetry ibonakalise utshintsho oluncinci kule minyaka ingama-20 idlulileyo.
Njengoko ubona, ukunyuka kwenqanaba lolwandle kufuneka kufundwe nzulu kuba zininzi iintlekele ezinokubangela kwiindawo eziselunxwemeni nakuqoqosho lwamazwe amaninzi.