Naphezu kwentuthuko ebalulekile kwezolimo yokondla umhlaba eminyakeni engama-60 edlule, ucwaningo oluholwa yiCornell lubonisa ukuthi umkhiqizo wezolimo emhlabeni wonke uphansi ngo-21% kunalokho obekungaba yikho ngaphandle kokushintsha kwesimo sezulu. Lokhu kufana nokulahlekelwa cishe iminyaka eyisikhombisa yokwanda komkhiqizo wezolimo kusukela ngawo-1960.
Imiphumela engaba khona yesikhathi esizayo yokushintsha kwesimo sezulu ekukhiqizweni kwezitshalo emhlabeni wonke ilinganiswe emibikweni eminingi yesayensi, kodwa ithonya lomlando lokushintsha kwesimo sezulu okubangelwa abantu emkhakheni wezolimo belingakafaneli lilinganiswe.
Manje, ucwaningo olusha lunikeza lokhu kuqonda: “Ukushintsha Kwesimo Sezulu Okubangelwa Yimvelo Kunciphise Ukukhula Kokukhiqiza Kwezolimo Emhlabeni Wonke,” eyanyatheliswa ngo-Ephreli 1 kuyi-Nature Climate Change, yayiholwa yisazi sezomnotho U-Ariel Ortiz-Bobea, uprofesa ohlangene eCharles H. Dyson School of Applied Economics and Management.
“Sithola ukuthi ukuguquka kwesimo sezulu kususe cishe iminyaka eyisikhombisa yokuthuthuka komkhiqizo wezolimo eminyakeni engama-60 edlule,” kusho u-Ortiz-Bobea. “Kufana nokucindezela inkinobho yokumisa ukukhula komkhiqizo emuva ngo-2013 futhi akukho okuthuthukisiwe kusukela ngaleso sikhathi. Ukushintsha kwesimo sezulu okubangelwa abantu sekuvele kusenza sihambe kancane.”
Ososayensi kanye nezazi zezomnotho bathuthukise imodeli yezomnotho ehlanganisa konke ehlanganisa izinguquko zonyaka nonyaka ezilinganisweni zesimo sezulu kanye nokukhiqiza kanye nomphumela ovela kumamodeli wesimo sezulu wakamuva eminyakeni engaphezu kwamashumi ayisithupha ukuze kulinganiswe umphumela wokushintsha kwesimo sezulu kwakamuva okubangelwe ngumuntu kulokho izazi zezomnotho ezikubiza ngokuthi “ukukhiqiza kwezinto eziphelele,” isilinganiso esibamba umkhiqizo wonkana womkhakha wezolimo.
U-Ortiz-Bobea uthe bacabangele ukwehluka okuhlelekile okungaphezu kuka-200 kwemodeli yezomnotho, futhi imiphumela yahlala ifana kakhulu. “Uma sisondela ezingxenyeni ezahlukene zomhlaba, sithola ukuthi imiphumela yomlando yokushintsha kwesimo sezulu ibe mikhulu ezindaweni ezifudumala kakade, okuhlanganisa izingxenye zase-Afrika, eLatin America nase-Asia,” kusho yena.
Abantu sebevele bashintshe uhlelo lwesimo sezulu, kusho u-Ortiz-Bobea, njengoba isayensi yesimo sezulu ikhombisa ukuthi umhlaba ufudumele cishe nge-1 degree Celsius kunangaphandle kwamagesi okushisa asemoyeni.
“Iningi labantu libona ukuguquka kwesimo sezulu njengenkinga ekude,” kusho u-Ortiz-Bobea. “Kodwa lokhu kuyinto esivele inomphumela. Kufanele sibhekane nokushintsha kwesimo sezulu manje ukuze sikwazi ukugwema umonakalo owengeziwe ezizukulwaneni ezizayo.”
U-Ortiz-Bobea noRobert G. Chambers, uprofesa wezomnotho wokukhiqiza eNyuvesi yaseMaryland, bebelokhu beqala ukubala okusha kokukhiqiza kwezolimo ukuze kufakwe idatha yesimo sezulu engakaze ibhekwe emlandweni, ihlose ukuletha ukunemba okusha kumamodeli wesimo sezulu.
“Ukukhiqiza empeleni ukubalwa kwezinto ozifakile uma kuqhathaniswa nezinto ozifakile, futhi ezimbonini eziningi, okuwukuphela kwendlela yokuthola ukukhula iwukusebenzisa izinto ezintsha,” kusho uChambers. “Ukulinganisa umkhiqizo wezolimo akuzange kufake idatha yesimo sezulu emlandweni, kodwa sifuna ukubona izitayela zalezi zinto ezifakile ezingaphandle kwamandla omlimi.”
UDavid Lobell, uprofesa wesayensi yesistimu yomhlaba eStanford, uthe imiphumela ikhombisa ngokusobala ukuthi imizamo yokuzivumelanisa nezimo kumele ibheke lonke uchungechunge lokuhlinzeka, okuhlanganisa abasebenzi kanye nemfuyo.
“Ziphinde zibonise ukuthi ngisho noma ezolimo ziba ngomshini futhi zithuthuke kakhulu, ukuzwela isimo sezulu akupheli,” esho. “Lokhu kuyaphikisana nabantu abaningi, futhi sidinga ukuqonda okujulile ukuthi kungani.
"Umqondo wami ukuthi sithuthuka nje ekuqedeni zonke izithiyo ezingezona ezesimo sezulu ekukhiqizeni, kodwa sidinga ukuhlola izincazelo ezahlukahlukene ezingaba khona."
“Lolu cwaningo luyigxathu elikhulu ngale kokugxila kwendabuko ezitshalweni ezimbalwa ezinkulu zokusanhlamvu,” kusho uLobell. “Ngokubheka lonke uhlelo — izilwane, abasebenzi, izitshalo ezikhethekile — singabona ukuthi wonke umnotho wezolimo uzwela kakhulu esimweni sezulu. Kubonakala sengathi kwezolimo, cishe yonke into iba nzima uma kushisa kakhulu.”
Ngaphezu kuka-Ortiz-Bobea, uChambers noLobell, ababhali ababambisene nabo bangu- UToby R. Ault, uprofesa wesayensi yomhlaba kanye neyomkhathi eKolishi Lezolimo Nesayensi Yokuphila; kanye noCarlos M. Carrillo, umlingani wocwaningo eMnyangweni Wezesayensi Yomhlaba Neyesimo Sezulu.
Imali ye-Cornell inikezwe yi-USDA National Institute of Food and Agriculture kanye ne-National Science Foundation.
U-Ortiz-Bobea no-Ault bangabafowenu ku- Isikhungo seCornell Atkinson Sustainability.
