Helmut Melzer
Pakhala kupita patsogolo kwakukulu pamaphunziro: Kodi 1800 akadali osadziwa kulemba ndi 88 peresenti, chiwerengerochi 2014 chatsika ndi 15 peresenti. Komabe, pali mayiko ena pozungulira kuchuluka kwa 30 ndi Nigeria, mwachitsanzo. Mulingo wamaphunziro wakwera kwambiri: chiwonetserochi chikuwonetsa mtundu wa sukulu yapamwamba kwambiri malinga ndi ziwerengero zathunthu (funde likuwonetsanso chitukuko cha chiwerengero cha anthu padziko lonse lapansi) kuphatikizapo chiwonetsero cha IIASA mpaka chaka cha 2100.
