A shekara ta 2006, masanin tattalin arziki na Burtaniya Nicholas Stern ya yi gargadin cewa daya daga cikin manyan hatsarori na sauyin yanayi shi ne hijira mai yawa. Ya rubuta: "Abubuwan da suka shafi yanayi sun haifar da tashin hankali a baya," in ji shi, "kuma rikici babban haɗari ne a yankunan yammacin Afirka, Kogin Nilu, da Asiya ta Tsakiya." Fiye da shekaru goma bayan…