A man ambles along a dried-out part of Lake Plastira near Karditsa in central Greece yesterday. The lake is 7 meters shallower than it was this time last year due to the lack of rain this winter. The head of a government committee to battle desertification said yesterday that parched land could trigger a mass exodus north from the Mediterranean. ‘Desertification means that people cannot earn a living off the land so they move,’ Professor Costas Cosmas told Reuters.