A drone buzzes back and forth above rows of verdant orange trees planted near Nabeul, eastern Tunisia. The black unmanned aircraft, equipped with a multi-lens camera and sensors, has been enlisted by Tunisian farmers to adapt to years of drought and erratic weather caused by climate change. "We don't have the seasons we used to have" says Yassine Gargouri, the head of a farmers' group, "we have climatic variations". The use of modern technologies in agriculture is globally on the rise, including in North Africa, whose countries rank among the world's 33 most water-stressed, according to the World Resources Institute. IMAGES AND SOUNDBITES