Tiny man-made lagoon plots, al-Qataya, stretch out towards the Mediterranean in the Ghar El Melh wetlands in Tunisia. It is home to a centuries-old system of agriculture that climate change threatens to wipe out. Invented in the 17th century by North Africa's Andalusian diaspora, the Ramli – meaning "sandy" in Arabic – agricultural system irrigates crops entrenched in a mix of sand and manure, at the same time keeping salt water at bay. The United Nations' Food and Agriculture Organisation last year added Ghar El Melh to its list of agricultural heritage systems of global importance. The system's reliance on a fragile balance of rain and sea tides means it faces unusual challenges. Farmer Ali Garsi notes that a lack of rain negatively affects the quantity of his yields. The rising sea levels and increase in temperature pose a threat to Ghar El Melh, and could end the area's unique system of irrigation and farming.