"Between 90 and 93 percent of Morocco is affected by aridity and other forms of drought," he said, blaming climate change and overuse and misuse of land.

Attempts to deal with it include reforestation, dune stabilisation and measures against erosion, but "these measures are insufficient", he added, calling for action by everyone concerned, including the use of renewable energy sources.

Some 22,000 hectares (55,000 acres) of arable land disappears under the desert every year in Morocco, according to official figures. Agriculture accounts for up to 20 percent of gross domestic product, but this can drop to 13 percent, depending on the weather.