Internally displaced men and children shelter from the sweltering afternoon sun under a tree beside a hut on March 14 at a makeshift camp on the outskirts of Baidoa, in the southwestern Bay region of Somalia, where thousands of people arrive daily after they fled the parched countryside.

The United Nations warned of an unprecedented global crisis with famine already gripping parts of South Sudan and looming over Nigeria, Yemen and Somalia, threatening the lives of 20 million people. For Somalis, the memory of the 2011 famine, which left a quarter of a million people dead, is still fresh.