For the first time in six years, there is famine in the world: a real, United Nations-declared famine, with more than 30 percent of the affected population suffering acute malnutrition and more than 1,000 people dying of hunger each day. And there are three more countries where famine may be declared any day now.

As you would expect, all four current and impending famines are in war zones. As you might not expect, one of the afflicted countries is not in Africa. It is war-torn Yemen, the poorest Arab country, whose 22 million people depended on imports for 90 percent of their food. With most of Yemen in rebel hands and daily air raids, the food is no longer making it in.

But the other three places are indeed African: South Sudan, Somalia and northeastern Nigeria. The official famine is in South Sudan, where, after three years of brutal civil war, 40 percent of the population, some 5 million people, are starting to starve. As usual, there are other contributing factors. There has been a months-long drought in much of East Africa, and the worst-hit provinces of South Sudan tend to support the rebels and may therefore be suffering from an undeclared government food blockade. But it's almost always Africa. Why?