Why are so many people still going hungry?
The basic problem is poverty.
Most Africans live in rural areas, where many are subsistence farmers, dependent on a good harvest to get enough food to eat.
There are hardly any irrigation systems, so people rely on the rains.
If one rainy season fails, people have very few savings - in either food or cash - to see them through.
Even in good years, there is a "hungry season", when last year's harvests have run out and the next crops are not yet ripe.
While people were starving in parts of Niger last year, shops in the capital, Niamey, were full of food but many could not afford to buy it.
In both the Horn of Africa and Niger, some of the most vulnerable were pastoralists, whose animals quickly succumbed when there was nothing left to graze.
When the animals die, their owners have no other way of getting enough food to eat.
Some say that the pastoralist lifestyle is no longer sustainable.
What are the other reasons?
Many farmers say that rains have become less reliable in recent years, which could be the result of global warming.
The Sahara desert is certainly expanding to the south, making life increasingly difficult for farmers and pastoralists in places like Niger.
Also, rising populations have led people to farm on increasingly marginal land, even more at risk from even a slight decline in rainfall.
Southern Africa has the world's highest rates of HIV/Aids and this is a major factor in that region's food crisis.
Some of those who should be the most productive farmers - young men and women - are either sick or have died, so their fields are being left untended, while their children go hungry.
What about the role of governments?
Nobel prize winning economist Amartya Sen said that no democracy has ever suffered from a famine and Africa's political problems have certainly contributed to the hunger of its people.
Some three million people are going hungry in Zimbabwe, which used to be the region's bread basket. Most donors say the government's seizure of productive, white-owned farms has worsened the effects of poor rains.
The government has also been accused of only delivering food aid to its own supporters and punishing areas which vote for the opposition.
Conflict obviously makes farming difficult, as people either run away from their fields or are too afraid to venture too far from their homes.
Farmers and pastoralists in countries such as Somalia and Democratic Republic of Congo face constant harassment by armed men.