By Keith Somerville BBC News Online

Nearly 30 million Africans could be facing famine within months.

Estimates from UN agencies, African governments and relief charities put the number at risk in the Horn of Africa at about 15 million, over 14 million in southern Africa and hundreds of thousands in the Sahel region of West Africa.

They are not able to buy enough food and as a consequence these people... live with hunger

Professor Amartya Sen

The immediate cause is drought, which has ruined harvests and left people and livestock without food and water.

But drought alone is not why Africa suffers regularly from famine and widespread malnutrition.

Most African countries are not self-sufficient in food and rely to varying extents on imports and on having the income to pay for them.

	:	Southern Africa famine
In pictures: Southern Africa famine

Other factors are at work, including: armed conflict, corruption and the mismanagement of food supplies, environmental degradation, trade policies that harm African agriculture and the long-term economic effects of Aids.

Poor food security

Famine is caused by the shortage or inability of people to obtain food.

This might be caused by low food production resulting from drought or other factors or it could be a result of the inability of a country or its population to afford to buy food.

Hunger is leading to malnutrition and death

Malnutrition is widespread across Africa, even in famine-free years where food production or imports appear to meet a country's needs.

The UN's Food and Agriculture Organisation (FAO) estimates that every year 40%-50% of the population of sub-Saharan Africa goes hungry and that the region "is worse off nutritionally today than it was 30 years ago".

Hunger and food insecurity are most serious in rural areas, where farming and livestock rearing are the main means of livelihood.

It is hardly surprising then that in a continent where nearly half the people are always short of food that drought, war and mismanagement of food supplies so regularly lead to famine on a wide scale.

Undernourished populations

The lack of food security and rampant poverty in Africa have left the continent with a population that is the most undernourished in the world.

UN figures show that over the past 30 years, developing countries as a group have reduced the percentage of undernourished in the population from 37% to 18%.

East and South Asia, where there have been massive increases in agricultural production and significant economic growth, have reduced the figure from 43% to 13%.

Sub-Saharan Africa has failed to get the rate below the 1969 figure of 34% of the population.

The poor cannot afford to buy food and have to beg

The Nobel Prize-winning economist Amartya Sen has argued that hunger and the resulting malnutrition and famine are products chiefly of poverty rather than specifically a country's ability to grow enough food.

Those who are malnourished are in this condition because "they are not able to buy enough food and as a consequence these people (including their family members) live with hunger".

Those who live with hunger every day are then vulnerable in the years that food supplies fail because of drought or other factors and become the first victims of famine.

Professor Sen argues that if countries in Africa were able to generate sufficient income they would be able to make themselves free of hunger as they could afford to import food to make up any shortfall in domestic production.

Under present terms of trade, African agricultural exports command low prices and cannot compete on world markets.

War and bad management

In a list of 18 African countries facing food emergencies in 2001, the FAO found that eight were experiencing civil strife and three were suffering the after-effects of conflict, such as internally displaced people and returning refugees.

The remaining seven had been affected by drought, flood, cyclones or food deficits that could not be made up by imports because of a lack of funds.

Many Africans are farming poor land

Those currently suffering from the threat of famine are doing so for a number of reasons.

But in countries like Angola, Ethiopia and Eritrea, recent conflict and a history of more or less constant war in previous years have played a major part in causing low food production, widespread poverty and dislocation of food distribution and trade networks.

Diversion of government finances, corruption or mismanagement have gone alongside conflict or developed from bad governance and have turned droughts and food shortages into famine.

Aids has also taken its toll, particularly in sub-Saharan Africa.

Countries like Malawi, Swaziland, Zambia and Zimbabwe are losing a high proportion of the economically-active population and gaining a large number of orphans and elderly people with no visible means of support.

It is against this bleak backdrop of chronic poverty, conflict, poor government and Aids that Africa is proving to be perpetually vulnerable to drought and floods.

These natural phenomena strike regularly, but it is when they hit countries already reeling from the effects of other ills that famine becomes inevitable.