(CNN) -- Here is some background information about famine, a severe and prolonged hunger in a significant portion of a region or country's population that results in malnutrition and death by starvation and disease.
To assess a country's food security, the United Nations uses the five-phase scale known as the Integrated Food Security Phase Classification (IPC).
Famine can stem from natural causes such as droughts, floods, earthquakes, insect plagues and plant disease; or man-made causes such as wars, civil disturbances, sieges and deliberate crop destruction.
Famine results from a triple failure of food production, access to food and response.
Basic Definitions: Undernutrition - The outcome of prolonged insufficient food intake and/or low absorption of food consumed. This generally applies to energy levels, but may also relate to vitamin and mineral deficiencies.
Undernourishment or Chronic Hunger - The status of persons when food consumption regularly provides less than their minimum energy requirements. The average minimum energy requirement per person is about 1,800 kilocalories (kilocalories are commonly referred to as Calories) per day (The exact requirement is determined by a person's age, body size, activity level and physiological conditions such as illness, infection, pregnancy and lactation).
Malnutrition - A general term for a range of circumstances that inhibit good health, caused by insufficient or unbalanced food intake or from poor absorption of food consumed; refers to both undernutrition (food deprivation) and overnutrition (excessive food consumption with regards to energy requirements).
Food security - Exists when all people at all times have access to sufficient, safe and nutritious food that meets their dietary needs for an active and healthy life.
Food insecurity - Exists when people lack access to sufficient amounts of safe and nutritious food, and therefore do not consume enough for an active and healthy life. Situation may result from unavailability of food, inadequate purchasing power, or inappropriate distribution at the household level.
Integrated Food Security Phase Classification (IPC) Phases: Phase 1: Generally Food Secure Phase 2: Moderately/Borderline Food Insecure Phase 3: Acute Food and Livelihood Crisis Phase 4: Humanitarian Emergency Phase 5: Famine/Humanitarian Catastrophe
Phase 5 - Famine/Humanitarian Catastrophe thresholds: Crude mortality rates exceed two deaths per 10,000 people per day.
Global acute malnutrition (GAM) rates exceed 30%.
Food consumption below 2,100 kcal per person per day, as well as an extreme lack of nutrients.
Less than four liters of water available per person per day.
Number and Percentage of Undernourished in the World: 1969-1971 - 878 million (26% of world)
1979-1981 - 853 million (21% of world)
1990-1992 - 848 million (16% of world)
1995-1997 - 792 million (14% of world)
2000-2002 - 836 million (14% of world)
2006-2008 - 850 million (13% of world)
2010-2012 - 868 million (12.5% of world)
2011-2013 - 842 million (12.1% of the world)
Percentage of the Population in a Condition of Undernourishment: 1990-1992 - 26% of Africa, 12% of Latin American and the Caribbean, 20% of Asia, 12% of Oceania
1995-1997 - 26% of Africa, 11% of Latin American and the Caribbean, 16% of Asia, 11% of Oceania
2000-2002 - 24% of Africa, 10%t of Latin American and the Caribbean, 16% of Asia, 13% of Oceania
2006-2008 - 23% of Africa, 8% of Latin American and the Caribbean, 15% of Asia, 12% of Oceania
Timeline of Significant Famines (1900-present): 1921-1922 - Soviet Union, results in 9 million deaths.
1927 - China (northwest), 3-6 million perish.
1929 - China (Hunan Province), results in 2 million deaths.
1932-1933 - Soviet Union (Ukraine), 7-8 million people die.
1943 - China (Henan), results in 3-5 million deaths.
1943 - India (Bengal), 2.1-3 million perish.
1946-1947 - Soviet Union, 2 million people die.
1959-1961 - China, results in 15-30 million deaths.
1974 - Bangladesh, 1.5 million perish.
1975-1979 - Cambodia, results in 1.5-2 million deaths.
1984-1985 - Ethiopian famine, affects more than 8 million people and resulted in approximately 1 million deaths.
1991-1993 - Somalia famine, after the government's fall and civil war, affecting more than 2 million people.
1995-1999 - North Korean famine, results in an estimated 2.5 million deaths.
2008 - The United Nations officially declares famine for the first time. In two areas of southern Somalia famine caused by drought, theft of food shipments by rebels, civil war, and an influx of refugees other war torn nations is declared; 3.7 million people are affected.
September 5, 2011 - The United Nations announces that famine has spread to the sixth area in Somalia and about 750,000 people are in danger of imminent starvation.
May 2, 2013 - The United Nations announces that 260,000 people in Somalia died from the famine between October 2010-April 2012. A top U.N. humanitarian official says the international community did not take action fast enough.