Famine, defined as excessive mortality due to extreme and protracted shortage of food, resulting from a mixture of political and economic factors, has been part of human history. Traditional thoughts of the causes of famine focused on acts of God or of nature. Later, the idea developed that famines were caused by population growth far exceeding growth in food production; however, famine still occurred in the twentieth century when there was a food surplus. The primary causes of famine in the twentieth and twenty-first centuries can be attributed to poverty, social inequality, and failed governance.