Between 1960 and 2000 the world’s population doubled to six billion people. So far, science has managed to keep pace with this growth. The Green Revolution increased global food production per capita by 24 percent during that period. However, history has taught us that producing enough food does not eliminate hunger. Factors such as swelling urban populations, war and desperate poverty are some of the principal contributors to today’s lopsided distribution of food that leaves 800 million people chronically undernourished.

The green revolution advocated intensive, technology driven agricultural methods which dramatically improved yields, but many experts say it also resulted in less traditional, subsistence farming and more urbanization. As people move from rural to urban settings they become more detached from their food source, and become more dependant on the cash economy to meet their nutritional needs. With so many urban poor living in cities like Calcutta, people may go hungry because they do not have the resources to buy food, even when food is available. Today, nearly half of the global population is living in urban areas, and an increasingly complex system for food production, transportation and distribution is forcing many of the neediest people to slip through the cracks.

War and politics also have important impacts on food availability throughout the world. Millions of people are put at risk of hunger during times of war because they may be displaced from the land where they produce food or imported food never reaches them because of political constraints. Politics and a globalized food market also have a major impact where famine occurs. According to Leisinger, Schmitt and Lorch, the cause of the 1973 famine in Ethiopia "was the export of food from the famine region to the more lucrative markets of the cities. As a result, people literally starved when full granaries were within reach."

The task of adequately feeding 6 billion mouths today has not yet been met. There have been significant strides made over the past 40 years, however, with world population projected to reach 9 billion by 2050, this challenge becomes bigger and more urgent every year. Scientists and environmentalists continue to debate whether and how much the answer lies in science, this time specifically in genetically modified foods. However an even larger question surrounds the need to build better systems to address the many fundamental problems of hunger that are not directly related to food production.