Expert Commentary

Global changes in diets and the consequences for land requirements for food

2012 study in PNAS on the problematic pace of global land consumption and agricultural output required to supply the world's growing population.

As the world population increases and more developing countries transform into middle-income countries, there will be substantially more demand for food. Agricultural production will need to increase volume through either the acquisition of more croplands, or increasing the efficiency of current cropland. How countries and regions will meet this increase in demand for food is not clear, and how any expansion is carried out has implications for the environment. Moreover, as studies have shown, food shortages and price volatility also have geopolitical implications.

A 2012 study from researchers at the University of Groningen, Alpen-Adria-Universitat, and the University of Graz, “Global Changes in Diets and the Consequences for Land Requirements for Food,” examines the dynamic relationship between changes in population, technology and diet in the land requirements for food globally. The study, published in Proceedings of the National Academy of Sciences (PNAS), analyzes data from the U.N. Food and Agriculture Organization (FAO) to measure the relationships between cropland requirements for food, and population, technology, and diet changes at the subcontinent level between 1961 and 2007.

Key findings include:

  • Over the entire period examined, there was a continuous increase in the average availability of daily food calories per person: from 2,250 kilo calories per person in 1961 to 2,750 kilo calories per person in 2007.
  • In order to supply the “projected global population of more than 9 billion people in 2050 with the present diet and agricultural technology of Northern America would mean that cropland area had to be almost doubled.” This is given the assumption that not only will the population increase by 2050, but also there will be a greater adoption of richer diets as a result of many more economically developed countries.
  • Foods linked to “rich diets” — diets consumed by individuals in higher income countries — showed significantly higher rates of increase. Foods which could be categorized as linked to rich diets include, “stimulants, vegetable oils, vegetables, fruits, and animal products.”
  • There were large variances in how the total per capita food supply changed in each region. East Asia experienced the highest increase, which was primarily driven by higher production and demand from China. Sub-Saharan Africa saw a slight increase in food supply per person, with the exception of a decrease in Central Africa. Northern Europe and Oceania remained relatively unchanged in the food supply per person over this time period.
  • Significantly less land is now needed to feed a person; the average amount of land needed to feed one person in 2005 is two-thirds of the amount needed in 1963.
  • Over this time period, the food group which accounted for “the largest share of land use shifted from cereals to animal products.” Cropland used for agriculture decreased from 40% in 1963 to 31% in 2005, while the amount for animal products increased from 35% in 1963 to 38% in 2005.
  • “Decreasing per capita land requirements were a common feature throughout almost all regions.” However, this was not the case in regions, primarily Eastern Europe and East Asia, which were experiencing significant dietary change towards a “richer diet.” Such changes subsequently increased the amount of cropland required per person.
  • “At the global scale, the technology improvements were not sufficient to compensate for increases in population and changes in diets.” The primary driver of this growing land demand was increases in population, followed by changes in diet in nations experiencing significant economic development.

Over all, the researchers’ findings suggest that, while population growth may become slower as countries experience greater economic development, this development also results in rapid dietary changes, and “pressures on land resources for the provision of food are likely to remain high in the coming decades, as these dietary changes affect a large share of the global population.“ Furthermore, the authors note that “recent increases in land use efficiency of food production … were largely realized by steep increases in the use of external inputs, such as fertilizers, pesticides, fossil fuels, and irrigation infrastructures, all of which have substantial environmental impacts.”

A related study in PNAS examines the water “footprint” of nations around the globe and looks at the emerging problems associated with food and agricultural production.

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