Peer review

Urban growth has received little attention in large-scale land change assessments, because the area of built-up land is relatively small on a global scale. However, this area is increasing rapidly, due to population growth, rural-to-urban migration, and wealth increases in many parts of the world. Moreover, the impacts of urban growth on other land uses further amplified by associated land uses, such as recreation and urban green. In this study we analyze urban land take in cropland areas for the years 2000 and 2040, using a land systems approach. As of the year 2000, 213 Mha can be classified as urban land, which is 2.06% of the earth’s surface. However, this urban land is more than proportionally located on land that is suitable and available for crop production. In the year 2040, these figures increase to 621 Mha, or 4.72% of all the earth’s surface. The increase in urban land between 2000 and 2040 is also more than proportionally located on land that is suitable and available for crop production, thus further limiting our food production capacity. The share of urban land take in cropland areas is highest in Europe, the Middle-East and Northern Africa, and China, while it is relatively low in Oceania and Sub-Saharan Africa. Between 2000 and 2040, urban growth caused the displacement of almost 65 Mton of crop production, which could yield an expansion of up to 35 Mha of new cropland. Land-use planning can influence both the location and the form of urbanization, and thus appears as an important measure to minimize further losses in crop production.

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