New study on direct and indirect land use change from urbanization published in Nature Sustainability
When urban areas expand, they often replace very productive cropland areas. As a result, the direct conversion of natural areas into urban land is small, but the indirect loss of natural areas due to cropland displacement is much larger.
08/02/2019 | 2:05 PM
For this analysis, IVM researcher Jasper van Vliet analyzed global data on land cover change over a period of 23 years, from 1992 to 2015, and combined this with data on agricultural productivity.
The direct effect of urban expansion on natural areas is small because most villages and towns are located in agricultural areas. As a result, urban expansion often happens by converting agricultural lands in the surroundings. However, because the demand for food does not decrease, this loss of agricultural land will be compensated elsewhere. New agricultural areas often come at the expense of natural areas, leading to an indirectly loss of nature elsewhere.
Van Vliet shows that this indirect loss is many times larger than the direct loss, depending on where the new agricultural areas are developed. This effect is further leveraged by the fact that existing agricultural areas are often very productive, while the yield of new agricultural areas is typically much lower. For instance, agricultural land near a city is often located on fertile soils, while nature areas often exists on soils that are less suitable for agricultural production.
These findings could further inform policies and measures towards sustainable land use. Currently, we mostly look for solutions for the conservation of natural areas in the context of agricultural land use and dietary changes. While it is clear that agriculture provides the largest potential for preserving natural areas, it could also be useful to look at compact urban development or the preservation of the most productive agricultural areas.