We indirectly lose a lot of nature due to urban expansion
Urban expansion leads to little direct loss of natural areas, but much larger indirect loss through displacement of agricultural land. This is the main result from new research by VU environmental geographer Jasper van Vliet.
07/31/2019 | 10:05 AM
The article appeared in Nature Sustainability on July 29. Van Vliet (Institute for Environmental Studies, IVM) analysed global land cover change over a period of 23 years, from 1992 to 2015, and combined this with data on agricultural productivity.
Large indirect effect
The direct effect of urban expansion on natural areas is small because most villages and towns are located in agricultural areas, globally. 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.
New research area
Jasper van Vliet’s research is the first to investigate this effect at a global scale based on recent land cover data. Previously, he analysed this effect only based on model-based simulations of future land use. “There is a lot of research into agricultural land expansion and its consequences for natural areas, but very little attention is paid to the impact of urban expansion.”
Consistently, we mostly look for solutions for the conservation of natural areas in the context of agricultural land use: “Common solutions are, for example, that we could eat less meat or that we could develop more intensive agriculture.” Van Vliet acknowledges that the largest gains can indeed be achieved there, but suggests to also look at other solutions. “Global urban growth is expected to continue in the next decades. It would be a good idea to focus on compact development or to protect the most productive agricultural areas when a new city district is being built, and thus to limit the loss of natural areas.”
NWO Vidi Grant
Jasper van Vliet received a Vidi grant from NWO this spring. With that money, he will conduct further research into urban expansion and sustainable land use.