Settlement changes after peak population--Land system projections for China until 2050

February 1, 2021 CLUMondo model Total reading of this article times

In this study, we further develop the CLUMondo land system model to simulate land system changes in China until 2050. Our application represents a range of settlement systems, from dense urban areas to village landscapes, differing in their built-up area as well as their population density to enable the simulation of different settlement change trajectories.

We developed a land system map for China for the year 2000 and the year 2015 using an expert-based classification. This classification is designed to represent multiple different settlement systems, which are normally not distinguished in land cover maps.

Urban areas have increased dramatically in China in recent decades, and many scenario studies suggest this expansion is likely to continue in the next few decades. Urban expansion mostly leads to a conversion of agricultural land, and indirectly to a decrease in natural areas, especially under the current cropland protection policies. However, projections indicate that population growth is expected to peak somewhere before 2050 and decline afterwards, and this change offers an opportunity for managing urban change.

Results of this study show that under conditions of constant population density (S1 and S3), population decline would allow to decrease the amount of built-up land and thus save space for natural land systems. However, results also show that a continuation of the current decline in population per area of built-up land (S2 and S4), leads to a large increase in urban area, even in the low population scenario. Hence, population decline alone doesn’t automatically lead to a reduction in built-up land and policies or other measures are needed to avoid further losses of natural areas as a result of urban development in China.