ABSTRACT
Worldwide urbanization has brought about diverse types of urban land change. The diversity of urban land change, however, has been greatly under-studied, because the major focus of past research has been on a single type of change, i.e., urban growth. In this study, we utilized nighttime light time series data and disentangle urban land changes of 34 global megacities into five categories: urban growth (UG), deurbanization (DU), urban land use intensification (LUI), urban land use degradation (LUD), and no significant change (NC). Our results showed that urban land changes occurred in 53% of built-up pixels of the selected megacities from 2012 to 2019. In contrast with UG (4%), LUI contributed to an unexpectedly large proportion of the changes (84%). Megacities in developing countries showed a wider extent and higher magnitude of the changes, as well as a larger proportion of LUI, than those in developed countries. Our findings not only offer a new insight into global urbanization, but also prompt further investigation on the environmental implications of the recent overwhelming LUI.
