Highly resolved satellite-remote-sensing-based land-use-change inventory yields weaker surface-albedo-induced global cooling

Abstract

Land-use change (LUC) is ranked as the second anthropogenic source of climate change after fossil fuel burning and yields negative albedo-induced radiative forcing (ARF). This cooling effect has been assessed using low spatiotemporally resolved LUC datasets derived from historical statistical data with large uncertainties. Herein, we implement a satellite-remote-sensing-derived highly resolved LUC dataset into a compact earth system model and reassess the global and regional surface ARF by LUC from 1983–2010 relative to 1750. We find that the magnitude of the negative ARF obtained from the present study is lower than that estimated by the Intergovernmental Panel on Climate Change by 20 %, implying a weaker cooling effect. The result reveals that the global LUC-induced surface albedo change may not significantly slow down global warming as was previously anticipated. Sub-Saharan Africa made the largest net contribution to the magnitude of the global ARF (39.2 %), due to substantial land-use conversions, typically the conversion from forest to other vegetation lands, which are accompanied by higher surface albedos. The most remarkable land cover changes occurred in East and Southeast Asia, which dominated the changes in the global ARF in recent decades. Based on major land cover types in these two regions, we infer that vegetation lands exert the most vital effect on global ARF variation.