Publication

The rate of surface warming in cities exceeds that in rural areas, but urban greening can partly offset enhanced urban warming that is driven by climate change and urban expansion, according to an analysis of satellite land surface temperature data in 2000 city clusters between 2002 and 2021. Warming trends in cities are influenced both by large-scale climate processes and by local-scale urbanization. However, little is known about how surface warming trends of global cities differ from those characterized by weather observations in the rural background. Here, through statistical analyses of satellite land surface temperatures (2002 to 2021), we find that the mean surface warming trend is 0.50 +/- 0.20 K center dot decade(-1) (mean +/- one S.D.) in the urban core of 2000-plus city clusters worldwide, and is 29% greater than the trend for the rural background. On average, background climate change is the largest contributor explaining 0.30 +/- 0.11 K center dot decade(-1) of the urban surface warming. In city clusters in China and India, however, more than 0.23 K center dot decade(-1) of the mean trend is attributed to urban expansion. We also find evidence of urban greening in European cities, which offsets 0.13 +/- 0.034 K center dot decade(-1) of background surface warming.