Chinese scientists discover significant warming due to land use changes
1/4 to 1/3 of observed warming trends in China from 1980 to 2015 are attributed to land use changes
Pengke Shen & Shuqing Zhao (2021), 1/4 to 1/3 of observed warming trends in China from 1980 to 2015 are attributed to land use changes, Climatic Change 164, 26 February 2021
Changes in land use, especially urbanization, alter the biophysical properties of Earth’s surface, which in turn affects local climate and even contributes to global warming. The observation minus reanalysis (OMR) approach has been widely applied to isolate the signal of surface forcing from observed temperature changes (which reflect all the sources of climate forcings, including surface effects), but bias in warming trends induced by surface change and estimation uncertainties still remain. Using the ensemble mean of eight temperature reanalysis datasets as background climate, along with in situ observations from 2353 meteorological stations, here we analyze the warming effects of land use changes in China between 1980 and 2015. Results show that OMR trends from land use changes collectively reached +0.100, +0.098, and +0.146 °C/decade for annual mean, maximum, and minimum temperature, contributing approximately 1/4 to 1/3 of overall observed warming trends, and stronger contributions were observed in the three largest urban agglomerations (i.e., Jing-Jin-Ji, the Yangtze River Delta, and the Pearl River Delta). The spatial distribution of OMR trends shows a great deal of heterogeneity that is closely related to impervious surface (positively) and vegetation cover (negatively). Warming trends induced by land use changes (including urbanization) present evident diurnal asymmetry (stronger for minimum than maximum) and vary with season (greater in winter/spring than in summer/autumn) and generally increase over time. Our results highlight that observed warming trends in China were likely influenced substantially by land use changes, especially in highly urbanized areas.