Contribution of urbanization to warming in China

摘要

China has warmed rapidly over the past half century(1) and has experienced widespread concomitant impacts on water availability, agriculture and ecosystems(2). Although urban areas occupy less than 1% of China's land mass, the majority of China's observing stations are situated in proximity to urban areas, and thus some of the recorded warming is undoubtedly the consequence of rapid urban development, particularly since the late 1970s(3-5). Here, we quantify the separate contributions of urbanization and other external forcings to the observed warming. We estimate that China's temperature increased by 1.44 degrees C (90% confidence interval 1.22-1.66 degrees C) over the period 1961-2013 and that urban warming influences account for about a third of this observed warming, 0.49 degrees C (0.12-0.86 degrees C). Anthropogenic and natural external forcings combined explain most of the rest of the observed warming, contributing 0.93 degrees C (0.61-1.24 degrees C). This is close to the warming of 1.09 degrees C (0.86-1.31 degrees C) observed in global mean land temperatures over the period 1951-2010, which, in contrast to China's recorded temperature change, is only weakly affected by urban warming influences'. Clearly the effects of urbanization have considerably exacerbated the warming experienced by the large majority of the Chinese population in comparison with the warming that they would have experienced as a result of external forcing alone.