J. Clim.http://doi.org/htt (2012)

Credit: © ISTOCKPHOTO/THINKSTOCK

The popularity of harvesting crops twice a year — double cropping — in China has grown in recent years as a result of rising food demand. However, the practice significantly alters regional climate, according to an analysis of observational data.

Chang-Hoi Ho of Seoul National University and colleagues used satellite observations of vegetation cover and land surface temperatures, together with meteorological data, to examine the climatic impact of double cropping in the plains of northern China between 1996 and 2005. According to the satellite data, this practice was common throughout the measurement period. Double-cropping regions experienced greater land surface temperatures than single-cropping regions in May and June, coincident with the mid-year harvest. Indeed, maximum temperatures in the double-cropping regions exceeded those in the single-cropping regions by up to 1.27 °C during June. Specific humidity, in contrast, was lower in these agriculturally intensive zones.

The researchers suggest that an intensification of agricultural production could exacerbate regional warming and enhance aridity in the northern China plains, with potential consequences for regional atmospheric circulations.