The recent observed global warming trend over land has been characterised by a faster warming at night, leading to a considerable decrease in the diurnal temperature range (DTR). Analysis of simulations of a climate model including observed increases in greenhouse gases and sulphate aerosols reveals a similar trend in the DTR of -0.2¿C per century, albeit of smaller magnitude than the observed -0.8¿C per century. This trend in the model simulations is related to changes in cloud cover and soil moisture. These results indicate that the observed decrease in the DTR could be a signal of anthropogenic forcing of recent climate change.